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LaBr_3:Ce(5%)闪烁探测器的MC研究 总被引:1,自引:0,他引:1
近年来一种采用LaBr3:Ce晶体的闪烁探测器被研发出来,这种新型探测器比NaI(Tl)探测器具有更高的能量分辨率,在662 keV大约为3%。利用蒙特卡罗通用程序MCNP4C分别模拟计算了LaBr3:Ce晶体和NaI(Tl)晶体的γ能谱,模拟能谱与相应的实验测量能谱符合很好。研究还发现晶体尺寸大小对能量分辨率没有影响,能量分辨率不随晶体体积的增加而提高。同样晶体尺寸下通过模拟探测不同入射能量γ射线的峰总比R(E)计算值与NaI(Tl)晶体的模拟值和实验值比较发现,LaBr3:Ce晶体对中高能量γ射线的探测效率较高,而在较低能量时探测效率低于NaI(Tl)晶体。 相似文献
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大体积NaI(Tl)探测器性能研究 总被引:1,自引:0,他引:1
利用蒙特卡洛方法,对不同体积NaI(Tl)探测器的探测效率进行了计算.对圣戈班(Saint-Gobain)5"×8"NaI(Tl)探测器的能量分辨及时间响应进行了测试.在14 MeV氘-氚中子源照射条件下,测量模拟样(化学式:HCNO)的特征瞬发伽马谱,与国产φ"×4"NaI(Tl)探测器进行了比较.结果表明,圣戈班的... 相似文献
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介绍了利用~(133)Ba点源的γ能峰(与~(131)I的γ能量相近)通过面积加权法对NaI(Tl)探测器模拟刻度碘盒中的~(131)I探测效率的原理和方法.其模拟刻度结果与标准刻度方法效率(~(133)Ba和~(131)I碘盒标准源刻度探测效率)进行了比较,其相对误差分别为7.15%和1.34%.研究表明,~(133)Ba点源面积加权法刻度NaI(Tl)探测器对碘盒中的~(131)I探测效率是一种简便而可靠的方法. 相似文献
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用蒙特卡罗方法对NaI(Tl)野外γ谱仪刻度进行模拟,计算谱仪的响应系数.通过与实验的比较,研究利用蒙特卡罗方法对NaI(Tl)野外γ谱仪进行刻度的可行性.结果表明,当模拟探测器对137Cs的能量分辨率从8%~14%变化时,模拟结果与实验结果的差别在12%以内. 相似文献
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本文利用光子和电子耦合输运MC程序的电子脉冲计数类型的能峰展宽模拟计算了NaI(T1)探测器的γ能谱,与实验测量的能谱符合较好.然后利用MCNP计算了NaI(T1)对不同能量γ射线的探测效率(峰总比),结果与实验值一致,验证了这种计算方法用于模拟NaI(T1)对γ能谱的探测效率是可行的. 相似文献
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通过蒙特卡罗程序MCNP(Monte Carlo N Particle Transport Code)建立了海洋γ谱连续监测的测量模型,模拟计算不同能量γ射线在海水中的衰减情况和有效探测距离。根据我国近岸海域海水中天然放射性核素活性浓度,模拟得到不同晶体尺寸NaI探测器连续监测的本底谱,分析能量分辨率对全能峰本底计数率的影响并探讨了影响NaI探测器能量分辨率的因素。最后针对我国核电厂周围海域中重点关注的人工放射性核素,并假设不同尺寸NaI晶体在能量662 keV处分辨率保持7.0%不变的条件下,分别计算了不同尺寸NaI晶体探测器在海洋γ谱连续监测中的探测效率、本底计数率和最小可探测活性浓度等技术参数。模拟结果为海洋或其它水体中γ谱连续监测方法的应用提供技术参考。 相似文献
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利用Geant4数值计算程序,对放射源137Cs和60Co发射的单能γ射线(0.662 MeV和1.331MeV)经过井型NaI(Tl)晶体探测器后的能谱进行了蒙特卡罗模拟,并通过改变放射源在井型NaI(Tl)晶体中的位置对探测效率的影响做了进一步的研究。计算结果表明:对比常用的圆柱形NaI(Tl)闪烁探测器,由于井型NaI(Tl)晶体对放射源所张立体角很大,所以其对γ射线的源峰探测效率更高,并随着放射源在井内高度的增加而逐渐减小;在固定了放射源在晶体井下深度的情况下,放射源位置在水平面内的变化对源峰探测效率的影响并不大。 相似文献
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为研制用于海洋放射性监测(特别是核电海域)的海水中就地γ能谱仪,利用Monte Carlo程序MCNP,采用分层抽样、结果加权叠加的方法,模拟了海水中NaI(Tl)、HPGe、CdZnTe、LaBr等探测器在理想状况下对几种有关γ射线的能谱,并分析计算出以上各探测器对海水中137Cs6、0Co5、4Mn4、0K等放射性核素的探测效率、有效探测距离。结果表明,各探测器对γ放射性核素的有效探测距离约为20~40cm,具体数值与探测器种类和γ射线能量有关。综合探测效率和能量分辨率而言,LaBr探测器具有最好的实际应用价值。该结果为实际的海水中就地γ能谱仪的探测器选择和应用提供了重要参考。 相似文献
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《Journal of Nuclear Science and Technology》2013,50(11):1032-1037
In order to simulate the low-energy tail in the response function of a Schottky CdTe detector, which is a high-resolution room temperature X- or γ-ray spectrometer, we introduced the effect of a nonuniform electric field within the detector to the response function by a Monte Carlo calculation using the EGS5 code. The simulated response functions were compared with measurements for γ-rays from 109Cd, 241Am, 133Ba, and 57Co sources. The present method successfully reproduced the low-energy tail due to the charge carrier trapping effect, while the conventional model assuming a uniform electric field underestimated the low-energy tail significantly, particularly for higher energy γ-rays. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(8):397-407
