This PDF file contains the front matter associated with SPIE Proceedings Volume 7732, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

The Johns Hopkins University sounding rocket group is building the Far-ultraviolet Off Rowland-circle Telescope for Imaging and Spectroscopy (FORTIS), which is a Gregorian telescope with rulings on the secondary mirror. FORTIS will be launched on a sounding rocket from White Sand Missile Range to study the relationship between Lyman alpha escape and the local gas-to-dust ratio in star forming galaxies with non-zero redshifts. It is designed to acquire images of a 30' x 30' field and provide fully redundant "on-the-fly" spectral acquisition of 43 separate targets in the field with a bandpass of 900 - 1800 Angstroms. FORTIS is an enabling scientific and technical activity for future cutting edge far- and near-uv survey missions seeking to: search for Lyman continuum radiation leaking from star forming galaxies, determine the epoch of He II reionization and characterize baryon acoustic oscillations using the Lyman forest. In addition to the high efficiency "two bounce" dual-order spectro-telescope design, FORTIS incorporates a number of innovative technologies including: an image dissecting microshutter array developed by GSFC; a large area (~ 45 mm x 170 mm) microchannel plate detector with central imaging and "outrigger" spectral channels provided by Sensor Sciences; and an autonomous targeting microprocessor incorporating commercially available field programable gate arrays. We discuss progress to date in developing our pathfinder instrument.

We have implemented cross strip readout microchannel plate detectors in a 40mm diameter active area format, open face (UV/particle) configuration. These have been tested with a field programmable gate array based parallel channel electronics for event encoding which can process high input event rates (> 5 MHz) with high spatial resolution. Using small pore MCPs (6μm) operated in a pair, we achieved spatial resolution of < 20μm FHWM at MCP gain of 1x10⁶ e^- per event. Future large aperture UV missions require detectors to have large formats (> 100 mm) with high event rate throughput (~ MHz) while retaining high spatial resolution. We will discuss our plans to scale our 47 mm square anodes to 100 mm and our ideas for the next front end ASIC that combines a state-of-the-art, fast charge sensitive amplifier with fast sampling analog storage and built in ADCs.

FIREBALL (the Faint Intergalactic Redshifted Emission Balloon) is a balloon-borne 1m telescope coupled to an ultraviolet fiber-fed spectrograph. FIREBALL is designed to study the faint and diffuse emission of the intergalactic medium, until now detected primarily in absorption. FIREBALL is a path finding mission to test new technology and make new constraints on the temperature and density of this gas. We report on the first successful science flight of FIREBALL, in June 2009, which proved every aspect of the complex instrument performance, and provided the strongest measurements and constraints on IGM emission available from any instrument.

We discuss the design of a new high-efficiency, high-resolution far ultraviolet echelle spectrograph. Our project concentrates on utilizing new technologies for gratings and detectors to reduce the impact of scattered light and maximize quantum efficiency over a large bandpass. This program will enable advances in a vast number of astrophysical subjects. Topics ranging from protoplanetary disks to the intergalactic medium can be addressed by incorporating such a spectrograph into a future, long-duration mission.

We have assembled and launched the Diffuse Interstellar Cloud Experiment (DICE), an instrument capable of recording high resolution (λ/δλ = 30,000) spectra in the Far Ultraviolet (FUV). Absorption measurements toward nearby bright stars can provide new insight into the processes governing warm-hot gas in the Local Interstellar Medium. It flew on May 21^st, 2010. An anomaly in the Black Brant motor subjected the payload to abnormally high vibration. As a result, the optics were misaligned and no spectral data fell on the detector. Here we present the details of mechanical and electrical integration with NASA launch systems, as well as optical alignment of the telescope and spectrograph. In addition, we summarize the flight results.

The great X-ray observatories of the 20th century relied exclusively on the Wolter Type I optics design to provided true imaging in the energy band 0.1-10 keV. What are the prospects for continued development of the W-I geometry in the 21st Century and what alternative designs, technologies and bright ideas maybe poised to make an impact in X-ray astronomy in the future?

Foil X-ray mirrors, introduced by the Goddard X-ray Group in the late 1970s, were envisioned as an interim and complementary approach toward increased sensitivity for small inexpensive astronomical instruments. The extreme light weight nature of these mirrors dovetailed beautifully with Japan's small payload missions, leading to several collaborative, earth orbiting observatories, designed primarily for spectroscopy, of which SUZAKU is still in earth orbit. ASTRO-H is the latest joint instrument with Japan, presently in the implementation phase. At Goddard, some 30 years after we introduced them, we are involved with four separate flight instruments utilizing foil X-ray mirrors, a good indication that this technology is here to stay. Nevertheless, an improved spatial resolution will be the most welcomed development by all. The task of preparing upwards of 1000 reflectors, then assembling them into a single mirror with arcmin resolution remains a formidable one. Many, performance limiting approximations become necessary when converting commercial aluminum sheets into 8 quadrant segments, each with ~200 nested conical, ~4Å surface reflectors, which are then assembled into a single mirror. In this paper we will dscribe the mirror we are presently involved with, slated for the Goddard high resolution imaging X-ray spectrometer (SXS) onboard ASTRO-H. Improved spatial resolution will be an important enhancement to the science objectives from this instrument. We are accordingly pursuing and will briefly describe in this paper several design and reflector assembly modifications, aimed toward that goal.

Future X-ray observatory missions, such as IXO or Gen-X, require grazing incidence optics of large collecting area in combination with a very good angular resolution. Wolter type I X-ray telescopes made of slumped glass segments could be a possible alternative to silicon pore optics. To achieve these requirements we develop slumping methods for high accuracy segments by experimental means. In particular, we follow the approach of indirect slumping and aim to produce parabola and hyperbola in one piece. In order to avoid internal stress in the glass segments the thermal expansion coefficient of the glass should closely match the thermal expansion of the mould material. Currently we focus on a combination of the alloy KOVAR for the mould and D263 for the glass; additionally a platinum-coated silica as mould material is studied. We investigate the behaviour of both materials during slumping in order to obtain the ideal environment for the slumping process. Additionally we report on the design of different metrology methods to measure the figure and thickness variations of the glass segments in visual light, e.g. interference, and on bearings used for shape measurements and integration.

The mirrors of the International X-ray Observatory (IXO) consist of a large number of high quality segments delivering a spatial resolution better than 5 arcsec. A study concerning the slumping of thin glass foils for the IXO mirrors is under development in Europe, funded by ESA and led by the Brera Observatory. We are investigating two approaches, the "Direct" and "Indirect" slumping technologies, being respectively based on the use of convex and concave moulds. In the first case during the thermal cycle the optical surface of the glass is in direct contact with the mould surface, while in the second case it is the rear side of the foil which touches the master. Both approaches present pros and cons and aim of this study is also to make an assessment of both processes and to perform a trade-off between the two. The thin plates are made of D263glass produced by Schott. Each plate is 0.4 mm thick, with a reflecting area of 200 mm x 200 mm; the mould are made of Fused Silica. After the thermal cycle the slumped MPs are characterized to define their optical quality and microroughness. The adopted integration process foresees the bonding of the slumped foils to a rigid backplane by means of reinforcing ribs. During the bonding process the plates are constrained to stay in close contact to the surface of the master (i.e. the same mould used for the hot slumping process) by the application of a vacuum pump suction. In this way spring-back deformations and low frequency errors still present on the foil profile after slumping can be corrected. In this paper we present the preliminary results concerning achieved during the first part of the project.

The Wide Field X-ray Telescope (WFXT) is a medium class mission for X-ray surveys of the sky with an unprecedented area and sensitivity. In order to meet the effective area requirement, the design of the optical system is based on very thin mirror shells, with thicknesses in the 1-2 mm range. In order to get the desired angular resolution (10 arcsec requirement, 5 arcsec goal) across the entire 1x1 degree FOV (Field Of View), the design of the optical system is based on nested modified grazing incidence Wolter-I mirrors realized with polynomial profiles, focal plane curvature and plate scale corrections. This design guarantees an increased angular resolution at large off-axis angle with respect to the normally used Wolter I configuration, making WFXT ideal for survey purposes. The WFXT X-ray Telescope Assembly is composed by three identical mirror modules of 78 nested shells each, with diameter up to 1.1 m. The epoxy replication process with SiC shells has already been proved to be a valuable technology to meet the angular resolution requirement of 10 arcsec. To further mature the telescope manufacturing technology and to achieve the goal of 5 arcsec, a deterministic direct polishing method is under investigation. The direct polishing method has already been used for past missions (as Einstein, Rosat, Chandra): the technological challenge now is to apply it for almost ten times thinner shells. Under investigation is quartz glass (fused silica), a well-known material with good thermo-mechanical and polishability characteristics that could meet our goal in terms of mass and stiffness, with significant cost and time saving with respect to SiC. Our approach is based on two main steps: first quartz glass tubes available on the market are grinded to conical profiles, and second the obtained shells are polished to the required polynomial profiles by CNC (Computer Numerical Control) polishing machine. In this paper, the first results of the direct grinding and polishing of prototypes shells made by quartz glass with low thickness, representative of the WFXT optical design, are presented.

The prospects for accomplishing X-ray polarization measurements appear to have grown in recent years after a more than 35-year hiatus. Unfortunately, this long hiatus has brought with it some confusion over the statistical uncertainties associated with polarization measurements of astronomical sources. The heart of this confusion stems from a misunderstanding (or potential misunderstanding) of a standard figure of merit-the minimum detectable polarization (MDP)-that one of us introduced many years ago. We review the relevant statistics, and quantify the differences between the MDP and the uncertainty of an actual polarization measurement. We discuss the implications for future missions.

We developed an instrument design capable of measuring linear X-ray polarization over a broad-band using conventional spectroscopic optics, using a method previously described by Marshall (2008) involving laterally graded, multilayer-coated flat mirrors. We present possible science investigations with such an instrument and two possible configurations. This instrument could be used in a small orbiting mission or scaled up for the International X-ray Observatory. Laboratory work has begun that would demonstrate the capabilities of key components.

X-ray polarimetry offers a unique vantage to investigate particle acceleration from compact objects and relativistic outflows. The HX-POL concept uses a combination of Si and Cadmium Zinc Telluride (CZT) detectors to measure the polarization of 50 keV - 500 keV X-rays from cosmic sources through the azimuthal distribution of Compton scattered events. HX-POL would allow us to measure the polarization degrees of Crab-like sources well below 10% for a one day balloon flight. A longer (15-30 day) flight would improve the polarization degree sensitivity to a few percent. In this contribution, we discuss the sensitivity of a space-borne HX-POL payload, and present new results from laboratory tests of the HX-POL Si and CZT detectors.

The Large Area Telescope (LAT) instrument on the Fermi Gamma ray Space Telescope mission was inspired by the breadth of discoveries in high energy gamma ray sky by the EGRET instrument on the Compton Gamma Ray Observatory. Founded in the new technologies and capabilities in high energy particle physics detectors, the first studies for the LAT concept were begun in 1992 and the foundations of the LAT international collaboration, bringing together the high energy particle physics community and astrophysics community, were established shortly thereafter. This paper reviews the evolution of the LAT design from concept to launch and attempts to highlight the successes, problems and lessons learned along the way.

The Large Area Telescope (LAT) is the primary instrument on the Fermi Gamma-ray Space Telescope (Fermi), an orbital astronomical observatory that was launched on 11 June 2008. Its tracker is a solid-state instrument that converts the gamma rays into electron-positron pairs which it then tracks in order to measure the incoming gamma-ray direction. The tracker comprises 36 planes of single-sided silicon strip detectors, for a total of 73 square meters of silicon, read out by nearly 900,000 amplifier-discriminator channels. The system operates on only 160 W of conditioned power while achieving > 99% single-plane efficiency within its active area and better than 1 channel per million noise occupancy. We describe the tracker's design and performance, and discuss in particular the excellent stability of the hardware response during the first two years of operation on orbit.

The Large Area Telescope (LAT), the primary instrument on the Fermi Gamma-ray Space Telescope, has been making revolutionary observations of the high-energy (20 MeV - 300 GeV) gamma-ray sky since its launch in June 2008. The LAT calorimeter is a modular array of 1536 CsI(Tl) crystals supported within 16 carbon fiber structures and read out at each crystal end with silicon PIN photodiodes to provide both energy and position information. The hodoscopic crystal stack allows imaging of electromagnetic showers and cosmic rays for improved energy measurement and background rejection. Signals from the array of photodiodes are processed by custom ASICs and commercial ADCs. We describe the calorimeter design and the primary factors that led those design choices.

Supernovae are the main sites of heavy element production in galaxies. Observing their remnants at a relatively early stage of a few hundred years after the explosion provides a direct view of the main synthesized elements produced by various supernova types. While the current observations offer a number of diagnostics and relevant information of the ejected material, further progresses are hampered by the performances of current instruments. I will discuss the main science drivers in the field of supernova remnants and their scientific requirements for future instruments.

The SWAP telescope (Sun Watcher using Active Pixel System detector and Image Processing) is an instrument launched on 2nd November 2009 on-board the ESA PROBA2 technological mission. SWAP is a space weather sentinel from a low Earth orbit, providing images at 174 nm of the solar corona. The instrument concept has been adapted to the PROBA2 mini-satellite requirements (compactness, low power electronics and a-thermal opto-mechanical system). It also takes advantage of the platform pointing agility, on-board processor, Packetwire interface and autonomous operations. The key component of SWAP is a radiation resistant CMOS-APS detector combined with onboard compression and data prioritization. SWAP has been developed and qualified at the Centre Spatial de Liège (CSL) and calibrated at the PTBBessy facility. After launch, SWAP has provided its first images on 14th November 2009 and started its nominal, scientific phase in February 2010, after 3 months of platform and payload commissioning. This paper summarizes the latest SWAP developments and qualifications, and presents the first light results.

