Use of a rad-hard silicon diode for photon spectrometry

In this paper we describe the performance of an ion-implanted diode (Al/p
⁺
/n/n
⁺
/Al), developed in the framework of R&D programs for the future CMS experiment at LHC, for detection and spectrometry of X- and gamma-rays envisaging its use in characterization of porous microstructures by X-ray microtomography. The effects of the reverse bias on both the electronic noise and the diode energy resolution were studied using
⁵⁷
Co,
¹³³
Ba and
²⁴¹
Am radioactive sources at room temperature. In the energy range between 30 and 360 keV, it was obtained reasonable good energy resolution (e.g., FWHM = 4.2 keV for 121.6 keV gamma ray from
⁵⁷
Co). In the same energy range, measurements of full-energy peak efficiencies were carried out and compared with the theoretical values. The results have demonstrated that this diode is appropriate for direct detection of low energy electromagnetic radiation.