Response of a rad-hard silicon diode for charged particles

In this paper, we describe the preliminary results about the response of an ion-implanted diode (Al/p+/n/n+/Al), developed in the framework of R&D programs for the future CMS experiment at Large Hadron Collider (LHC), for detection and spectrometry of alpha particles, internal conversion electrons and minimum ionizing particles (MIPs) envisaging its application to isotopic analysis of heavy elements. The effects of reverse bias voltage on capacitance and leakage current of the diode, as well as on its energy resolution, were also studied at room temperature. In spite of having a thick (650 nm) frontal layer of SiO2, responsible for an important straggling in the energy of the incident heavy charged particles, the results demonstrate that the diode under investigation has good performance for alpha spectrometry (FWHM=18.8 keV for 5.486 MeV alpha particles from 241Am), comparable to those obtained with ordinary surface barrier detectors. Furthermore, internal conversion electrons with energies up to approximately 350 keV could be detected with a reasonable good energy resolution (FWHM=6.6 keV for 320.32 keV electrons from 133Ba).