Low-energy protons scanning of intentionally partially damaged silicon MESA radiation detectors

The main aim of this work was to measure the spectroscopic response of intentionally damaged MESA silicon detectors. A uniformly damaged region was created using protons delivered by the Montreal University 6 MV tandem accelerator at different energies and fluences. Only the back half of the detector was damaged. The vacancy density created in the damaged region was built at a level of 7/spl times/10/sup 15/ vacancies/cm/sup 3/. The detector responses were scanned over their whole volume with protons of well defined ranges. Their response characteristics were studied using protons of 9 different energies. The highest energy was selected for allowing the protons to reach precisely the ohmic side (n/sup +/-side) of the 296 /spl mu/m thick detector. The scanning of the detector from the undamaged front side was performed with three different proton energies of ranges within the undamaged region. Two proton energies were selected for probing the transient region extending between the damaged and undamaged regions of the detector. Three energies of protons were chosen to probe the damaged region of the diode. The same set of energies was selected for the study of the detector spectroscopic features while illuminating the detector back side. The measured spectroscopic responses of the irradiated detectors were compared to the response of the undamaged detector. The charge collection efficiency (CCE) in the undamaged, transient and damaged regions of the detector volume was determined.