摘要
针对高能伽马射线标准源稀缺导致高能区伽马射线探测效率标定困难的问题,本研究基于长寿命核素^(226)Ra及其长期衰变平衡的放射性子体^(214)Pb和^(214)Bi,研制包含高能区伽马射线的标准面源,能量范围可覆盖186~2448 keV。以^(226)Ra溶液制备了密封式平面源,通过改进源盒结构,以降低纵向空间分布对面源准确性的影响。通过计量站标准装置标定各条伽马射线的活度,并对其稳定性和准确性进行检验。连续30 d跟踪测量结果表明,各条伽马射线计数率稳定性均>1.5%,利用该平面源刻度的效率曲线与^(152)Eu标准源刻度结果在2%以内一致,表明所制备的^(226)Ra面源稳定可靠、活度准确。该面源可长期使用,避免了高能伽马射线探测效率标定中制备^(24)Na等短寿命标准源的繁琐过程,可显著提高工作效率。
The calibration of gamma-ray detection efficiency is the basic work of radioactivity measurement.Because of the scarcity of high-energy gamma-ray standard source,it is difficult to calibrate the high-energy gamma-ray detection efficiency.Based on long-lived radionuclide ^(226)Ra and its long-term decay equilibrium radioactive daughter ^(214)Pb and ^(214)Bi,a standard surface source containing high-energy region gamma rays was developed.The energy range can cover 186 keV-2448 keV.The sealed planar source was prepared with ^(226)Ra solution.By improving the structure of the source box,the effect of vertical spatial distribution on the accuracy of the source was significantly reduced.The activity of each gamma ray is calibrated by the standard device of the metering station,its stability and accuracy are tested.The results of tracking measurement for 30 days in succession show that the stability of each gamma ray counting rate is better than 1.5%.The efficiency curve of the calibration of the planar source is consistent with that of the ^(152)Eu standard source within 2%.The results show that the ^(226)Ra surface source is stable,reliable and accurate.The surface source can be used for a long time,avoiding the cumbersome process of preparing ^(24)Na and other short-life standard source in high energy gamma ray detection efficiency calibration.
作者
康泰
李雪松
余功硕
徐江
张小林
郭思琪
席瑞阳
余青江
王春杰
KANG Tai;LI Xuesong;YU Gongshuo;XU Jiang;ZHANG Xiaolin;GUO Siqi;XI Ruiyang;YU Qingjiang;WANG Chunjie(Northwest Institute of Nuclear Technology,Xi’an 710024,China)
出处
《同位素》
2025年第4期382-387,共6页
Journal of Isotopes
