Solaris is a scientific and technological project aimed at the development of a smart Solar monitoring system at high radio frequencies, based on single-dish imaging techniques. It combines the implementation of dedicated and interchangeable high-frequency receivers on existing small single-dish radio telescope systems (1.5/2.6m class) available in our laboratories and in Antarctica, to be adapted for Solar observations. Solaris can perform Solar imaging observations nearly 20h/day during Antarctic summer with optimal sky opacity, and it will be the only Solar facility offering continuous monitoring at 100GHz. In perspective, our system could be implemented also in the Northern hemisphere to offer unprecedented Solar radio monitoring and imaging for the whole year.
The Tenerife Microwave Spectrometer (TMS) is a new 10-20 GHz experiment that will be installed at the Teide Observatory (Tenerife, Spain), next to the QUIJOTE CMB experiment. The main TMS scientific driver is to accurately measure absolute distortions of the sky spectrum in the 10-20 GHz frequency range, with special emphasis on the characterization of the absolute synchrotron monopole from our Galaxy, and the possible deviations of the CMB spectrum from a pure blackbody law. TMS will provide an absolute calibration for the QUIJOTE experiment, and it will also serve as a prototype for future instruments of its type, both ground-based and satellites. Among its new instrumental design is an octave bandwidth high quality cryogenic front-end, a thermally stabilized cold black body and a new design of wide-band Fourier transform spectrometer. The spectrometer will have a resolution of 250 MHz, giving 40 spectrally stable sub-bands.
The Tenerife Microwave Spectrometer (TMS) is part of a renewed effort to study and characterize the CMB frequency distribution. The spectrometer is based on a pseudo-correlation architecture with two 10–20 GHz radiometer chains making use of both orthogonal linear polarizations, and will observe in this band with an angular and frequency resolutions of 3° and 1 MHz. The optical arrangement includes two corrugated feedhorns, one facing an internal calibrator to provide a cold reference signal, and the other pointing to the sky through the cryostat window by means of an offset-fed reflector. The optical system provides optimal cross-polarization properties (≤-30 dB) and symmetric beams, with minimum frequency dependence. The readout system is based on a SoC FPGA, providing fast data acquisition, high spectral resolution and stability. We present the current status of the TMS instrument, having described the scientific case of this instrument in the accompanying publication.
In this paper we discuss the latest developments of the STRIP instrument of the “Large Scale Polarization Explorer” (LSPE) experiment. LSPE is a novel project that combines ground-based (STRIP) and balloon-borne (SWIPE) polarization measurements of the microwave sky on large angular scales to attempt a detection of the “B-modes” of the Cosmic Microwave Background polarization. STRIP will observe approximately 25% of the Northern sky from the “Observatorio del Teide” in Tenerife, using an array of forty-nine coherent polarimeters at 43 GHz, coupled to a 1.5 m fully rotating crossed-Dragone telescope. A second frequency channel with six-elements at 95 GHz will be exploited as an atmospheric monitor. At present, most of the hardware of the STRIP instrument has been developed and tested at sub-system level. System-level characterization, starting in July 2018, will lead STRIP to be shipped and installed at the observation site within the end of the year. The on-site verification and calibration of the whole instrument will prepare STRIP for a 2-years campaign for the observation of the CMB polarization.
The X-ray Integral Field Unit (X-IFU) is one of the two instruments of the Athena astrophysics space mission approved by ESA in the Cosmic Vision 2015-2025 Science Programme. The X-IFU consists of a large array of transition edge sensor micro-calorimeters that will operate at ~100 mK inside a sophisticated cryostat. A set of thin filters, highly transparent to X-rays, will be mounted on the opening windows of the cryostat thermal shields in order to attenuate the IR radiative load, to attenuate radio frequency electromagnetic interferences, and to protect the detector from contamination. Thermal filters are critical items in the proper operation of the X-IFU detector in space. They need to be strong enough to survive the launch stresses but very thin to be highly transparent to X-rays. They essentially define the detector quantum efficiency at low energies and are fundamental to make the photon shot noise a negligible contribution to the energy resolution budget. In this paper, we review the main results of modeling and characterization tests of the thermal filters performed during the phase A study to identify the suitable materials, optimize the design, and demonstrate that the chosen technology can reach the proper readiness before mission adoption.
