engleski

scCVD Diamond Detector: Spectroscopic Performance and Radiation Hardness Tests

A high purity single crystal diamond detector 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. 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 (1 mm^2 surface area and 500 μm thickness). Inhomogeneities of the CCE spatial distribution in diamond single crystal have been studied by different ions (protons, carbon and silicon) in the energy range (1-15 MeV), having different ionization depth profiles. Non Ionizing Energy Loss (NIEL) concept was used for studies of the induced charge value decrease and the energy resolution deterioration obtained with selectively irradiated detectors with various focused ion beams up to fluences of 1011 ions/cm^2. These results are needed to assess the radiation hardness of diamond for MeV heavy ion detection. In addition, diamond and silicon radiation hardness will be compared on basis of our previously obtained results for silicon particle detectors. Problems associated with the polarization effect in diamond, which is a specific problem of diamond detectors, will be discussed as well.

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

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