The Focusing Optics X-ray Solar Imager (FOXSI) is a rocket experiment scheduled for January 2011 launch. FOXSI observes 5 - 15 keV hard X-ray emission from quiet-region solar flares in order to study the acceleration process of electrons and the mechanism of coronal heating. For observing faint hard X-ray emission, FOXSI uses focusing optics for the first time in solar hard X-ray observation, and attains 100 times higher sensitivity than RHESSI, which is the present solar hard X-ray observing satellite. Now our group is working on developments of both Double-sided Silicon Strip Detector (DSSD) and read-out analog ASIC "VATA451" used for FOXSI. Our DSSD has a very fine strip pitch of 75 μm, which has sufficient position resolution for FOXSI mirrors with angular resolution (FWHM) of 12 arcseconds. DSSD also has high spectral resolution and efficiency in the FOXSI's energy range of 5 - 15 keV, when it is read out by our 64-channel analog ASIC. In advance of the FOXSI launch, we have established and tested a setup of 75 μm pitch DSSD bonded with "VATA451" ASICs. We successfully read out from almost all the channels of the detector, and proved ability to make a shadow image of tungsten plate. We also confirmed that our DSSD has energy resolution (FWHM) of 0.5 keV, lower threshold of 5 keV, and position resolution less than 63 μm. These performance satisfy FOXSI's requirements.

The Extreme Ultraviolet Imager (EUI) onboard Solar Orbiter consists of a suite of two high-resolution imagers (HRI) and one dual-band full Sun imager (FSI) that will provide EUV and Lyman-α images of the solar atmospheric layers above the photosphere. The EUI instrument is based on a set of challenging new technologies allowing to reach the scientific objectives and to cope with the hard space environment of the Solar Orbiter mission. The mechanical concept of the EUI instrument is based on a common structure supporting the HRI and FSI channels, and a separated electronic box. A heat rejection baffle system is used to reduce the Sun heat load and provide a first protection level against the solar disk straylight. The spectral bands are selected by thin filters and multilayer mirror coatings. The detectors are 10μm pitch back illuminated CMOS Active Pixel Sensors (APS), best suited for the EUI science requirements and radiation hardness. This paper presents the EUI instrument concept and its major sub-systems. The current developments of the instrument technologies are also summarized.

The Nuclear Spectroscopic Telescope Array (NuSTAR) is a NASA Small Explorer mission that will carry the first focusing hard X-ray (6 - 80 keV) telescope to orbit. NuSTAR will offer a factor 50 - 100 sensitivity improvement compared to previous collimated or coded mask imagers that have operated in this energy band. In addition, NuSTAR provides sub-arcminute imaging with good spectral resolution over a 12-arcminute eld of view. After launch, NuSTAR will carry out a two-year primary science mission that focuses on four key programs: studying the evolution of massive black holes through surveys carried out in fields with excellent multiwavelength coverage, understanding the population of compact objects and the nature of the massive black hole in the center of the Milky Way, constraining the explosion dynamics and nucleosynthesis in supernovae, and probing the nature of particle acceleration in relativistic jets in active galactic nuclei. A number of additional observations will be included in the primary mission, and a guest observer program will be proposed for an extended mission to expand the range of scientic targets. The payload consists of two co-aligned depth-graded multilayer coated grazing incidence optics focused onto a solid state CdZnTe pixel detectors. To be launched in early 2012 on a Pegasus rocket into a low-inclination Earth orbit, NuSTAR largely avoids SAA passage, and will therefore have low and stable detector backgrounds. The telescope achieves a 10.14-meter focal length through on-orbit deployment of an extendable mast. An aspect and alignment metrology system enable reconstruction of the absolute aspect and variations in the telescope alignment resulting from mast exure during ground data processing. Data will be publicly available at GSFC's High Energy Archive Research Center (HEASARC) following validation at the science operations center located at Caltech.

The Nuclear Spectroscopic Telescope Array (NuSTAR) is a NASA Small Explorer mission scheduled for launch in February 2012. NuSTAR will deploy two imaging CdZnTe spectrometers in the 6-79 keV energy band. The two NuSTAR optics utilize multilayer-coated, thermally-slumped glass integrated into a titanium-glass-epoxy-graphite composite structure, along with an extendable mast, to obtain 10.15 meter focal length. Using this approach, the NuSTAR optics will obtain subarcminute imaging with large effective area over its entire energy band. NuSTAR's conic-approximation Wolter-I optics are the first true hard X-ray focusing optics to be deployed on a satellite experiment. We report on the design of the NuSTAR optics, present the status of the two flight optics under construction, and report preliminary measurements that can be used to predict performance.

eROSITA (extended ROentgen Survey with an Imaging Telescope Array) is the core instrument on the Russian Spektrum-Roentgen-Gamma (SRG) mission which is scheduled for launch in late 2012. eROSITA is fully approved and funded by the German Space Agency DLR and the Max-Planck-Society. The instrument development is in phase C/D since fall 2009. The design driving science is the detection 100.000 Clusters of Galaxies up to redshift z ~1.3 in order to study the large scale structure in the Universe and test cosmological models, especially Dark Energy. This will be accomplished by an all-sky survey lasting for four years plus a phase of pointed observations. eROSITA consists of seven Wolter-I telescope modules, each equipped with 54 Wolter-I shells having an outer diameter of 360 mm. This would provide an effective area of ~1500 cm² at 1.5 keV and an on axis PSF HEW of 15 arcsec resulting in an effective angular resolution of 28 - 30 arcsec, averaged over the field of view. In the focus of each mirror module, a fast frame-store pn-CCD provides a field of view of 1° in diameter.

The Gravity and Extreme Magnetism Small Explorer (GEMS), currently in Phase B, will be the 13th in NASA's Small Explorer series and is being developed for an April 2014 launch readiness date. Sensitive X-ray polarization measurements are enabled by advances in photoelectric polarimetry. This paper summarizes the scientific objectives and mission characteristics which exploit this advance.

The Gravity and Extreme Magnetism Small Explorer (GEMS) is an astrophysical observatory dedicated to X-ray polarimetry (2-10 keV) and is being developed for launch in 2014. To maximize the polarization sensitivity of the observatory, GEMS uses polarimeters based on the photoelectric effect with a gas micropattern time projection chamber (TPC). We describe the TPC polarimeter concept and the details of the GEMS implementation, including factors that affect the ultimate polarization sensitivity, including quantum efficiency, modulation factor, systematic errors, and background.

MAXI, the first astronomical payload on JEM-EF of ISS, began operation on August 3, 2009 for monitoring all-sky X-ray images every ISS orbit (92 min). All instruments as well as two main X-ray slit cameras, the GSC and SSC, worked well as expected for one month test operation. The MAXI has been operated since August, 2009 and monitored more than 300 X-ray sources, which include Galactic black holes and black hole candidates (BH/BHC), transient X-ray pulsars, X-ray novae, X-ray bursts, CVns, a considerable number of AGNs and so on. Automatic nova-alert and rapid report system is starting up, while we have published more than 30 results publicly on GCN and ATel with manual analysis. We are also releasing daily data more than 200 targets publicly. Now MAXI has continued steady operation since the beginning of 2010 although capability of a part of X-ray detectors is going down from initial ability. We have obtained some remarkable results concerning BH/BHC, X-ray pulsars and AGNs. As one of the results XTE J1752-223, an X-ray nova accompanying a black hole candidate, has revealed an evolution of accretion disc and high energy plasma from the data for seven-month observations. In this paper we report the operation status of MAXI on the ISS as well as early several astronomical results.

The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the high-energy universe by performing high-resolution, high-throughput spectroscopy with moderate angular resolution. ASTRO-H covers very wide energy range from 0.3 keV to 600 keV. ASTRO-H allows a combination of wide band X-ray spectroscopy (5-80 keV) provided by multilayer coating, focusing hard X-ray mirrors and hard X-ray imaging detectors, and high energy-resolution soft X-ray spectroscopy (0.3-12 keV) provided by thin-foil X-ray optics and a micro-calorimeter array. The mission will also carry an X-ray CCD camera as a focal plane detector for a soft X-ray telescope (0.4-12 keV) and a non-focusing soft gamma-ray detector (40-600 keV) . The micro-calorimeter system is developed by an international collaboration led by ISAS/JAXA and NASA. The simultaneous broad bandpass, coupled with high spectral resolution of ΔE ~7 eV provided by the micro-calorimeter will enable a wide variety of important science themes to be pursued.

We are designing an X-ray CCD camera (SXI) for ASTRO-H, including many new items. We have developed the CCD, CCD-NeXT4, that is a P-channel type CCD. It has a thick depletion layer of 200μm with an imaging area of 30mm square. Since it is back-illuminated, it has a good low energy response and is robust against the impact of micro-meteorites. We will employ 4 chips to cover the area of 60mm square. A mechanical rather than peltier cooler will be employed so that we can cool the CCD to -120°C. We will also introduce an analog ASIC that is placed very close to the CCD. It performs well, having a similar noise level to that assembled by using individual parts used on SUZAKU. We also employ a modulated X-ray source (MXS), that improves the accuracy of the calibration. The SXI will have one of the largest SΩ among various satellites.

We present the science and an overview of the Soft X-ray Spectrometer onboard the ASTRO-H mission with emphasis on the detector system. The SXS consists of X-ray focusing mirrors and a microcalorimeter array and is developed by international collaboration lead by JAXA and NASA with European participation. The detector is a 6×6 format microcalorimeter array operated at a cryogenic temperature of 50 mK and covers a 3' ×3' field of view of the X-ray telescope of 5.6 m focal length. We expect an energy resolution better than 7 eV (FWHM, requirement) with a goal of 4 eV. The effective area of the instrument will be 225 cm² at 7 keV; by a factor of about two larger than that of the X-ray microcalorimeter on board Suzaku. One of the main scientific objectives of the SXS is to investigate turbulent and/or macroscopic motions of hot gas in clusters of galaxies.

The Japanese Astro-H mission will include the Soft X-ray Spectrometer (SXS) instrument, whose 36-pixel detector array of ultra-sensitive x-ray microcalorimeters requires cooling to 50 mK. This will be accomplished using a 3-stage adiabatic demagnetization refrigerator (ADR). The design is dictated by the need to operate with full redundancy with both a superfluid helium dewar at 1.3 K or below, and with a 4.5 K Joule-Thomson (JT) cooler. The ADR is configured as a 2-stage unit that is located in a well in the helium tank, and a third stage that is mounted to the top of the helium tank. The third stage is directly connected through two heat switches to the JT cooler and the helium tank, and manages heat flow between the two. When liquid helium is present, the 2-stage ADR operates in a single-shot manner using the superfluid helium as a heat sink. The third stage may be used independently to reduce the time-average heat load on the liquid to extend its lifetime. When the liquid is depleted, the 2nd and 3rd stages operate as a continuous ADR to maintain the helium tank at as low a temperature as possible - expected to be 1.2 K - and the 1st stage cools from that temperature as a single-stage, single-shot ADR. The ADR's design and operating modes are discussed, along with test results of the prototype 3-stage ADR.

The SXS instrument is the Soft X-ray micro-calorimeter Spectrometer planned for the Japanese ASTRO-H satellite, scheduled to be launched in 2014. In this paper, the trade off and modelling for the X-ray absorption and optical blocking filters will be described. The X-ray absorption filter will optimize the efficiency for high spectral resolution observations for bright sources at higher energies (notably around the Fe-K line at 6.4 KeV), given the characteristics of the instrument while the optical blocking filter allows X-ray observations of optically bright sources. For this mission a novel type of on-off-switchable X-ray calibration source, using light sensitive photo-cathodes, is being developed, which will be used for gain calibration and contamination monitoring. These sources will be used by both the SXS and SXI (Soft X-ray Imager) instruments and have the capability to be pulsed at millisecond intervals. Details of these sources will also be discussed.

The new Japanese X-ray Astronomy satellite, ASTRO-H will carry two identical hard X-ray telescopes (HXTs), which cover 5 to 80 keV. The HXT mirrors employ tightly-nested, conically-approximated thin-foil Wolter-I optics, and the mirror surfaces are coated with Pt/C depth-graded multilayers to enhance hard X-ray effective area by means of Bragg reflection. The HXT comprises foils 450 mm in diamter and 200 mm in length, with a focal length of 12 m. To obtain a large effective area, 213 aluminum foils 0.2 mm in thickness are tightly nested confocally. The effective area is expected to be ~ 310 cm² at 30 keV and the image quality to be ~1.′7 in half-power diameter.

The Hard X-ray Imager (HXI) is one of four detectors on board the ASTRO-H mission (6th Japanese X-ray satellite), which is scheduled to be launched in 2014. Using the hybrid structure composed of double-sided silicon strip detectors and a cadmium telluride double-sided strip detector, the instrument fully covers the energy range of photons collected with the hard X-ray telescope up to 80 keV with a high quantum efficiency. High spatial resolution of 250 μm and an energy resolution of 1-2 keV (FWHM) are both achieved with low noise front-end ASICs. In addition, the thick BGO active shields surrounding the main detector package is a heritage of the successful performance of the Hard X-ray Detector on board the Suzaku satellite. This feature enables the instrument to achieve an extremely high background reduction caused by cosmic-ray particles, cosmic X-ray background, and in-orbit radiation activation. In this paper, we present the detector concept, design, latest results of the detector development, and the current status of the hardware.

ASTRO-H is the next generation JAXA X-ray satellite, intended to carry instruments with broad energy coverage and exquisite energy resolution. The Soft Gamma-ray Detector (SGD) is one of ASTRO-H instruments and will feature wide energy band (40-600 keV) at a background level 10 times better than the current instruments on orbit. SGD is complimentary to ASTRO-H's Hard X-ray Imager covering the energy range of 5-80 keV. The SGD achieves low background by combining a Compton camera scheme with a narrow field-of-view active shield where Compton kinematics is utilized to reject backgrounds. The Compton camera in the SGD is realized as a hybrid semiconductor detector system which consists of silicon and CdTe (cadmium telluride) sensors. Good energy resolution is afforded by semiconductor sensors, and it results in good background rejection capability due to better constraints on Compton kinematics. Utilization of Compton kinematics also makes the SGD sensitive to the gamma-ray polarization, opening up a new window to study properties of gamma-ray emission processes. The ASTRO-H mission is approved by ISAS/JAXA to proceed to a detailed design phase with an expected launch in 2014. In this paper, we present science drivers and concept of the SGD instrument followed by detailed description of the instrument and expected performance.

