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CdZnTe Background Measurements at Balloon Altitudes with PoRTIAMeasurements of the CdZnTe internal background at balloon altitudes are essential to determine which physical processes make the most important background contributions. We present results from CdZnTe background measurements made by PoRTIA, a small CdZnTe balloon instrument that was flown three times in three different shielding configurations. PoRTIA was passively shielded during its first flight from Palestine, Texas and actively shielded as a piggyback instrument on the GRIS balloon experiment during its second and third flights from Alice Springs, Australia, using the thick GRIS Nal anticoincidence shield. A significant CdZnTe background reduction was achieved during the third flight with PoRTIA placed completely inside the GRIS shield and blocking crystal, and thus completely surrounded by 15 cm of Nal. A unique balloon altitude background data set is provided by CdZnTe and Ge detectors simultaneously surrounded by the same thick anticoincidence shield; the presence of a single coxial Ge detector inside the shield next to PoRTIA allowed a measurement of the ambient neutron flux inside the shield throughout the flight. These neutrons interact with the detector material to produce isomeric states of the Cd, Zn and Te nuclei that radiatively decay; calculations are presented that indicate that these decays may explain most of the fully shielded CdZnTe background.
Document ID
20030032936
Acquisition Source
Goddard Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Parsons, A.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Barthelmy, S.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Bartlett, L.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Gehrels, N.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Naya, J.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Stahle, C. M.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Tueller, J.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Teegarden, B.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
September 8, 2013
Publication Date
January 1, 2003
Subject Category
Mechanical Engineering
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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