The X-ray Integral Field Unit (X-IFU) is one of the two detectors of the ATHENA astrophysics space mission approved by ESA in the Cosmic Vision 2015-2025 Science Programme. The X-IFU consists of a large array of transition edge sensors (TES) micro-calorimeters covering a field of view of ~5’ diameter, sensitive in the energy range 0.2-12 keV, and providing a spectral resolution of 2.5 eV at 7 keV. Both the TES and superconducting quantum interference devices (SQUID) based read-out electronics are very sensitive to electromagnetic interferences (EMI), and a proper shielding of the focal plane assembly (FPA) is required to prevent a deterioration of the energy resolution. A set of thin filters, highly transparent to X-rays, will be mounted on the FPA and on the cryostat thermal shields in order to attenuate the infrared radiative load, and to protect the detector from contamination. Some of these filters are also aimed at providing proper radio frequency (RF) shielding in the frequency range of the satellite telemetry downlink antenna. In addition, filters should also be effective in shielding any RF interference generated by other on-board electronics. In this paper, we present results from RF measurements performed on thin plastic foils coated with an aluminum layer, with and without metal meshes, and identify the filter characteristics matching the RF shielding requirements.
ALMA is the largest radio astronomical facility in the world providing high sensitivity between 35 and 950 GHz,
divided in 10 bands with fractional bandwidths between 19 and 36%. Having a lifespan of at least 30 years, ALMA
carries out a permanent upgrading plan which, for the receivers, is focused on achieving better sensitivity and larger
bandwidths. As result, an international consortium works on demonstrating a prototype receiver covering currents Bands
2 and 3 (67 to 116 GHz) which corresponds to a fractional bandwidth of 54%. Here we present the preliminary design,
implementation and characterization of suitable refractive optics. Results indicate an excellent performance in good
agreement with simulations.
S. Aiola, G. Amico, P. Battaglia, E. Battistelli, A. Baù, P. de Bernardis, M. Bersanelli, A. Boscaleri, F. Cavaliere, A. Coppolecchia, A. Cruciani, F. Cuttaia, A. D' Addabbo, G. D' Alessandro, S. De Gregori, F. Del Torto, M. De Petris, L. Fiorineschi, C. Franceschet, E. Franceschi, M. Gervasi, D. Goldie, A. Gregorio, V. Haynes, N. Krachmalnicoff, L. Lamagna, B. Maffei, D. Maino, S. Masi, A. Mennella, G. Morgante, F. Nati, M. W. Ng, L. Pagano, A. Passerini, O. Peverini, F. Piacentini, L. Piccirillo, G. Pisano, S. Ricciardi, P. Rissone, G. Romeo, M. Salatino, M. Sandri, A. Schillaci, L. Stringhetti, A. Tartari, R. Tascone, L. Terenzi, M. Tomasi, E. Tommasi, F. Villa, G. Virone, S. Withington, A. Zacchei, M. Zannoni
The LSPE is a balloon-borne mission aimed at measuring the polarization of the Cosmic Microwave Background (CMB)
at large angular scales, and in particular to constrain the curl component of CMB polarization (B-modes) produced by
tensor perturbations generated during cosmic inflation, in the very early universe. Its primary target is to improve the
limit on the ratio of tensor to scalar perturbations amplitudes down to r = 0.03, at 99.7% confidence. A second target is
to produce wide maps of foreground polarization generated in our Galaxy by synchrotron emission and interstellar dust
emission. These will be important to map Galactic magnetic fields and to study the properties of ionized gas and of
diffuse interstellar dust in our Galaxy. The mission is optimized for large angular scales, with coarse angular resolution
(around 1.5 degrees FWHM), and wide sky coverage (25% of the sky). The payload will fly in a circumpolar long
duration balloon mission during the polar night. Using the Earth as a giant solar shield, the instrument will spin in
azimuth, observing a large fraction of the northern sky. The payload will host two instruments. An array of coherent
polarimeters using cryogenic HEMT amplifiers will survey the sky at 43 and 90 GHz. An array of bolometric
polarimeters, using large throughput multi-mode bolometers and rotating Half Wave Plates (HWP), will survey the same
sky region in three bands at 95, 145 and 245 GHz. The wide frequency coverage will allow optimal control of the
polarized foregrounds, with comparable angular resolution at all frequencies.
M. Bersanelli, A. Mennella, G. Morgante, M. Zannoni, G. Addamo, A. Baschirotto, P. Battaglia, A. Baù, B. Cappellini, F. Cavaliere, F. Cuttaia, F. Del Torto, S. Donzelli, Z. Farooqui, M. Frailis, C. Franceschet, E. Franceschi, T. Gaier, S. Galeotta, M. Gervasi, A. Gregorio, P. Kangaslahti, N. Krachmalnicoff, C. Lawrence, G. Maggio, R. Mainini, D. Maino, N. Mandolesi, B. Paroli, A. Passerini, O. Peverini, S. Poli, S. Ricciardi, M. Rossetti, M. Sandri, M. Seiffert, L. Stringhetti, A. Tartari, R. Tascone, D. Tavagnacco, L. Terenzi, M. Tomasi, E. Tommasi, F. Villa, Gi. Virone, A. Zacchei
We discuss the design and expected performance of STRIP (STRatospheric Italian Polarimeter), an array of coherent receivers designed to fly on board the LSPE (Large Scale Polarization Explorer) balloon experiment. The STRIP focal plane array comprises 49 elements in Q band and 7 elements in W-band using cryogenic HEMT low noise amplifiers and high performance waveguide components. In operation, the array will be cooled to 20 K and placed in the focal plane of a ~0.6 meter telescope providing an angular resolution of ~1.5 degrees. The LSPE experiment aims at large scale, high sensitivity measurements of CMB polarization, with multi-frequency deep measurements to optimize component separation. The STRIP Q-band channel is crucial to accurately measure and remove the synchrotron polarized component, while the W-band channel, together with a bolometric channel at the same frequency, provides a crucial cross-check for systematic effects.