The New Hard X-ray Mission (NHXM) has been designed to provide a real breakthrough on a number of hot astrophysical issues that includes: black holes census, the physics of accretion, the particle acceleration mechanisms, the effects of radiative transfer in highly magnetized plasmas and strong gravitational fields. NHXM combines fine imaging capability up to 80 keV, today available only at E<10 keV, with sensitive photoelectric imaging polarimetry. It consists of four identical mirrors, with a 10 m focal length, achieved after launch by means of a deployable structure. Three of the four telescopes will have at their focus identical spectral-imaging cameras, while a X-ray imaging polarimeter will be placed at the focus of the fourth. In order to ensure a low and stable background, NHXM will be placed in a low Earth equatorial orbit. Here we will provide an overall description of this mission and of the developments that are currently occurring in Italy. In the meanwhile we are forming an international collaboration, with the goal to have a consortium of leading Institutes and people that are at the forefront of the scientific and technological developments that are relevant for this mission.

The New Hard X-ray Mission (NHXM) project will be operated by 2016 and is currently undergoing the Phase B study. It is based on 4 hard X-ray optics modules, each formed by 60 evenly spaced multilayer coated Wolter I mirror shells. An extensible bench is used to reach the 10 m focal length. The Wolter I monolithic substrates with multilayer coating are produced in NiCo by electroforming replication. Three of the mirror modules will host in the focal plane a hybrid a detector system (a soft X-ray Si DEPFET array plus a high energy CdTe detector). The detector of the fourth telescope will be a photoelectric polarimeter with imaging capabilities, operating from 2 up to 35 keV. The total on axis effective area of the three telescopes at 1 keV and 30 kev is of 1500 cm² and 350 cm² respectively, with an angular resolution of 20 arcsec HEW at 30 keV. In this paper we report on the design and development of the multilayer optics of the mission, based on thin replicated Ni mirror shells.

The New Hard X-ray Mission (NHXM) is conceived to extend the grazing-angle reflection imaging capability up to energy of 80 keV. The NHXM payload consists of four telescopes. Three of them have at their focal plane identical spectral-imaging camera operating between 0.2 and beyond 80 keV, while the fourth has a X-ray imaging polarimeter. The spectral-imaging cameras are constituted by two detection layers: a Low Energy Detector (LED) and a High Energy Detector (HED) surrounded by an Anti Coincidence (AC) system. Here we will present the preliminary design and the solutions that we are currently studying to meet the top level system requirements of these cameras.

The New Hard X-Ray Imaging and Polarimetric Mission makes a synergic use of Hard X-Ray Imaging, Spectroscopy and Polarimetry, as independent diagnostic of the same physical systems. It exploits the technology of multi-layer optics that, with a focal length of 10 m, allow for spectroscopic and imaging, with a resolution from 15 to 20 arcseconds, on the band 0.2 - 80 keV. One of the four telescopes is devoted to polarimetry. Since the band of a photoelectric polarimeter is not that wide, we foresee two of them, one tuned on the lower energy band (2-10 keV) and another one tuned on higher energies (6 - 35 keV). The blurring due to the inclined penetration of photons in the gas , thanks to the long focal length is practically negligible. In practice the polarimeters fully exploit the resolution the telescope and NHXM can perform angular resolved simultaneous spectroscopy and polarimetry on the band 2 - 35 keV. We are also studying the possibility to extend the band up to 80 keV by means of a focal plane scattering polarimeter.

The International X-ray Observatory (IXO) project is the result of a merger between the NASA Con-X and ESA/JAXA XEUS mission concepts. A facility-class mission, IXO will address the leading astrophysical questions in the "hot universe" through its breakthrough optics with 20 times more collecting area at 1 keV than any previous X-ray observatory, its 3 m² collecting area with 5 arcsec angular resolution will be achieved using a 20m focal length deployable optical bench. To reduce risk, two independent optics technologies are currently under development in the U.S. and in Europe. Focal plane instruments will deliver a 100-fold increase in effective area for high-resolution spectroscopy, deep spectral imaging over a wide field of view, unprecedented polarimetric sensitivity, microsecond spectroscopic timing, and high count rate capability. IXO covers the 0.1-40 keV energy range, complementing the capabilities of the next generation observatories, such as ALMA, LSST, JWST, and 30-m ground-based telescopes. These capabilities will enable studies of a broad range of scientific questions such as what happens close to a black hole, how supermassive black holes grow, how large scale structure forms, and what are the connections between these processes? This paper presents an overview of the IXO mission science drivers, its optics and instrumental capabilities, the status of its technology development programs, and the mission implementation approach.

The International X-ray Observatory (IXO) is an L class mission candidate within the science programme Cosmic Vision 2015-2025 of the European Space Agency, with a planned launch by 2020. IXO is an international cooperative project, pursued by ESA, JAXA and NASA. By allowing astrophysical observations between 100 eV and 40 keV, IXO would represent the new generation X-ray observatory, following the XMM-Newton, Astro-H and Chandra heritage. The IXO mission concept is based on a single aperture telescope with an external diameter of about 3.5 m, a focal length of 20 m and a number of focal plane instruments, positioned at the focal point via a movable platform. A grating spectrometer, enabling parallel measurements, is also included in the model payload. Two parallel competitive industrial assessment studies are being carried out by ESA on the overall IXO mission, while the instruments are being studied by dedicated instrument consortia. The main results achieved during this study are summarised.

The International X-ray Observatory (IXO) is an L class mission candidate within the science programme Cosmic Vision 2015-2025 of the European Space Agency, with a planned launch by 2020. IXO is an international cooperative project, pursued by ESA, JAXA and NASA. By allowing astrophysical observations between 100 eV and 40 keV using a very large effective collecting area mirror and state-of-the art instruments, IXO would represent the new generation X-ray observatory, following the XMM-Newton, Astro-H and Chandra heritage. The IXO mission concept is based on a single aperture telescope with an external diameter of about 3.5 m and a focal length of 20 m. The focal plane consists of a fixed and a moveable instrument platform (FIP and MIP respectively). The model payload consists of a suite of five instruments which can each be located at the telescope's focus by the MIP, these are: 1. a wide field imager (WFI) based on a silicon DEPFET array; 2. a Hard-X-ray Imager (HXI), which will be integrated together with the WFI; 3. an X-ray microcalorimeter spectrometer (XMS); 4. an X-ray Polarimeter camera (X-POL) based on a gas cell with integrated anode array; 5. a High-Time Resolution Spectrometer (HTRS) based on a silicon drift detector array. In addition, the FIP will carry a grating spectrometer (XGS) mounted in a fixed position and which will allow simultaneous observations with the on-axis instrument. This paper provides a summary of the preliminary results achieved during the assessment activities presently ongoing at ESA. Whereas we will provide a brief overview on the overall spacecraft design, we will focus on the payload description, characteristics, the technology used and the accommodation on the instrument platform.

The International X-ray Observatory (IXO) is a candidate mission in the ESA Space Science Programme Cosmic Visions 1525. IXO is being studied as a joint mission with NASA and JAXA. The mission is building on novel optics technologies to achieve the required performance for this demanding astrophysics observatory. The European X-ray optics technology baseline is the Silicon Pore optics (SPO), which is being developed by an industrial consortium. In a phased approach the performance, environmental compatibility and industrial production aspects are being addressed. As a back-up technology ESA is also investigating slumped glass optics, which forms the baseline for the NASA approach. The paper presents a summary of the ESA led optics technology preparation activities and the associated roadmap.

Silicon pore optics is a technology developed to enable future large area X-ray telescopes, such as the International X-ray Observatory (IXO), a candidate mission in the ESA Space Science Programme 'Cosmic Visions 2015-2025'. IXO uses nested mirrors in Wolter-I configuration to focus grazing incidence X-ray photons on a detector plane. The IXO optics will have to meet stringent performance requirements including an effective area of >2.5 m² at 1.25 keV and >0.65 m² at 6 keV and angular resolution better than 5 arc seconds. To achieve the collecting area requires a total polished mirror surface area of ~1300 m² with a surface roughness better than 0.5 nm rms. By using commercial high-quality 12" silicon wafers which are diced, structured, wedged, coated, bent and stacked, the stringent performance requirements of IXO can be attained without any costly polishing steps. Two of these stacks are then assembled into a co-aligned mirror module, which is a complete X-ray imaging system. Included in the mirror module are the isostatic mounting points, providing a reliable interface to the telescope. Hundreds of such mirror modules are finally integrated into petals, and mounted onto the spacecraft to form an X-ray optic of approximately 4 m in diameter. In this paper we will present the silicon pore optics mass manufacturing process and latest X-ray test results of mirror modules mounted in flight configuration.

The International X-ray Observatory (IXO) is designed to conduct spectroscopic, imaging, and timing studies of astrophysical phenomena that take place as near as in the solar system and as far as in the early universe. It is a collaborative effort of ESA, JAXA, and NASA. It requires a large X-ray mirror assembly with an unprecedented X-ray collection area and a suite of focal plane detectors that measure every property of each photon. This paper reports on our effort to develop the necessary technology to enable the construction of the mirror assembly required by IXO.

One of the instruments on the International X-ray Observatory (IXO), under study with NASA, ESA and JAXA, is the X-ray Microcalorimeter Spectrometer (XMS). This instrument, which will provide high spectral resolution images, is based on X-ray micro-calorimeters with Transition Edge Sensor thermometers. The pixels have metallic X-ray absorbers and are read-out by multiplexed SQUID electronics. The requirements for this instrument are demanding. In the central array (40 x 40 pixels) an energy resolution of < 2.5 eV is required, whereas the energy resolution of the outer array is more relaxed (≈ 10 eV) but the detection elements have to be a factor 16 larger in order to keep the number of read-out channels acceptable for a cryogenic instrument. Due to the large collection area of the IXO optics, the XMS instrument must be capable of processing high counting rates, while maintaining the spectral resolution and a low deadtime. In addition, an anti-coincidence detector is required to suppress the particle-induced background. In this paper we will summarize the instrument status and performance. We will describe the results of design studies for the focal plane assembly and the cooling systems. Also the system and its required spacecraft resources will be given.

The Wide Field Imager (WFI) of the International X-ray Observatory (IXO) is an X-ray imaging spectrometer based on a large monolithic DePFET (Depleted P-channel Field Effect Transistor) Active Pixel Sensor. Filling an area of 10 x 10 cm² with a format of 1024 x 1024 pixels it will cover a field of view of 18 arcmin. The pixel size of 100 x 100 μm² corresponds to a fivefold oversampling of the telescope's expected 5 arcsec point spread function. The WFI's basic DePFET structure combines the functionalities of sensor and integrated amplifier with nearly Fano-limited energy resolution and high efficiency from 100 eV to 15 keV. The development of dedicated control and amplifier ASICs allows for high frame rates up to 1 kHz and flexible readout modes. Results obtained with representative prototypes with a format of 256 x 256 pixels are presented.

High-resolution spectroscopy at energies below 1 keV covers the lines of C, N, O, Ne and Fe ions, and is central to studies of the Interstellar Medium, the Warm Hot Intergalactic Medium, warm absorption and outflows in Active Galactic Nuclei, coronal emission from stars, etc. The large collecting area, long focal length, and 5 arcsecond half power diameter telescope point-spread function of the International X-ray Observatory will present unprecedented opportunity for a grating spectrometer to address these areas at the forefront of astronomy and astrophysics. We present the current status of a transmission grating spectrometer based on recently developed high-efficiency critical-angle transmission (CAT) gratings that combine the traditional advantages of blazed reflection and transmission gratings. The optical design places light-weight grating arrays close to the telescope mirrors, which maximizes dispersion distance and thus spectral resolution and minimizes demands on mirror performance. It merges features from the Chandra High Energy Transmission Grating Spectrometer and the XMM-Newton Reflection Grating Spectrometer, and provides resolving power R = E/ΔE = 3000 - 5000 (full width half max) and effective area >1000 cm² in the soft x-ray band. We discuss recent results on ray-tracing and optimization of the optical design, instrument configuration studies, and grating fabrication.

The International X-ray Observatory (IXO) is a collaborative effort between NASA, ESA, and JAXA. The IXO science goals are heavily based on obtaining high quality X-ray spectra. In order to achieve this goal the science payload will incorporate an array of gratings for high resolution, high throughput spectroscopy at the lowest X-ray energies, 0.3 - 1.0 keV. The spectrometer will address a number of important astrophysical goals such as studying the dynamics of clusters of galaxies, determining how elements are created in the explosions of massive stars, and revealing most of the "normal" matter in the universe which is currently thought to be hidden in hot filaments of gas stretching between galaxies. We present here a mature design concept for an Off-Plane X-ray Grating Spectrometer (OP-XGS). This XGS concept has seen recent significant advancements in optical and mechanical design. We present here an analysis of how the baseline OP-XGS design fulfills the IXO science requirements for the XGS and the optical and mechanical details of this design.

The Hard X-ray Imager (HXI) is one of the instruments onboard International X-ray Observatory (IXO), to be launched into orbit in 2020s. It covers the energy band of 10-40 keV, providing imaging-spectroscopy with a field of view of 8 x 8 arcmin². The HXI is attached beneath the Wide Field Imager (WFI) covering 0.1-15 keV. Combined with the super-mirror coating on the mirror assembly, this configuration provides observation of X-ray source in wide energy band (0.1-40.0 keV) simultaneously, which is especially important for varying sources. The HXI sensor part consists of the semiconductor imaging spectrometer, using Si in the medium energy detector and CdTe in the high energy detector as its material, and an active shield covering its back to reduce background in orbit. The HXI technology is based on those of the Japanese-lead new generation X-ray observatory ASTRO-H, and partly from those developed for Simbol-X. Therefore, the technological development is in good progress. In the IXO mission, HXI will provide a major assets to identify the nature of the object by penetrating into thick absorbing materials and determined the inherent spectral shape in the energy band well above the structure around Fe-K lines and edges.

