Since the room-temperature detector CdZnTe(CZT) has advantages in terms of detection efficiency,energy resolution, and size, it has been extensively used to detect X-rays and gamma-rays. So far, nuclear radiation dete...Since the room-temperature detector CdZnTe(CZT) has advantages in terms of detection efficiency,energy resolution, and size, it has been extensively used to detect X-rays and gamma-rays. So far, nuclear radiation detectors such as cerium chloride doped with lanthanum bromide(LaBr_3(Ce)), thallium doped with cesium iodide(sI(Tl)), thallium doped with sodium iodide(NaI(Tl)),and high-purity germanium(HPGe) primarily use the spectroscopy-dose rate function(G(E)) to achieve the accurate measurement of air kerma rate(K_a) and ambient dose equivalent rate(H*(10)). However, the spectroscopy-dose rate function has been rarely measured for a CZT detector. In this study, we performed spectrum measurement using a hemispherical CZT detector in a radiation protection standards laboratory. The spectroscopy-dose rate function G(E) of the CZT detector was calculated using the least-squares method combined with the standard dose rate at the measurement position. The results showed that the hemispherical CZT detector could complete the measurement of air kerma rate(K_a) and ambient dose equivalent rate(H*(10)) by using the G(E) function at energies between 48 keV and 1.25 MeV, and the relative intrinsic errors were, respectively, controlled within ± 2. 3 and ± 2. 1%.展开更多
目的了解某市地铁2号线X射线行李包检查系统(以下称为安检系统)放射防护的情况,为加强放射卫生管理工作提供技术支撑及基础资料。方法选取某市地铁2号线,共57台X射线安检系统,在距离其外表面5cm处进行防护检测其关注点的空气比释动能率...目的了解某市地铁2号线X射线行李包检查系统(以下称为安检系统)放射防护的情况,为加强放射卫生管理工作提供技术支撑及基础资料。方法选取某市地铁2号线,共57台X射线安检系统,在距离其外表面5cm处进行防护检测其关注点的空气比释动能率。结果旅客通道、安检工作人员操作处、安检机的左右侧板和顶盖、取包处的检测值均与本底环境值差异无统计学意义(P>0.05)。安检机里面以及行李出入口铅帘处的检测结果高于本底,且差异有统计学意义(P<0.05),其中的行李包入口处在57台安检机中有1台的监测结果超过5μGy/h的限值要求,为6.7μGy/h,且该设备周围的平均空气比释动能率最大,为0.79μGy/h。安检系统里面的辐射量差别较大,不同安检系统或者同型号的安检系统之间都存在差别,最高值为5.4 m Gy/h,均值为0.4 m Gy/h。结论 X射线指示灯亮起时安检机入口和出口可能存在X射线泄漏,但对乘客、安检工作人员的辐射危害影响较小,建议加强地铁安检系统的放射防护管理;在安检机的选购方面也值得关注其性能。展开更多
基金supported by the National Key Scientific Instruments to Develop Dedicated(Nos.2013YQ090811 and 2016YFF0103800)
文摘Since the room-temperature detector CdZnTe(CZT) has advantages in terms of detection efficiency,energy resolution, and size, it has been extensively used to detect X-rays and gamma-rays. So far, nuclear radiation detectors such as cerium chloride doped with lanthanum bromide(LaBr_3(Ce)), thallium doped with cesium iodide(sI(Tl)), thallium doped with sodium iodide(NaI(Tl)),and high-purity germanium(HPGe) primarily use the spectroscopy-dose rate function(G(E)) to achieve the accurate measurement of air kerma rate(K_a) and ambient dose equivalent rate(H*(10)). However, the spectroscopy-dose rate function has been rarely measured for a CZT detector. In this study, we performed spectrum measurement using a hemispherical CZT detector in a radiation protection standards laboratory. The spectroscopy-dose rate function G(E) of the CZT detector was calculated using the least-squares method combined with the standard dose rate at the measurement position. The results showed that the hemispherical CZT detector could complete the measurement of air kerma rate(K_a) and ambient dose equivalent rate(H*(10)) by using the G(E) function at energies between 48 keV and 1.25 MeV, and the relative intrinsic errors were, respectively, controlled within ± 2. 3 and ± 2. 1%.
文摘目的了解某市地铁2号线X射线行李包检查系统(以下称为安检系统)放射防护的情况,为加强放射卫生管理工作提供技术支撑及基础资料。方法选取某市地铁2号线,共57台X射线安检系统,在距离其外表面5cm处进行防护检测其关注点的空气比释动能率。结果旅客通道、安检工作人员操作处、安检机的左右侧板和顶盖、取包处的检测值均与本底环境值差异无统计学意义(P>0.05)。安检机里面以及行李出入口铅帘处的检测结果高于本底,且差异有统计学意义(P<0.05),其中的行李包入口处在57台安检机中有1台的监测结果超过5μGy/h的限值要求,为6.7μGy/h,且该设备周围的平均空气比释动能率最大,为0.79μGy/h。安检系统里面的辐射量差别较大,不同安检系统或者同型号的安检系统之间都存在差别,最高值为5.4 m Gy/h,均值为0.4 m Gy/h。结论 X射线指示灯亮起时安检机入口和出口可能存在X射线泄漏,但对乘客、安检工作人员的辐射危害影响较小,建议加强地铁安检系统的放射防护管理;在安检机的选购方面也值得关注其性能。
