金刚石膜α粒子探测器的电学性能研究

Electrical properties of alpha-particle detectors based on CVD diamond films

从外加偏压、预辐照处理等方面对三明治结构金刚石膜探测器在α粒子辐照下的电学性能进行了研究.电流-电压特性和脉冲高度分布测试和分析表明,金刚石膜探测器在能量为5·5MeV的241Amα粒子辐照一定时间后,其暗电流有所增加.探测器顶电极施加负偏压时,在α粒子辐照下得到的净电流和信噪比均较大.Raman光谱测试表明,造成上述现象的原因很可能是金刚石膜厚度方向的不均匀性分布.负偏压下探测器对α粒子的能量分辨率为25·0%,优于正偏压下的能量分辨率(38·4%).随着α粒子辐照时间的延长,探测器的净电流和电荷收集效率均有明显增加.

The influences of the applied bias voltage and the pre-irradiation treatment by alpha particles on the electrical properties of sandwich structural diamond film detectors under 5.5 MeV ^241 Am alpha-particle irradiation were investigated. Results of currentvoltage（I-V） and pulse height distribution measurements showed that the dark current of the diamond film detector would increase due to the pre-irradiation by alpha particles. Under the alpha irradiation, the detector under negative bias voltage had a higher response current and a better signal-to-noise ratio than that under a positive bias. Raman scattering studies directly demonstrated that the above phenomenon resulted mainly from the different structural imperfection distributions along the thickness direction. An energy resolution of about 25.0% was obtained for the detector under a negative bias voltage and 38.4% under a positive bias voltage. With increasing alpha-particle irradiation time, both the response current and the charge collection efficiency increased obviously.