Development of Diamond Detectors For Alpha Particle Spectroscopy

Abstract

In nuclear fusion reactors, the diagnosis of lost alpha particles gives crucial newlineinformation about the energy balance in fusion reactors. In nuclear fusion reactors, the newlineoperational lifetime of the diagnostic semiconductor detectors is reduced upon newlineexposure to neutrons and gamma rays. Wide bandgap semiconductor such as diamond newlinehas the potential to overcome the radiation limitations of silicon due to its superior newlinephysical properties. Hence, this work is targeted to develop diamond detector newlineprototypes for alpha particle spectroscopy. newlineThe bulk diamond detectors are fabricated on commercially available singlecrystal newlinediamond plates of varying nitrogen and boron concentrations. The material newlinecharacterization of the diamond plates before fabrication are carried out using Raman newlinespectroscopy, photoluminescence spectroscopy and time-resolved photoluminescence newline(TR-PL). After detector fabrication, electrical characterization and ultra-violet current newlineresponse measurements are carried out. The photodetectors showed non-radiative newlinelifetimes in accordance with the Shockley-Read-Hall (SRH) statistics. Based on the newlinecombined UV response and TR-PL measurements it is concluded that the newlineconcentration of the NV and H3 color centers modulate the photo-response of the newlinediamond photodetectors. newlineThe diamond detectors are thereafter packaged in TO8 headers are alpha newlinespectroscopy measurements are carried out. Only one diamond detector out of three newlinedetectors produced alpha spectrum. The alpha spectral characteristics of the detectors newlineare mapped to the electrically active defects in the diamond bulk using Thermally newlinestimulated current (TSC) spectroscopy and zero-bias thermally stimulated current newline(ZB-TSC) spectroscopy. newlineOf all the three diamond detectors, the electronic grade diamond is found to newlinehave contain the least defect density for the dominant high temperature peak. newline