Currently, there are 4 existing methods that are used for alpha particle detection in water: Gas flow proportional counter, PMT-based scintillation counter, liquid scintillation counting and alpha-particle spectrometry. However, NONE of these existing methods can be tested directly in water or in real-time due mainly to the limitation of the detector material itself as well as associated device design. These existing detector technologies all require some form of evaporation, sample preparation as well as laboratories test procedures in the lab, which is clearly not practical for time-critical situations as in war-fare environment or future threads. In this work, we report the development of a novel scintillation detector material and its associated device design, the ultra-compact, lightweight SiPM-based Hg2Br2 scintillation detector that can directly detect gross alpha in drinking water in the field, and in real-time while being wearable as needed, especially for soldiers and military personnel in general. This novel detector does not require test sample preparation. Besides environmental and health safety, the detector also has additional capabilities such as energy discrimination and good counting efficiency so that it can be practically used in low radioactivity scenarios. Moreover, the novel Hg2Br2 scintillation detector material is also simultaneously capable of detecting other forms of radiation emanating from radioactive materials, including dual gamma-neutron detection capability, and having excellent radiation hardness.
The Acousto-Optic Tunable Filter (AOTF) devices are used in a variety of applications including hyperspectral and spectrapolarimetric based imaging. The AOTF devices provide several advantages including speed and random access to desired spectral bands and enable all-solid-state operation that are attractive for space applications. In this paper, the performance of Tellurium Dioxide (TeO2) and Mercurous Bromide (Hg2Br2) AOTF devices in space environment carried out under the NASA’s Materials International Space Station Experiments 11 (MISSE-11) mission is discussed. The purpose of the MISSE-11 mission was to study materials and devices subjected to space conditions for long term while attached to the International Space Station (ISS). The TeO2 AOTF was developed for Short Wavelength IR (SWIR) operation while the Hg2Br2 AOTF device was developed for Long Wavelength IR (LWIR) operation. These devices were attached to the ISS platform for more than a year. Pre-flight and post-flight performance characterization were performed on these devices. In the case of TeO2 AOTF, the preflight efficiency was around 87% with a center frequency at 68MHz while the post-flight efficiency was around 83%. However, the optical transmission of Hg2Br2 AOTF had deteriorated considerably. The details of performance testing and analysis of both AOTF devices are discussed.
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