Radiation hardness characteristics of Si-PIN radiation detectors

The Korea Atomic Energy Research Institute (KAERI) has fabricated Si-PIN radiation detectors with low leakage current, high resistivity ( > 11 k Omega cm) and low capacitance for high-energy physics and X-ray spectroscopy. Floating-zone (FZ) 6-in. diameter N-type silicon wafers, with (1 I 1) crystal orientation and 675 pm thick, were used in the detector fabrication. The active areas are 3 mm x 3 mm, 5 mm x 5 mm and 10 mm x 10 mm. We used a double deep-diffused structure at the edge of the active area for protection from the surface leakage path. We also compared the electrical performance of the Si-PIN detector with anti-reflective coating (ARC). For a detector with an active area of 3 mm x 3 mm, the leakage current is about 1.9 nA and 7.4 nA at a 100 V reverse bias voltage, and 4.6 pF and 4.4 pF capacitance for the detector with and without an ARC, respectively. In addition, to compare the energy resolution in terms of radiation hardness, we measured the energy spectra with Co-57 and Ba-133 before the irradiation. Using developed preamplifiers (KAERI-PA1) that have ultra-low noise and high sensitivity, and a 3 mm x 3 mm Si-PIN radiation detector, we obtained energy resolutions with 122 keV of Co-57 and 81 keV of Ba-133 of 0.221 keV and 0.261 keV, respectively. After 10, 100, 10(3), 10(4) and 10(5) Gy irradiation, we tested the characteristics of the radiation hardness on the Si-PIN radiation detectors in terms of electrical and energy spectra performance changes. The fabricated Si-PIN radiation detectors are working well under high dose irradiation conditions. (C) 2014 Elsevier B.V. All rights reserved.