engleski

Single crystal CVD diamond detectors, spectroscopy and radiation hardness tests

High purity single crystal diamond detectors for spectroscopy, produced by a chemical vapor deposition (CVD) process, became recently commercially available. These detectors show good energy resolution and superior timing properties for charge particle detection due to excellent crystal uniformity. These devices should maintain their characteristics in harsh environments (e.g. high temperatures, elevated radiation, etc.), and therefore could be used in future applications when silicon detector either cannot operate, or their spectroscopic performance deteriorates fast. The ion beam induced charge (IBIC) technique preformed at the ion microprobe is a very suitable tool for studies of the charge collection efficiency (CCE) properties at microscopic level. IBIC can be also used for a radiation hardness testing during and after irradiation process. Inhomogeneities of the CCE spatial distribution in commercial scCVD diamond detector (1 mm^2 area, 500 μm thickness) with novel Ohmic electrical contact have been studied by different ions: 430 keV and 2 MeV protons, as well as 6.5 MeV carbon, having different ionization depth profiles. Non Ionizing Energy Loss (NIEL) concept was used to assess the radiation hardness test obtained by selectively irradiating detector with 6.5 MeV focused carbon beam up to fluencies of 10^11 ions/cm^2. In addition, an energy resolution of 1.4 % was obtained for the 3 MeV proton detection over the whole active area of the pristine scCVD diamond detector. This report is the first systematic IBIC study of MeV heavy ion induced radiation damage in single crystal diamond. Preliminary results do not confirm better radiation hardness of diamond comparing to silicon for detection of short range heavy ions.

single crystal CVD diamond detector; IBIC; CCE; radiation hardness; NIEL concept

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