Solar proton event damage in space-borne Ge detectors

By means of annealing it has been possible to fully restore the spectral performance of Ge detector after exposure to simulated Solar Proton Events (SPE) of integrated fluences up to 6 x 10(10) protons/cm(2).The required annealing time to achieve the restoration of energy resolution, the ratio FWTM/FWHM and detection efficiency to pre-irradiation values is of the order of 25 weeks. However, about half of this time might be considered sufficient to restore the detector within acceptable operational limits for most applications.The long annealing time required to restore the detection performances opens a question on the actual suitability of Ge detector for inner solar system missions, as BepiColombo and Solar Orbiter, unless enhanced robustness or faster recovering capability can be developed, for instance using specific crystal encapsulation. (C) 2009 Elsevier B.V. All rights reserved.