Superior radiation tolerance of thin epitaxial silicon detectors

Abstract For the LHC upgrade (fluences up to 10 16 p / cm 2 ) epi-Si devices are shown to be a viable solution. No type inversion was measured up to 1.3×10 15 24 GeV /c protons/cm 2 and the charge collection efficiency (CCE) remained close to 100%. For reactor neutrons CCE was measured to be 60% at 8×10 15 n / cm 2 . Annealing measurements have shown that only moderate cooling during beam off periods would be necessary. As a tentative explanation for the superior quality of these devices, we assume that radiation-induced donor generation leads to compensation effects of deep acceptors. In the future, we will extend the experiments to fluences up to 10 16 p / cm 2 and use also different variants of the epi-Si material and device geometry.