使用单能X射线辐射装置对CdTe探测效率的实验刻度

CdTe探测器对单能平行光子源的绝对测量之前,需要进行效率刻度。利用MCNP5蒙特卡罗模拟程序建立CdTe探测器物理模型,模拟计算了10~260keV能量段能点的本征探测效率,在10~60keV能量段探测效率高于75%。用单能X射线装置和HPGe探测器对CdTe探测器本征探测效率进行了实验刻度。结果表明,在10~100keV能量范围内CdTe探测器的模拟效率与实验效率趋势一致,最大误差不超过5.6%。因为Te元素在27keV和32keV处会产生逃逸峰,导致探测效率在这2个能量处有明显下降趋势。用241Am和133Ba放射源对CdTe探测器进行效率刻度验证,在能量为59.54keV和81keV放射源标定的探测效率与单能X射线辐射装置测量值相符。

Experimental Calibration of CdTe Detection Efficiency Using Single-energy X-ray Radiation Device

Before realizing the absolute measurement of the single-energy parallel photon source, it is necessary to calibrate the efficiency of the CdTe detector. The physical model of the CdTe detector was established by using the MCNP5 Monte Carlo simulation program, the intrinsic detection efficiency of the energy point in the 10~260keV energy range was simulated and calculated, the detection efficiency was higher than 75% in the energy range of 10 ~ 60keV. The intrinsic detection efficiency of the CdTe detector was experimentally calibrated with a single energy X-ray device and a HPGe detector. The results show that the simulated efficiency of the CdTe detector is consistent with the experimental efficiency trend in the energy range of 10 ~ 100keV, and the maximum error does not exceed 5.6%. Because the Te element produces escape peaks at 27keV and 32keV, the detection efficiency has a clear downward trend at these two energies. Efficiency calibration of CdTe detector was carried out with 241Am and 133Ba radioactive sources, and the calibration efficiency of radioactive sources with energies of 59.54keV and 81keV was consistent with the measured value of single energy X-ray radiation device.