The High Time Resolution Spectrometer (HTRS) is one of the five focal plane instruments of the International X-ray Observatory (IXO). The HTRS is the only instrument matching the top level mission requirement of handling a one Crab X-ray source with an efficiency greater than 10%. It will provide IXO with the capability of observing the brightest X-ray sources of the sky, with sub-millisecond time resolution, low deadtime, low pile-up (less than 2% at 1 Crab), and CCD type energy resolution (goal of 150 eV FWHM at 6 keV). The HTRS is a non-imaging instrument, based on a monolithic array of Silicon Drift Detectors (SDDs) with 31 cells in a circular envelope and a X-ray sensitive volume of 4.5 cm² x 450 μm. As part of the assessment study carried out by ESA on IXO, the HTRS is currently undergoing a phase A study, led by CNES and CESR. In this paper, we present the current mechanical, thermal and electrical design of the HTRS, and describe the expected performance assessed through Monte Carlo simulations.

The IXO/XMS instrument baseline is an array of TES sensors. Alternatively, we are now developing a μ- calorimeter array based on Silicon doped sensors. Our strength stands in a very low power consumption at 50 mK, allowing more than 4000 readout channels in the limited power budget of the IXO/XMS cryostat, for a Field of View as large as 6'x6' square while keeping the same spectral resolution. In parallel, we develop the cold (2-4K) frontend electronics based on High Electron Mobility Transistors (GaAlAs/GaAs) and SiGe ASIC electronics to readout, amplify and multiplex the signals. We present the status of our development and our current design study.

Micro-X is a rocket-borne X-ray telescope which will use an array of Transition Edge Sensor (TES) microcalorimeters to obtain high resolution soft X-ray spectra of extended astronomical sources. The microcalorimeter array consists of 128 pixels with a size of 590 μm × 590 μm each. The TESs are read out with a time-division Superconducting Quantum Interference Device (SQUID) multiplexing system. The instrument's front end assembly, which contains the microcalorimeter array and two SQUID amplification stages, is located at the focal point of a conically approximated Wolter mirror with a focal length of 2100 mm and a point spread function of 2.4 arcmin half-power diameter. The telescope's effective area amounts to ~ 300 cm² at 1 keV. The TES array is cooled with an Adiabatic Demagnetization Refrigerator. The first flight of Micro-X is scheduled for 2011, and will likely target a Si knot in the Puppis A supernova remnant. The time available for the observation above an altitude of 160 km will be in excess of 300 seconds. The design, manufacturing and assembly of the flight hardware has recently been completed, and system testing is underway. We describe the final design of the Micro-X instrument, and report on the overall status of the project.

We present results from the Extended X-ray Off-Plane Spectrometer (EXOS) sounding rocket payload. The payload was launched on November 13, 2009 and successfully obtained a spectrum of the Cygnus Loop Supernova Remnant. The instrument observed in the ~20 - 110 Angstrom bandpass with high resolution (~50) by utilizing an offplane reflection grating array. This payload is also the 2^nd flight for a relatively new type of detector, the Gaseous Electron Multiplier (GEM) detector. We discuss the performance of these technologies in flight, as well as an overview of our plans for the next flight of this design.

DIOS (Diffuse Intergalactic Oxygen Surveyor) is a small scientific satellite with a main aim for the search of warm-hot intergalactic medium using redshifted OVII and OVIII lines. The instrument will consist of a 4-stage X-ray telescope and an array of TES microcalorimeters with 256 pixels, cooled with mechanical coolers. Hardware development of DIOS and the expected results are described. Survey observations over about 5° x 5° area will reveal new filamentary structures. DIOS will be proposed to the 3rd mission in JAXA's small satellite series in 2011, aiming for launch around 2016 if it will be selected.

Xenia is a medium-sized mission optimized to study cosmic reionization, cluster formation and evolution, and the WHIM, following cosmo-chemical evolution from the very earliest times to the present. Reconstructing the cosmic history of metals, from the first population of stars to the processes involved in the formation of galaxies and clusters of galaxies, is a key observational challenge. Most baryons reside in diffuse structures, in (proto)-galaxies and clusters of galaxies, and are predicted to trace the vast filamentary structures created by the ubiquitous Dark Matter. X-ray spectroscopy of diffuse matter has the unique capability of simultaneously probing a broad range of elements (C through Fe) in all their ionization stages and all binding states (atomic, molecular, and solid), and thus provides a model-independent survey of the metals. Xenia - proposed to the Astro2010 Decadal Survey - will combine cryogenic imaging spectrometers and wide field X-ray optics with fast repointing to collect essential information from three major tracers of metals: Gamma Ray Bursts (GRBs), Galaxy Clusters, and the Warm-Hot Intergalactic Medium (WHIM). We give an overview of the mission and discuss the instruments designed to carry out these observations.

Gamma-ray bursts (GRBs) provide extremely luminous background light sources that can be used to study the high redshift universe out to z ~ 12. Identification of high-z GRBs has been difficult to date because no good high-z indicators have been found in the prompt or afterglow emission of GRBs, so ground-based spectroscopic observations are required. JANUS is an Explorer mission that incorporates a GRB locator and a near-IR telescope with low resolution spectroscopic capability so that it can measure the redshifts of GRBs immediately after their discovery. It is expected to discover 50 GRBs with z > 5 as well as hundreds of high redshift quasars. JANUS will facilitate study of the reionization phase, star formation, and galaxy formation in the very early universe. Here we discuss the mission design and status.

The X-ray sky in high time resolution holds the key to a number of observables related to fundamental physics, inaccessible to other types of investigations, such as imaging, spectroscopy and polarimetry. Strong gravity effects, the measurement of the mass of black holes and neutron stars, the equation of state of ultradense matter are among the objectives of such observations. The prospects for future, non-focused X-ray timing experiments after the exciting age of RXTE/PCA are very uncertain, mostly due to the technological limitations that need to be faced to realize experiments with effective areas in the range of several square meters, meeting the scientific requirements. We are developing large-area monolithic Silicon drift detectors offering high time and energy resolution at room temperature, with modest resources and operation complexity (e.g., read-out) per unit area. Based on the properties of the detector and read-out electronics we measured in laboratory, we built a concept for a realistic unprecedented large mission devoted to X-ray timing in the energy range 2-30 keV. We show that effective areas in the range of 10-15 square meters are within reach, by using a conventional spacecraft platform and launcher.

Sensitive surveys of the X-ray universe have been limited to small areas of the sky due to the intrinsically small field of view of Wolter-I X-ray optics, whose angular resolution degrades with the square of the off axis angle. High angular resolution is needed to achieve a low background per source, minimize source confusion, and distinguish point from extended objects. WFXT consists of three co-aligned wide field X-ray telescopes with a 1° field of view and a≲ 10" (goal of 5") angular resolution (HEW) over the full field. Total effective area at 1 keV will be > 5000 cm². WFXT will perform three surveys that will cover most of the extragalactic sky to 100-1000 times the sensitivity of the ROSAT All Sky Survey, ≳ 2000 deg² to deep Chandra or XMM-Newton sensitivity, and ≳ 100 deg² to the deepest Chandra sensitivity. WFXT will generate a legacy X-ray data set of ≳ 5 x 10⁵ clusters and groups of galaxies to z ~ 2, also characterizing the physics of the intracluster gas for a significant fraction of them, thus providing an unprecedented data set for cosmological applications; it will detect > 10⁷ AGN to z > 6, again obtaining spectra for a substantial fraction; it will detect > 10⁵ normal/starburst galaxies; and it will detect and characterize star formation regions across the Galaxy. WFXT is the only X-ray survey mission that will match, in area and sensitivity, the next generation of wide-area optical, IR and radio surveys. http://wfxt.pha.jhu.edu

The Energetic X-ray Imaging Survey Telescope (EXIST) is designed to i) use the birth of stellar mass black holes, as revealed by cosmic Gamma-Ray Bursts (GRBs), as probes of the very first stars and galaxies to exist in the Universe. Both their extreme luminosity (~10⁴ times larger than the most luminous quasars) and their hard X-ray detectability over the full sky with wide-field imaging make them ideal "back-lights" to measure cosmic structure with X-ray, optical and near-IR (nIR) spectra over many sight lines to high redshift. The full-sky imaging detection and rapid followup narrowfield imaging and spectroscopy allow two additional primary science objectives: ii) novel surveys of supermassive black holes (SMBHs) accreting as very luminous but rare quasars, which can trace the birth and growth of the first SMBHs as well as quiescent SMBHs (non-accreting) which reveal their presence by X-ray flares from the tidal disruption of passing field stars; and iii) a multiwavelength Time Domain Astrophysics (TDA) survey to measure the temporal variability and physics of a wide range of objects, from birth to death of stars and from the thermal to non-thermal Universe. These science objectives are achieved with the telescopes and mission as proposed for EXIST described here.

The hard X-ray sky now being studied by INTEGRAL and Swift and soon by NuSTAR is rich with energetic phenomena and highly variable non-thermal phenomena on a broad range of timescales. The High Energy Telescope (HET) on the proposed Energetic X-ray Imaging Survey Telescope (EXIST) mission will repeatedly survey the full sky for rare and luminous hard X-ray phenomena at unprecedented sensitivities. It will detect and localize (<20", at 5σ threshold) X-ray sources quickly for immediate followup identification by two other onboard telescopes - the Soft X-ray imager (SXI) and Optical/Infrared Telescope (IRT). The large array (4.5 m²) of imaging (0.6 mm pixel) CZT detectors in the HET, a coded-aperture telescope, will provide unprecedented high sensitivity (~0.06 mCrab Full Sky in a 2 year continuous scanning survey) in the 5 - 600 keV band. The large field of view (90° × 70°) and zenith scanning with alternating-orbital nodding motion planned for the first 2 years of the mission will enable nearly continuous monitoring of the full sky. A 3y followup pointed mission phase provides deep UV-Optical-IR-Soft X-ray and Hard X-ray imaging and spectroscopy for thousands of sources discovered in the Survey. We review the HET design concept and report the recent progress of the CZT detector development, which is underway through a series of balloon-borne wide-field hard X-ray telescope experiments, ProtoEXIST. We carried out a successful flight of the first generation of fine pixel large area CZT detectors (ProtoEXIST1) on Oct 9, 2009. We also summarize our future plan (ProtoEXIST2 & 3) for the technology development needed for the HET.

The EXIST mission has been recently re-designed prior to being proposed to the ASTRO2010 Decadal Survey. One of the most recent improvements has been the addition of a third instrument consisting of a powerful Soft X-ray Imager (SXI) that will study in detail and help characterizing the high energy sources detected by the High Energy Telescope (HET). The EXIST concept fully exploits the heritage of Swift in the fast follow-up of transients and in particular GRBs, with 10 to 20 times more sensitivity in the high energy band (from 0.2 to 600 keV) and exceptional performance in the near-IR/optical provided by the Infrared Telescope (IRT). SXI has an important role in extending by more than one decade in energy, down to the soft X-rays the coverage of HET. Such combination will be fully exploited when performing pointed observations. Within the EXIST follow-up program, foreseen during the second part of the mission, SXI and HET will be able to collect high quality spectra for thousands of sources covering the energy range 0.1- hundreds keV. Furthermore, while working in survey mode SXI will cover about half the sky in 2 years and will be able to improve the location accuracy of many faint HET sources (reducing the positional uncertainty from 20 arcsec to ~ 1-2 arcsec). In this paper we will address the performance and the main scientific contributions expected from SXI.

The EXIST observatory planned for launch in the next decade will carry outstanding contributions in both Galactic and Extragalactic science with a sensitivity about 10-20 better respect to the flown hard X-ray missions and full sky survey capability. Designed mainly for the survey of SMBH and transients, thanks to the wide field of view (~70x90deg) and large effective area of the High Energy Telescope (HET), the study of spectra and variability at all timescales of all types of Galactic sources will be made possible. EXIST will be also capable to study in detail the Galactic Center (GC) in the hard X-rays. This crowded region as observed recently by Chandra, Integral and Swift has been found to possibly host a high number of high energy sources. In this work we report on the capabilities of EXIST to image the GC region and to detect and characterize the different classes of sources on the basis of their known spectral and variability properties. EXIST will perform the crucial observation tests to study the emission from Sgr A*, using the simultaneous observations of IR and X-ray flares, searching for periodicity to study the Keplerian flow with NIR and/or X QPO, confirm or not the high energy counterpart of SgrA* detected by INTEGRAL and define the spectral shape of the high energy tail. Finally, EXIST can effectively and continuously monitor spectra from Sgr B2 to confirm the correlation of the iron line emission with the hard X-ray continuum and establish its origin.

Progress in high-energy gamma-ray science has been dramatic since the launch of INTEGRAL, AGILE and FERMI. These instruments, however, are not optimized for observations in the medium-energy (~0.3< E_γ < ~200 MeV) regime where many astrophysical objects exhibit unique, transitory behavior, such as spectral breaks, bursts, and flares. We outline some of the major science goals of a medium-energy mission. These science goals are best achieved with a combination of two telescopes, a Compton telescope and a pair telescope, optimized to provide significant improvements in angular resolution and sensitivity. In this paper we describe the design of the Advanced Energetic Pair Telescope (AdEPT) based on the Three-Dimensional Track Imager (3-DTI) detector. This technology achieves excellent, mediumenergy sensitivity, angular resolution near the kinematic limit, and gamma-ray polarization sensitivity, by high resolution 3-D electron tracking. We describe the performance of a 30×30×30 cm³ prototype of the AdEPT instrument.

The field of medium-energy gamma-ray astronomy urgently needs a new mission to build on the success of the COMPTEL instrument on the Compton Gamma Ray Observatory. This mission must achieve sensitivity significantly greater than that of COMPTEL in order to advance the science of relativistic particle accelerators, nuclear astrophysics, and diffuse backgrounds, and bridge the gap between current and future hard X-ray missions and the high-energy Fermi mission. Such an increase in sensitivity can only come about via a dramatic decrease in the instrumental background. We are currently developing a concept for a low-background Compton telescope that employs modern scintillator technology to achieve this increase in sensitivity. Specifically, by employing LaBr₃ scintillators for the calorimeter, one can take advantage of the unique speed and resolving power of this material to improve the instrument sensitivity while simultaneously enhancing its spectroscopic and imaging performance. Also, using deuterated organic scintillator in the scattering detector will reduce internal background from neutron capture. We present calibration results from a laboratory prototype of such an instrument, including time-of-flight, energy, and angular resolution, and compare them to simulation results using a detailed Monte Carlo model. We also describe the balloon payload we have built for a test flight of the instrument in the fall of 2010.