A. Mennella, B. Aja, E. Artal, M. Balasini, G. Baldan, P. Battaglia, T. Bernardino, M. Bersanelli, E. Blackhurst, L. Boschini, C. Burigana, R. Butler, B. Cappellini, F. Colombo, F. Cuttaia, O. D'Arcangelo, S. Donzelli, R. Davis, L. De La Fuente, F. Ferrari, L. Figini, S. Fogliani, C. Franceschet, E. Franceschi, T. Gaier, S. Galeotta, S. Garavaglia, A. Gregorio, M. Guerrini, R. Hoyland, N. Hughes, P. Jukkala, D. Kettle, M. Laaninen, P. Lapolla, D. Lawson, R. Leonardi, P. Leutenegger, G. Mari, P. Meinhold, M. Miccolis, D. Maino, M. Malaspina, N. Mandolesi, M. Maris, E. Martinez-Gonzalez, G. Morgante, L. Pagan, F. Pasian, P. Platania, M. Pecora, S. Pezzati, L. Popa, T. Poutanen, M. Pospieszalski, N. Roddis, M. Salmon, M. Sandri, R. Silvestri, A. Simonetto, C. Sozzi, L. Stringhetti, L. Terenzi, M. Tomasi, J. Tuovinen, L. Valenziano, J. Varis, F. Villa, A. Wilkinson, F. Winder, A. Zacchei
In this paper we present the test results of the qualification model (QM) of the LFI instrument, which is being
developed as part of the ESA Planck satellite. In particular we discuss the calibration plan which has defined
the main requirements of the radiometric tests and of the experimental setups. Then we describe how these
requirements have been implemented in the custom-developed cryo-facilities and present the main results. We
conclude with a discussion of the lessons learned for the testing of the LFI Flight Model (FM).
The ESA Planck mission is the third generation (after COBE and WMAP) space experiment dedicated to the measurement
of the Cosmic Microwave Background (CMB) anisotropies. Planck will map the whole CMB sky using two instruments in
the focal plane of a 1.5 m off-axis aplanatic telescope. The High Frequency Instrument (HFI) is an array of 52 bolometers
in the frequency range 100-857 GHz, while the Low Frequency Instrument (LFI) is an array of 11 pseudo-correlation
radiometric receivers which continuously compare the sky signal with the reference signal of a blackbody at ~ 4.5 K.
The LFI has been tested and calibrated at different levels of integration, i.e. on the single units (feed-horns, OMTs, amplifiers,
waveguides, etc.), on each integrated Radiometric Chain Assembly (RCA) and finally on the complete instrument,
the Radiometric Array Assembly (RAA). In this paper we focus on some of the data analysis algorithms and methods that
have been implemented to estimate the instrument performance and calibration parameters.
The paper concludes with the discussion of a custom-designed software package (LIFE) that allows to access the
complex data structure produced by the instrument and to estimate the instrument performance and calibration parameters
via a fully graphical interface.
The Low Frequency Instrument aboard the PLANCK satellite will employ pseudo-correlation radiometers, operating over three broad bands centred at 30, 44 ,and 70 GHz. The radiometer scheme is based on the simultaneous comparison of two input signals, one coming from the sky and the other coming from a reference blackbody at a stable cryogenic temperature (near 4K) as close as possible to the sky temperature (about 2.7K). This choice is made in order to minimize non-white instrumental noise, typically exhibiting a 1/f spectrum. Effects due to the residual offset are minimised with a gain modulation factor applied in software. Fluctuations of the reference signal, due to fluctuation in the cooling chain or to straylight radiation, can also produce a parasitic signal which would mimic a true sky fluctuation. The PLANCK scientific goal of a high precision imaging of the CMB anisotropy requires an accurate characterisation of each part constituting the chain by using tools of modellisation and experimental tests.
In this work we describe the concept of the radiometric chain, its functioning and the main sources of systematic errors, showing how, only with a hard modelling effort, it is possible to characterise, reduce and then remove in the data processing those systematic effects that may in principle compromise the quality of the whole instrument response.
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