Response Of Windowless Silicon Avalanche Photo-Diodes To Electrons In The 90-900 Ev Range

We report on the characterization of the response of windowless silicon avalanche photodiodes to electrons in the 90-900 eV energy range. The electrons were provided by a monoenergetic electron gun present in the LASEC laboratories of University of Roma Tre. We find that the avalanche photo-diode generates a current proportional to the current of electrons hitting its active surface. The gain is found to depend on the electron energy E-e, and varies from 2.147 +/- 0.027 (for E-e = 90 eV) to 385.8 +/- 3.3 (for E-e = 900 eV), when operating the diode at a bias of V-apd = 350 V. This is the first time silicon avalanche photo-diodes are employed to measure electrons with E-e < 1 keV.