We have developed a sub-MeV and MeV gamma-ray imaging Compton camera for use in gamma-ray astronomy; it consists of a gaseous time-projection chamber (TPC) to convert the Compton scattering events and a scintillator array to absorb photons. The TPC measures the energy and three-dimensional tracks of Compton-recoil electrons, while the pixel scintillator arrays measure the energy and positions of scattered gamma rays. Therefore, our camera can reconstruct the incident gamma rays, event by event, over a wide field of view of approximately 3 str. We are now developing a Compton camera for a balloon-borne experiment.

The Nuclear Compton Telescope (NCT) is a balloon-borne soft gamma-ray telescope. Its compact design uses cross-strip germanium detectors, allowing for wide-field imaging with excellent efficiency from 0.2-10 MeV. Additionally, the Compton imaging principle employed by NCT provides polarimetric sensitivity to several MeV. NCT is optimized for the study of astrophysical sources of nuclear line emission. A ten-detector instrument participated in the 2010 balloon campaign in Alice Springs, Australia, in order to conduct observations of the Galactic Center Region. Unfortunately, a launch accident caused major damage to the payload, and no flight was possible. We discuss the design, calibration, and performance of the instrument as well as prospects for its future.

ECLAIRs is an X and gamma-rays wide-field coded mask camera onboard the Chinese-French mission SVOM (Space-based multi-wavelength Variable Objects Monitor) that is dedicated to study Gamma-ray bursts (GRBs). SVOM is due to be launched in 2015 in a low Earth orbit (630 km circular orbit with 30° inclination) for a three years duration. SVOM is designed to operate "a la SWIFT" in order to provide fast and accurate GRB positions to ground-based and space facilities, thanks to the combined use of ECLAIRs and 2 narrow-field instruments covering the Xrays and the optical. Within this strategy, ECLAIRs will play a key role since it is the instrument responsible for the detection and the first localization of GRBs in near real time. One of the primary goals of the mission is to study high redshift (z>6) GRBs that may appear as very soft events in Gamma-rays. For this reason, ECLAIRs is designed to have an increased sensitivity in the X-rays, when compared to previous equivalent instruments, thanks to a low energy threshold of 4 keV. In this talk we present the latest developments of the ECLAIRs design along with the expected scientific performances.

Laue lenses are an emerging technology allowing the concentration of soft gamma rays in the ~ 100 keV - 1.5 MeV energy range. Two lens designs based on recently measured crystals are presented in this paper. A lens dedicated to the understanding of the progenitors and explosion physics of Type Ia supernovae through the observation of the 847 keV line produced by the decay chain of the radionuclide ⁵⁶Co. With a Compton camera at the focus (as proposed for the DUAL mission), we find that a space-borne telescope could reach a 3-σ sensitivity of 1.5×10^-6 ph/s/cm² for a 3% broadened line in 10⁵ s, enabling the detection of several events per year with enough significance to strongly constrain the models. On the other hand, a second generation prototype is proposed. Made to realize a balloon-borne telescope focusing around the electron-positron annihilation line (511 keV), this lens would primarily be a technological demonstrator. However with an estimated sensitivity of 5×10^-6 ph/s/cm² in 10⁴ s observation time, this Laue lens telescope could bring new hints in the search of the origin of the Galactic positrons. To build this prototype, a dedicated X-ray beamline has been built at the Space Sciences Laboratory.

FIREBall (the Faint Intergalactic Redshifted Emission Balloon) is a balloon-borne 1m telescope coupled to an ultraviolet fiber-fed spectrograph. FIREBall is designed to study the faint and diffuse emission of the warm hot intergalactic medium, until now detected primarily in absorption. FIREBall is a pathfinding mission to test new technology and make new constraints on the temperature and density of this gas. FIREBall has flown twice, the most recent flight (June 2009) a fully functioning science flight. Here we describe the spectrograph design, current setup, and calibration measurements from the campaign.

The Faint Intergalactic Redshifted Emission Balloon (FIREBALL) had its first scientific flight in June 2009. The instrument combines microchannel plate detector technology with fiber-fed integral field spectroscopy on an unstable stratospheric balloon gondola platform. This unique combination poses a series of calibration and data reduction challenges that must be addressed and resolved to allow for accurate data analysis. We discuss our approach and some of the methods we are employing to accomplish this task.

The Faint Intergalactic Redshifted Emission Balloon (FIREBALL) had its first scientific flight in June 2009. The instrument is a 1 meter class balloon-borne telescope equipped with a vacuum-ultraviolet integral field spectrograph intended to detect emission from the inter-galactic medium at redshifts 0.3 < z < 1.0. The scientific goals and the challenging environment place strict constraints on the pointing and tracking systems of the gondola. In this manuscript we briefly review our pointing requirements, discuss the methods and solutions used to meet those requirements, and present the aspect reconstruction results from the first successful scientific flight.

EXtreme ultraviolet spectrosCope for ExosphEric Dynamics (EXCEED) is the earth-orbiting Extreme Ultraviolet (EUV) spectroscope mission which dedicates to the planetary space science. Our mission will carry out the EUV spectroscopic imaging which clarifies the plasma distributions and compositions around the planets and examines the interaction with the solar wind. Orbital altitude should be enough high so that the earth's atmospheric absorption is free. The spectral range of the mission is from 60 to 145 nm and the resolution is 0.2 to 0.5 nm FWHM. The mission is planned to be launched in 2013, beginning of the next period of solar maximum. In this paper, we will introduce the general mission overview, its instrument and its scientific targets.

We report on a theoretical study of binary phase transmission gratings for high-resolution EUV and soft X-ray spectroscopy and investigate their optical properties. Designed for wavelengths between about 2 and 40 nm, the devices may provide a first order diffraction efficiency beyond 30%. We use RCWA methods in order to optimize the grating design parameters and discuss special features of segmented grating arrays. Several elemental as well as compound materials like Be, Mo, LiF and PMMA are considered with respect to their potential and practical limitations in terms of feasibility and sensitivity to radiation damage. Simulations are performed for several samples on the radiation produced by a table-top EUV plasma source and applications to astrophysical problems are considered.

Temperature and velocity-distribution remote-sensing of faint diffuse sources such as the interplanetary medium (IPM), comets and planetary atmospheres, is an instrumental challenge that becomes more pronounced in the ultraviolet. All-reflective Spatial-Heterodyne Spectrometers (SHS), an emerging new class of instruments that combines both high étendue and high resolving power (greater than 10⁵), are ideally suited to these types of observations. Their all-reflective configuration and their self-compensating monolithic design enable them to operate under the tight tolerances of the ultraviolet and to survive the rigors of space launch. An in-development sounding-rocket experiment, the Hydrogen Polarimetric Explorer (HYPE), will merge an all-reflective SHS with a half-wave Brewster reflection polarimeter to obtain the first interferometric polarimetry of an ultraviolet emission line source. Its initial flight will target the IPM at the hydrogen Lyman-alpha transition (121.6nm). HYPE's novel optical configuration also combines several improvements in reflective SHS design, including true zero-path interferometry, no aliasing, and one-dimensional imaging. The optical layout and performance of the HYPE prototype will be described along with simulation results from ray-tracing computations.

We propose a new concept of diffractive optics: Fresnel arrays, for a 4 m aperture space telescope in the UV domain. Fresnel arrays focus light by diffraction through a very thin binary mask. They form images optically and deliver very high quality wavefronts, specially in the UV. Up to 8% of the incident light is focussed, providing high angular resolution and high contrast images of compact objects. Due to their focal lengths of a few kilometers in the UV, large Fresnel arrays will require two spacecraft in formation flying, but with relatively tolerant positioning. Diffraction focusing is also very chromatic; this chromatism is corrected, allowing relatively broad (30 to 100 nm) spectral channels in the 120-350 nm range. A 4 m aperture Fresnel imager providing 7 to 10 milli arc seconds resolution is very competitive for imaging compact and high contrast objects such as protoplanetary disks and young planetary systems, AGNs, and deep sky objects. We have developed prototypes to validate the optical concept and related technologies : first a laboratory setup, then a 20 cm aperture ground-based prototype, which provides high contrast and diffraction limited images of sky objects in the visible and close IR. A new laboratory prototype is also being prepared for validation in the 250 - 350 nm wavelength range.

The EUV waveband includes critical spectral features containing diagnostic information often not available at other wavelengths, and the bulk of radiation from million degree plasmas is emitted in the EUV. Such plasmas are ubiquitous, and examples include white dwarf photospheres; accretion phenomena in young stars, CVs and AGN; stellar coronae; and the ISM of our galaxy and of others. However, sensitive high-resolution spectroscopy is required to resolve and identify source and ISM spectral features unambiguously, and to measure line profiles and Doppler shifts. This allows exploitation of the full range of plasma diagnostic techniques developed in laboratory and solar physics. The J-PEX high-resolution EUV spectrometer has made a breakthrough in capability with an effective area of 7 cm² (220-250 Å) and resolving power of 4000, which exceed EUVE by factors of 7 and 20 respectively, and cover a range beyond the 170-Å cutoff of the Chandra LETG. J-PEX has flown successfully twice on NASA sounding rockets, but NASA has approved no new orbital EUV mission. It is time for one. Here we describe the scientific case for high-resolution EUV spectroscopy, summarize the technology that makes practical such measurements, and present concepts for a ~3-month orbital mission and for larger missions.

FIRE (Far-ultraviolet Imaging Rocket Experiment) is a sounding rocket payload telescope designed to image between 900-1100Å. It is scheduled to launch on January 29th, 2011 from the Poker Flats complex in northern Alaska. For its first flight, it will target G191B2B, a white dwarf calibration source, and M51 (the Whirlpool Galaxy), the science target, to help determine the number of hot, young O stars, as well as the intervening dust attenuation. FIRE primary consists of a single primary mirror coated in silicon carbide, a 2000Å thick indium filter and a micro-channel plate detector coated with rubidium bromide. Combined, these create a passband of 900-1100Å for the system and reject the hydrogen Lyman-α to approximately a factor of 10^-4. To ensure that the filter survives the launch, a small vacuum chamber has been built around it to keep the pressure at 10^-8 torr or lower.

As-fabricated free-standing indium foils were found to have transmission in the 90nm to 120nm band ranging from 10% to 70% of modeled values based on pure indium. Auger depth profiling of the as-deposited indium showed little surface contamination and high purity. However, final freestanding filters were found to have heavy contamination, particularly on the surface. An argon/hydrogen plasma bombardment was developed which improved EUV transmission by 50% to 500% in the finished filters without causing significant pinholes to develop in the foils or appreciably affecting blocking characteristics.

The Cosmic Origins Spectrograph (COS) was installed on the Hubble Space Telescope (HST) in May 2009 during Servicing Mission 4 (SM4). This paper discusses the initial on-orbit performance of the HST-COS far ultraviolet (FUV) detector designed and built by the Experimental Astrophysics Group at the Univ. of California, Berkeley. The HST-COS FUV detector is an open face, photon counting, microchannel plate (MCP) based device employing a cross delay line (XDL) readout. The detector consists of two separate, end-to-end segments (2x 85mm x 10mm - 179mm x 10mm total with a gap between segments), each digitized within a 16384x1024 space. The input surface is curved to match the Rowland circle of HST-COS. The CsI photocathode and open face nature result in sensitivity from <900Å to ~1750Å. Spatial resolution is approximately 25-30μm. Comparisons of on-orbit behavior relative to expectations from ground testing are performed. Areas of discussion include background (rate and morphology), sensitivity (system throughput and short wavelength response), and imaging performance (apparent spatial resolution and flat field fixed pattern). A measured increase in the MCP gain relative to ground testing is also discussed.

The Advanced CCD Imaging Spectrometer (ACIS) is one of two focal-plane instruments on the Chandra X-ray Observatory. During initial radiation-belt passes, the exposed ACIS suffered significant radiation damage from trapped soft protons scattering off the x-ray telescope's mirrors. The primary effect of this damage was to increase the charge-transfer inefficiency (CTI) of the ACIS 8 front-illuminated CCDs. Subsequently, the Chandra team implemented procedures to remove the ACIS from the telescope's focus during high-radiation events: planned protection during radiation-belt transits; autonomous protection triggered by an on-board radiation monitor; and manual intervention based upon assessment of space-weather conditions. However, as Chandra's multilayer insulation ages, elevated temperatures have reduced the effectiveness of the on-board radiation monitor for autonomous protection. Here we investigate using the ACIS CCDs themselves as a radiation monitor. We explore the 10-year database to evaluate the CCDs' response to particle radiation and to compare this response with other radiation data and environment models.

Hard X-ray Detector (HXD) onboard Suzaku, the Japanese 5th X-ray observatory, consists of 64 PIN photo diodes with 2 mm thickness (10-70 keV) and 16 phoswich detectors using 5 mm-thick GSO scintillators and BGO active collimators (40-600 keV), and these are surrounded by 20 units of BGO Active shields. All the detector units have been working well with no significant troubles in four and a half years since the launch on July 2005, and given many important scientific results. In this paper, we report the recent status of on-orbit calibrations for PIN/GSO detectors. For the PIN, analog/digital threshold levels of both in-orbit and on-ground are raised up to avoid the increasing noise events due to in-orbit radiation damage. For the GSO, the accuracy of the energy scale and modeling of gain variations are improved, and newly calibrated data set including background files and response matrices are released on April 2010.

