Beam test results of 25 $\hat{I}¼$m and 35 $\hat{I}¼$m thick FBK UFSD]{Beam test results of 25 $\hat{I}¼$m and 35 $\hat{I}¼$m thick FBK ultra fast silicon detectors

Abstract

This paper presents the measurements on first very thin Ultra Fast Silicon Detectors (UFSDs) produced by Fondazione Bruno Kessler; the data have been collected in a beam test setup at the CERN PS, using beam with a momentum of 12 GeV/c. UFSDs with a nominal thickness of 25 $\hat{I}¼$m and 35 $\hat{I}¼$m and an area of 1 $\times$ 1 ${\text{mm}}^2$ have been considered, together with an additional HPK 50-$\hat{I}¼$m thick sensor, taken as reference. Their timing performances have been studied as a function of the applied voltage and gain. A time resolution of about 25 ps and of 22 ps at a voltage of 120 V and 240 V has been obtained for the 25 and 35 $\hat{I}¼$m thick UFSDs, respectively.