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Advisor(s)
Abstract(s)
Future high-energy space telescope missions require further analysis of orbital environment induced activation
and radiation damage on main instruments. A scientific satellite is exposed to the charged particles harsh
environment, mainly geomagnetically trapped protons (up to ∼300 MeV) that interact with the payload materials,
generating nuclear activation background noise within instruments’ operational energy range and causing
radiation damage in detector material. As a consequence, instruments’ performances deteriorate during the
mission time-frame. In order to optimize inflight operational performances of future CdTe high-energy telescope
detection planes under orbital radiation environment, we measured and analyzed the effects generated by
protons on CdTe ACRORAD detectors with 2.56 cm2 sensitive area and 2 mm thickness. To carry-out this study,
several sets of measurements were performed under a ∼14 MeV cyclotron proton beam. Nuclear activation
radionuclides’ identification was performed. Estimation of activation background generated by short-lived
radioisotopes during one day was less than ∼1.3×10−5 counts cm−2 s−1 keV−1 up to 800 keV. A noticeable
gamma-rays energy resolution degradation was registered (∼60% @ 122 keV, ∼14% @ 511 and ∼2.2% @
1275 keV) after an accumulated proton fluence of 4.5×1010 protons cm−2, equivalent to ∼22 years in-orbit
fluence. One year later, the energy resolution of the irradiated prototype showed a good level of performance
recovery.
Description
Keywords
CdTe Gamma-ray detectors Astrophysics Space radiation Activation Radiation damage