One of the most important parameters determining the sensitivity of X-ray telescopes is their effective area as a function of the X-ray energy. The computation of the effective area of a Wolter-I mirror, with either a single layer or multilayer coating, is a very simple task for a source on-axis at astronomical distance. Indeed, when the source moves off-axis the calculation is more complicated, in particular for new hard X-ray imaging telescopes (NuSTAR, ASTRO-H, NHXM, IXO) beyond 10 keV, that will make use of multilayer coatings to extend the reflectivity band in grazing incidence. Unlike traditional single-layer coatings (in Ir or Au), graded multilayer coatings exhibit an oscillating reflectivity as a function of the incidence angle, which makes the effective area not immediately predictable for a source placed off-axis within the field of view. For this reason, the computation of the off-axis effective area has been so far demanded to raytracing codes, able to sample the incidence of photons onto the mirror assembly. Even if this approach should not be disdained, it would be interesting to approach the same problem from an analytical viewpoint. This would speed up and simplify the computation of the effective area as a function of the off-axis angle, a considerable advantage especially whenever the mirror parameters are still to be optimized. In this work we present the application of a novel, analytical formalism to the computation of the off-axis effective area and the grasp of the NHXM optical modules, requiring only the standard routines for the multilayer reflectivity computation.

We are working on the development of a method for optimizing wide-field X-ray telescope mirror prescriptions, including polynomial coefficients, mirror shell relative displacements, and (assuming 4 focal plane detectors) detector placement along the optical axis and detector tilt. With our methods, we hope to reduce number of Monte-Carlo ray traces required to search the multi-dimensional design parameter space, and to lessen the complexity of finding the optimum design parameters in that space. Regarding higher order polynomial terms as small perturbations of an underlying Wolter I optic design, we begin by using the results of Monte-Carlo ray traces to devise trial analytic functions, for an individual Wolter I mirror shell, that can be used to represent the spatial resolution on an arbitrary focal surface. We then introduce a notation and tools for Monte-Carlo ray tracing of a polynomial mirror shell prescription which permits the polynomial coefficients to remain symbolic. In principle, given a set of parameters defining the underlying Wolter I optics, a single set of Monte-Carlo ray traces are then sufficient to determine the polymonial coefficients through the solution of a large set of linear equations in the symbolic coefficients. We describe the present status of this development effort.

We present a diffractive-refractive X-ray telescope for simultaneous imaging in multiple energy bands. Based on segmented dispersion corrected hybrid lenses, the system yields an angular resolution around 1 mas for photon energies between 5 and 10 keV. The total sensitivity, measured in terms of effective area times spectral bandwidth, reaches several 10³ cm² keV. The suggested arrangement exploits Fresnel lenses used in higher diffraction orders for orderly protection from scattered radiation as well as reduced refractive profiles for an enhanced throughput. With a focal distance of a few 10² km, the telescope having its focal plane detector on a separated spacecraft, may be re-oriented to new astrophysical targets on short timescales. Scientific applications are briefly discussed for active galactic nuclei (AGN).

Arrays of achromatic Fresnel lenses are investigated for future high-resolution X-ray imaging missions. Unlike single-focus instruments, parallel arrangements of numerous tiny telescopes provide an easy and natural approach to spectroscopic observations in several energy bands, at an unprecedented short focal length of few 10³ m. We suggest an optimized design with an angular resolution around 1 mas between 5 and 10 keV and analyze its optical capabilities as well as issues like the background problem which affects the achievable signal-to-noise ratio. An astronomical simulation is performed on the sun-like star Capella.

We discuss various astrophysical science drivers for upcoming high-resolution X-ray instruments on the mas scale. Even more than current missions like Chandra and XMM-Newton, planned diffraction-limited telescopes would provide unprecedented insights into hottest-ever physical processes in the universe. We apply an efficient and simple Fresnel lens design to samples of well-known targets like stellar coronae, X-ray binaries, AGN, ultraluminous X-ray sources and supernova remnants. The cosmological impact of deep observations is discussed as well as potential applications to low-mass gravitational lenses.

Multilayer coatings can be used as broad-band reflecting layer in X-ray focusing optics. The effective area over the field of view is determined by the energetic and angular dependence of the coating reflectivity, with a different behavior in dependence of the coating structure, that can be designed in order to enhance the effective area. Often the best design is selected to maximize the on-axis effective area, but this does not ensure the performances off-axis, where the most of the detector area is allocated. We demonstrate the possibility of optimizing the coating over the whole field of view by means of a new method, that does not require the use of ray-tracing procedures, being based on the computation of a simple analytical expression computed over a limited number of points. Our method is used to optimize a multilayer structure over the field of view. The effectiveness of the method is tested by comparison with ray-tracing results. The performances of the multilayer structure resulting from the optimization are then compared with a not optimized broad-band multilayer and with a multilayer optimized for on-axis effective area.

The angular resolution degradation of an X-ray mirror, represented by its Point Spread Function (PSF), is usually simulated accounting for geometrical deformations and microroughness of its surface. When the surface profile is analyzed in terms of Fourier components, figure errors comprise the spectral regime of long spatial wavelengths, whilst microroughness falls in the regime of high spatial frequencies. The first effect is in general simulated along with geometrical optics, while the second contribution - that heavily depends on the energy of X-rays - is derived from the first order scattering theory. A drawback of this method, indeed, is that the separation between the geometrical and physical optics regime is not abrupt. Moreover, it is not clear how one should merge the PSFs derived from the two computations to retrieve an affordable reconstruction of the PSF of the mirror. In this paper we suggest a method to compute the mirror PSF from longitudinal profiles of a grazing incidence mirror, based uniquely on physical optics. The treatment makes use of Fresnel diffraction from measured/simulated profiles, accounting for the surface roughness in terms of its PSD (Power-Spectral-Density). Even though this approach was already adopted in the past to simulate the sole X-ray scattering, in this work we show, along a series of simulations, that it can be applied to reproduce the effect of scattering, aperture diffraction and figure errors as well. The computation returns the PSF at any X-ray energy, it is self-consistent and does not require setting any boundary between figure errors and roughness.

Mandrel replication by NiCo electroforming is an upgrade of the well-suited X-ray mirrors manufacturing process with pure Nickel. In this process, a Gold layer deposited on the mandrel acts as release agent and, at the same time, as reflective coating. To increase the optical performances of X-ray mirrors, the replicated optical surface is meant to reproduce the smooth topography of the mandrel: a surface degradation is commonly observed, indeed. A factor leading to surface smoothness worsening can be the spontaneous roughness growth of the Gold layer itself; therefore, the optical quality of the reflecting surface might be improved by optimizing the Gold layer thickness. A preliminary study, aimed at investigating the effects of Gold thickness reduction (< 100 nm Vs. the usual 200 nm), had already been dealt in the spectral range 0.02-1000 μm: measurements performed on flat electroformed samples showed that the Gold thickness reduction chiefly affects the roughness around 1 μm. Here we presents a study of the effectiveness of a Gold layer with reduced (< 100 nm) thickness in the NiCo X-ray mirrors electroforming, aimed at surface micro-roughness mitigation. The characterization, in the spectral range 0.02-1000 μm, of 3 X-ray mirrors manufactured utilizing Gold layers with different thickness values from a flight mandrel is reported. The performed investigation is organized as follows: (a) characterization of the flight mandrel; (b) dependence of the micro-roughness from different Gold layers thicknesses supported by XRD study; (c) comparison of the micro-roughness of mirrors manufactured in NiCo in Ni, with the same Gold layer thickness. As a conclusive remark the effects of the Gold layer thinning on the angular degradation at high energy are reported.

Phase Retrieval analysis of off-axis or defocused focal-plane data from telescope optics has been proven effective in understanding misalignments and optical aberrations in normal incidence telescopes. The approach is used, e.g., in commissioning of the James Webb Space Telescope (JWST) segmented primary mirror. There is a similar need for evaluating low-order figure errors of grazing incidence mirrors and nested telescope assemblies. When implemented in these systems, phase retrieval does not depend on normal incidence access to each mirror (shell) surface and, therefore, provides an effective means for evaluating nested x-ray telescopes during integration and test. We have applied a well-known phase retrieval algorithm to grazing incidence telescopes. The algorithm uses the Levenberg-Marquardt optimization procedure to perform a non-linear least-squares fit of the telescope Point Spread Function (PSF). The algorithm can also retrieve low order figure errors at visible wavelengths where optical diffraction is the dominant defect in the PSF. In this paper we will present the analytical approach and its implementation for grazing incidence mirrors of the International X-Ray Observatory (IXO). We analyze the effects of low order axial surface errors individually, and in combination on the system PSF at 633 nanometers. We demonstrate via modeling that the wavefront sensing algorithm can recover axial errors (of the grazing incidence mirrors) to a small fraction of the known axial figure errors using simulated PSFs as input data to the algorithm.

In this paper we present the latest developments on the ruggedisation of the Silicon Pore Optics (SPO) mirror modules. SPO is one of the candidate technologies for producing the X-ray optics for the future space based Xray telescope, the International X-ray Observatory (IXO). To produce SPO mirror modules, Si mirrors are first bonded together using direct Si bonding to form a stack. These stacks are the glued into brackets, which then connect to the supporting optical bench by invar pins. The combination of brackets and invar pins now forms a full isostatic mount, and is rugged enough to allow the mirror module to survive the high loads of a launch. The mounting system furthermore allows for a certain level of manufacturing tolerances for the support structure, and ensures interchangeability of the mirror modules within one single ring of the optical bench. To prove this, a test interface has been designed and manufactured, on which a single, full fledged mirror module will be mounted to be exposed to environmental tests.

The potential of a return of human presence to the Moon, raises the possibility of significant lunar infrastructure and with it the possibility of astronomical installations which can make use of the lunar surface as a stable platform and take advantage of the lack of atmosphere. Studies have been done in the US and Canada on the feasibility of such installations, and in particular studies of large lunar liquid mirror telescopes have been performed. We report here on the structural design concepts undertaken for one of these studies.

Particulate and molecular contamination can each impact the performance of x-ray telescope systems. Furthermore, any changes in the level of contamination between on-ground calibration and in-space operation can compromise the validity of the calibration. Thus, it is important to understand the sensitivity of telescope performance---especially the net effective area and the wings of the point spread function---to contamination. Here, we quantify this sensitivity and discuss the flow-down of science requirements to contamination-control requirements. As an example, we apply this methodology to the International X-ray Observatory (IXO), currently under joint study by ESA, JAXA, and NASA.

Multilayer-coated optics can strongly polarize X-rays and are central to a new design of a broad-band, soft X-ray polarimeter. We have begun laboratory work to verify the performance of components that could be used in future soft X-ray polarimetric instrumentation. We have reconfigured a 17 meter beamline facility, originally developed for testing transmission gratings for Chandra, to include a polarized X-ray source, an X-ray-dispersing transmission grating, and a multilayer-coated optic that illuminates a CCD detector. The X-rays produced from a Manson Model 5, multi-anode source are polarized by a multilayer-coated flat mirror. The current configuration allows for a 180 degree rotation of the source in order to rotate the direction of polarization. We will present progress in source characterization and system modulation measurements as well as null and robustness tests.

A gamma-ray burst polarimeter (GRBP) is being developed at NASA Goddard Space Flight Center for measuring the Xray polarization of energetic transients in the 2 - 10 keV energy range. The primary goal is to measure the polarization of the prompt X-ray emission from gamma-ray bursts (GRBs) in order to distinguish between the possible emission mechanisms. The instrument could also be capable of measuring polarization from other X-ray transients, such as soft gamma repeaters (SGRs) or black hole transients. An instrument with a wide field of view is required to detect transient events and a large collecting area is required to have sufficient sensitivity. The GRBP is a time projection chamber (TPC) that uses negative ions as a charge carrier enabling a large volume, high spatial resolution detector. We describe a GRBP prototype that is suitable for a sounding rocket measurement of the Crab Nebula or for measurements of bright transient sources from a small satellite.

The SuperAGILE experiment is the hard X-ray monitor of the AGILE mission. It is a 2 x one-dimensional imager, with 6-arcmin angular resolution in the energy range 18 - 60 keV and a field of view in excess of 1 steradian. SuperAGILE is successfully operating in orbit since Summer 2007, providing long-term monitoring of bright sources and prompt detection and localization of gamma-ray bursts. Starting on October 2009 the AGILE mission lost its reaction wheel and the satellite attitude is no longer stabilized. The current mode of operation of the AGILE satellite is a Spinning Mode, around the Sun-pointing direction, with an angular velocity of about 0.8 degree/s (corresponding to 8 times the SuperAGILE point spread function every second). In these new conditions, SuperAGILE continuously scans a much larger fraction of the sky, with much smaller exposure to each region. In this paper we review some of the results of the first 2.5 years of "standard" operation of SuperAGILE, and show how new implementations in the data analysis software allows to continue the hard X-ray sky monitoring by SuperAGILE also in the new attitude conditions.

The paper describes the SIDERALE experiment that was hosted as a piggy back payload on SoRa LDB (Sounding Radar Long Distance Balloon) mission by the Italian Space Agency (ASI). SIDERALE was aimed at testing a detector for high energy astrophysics applications based on a 4x4 pixel CZT solid state sensor. An onboard data handling computer, a mass memory and a power supply units were integrated in SIDERALE. Furthermore an innovative telemetry system BIT (Bi-directional Iridium Telemetry) was used in order for SIDERALE to be autonomous and independent from the hosting payload. In the paper a preliminary analysis of flight and scientific data is discussed.

We present the design for a stigmatic grazing incidence X-ray spectrograph designed for solar coronal observations. The spectrograph is composed of a slit, a pair of paraboloid mirrors and a plano varied-line-space grating. All reflective surfaces of the spectrograph operate at an angle of incidence of 88 degrees, and covers a wavelength range of 0.6 to 2.4nm (0.5 to 2.0keV). The design achieves 1.5pm spectral resolution and 15 μm spatial resolution over a 2.5mmlong slit. The current spectrograph design is intended for a sounding rocket experiment, and designed to fit inside a NASA sounding rocket payload behind a 1.1m focal length Wolter Type-1 telescope. This combination will have a 2.5arcsec spatial resolution and a 8 arcminute slit length. We are currently fabricating a laboratory prototype of the spectrograph to demonstrate the performance and establish the alignment procedures for a flight model.

The study of the outer solar atmosphere requires combining imaging and spectroscopy in the UV lines formed in the high chromosphere, the transition region and the corona. We start from the science requirements and we define the instrumental specifications in terms of field-of-view (FOV), spatial, temporal and spectral resolution and bandpass. We propose two different all-reflection optical architectures based on interferometric techniques: Spatial Heterodyne Spectroscopy (SHS); and Imaging Transform Spectrometer (IFTS). We describe the different set-ups and compare the potential performances of the two types of solutions, and discuss their feasibility. We conclude that IFTS appears to be the best solution, meeting the needs of UV solar physics. However, we point out the many difficulties to be encountered, especially as far as metrology is concerned.

