Departamento de Física
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Browsing Departamento de Física by Author "Alves, Francisco José Cerqueira"
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- Inflight proton activation and damage on a CdTe detection planePublication . Simões, N.; Maia, Jorge; Silva, Rui M. C.; Ghithan, S.; Crespo, P.; Carmo, Sérgio J. C. do; Alves, Francisco José Cerqueira; Moita, Miguel; Auricchio, Natalia; Caroli, EzioFuture 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.