Study on the Development of InSb Radiation Detectors with High Efficicency and High Energy Resolution at Low Operating Temperature

进行了InSb晶体的生长。在上一个财政年度，我们获得了晶体速度为0.47 mm/h的单晶。所用原料为In和Sb，其纯度大于99.9999%。在晶体生长之后，我们将晶体切割成晶片。对于在晶体的顶部、中间和末端的三个晶片，以及商业InSb晶片，检查化学计量。此外，电性能，如电阻率，载流子浓度和霍尔迁移率测量这些晶片作为工作温度的函数。实验结果表明，InSb的电学性质对杂质的敏感性高于化学计量比。用该InSb探测器探测了Ba-133发射的γ射线，观测到81 keV的能量峰和55 keV的逃逸峰。利用EGS 4程序计算了InSb探测器耗尽层厚度变化时55 ~ 81 keV峰值的事例比。根据该模拟，耗尽层的有效厚度被确定为3微米。

Crystal growth of InSb was carried out. In the previous fiscal year, we have got a single crystal with the crystal velocity of 0.47 mm/h. The employed raw materials were In and Sb with their purities greater than 99.9999 %. After the crystal growth, we have cut the crystal into wafers. For the three wafers at the top, middle and end of the crystal were examined for stoichiometry, as well as commercial InSb wafers. Also, electric properties such as resistivity, carrier concentration and Hall mobility were measured for these wafers as a function of operating temperature. From these measurements, the electric properties of InSb were found more sensitive to the impurities than stoichiometry.For the measurements of radiation, undoped InSb detectors with 1 mm diameter were fabricated. With this InSb detector, gamma ray emitted by Ba-133 were detected and the energy peak of 81 keV and its escape peak, 55 keV, were observed. The event ratio of the peaks of 55 keV to 81 keV were calculated by the simulation code EGS4 with changing the thickness of the depletion layer of InSb detector. From this simulation, the effective thickness of the depletion layer was determined as 3 micro-m.