The Solar Ultraviolet Imager (SUVI) is one of several instruments being fabricated for use on board the upcoming Geostationary Operational Environmental Satellites, GOES-R and -S platforms, as part of NOAA's space weather monitoring fleet. SUVI is a Generalized Cassegrain telescope that employs multilayer coatings optimized to operate in six extreme ultraviolet (EUV) narrow bandpasses centered at 93.9, 131.2, 171.1, 195.1, 284.2 and 303.8 Å. Over the course of its operational lifetime SUVI will image and record full disk, EUV spectroheliograms approximately every few minutes, and telemeter the data to the ground for digital processing. This data will be useful to scientists and engineers wanting to better understand the effects of solar produced EUV radiation with the near-Earth environment. At the focus of the SUVI telescope is a thin, back-illuminated CCD sensor with 21 μm (2.5 arc sec) pixels. At the shortest EUV wavelengths, image degradation from mirror surface scatter effects due to residual optical fabrication errors dominate the effects of both diffraction and geometrical aberrations. Discussed herein, we present a novel forward model that incorporates: (i) application of a new unified surface scatter theory valid for moderately rough surfaces to predict the bidirectional reflectance distribution function (BRDF) produced by each mirror (which uses optical surface metrology to determine the power spectral density, PSD, that characterizes the "smoothness" of an optical surface); (ii) use of the BRDF for each mirror at each EUV wavelength, in tandem with the optical design, to calculate the in-band point spread function (PSF); (iii) use of the PSF to calculate the fractional ensquared energy in the focal plane of SUVI; (iv) comparison of BRDF measurements taken at 93.9 Å with the forward model predictions and (v) final prediction of the in-band, total system responsivity.

High spectral resolution, high cadence, imaging x-ray spectroscopy has the potential to revolutionize the study of the solar corona. To that end we have been developing transition-edge-sensor (TES) based x-ray microcalorimeter arrays for future solar physics missions where imaging and high energy resolution spectroscopy will enable previously impossible studies of the dynamics and energetics of the solar corona. The characteristics of these xray microcalorimeters are significantly different from conventional microcalorimeters developed for astrophysics because they need to accommodate much higher count rates (300-1000 cps) while maintaining high energy resolution of less than 4 eV FWHM in the X-ray energy band of 0.2-10 keV. The other main difference is a smaller pixel size (less than 75 x 75 square microns) than is typical for x-ray microcalorimeters in order to provide angular resolution less than 1 arcsecond. We have achieved at energy resolution of 2.15 eV at 6 keV in a pixel with a 12 x 12 square micron TES sensor and 34 x 34 x 9.1 micron gold absorber, and a resolution of 2.30 eV at 6 keV in a pixel with a 35 x 35 micron TES and a 57 x 57 x 9.1 micron gold absorber. This performance has been achieved in pixels that are fabricated directly onto solid substrates, ie. they are not supported by silicon nitride membranes. We present the results from these detectors, the expected performance at high count-rates, and prospects for the use of this technology for future Solar missions.

We are developing an ASTRO-H data analysis framework with the Geant4-based Monte Carlo simulation core, and numerical models of the on-orbit environmental radiation and full-satellite mass structure. In addition, the framework also includes a mechanism to connect and control data processing modules that are developed independently and data communication channels among them, which has been technically proven by simulations and analysis of the Suzaku HXD, many other detectors and astrophysical issues.

The thin film technology called "depth-graded multi-layer" is used to manufacture reflector foils, which are inserted in a hard X-ray telescope. When the temperature of the foil changes from the temperature at which the foil was produced; thermal deformation is induced due to difference of linear coefficient of expansion of its constituents. The deformation causes performance of X-ray image formation to deteriorate. Therefore, it is absolutely imperative to estimate the amount of deformation quantitatively and to establish a method of temperature control for the foil under the thermal environment on orbit. We used the hard X-ray telescope, which is part of the currently-projected the ASTRO-H X-ray satellite, as an example for investigation. The effective method of the HXT thermal control was examined with the thermal analytical software, "Thermal Desktop". The deformation of the foil when the temperature was changed by 1 degree C was predicted by a finite element analysis (FEA). The thermal desktop analysis shows that the overall foil temperature in orbit can be close to the temperature at which the foils were produced (~22degree C) by the newly developed thermal control method. The FEM analysis shows that the prediction of the foil deformation due to a temperature change of 1 degree C is about 8 μm.

Soft Gamma-ray Detector (SGD:40-600 keV) will be mounted on the 6th Japanese X-ray observatory ASTROH to be launched in 2014. The main part of the SGD is a Compton camera with a narrow field of view and surrounded by BGO active shields (SGD-BGO). Via this combination, the SGD can achieve sensitivity more than ten times superior to the Suzaku/HXD. The BGO active shield will also function as a gamma-ray burst monitor as proven by the wide-band all-sky monitor (WAM) of the Suzaku/HXD. Avalanche Photodiodes (APDs) are used to read out scintillation lights from the BGO. The size of the former also means we need to focus on collecting light from large, complex-shaped BGO blocks. The significant leakage current of the APD means a lower temperature is preferred to minimize the noise while a higher temperature is preferred to simplify the cooling system. To optimize the BGO shape and the operating temperature, we tested the performance of the BGO readout system with various BGO shapes under different operating temperatures. We also apply waveform sampling by flash-ADC and digital filter instead of a conventional analog filter and ADC scheme to reduce the space and power of the circuit with increased flexibilities. As an active shield, we need to achieve a threshold level of 50-100 keV. Here, we report on the studies of threshold energy of active shield under various conditions and signal processings.

The Soft Gamma-ray Detector onboard the ASTRO-H satellite, scheduled for launch in 2014, is a Si/CdTe Compton telescope surrounded by a thick BGO active shield. The SGD covers the energy range from 40 to 600 keV and studies non-thermal phenomena in the universe with high sensitivity. For the success of the SGD mission, careful examination of the expected performance, particularly the instrumental background in orbit, and optimization of the detector configuration are essential. We are developing a Geant4-based Monte Carlo simulation framework on the ANL++ platform, employing the MGGPOD software suite to predict the radioactivation in orbit. A detailed validation of the simulator through the comparison with literature and the beam test data is summarized. Our system will be integrated into the ASTRO-H simulation framework.

We have developed a new back-illuminated (BI) CCD which has an Optical Blocking Layer (OBL) directly coating its X-ray illumination surface with Aluminum-Polyimide-Aluminum instead of Optical Blocking Filter (OBF). OBL is composed of a thin polyimide layer sandwiched by two Al layers. Polyimide and Al has a capability to cut EUV and optical light, respectively. The X-ray CCD is affected by large doses of extreme ultraviolet (EUV) radiation from Earth sun-lit atmosphere (airglow) in orbit as well as the optical light. In order to evaluate the performance of the EUV-attenuating polyimide of the OBL, we measured the EUV transmission of both the OBL and the OBF at energies between 15-72 eV by utilizing a beam line located at the Photon Factory in High Energy Accelerator Research Organization (KEK-PF). We obtained the EUV transmission to be 3% at 41 eV which is the same as the expected transmission from the designed thickness of the polyimide layer. We also found no significant change of the EUV transmission of polyimide over the nine month interval spanned by out two experiments. We also measured the optical transmission of the OBL at wavelengths between 500-900Å to evaluate the performance of the Al that attenuates optical light, and found the optical transmission to be less than 4×10^-5.

We present the current status of the pre-collimator for the stray-light reduction, mounted on the ASTRO-H X-Ray Telescopes (XRT). Since the ASTRO-H XRTs adopt the conical approximation of the Wolter-I type grazing incident optics, X-rays from a source located far from the telescope boresight create a ghost image in the detector field of view (FOV) as a stray light, and then reduce the signal-to-noise ratio even in the hard X-ray band. We thus plan to mount the pre-collimator, which is comprised of cylindrical blades aligned with each primary mirror, onto the XRTs to remove the stray light. While the pre-collimator for the Soft X-ray Telescopes is designed by the similar principle adopted for the Suzaku pre-collimator, that for the Hard X-ray Telescopes requires some trade-off studies to select an appropriate blade material. The HXT pre-collimator currently utilizes the aluminum blade with the 50 mm height and 150 μm thickness. We examined the observational effects by the hard X-ray (> 10 keV) stray light and the expected performance of the pre-collimator in some scientific cases, using a ray-tracing simulator. We found that the Galactic center may be mostly covered with the stray light from the well-known bright X-ray sources. In addition, the flux estimation of the extended X-ray emission such as the Cosmic X-ray Background is also found to have large (~ 30%) uncertainty due to the stray light from the outside of the XRT FOV. The pre-collimator improves the situations; the stray light covering the source-free region in the Galactic center can be reduced by half and the uncertainty of the flux determination for the diffuse source decreases down to < 10%.

Japan's 6th X-ray satellite mission ASTRO-H, which is planed to be launched in the fiscal year 2013, will carry two hard X-ray telescopes (HXT) using depth-graded multilayer reflectors which provide us the capability of hard X-ray imaging observation up to 80 keV. ASTRO-H/HXT is the light-weight hard X-ray telescope using Pt/C depth-graded multilayer and high-throughput thin-foil optics. The basic technology for fabricating ASTROH /HXT has been established through the balloon borne experiments, InFOCμS and SUMIT mission. The HXT consists of about 1300 foil reflectors of which a size of the 200 mm mirror length and the diameter range of 120-450 mm which is much larger that those for the balloon borne experiments. To clear the requirements of the angular resolution and the effective photon collecting area for ASTRO-H/HXT, we should produce twice the total number of reflectors and select them. Therefore we need to produce more than 5000 foil reflectors for the two flight telescopes. The installation of the production line and optical evaluation system dedicated to the ASTRO-H/HXT has been almost done. We are testing and improving the production line through productions of several sizes of reflectors. The mass production of the reflectors for the flight model is scheduled to start from July 2010.

ASTRO-H is the new Japanese X-ray astronomy satellite for launch in 2013. HXT on board the satellite has a mirror housing which is a cylindrical case and contains reflection mirror foils, which are constrained by alignment bars. In order to investigate vibration properties of HXT on board the satellite, vibration tests and FEM analyses were conducted. From the results of x-vibration test, it was found that there were no resonant frequencies at frequency less than 120 Hz. It also appeared that foils move along grooves of alignment bars when the housing was vibrated because kinetic connection between foils and alignment bars is only friction force. From the simulated results, this loose connection used in the actual HXT housing is useful to suppress a strong resonance at 51Hz predicted by supposing tight connections such as adhesiveness. As for z-vibration properties, vibration property of the housing was complicated since foils leap when zacceleration becomes larger than 1G. However it could be confirmed that the distinct resonant peaks did not appear at frequency less than 200 Hz. From these results, it was found that HXT housing had not any resonant frequencies less than 120 Hz, which is the maximum frequency of sinusoidal vibrations applied when launched.

The Soft X-ray Spectrometer (SXS) is a cryogenic high resolution X-ray spectrometer onboard the X-ray astronomy satellite ASTRO-H. The detector array is cooled down to 50 mK using a 3-stage adiabatic demagnetization refrigerator (ADR). The cooling chain from room temperature to the ADR heat-sink is composed of superfluid liquid He, a ⁴He Joule-Thomson cryocooler, and 2-stage Stirling cryocoolers. It is designed to keep 30 L of liquid He for more than 3 years in the nominal case. It is also designed with redundant subsystems throughout from room temperature to the ADR heat-sink, to alleviate failure of a single cryocooler or loss of liquid He.

We present the current status of hard X-ray telescope developments of ASTRO-H. ASTRO-H is Japan's 6th Xray satellite mission following to Suzaku. It will be launched in 2014. The HXT onboard ASTRO-H is thin-foil, multi-nested conical optics as well as Suzaku XRT. To reflect hard X-rays efficiently, reflector surfaces are coated with depth-graded Pt/C multilayer. Reflectors are fabricated by the epoxy-replication method. Currently, we have finished the preparation of mirror production facility at Nagoya University, and started test production of reflectors for HXT. The selected 22 pairs of multilayer reflectors have been characterized at the SPring-8 beamline BL20B2.

The Soft X-ray Spectrometer (SXS) instrument on the Astro-H observatory is based on a 36 pixel x-ray calorimeter array cooled to 50 mK in a sophisticated spaceflight cryostat. The SXS is a true spatial-spectral instrument, where each spatially discrete pixel functions as a high-resolution spectrometer. Here we discuss the SXS detector subsystem that includes the detector array, the anticoincidence detector, the first stage amplifiers, the thermal and mechanical staging of the detector, and the cryogenic bias electronics. The design of the SXS detector subsystem has significant heritage from the Suzaku/XRS instrument but has some important modifications that increase performance margins and simplify the focal plane assembly. Notable improvements include x-ray absorbers with significantly lower heat capacity, improved load resistors, improved thermometry, and a decreased sensitivity to thermal radiation. These modifications have yielded an energy resolution of 3.5-4.0 eV FWHM at 6 keV for representative devices in the laboratory, giving considerable margin against the 7 eV instrument requirement. We expect similar performance in flight.

The X-ray telescope eROSITA is the core instrument besides the Russian ART-XC on the Russian Spektrum-Roentgen- Gamma satellite which will be launched in 2012 to an orbit around the L2 point of the Earth-Sun-system. During both survey and pointing phase the solar panels and the antenna constrain the possible mission scenario. The scan axis is supposed to point constantly towards the earth in the survey phase. In combination with the orbit, the points of largest exposure - the scan poles - then would be areas of a few hundred deg² instead of small singularities. The background as a permanent interference factor is limiting the performance as well as transient disruptions like solar flares. Constraints on the instrument's side are amongst others vignetting, effectivity and aligning of the different components. The mission objectives and related performance imply very stringent requirements. Extremely challenging mechanical requirements in terms of mirror accuracy, alignment and dimensional stability have to be ensured by design and realized during manufacturing and integration. Although the Wolter telescope design is quite similar to those of XMM, the manufacturing of the mirrors is even more challenging due to the more unfavorable geometry of the mirrors. Mirrors, CCD-cameras and camera electronics all have their own, partly narrow working temperature ranges. Therefore accurate thermal control has to be implemented to ensure that the telescopes are performing within specification. Objectives of this work are to find the optimum mission scenario as well as certain operating parameters, taking into account all environmental boundary conditions.

We report the in orbit status of the MAXI/SSC onboard the international space station (ISS). It was commissioned in August 2009. This is the first all sky survey mission employing X-ray CCDs. It is a slit camera with a field of view of 1.5° × 90° and it scans the sky as the ISS rotates around the earth. The CCD's are cooled down to about -60°C by peltier device and a loop heat pipe. The observation efficiency of the SSC is about 30% due to edge glow, but all of the 32 CCDs in the SSC are cooled down as we expected and functioning property. The performance of the CCD is continuously monitored both by the Mn-K X-rays and by the Cu-K X-rays. There are many sources detected not only point sources but extended sources. But further work in data screening and more observation time is needed to obtain the clear structure of the extended emission.

NHXM, under study by ASI (Agenzia Spaziale Italiana), is an X-ray observatory in the energy band between 0.5 and 80 keV and will have 3 telescopes dedicated to X-ray imaging with a field of view diameter of 12 arcmin and a focal length of 10 m. We report on the development of high-speed and low-noise readout of a monolithic array of DEPFET detector. The DEPFET based detectors, thanks to an intrinsic low anode capacitance, are suitable as low-energy detectors (from 0.5 to 10 keV) of the new NHXM telescope. The challenging requirements of the NHXM cameras regard the necessity to obtain images and spectra with nearly Fano-limited energy resolution with an absolute time resolution of about 100 μs. In order to exploit the speed capability of the DEPFET array, it has been developed a readout architecture based on the VELA circuit: a drain current readout configuration to implement an extremely fast readout (2 μs/row) and preserve the excellent noise performance of the detector. In the paper the foreseen maximum achievable frame-rate and the best energy resolution will be presented in order to assert the VELA suitability for X-ray imaging and spectroscopy.

The New Hard X-ray Mission (NHXM) is conceived to extend the grazing-angle reflection imaging capability up to 80 keV energy. The payload of the mission consists of four telescopes: three of the them having at their focal plane an identical spectral-imaging camera operating between 0.2 and 80 keV, while the fourth one is equipped with a X-ray imaging polarimeter. The three cameras consist of two detection layers: a Low Energy Detector (LED) and a High Energy Detector (HED) surrounded by an Anti Coincidence (AC) system. Here we present the preliminary design and the solutions that we are currently studying to meet the requirements for the high energy detectors. These detectors will be based on Cadmium Telluride (CdTe) pixel sensors coupled to pixel read-out electronics using custom CMOS ASICs.

Focusing mirrors manufactured via galvanic replication process from negative shape mandrels is the candidate solution for some of next future X-ray missions. Media Lario Technologies (MLT) is the industrial enabler developing, in collaboration with Brera Astronomical Observatory (INAF/OAB) and Italian Space Agency, the Optical Payload for the New Hard X-ray Mission (NHXM) Italian project. The current and ongoing development activities in Media Lario Technologies complement the electroforming technology with a suite of critical manufacturing and assembly of the Mirror Module Unit. In this paper, the progress on mandrels manufacturing, mirror shell replication, multilayer coating deposition and mirror module integration, leading to the manufacturing and testing of some astronomical Hard X-ray Engineering Models, is reported. Mandrel production is a key point in terms of performances and schedule; the results from mandrels fabricated using a proprietary multistep surface finishing process are reported. The progress in the replication of ultrathin Nickel and Nickel-Cobalt substrates gold coated mirror shells is reported together with the results of MLT Magnetron Sputtering multilayer coating technology for the hard x-ray waveband and its application to Pt/C.

A suspension-mounting scheme is developed for the IXO (International X-ray Observatory) mirror segments in which the figure of the mirror segment is preserved in each stage of mounting. The mirror, first fixed on a thermally compatible strongback, is subsequently transported, aligned and transferred onto its mirror housing. In this paper, we shall outline the requirement, approaches, and recent progress of the suspension mount processes.

Platinum is being explored as an alternative to the sprayed boron nitride mandrel release coating under study at GSFC for the International X-ray Observatory (IXO). Two and three inch diameter, polished (PFS) and superpolished (SPFS) fused silica flat mandrels, were used for these tests. Pt was applied to the mandrels by DC magnetron sputtering. The substrate material was 400 micron thick D263 glass, the material which has been proposed for the IXO segmented optics. These substrates were placed on the mandrels and thermally cycled with the same thermal profile being used at GSFC in the development of the BN slumping for IXO. After the thermal cycle was complete, the D263 substrates were removed; new D263 substrates were placed on the mandrels and the process was repeated. Four thermal cycles have been completed to date. After initially coating the mandrels with Pt, no further conditioning was applied to the mandrels before or during the thermal cycles. The microroughness of the mandrels and of the D263 substrates was measured before and after thermal cycling. Atomic force microscopy (AFM) and 8 keV X-ray reflectivity data are presented.

The requirements for the IXO (International X-ray Observatory) telescope are very challenging in respect of angular resolution and effective area. Within a clear aperture with 1.7 m > R > 0.25 m that is dictated by the spacecraft envelope, the optics technology must be developed to satisfy simultaneously requirements for effective area of 2.5 m² at 1.25 keV, 0.65 m² at 6 keV and 150 cm² at 30 keV. The reflectivity of the bare mirror substrate materials does not allow these requirements to be met. As such the IXO baseline design contains a coating layout that varies as a function of mirror radius and in accordance with the variation in grazing incidence angle. The higher energy photon response is enhanced through the use of depth-graded multilayer coatings on the inner radii mirror modules. In this paper we report on the first reflectivity measurements of wedged ribbed silicon pore optics mirror plates coated with a depth graded W/Si multilayer. The measurements demonstrate that the deposition and performance of the multilayer coatings is compatible with the SPO production process.

Over the last two years, we have studied system concepts for the International X-ray Observatory (IXO) with the goal of increasing the science return of the mission and to reduce technical and cost risk. We have developed an optical bench concept that has the potential to increase the focal length from 20 to 25 m within the current mass and stability requirements. Our deployable bench is a tensegrity structure formed by two telescoping booms (compression) and a hexapod cable (tension) truss. This arrangement achieves the required stiffness for the optical bench at minimal mass while employing only high TRL components and flight proven elements. The concept is based on existing elements, can be fully tested on the ground and does not require new technology. Our design further features hinged, articulating solar panels, an optical bench fully enclosed in MLI and an instrument module with radially facing radiator panels. We find that our design can be used over a wide range of sun angles, thereby greatly increasing IXO's field of regard, without distorting the optical bench. This makes a much larger fraction of the sky instantaneously accessible to IXO.

An Off-Plane X-ray Grating Spectrometer (OP-XGS) concept is being developed to meet the needs of the International X-ray Observatory (IXO). The OP-XGS will provide the required spectral resolution of R >3000 over the 0.3 - 1 keV band with >1000 cm² effective collecting area, using experience gained with the current generation of reflection gratings already flown on rocket experiments. We have developed several potential configurations that meet or exceed these requirements. This paper will focus on the mechanical design and requirements for one of these configurations, the "tower" concept. This configuration mounts the grating modules to the instrument platform via a tower, allowing direct alignment with the camera module. This reduces the complexity of the alignment problem while also minimizing the overall mass of the XGS. We have developed an initial interface concept and resource requirements for this option to be reviewed by the mission teams for design drivers. We contrast the resource requirements for this concept with those required for other concepts which have been reviewed by the OP-XGS team. Further, we have identified those portions of the tower design concept that will require potential technology demonstration to reach TRL 6 prior to the Preliminary Design Review.

We present a study of the background for the array of microcalorimeters onboard of the International X-ray Observatory space mission. We investigated through simulations the rates at the focal plane of soft and hard particles in L2 orbit. Assuming the presence of an anticoincidence instrument, we derived an estimate of the residual background. The preliminary results reported in this paper are based on a number of simplifications of the actual picture. Efforts to improve the model are on-going.

The technique which combines high resolution spectroscopy with imaging capability is a powerful tool to extract fundamental information in X-ray Astrophysics and Cosmology. TES (Transition Edge Sensors)-based microcalorimeters match at best the requirements for doing fine spectroscopy and imaging of both bright (high count rate) and faint (poor signal-to-noise ratio) sources. For this reason they are considered among the most promising detectors for the next high energy space missions and are being developed for use on the focal plane of the IXO (International X-ray Observatory) mission. In order to achieve the required signal-to-noise ratio for faint or diffuse sources it is necessary to reduce the particle-induced background by almost two orders of magnitude. This reduction can only be achieved by adopting an active anticoincidence technique. In this paper, we will present a novel anticoincidence detector based on a TES sensor developed for the IXO mission. The pulse duration and the large area of the IXO TESarray (XMS X-ray Microcalorimeter Spectrometer) require a proper design of the anticoincidence detector. It has to cover the full XMS area, yet delivering a fast response. We have therefore chosen to develop it in a four-pixel design. Experimental results from the large-area pixel prototypes will be discussed, also including design considerations.

The optics for the International X-Ray Observatory (IXO) require alignment and integration of about fourteen thousand thin mirror segments to achieve the mission goal of 3.0 square meters of effective area at 1.25 keV with an angular resolution of five arc-seconds. These mirror segments are 0.4 mm thick, and 200 to 400 mm in size, which makes it hard not to impart distortion at the sub-arc-second level. This paper outlines the precise alignment, verification testing, and permanent bonding techniques developed at NASA's Goddard Space Flight Center (GSFC). These techniques are used to overcome the challenge of aligning thin mirror segments and bonding them with arc-second alignment and minimal figure distortion. Recent advances in technology development in the area of permanent bonding have produced significant results. This paper will highlight the recent advances in alignment, testing, and permanent bonding techniques as well as the results they have produced.

Different optical designs are under consideration for the International X-ray Observatory (IXO). In this paper we show results of simulations of the segmented shell Wolter-I design, of the Silicon Pore Optics (SPO) conical Wolter-I approximation and of the Silicon based Kirkpatrick-Baez design. We focus particularly on the issue of stray light. When a source is off axis, such that it is not imaged on the detector, some of its light may still be directed by the optics onto the detector plane. Sources close to the pointing direction can thereby introduce an extra background radiation level in the detectors. This phenomenon is investigated by numerical ray tracing of the three designs, yielding detector images of the stray light, and an indication of which part of the mirror that light originates. Results show the similarities and differences of the designs with respect to stray light, and give a quantitative indication of the level of background radiation in different cases. Furthermore, for the Silicon Pore Optics design, two different ways of partially blocking the stray light have been modelled, indicating that a reduction of the stray light can be achieved. In general, the results that have been found indicate that for the simulated set-ups the stray light levels are compliant with the design specifications of the International X-ray Observatory.

The mirror design for the International X-ray Observatory (IXO) is currently following two paths: a segmented slumped glass shell Wolter-I design, and a Silicon Pore Optics (SPO) conical approximation to the Wolter-I design. The conical approximation used for the SPO imposes a lower limit to the angular resolution which puts this option at a potential disadvantage. In this paper we describe ways in which this can be circumvented. We analyse the surface profile modifications that can be made to lift this limitation and show that a much closer approximation to the Wolter I ideal is possible. We describe several ways in which a much tighter angular resolution limit could be achieved in practice and discuss ways in which this can be implemented in the manufacture of the SPO.

The International X-ray Observatory (IXO) is being studied as a joint mission by the NASA, ESA and JAXA space agencies. The main goals of the mission are large effective area (>3m² at 1 keV) and a good angular resolution (<5 arcsec HEW at 1 keV). This paper reports on an activity ongoing in Europe, supported by ESA and led by the Brera Astronomical Observatory (Italy), aiming at providing an alternative method for the realization of the mirror unit assembly. This is based on the use of thin glass segments and an innovative assembly concept making use of glass reinforcing ribs that connect the facets to each-other. A fundamental challenge is the achievement with a hot slumping technique of the required surface accuracy on the glass segments. A key point of the approach is represented by the alignment of the mirror segments and co-alignment of the mirror pairs assembled together. In this paper we present the mirror assembly conceptual design, starting from the design of the optical unit, the error budgets contributing to the image degradation and the performance analysis to assess error sensitivities. Furthermore the related integration concept and the preliminary results obtained are presented.

The next large x-ray astrophysics mission launched will likely include soft x-ray spectroscopy as a primary capability. A requirement to fulfill the science goals of such a mission is a large-area x-ray telescope focusing sufficient x-ray flux to perform high-resolution spectroscopy with reasonable observing times. The IXO soft x-ray telescope effort in the US is focused on a tightly nested, thin glass, segmented mirror design. Fabrication of the glass segments with the required surface accuracy is a fundamental challenge; equally challenging will be the alignment of the ~7000 secondary mirror segments with their corresponding primary mirrors, and co-alignment of the mirror pairs. We have developed a system to perform this alignment using a combination of a coordinate measuring machine (CMM) and a double-pass Hartmann test alignment system. We discuss the technique, its ability to correct low-order mirror errors, and results of a recent pair alignment including progress toward the required alignment accuracy of < 2 arcseconds, and discuss the influence of the alignment process on mirror figure. We then look forward toward its scalability to the task of building the IXO telescope.

The International X-ray Observatory (IXO) has a top level requirement that the observing efficiency be 85%. This is a challenging requirement, given that the observing efficiencies for CXO and XMM-Newton are between 60% and 70%. However, the L2 orbit for IXO means that it will not be subject to the earth block/radiation zone effects that are seen for CXO and XMM-Newton. Outside of these effects the efficiencies for CXO and XMM-Newton do approach 85%, so this requirement appears achievable for IXO. In this paper we itemize the effects which impact the observing efficiency, in order to guide the design of the observatory. Meeting the 85% requirement should be possible but will require careful attention to detail.