Scattered γ-rays were measured with 5-in. diameter by 5-in. long Nal(Tl) scintillator for the purpose of obtaining information on the transmission of 60Co γ-rays incident to polyethylene and iron slabs, and layered combinations thereof. The primary γ-rays were collimated, and the detector was used without collimator. The spectra of scattered γ-rays above 300 keV were quite similar to each other irrespective of material and thickness when the scattering angle and scatterer thickness in mean free path units were normalized. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(4):281-290
A conversion function (G(E) function) was determined to obtain an exposure rate directly from a γ-rays spectrum measured by an in-situ Ge(Li) spectrometer. In order to verify the utility of the G(E) function method, three kinds of detector, namely, a portable Ge(Li) detector, a Nal(Tl) detector and an ionization chamber, were used to measure exposure rate due to environmental γ-rays at the same place, and the measured values of exposure rate were compared with each other. Two exposure rate values were obtained from a γ-ray spectrum measured by the Ge(Li) detector, using two different methods, namely, the G(E) function method and the HASL method. The average of exposure rates obtained by four different methods was 4.15 üR/h, and the deviation was 15% of the average. By applying both the G(E) function method and the HASL method to an environmental γ-ray spectrum, a total exposure rate can be determined directly without information on the distribution of the radionuclides in soil, and individual exposure rates due to 40K, 238U and 232Th series and 137Cs of the known distribution in soil can be also determined. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(6):327-332
Abstract Plutonium samples (3–30 μg) of various isotopic compositions were measured with a high-resolution Ge(Li) detector. The γ-rays counted are the 43.5 keV of 238Pu, the 38.7, 51.6 and 129.3 keV of 239Pu, the 45.2 keV of 240Pu, and the 148.6 keV of 241Pu. To estimate the relative photopeak efficiencies of the γ-rays, an empirical curve was derived from measurements of the three γ-rays of 239Pu adopted as internal standard. Data treatment is described in detail as well as the method of correction to account for the activities of 237U and 241Am inherently accumulating in the plutonium sample. The branching ratios of the γ-rays of plutonium were also evaluated by comparing the γ-ray spectrometric results with mass-spectrometric data. 相似文献
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叙述了γ射线探测器能量响应的标定原理和方法,即利用Compton散射将强60Co源的1.25MeVγ射线转换为0.36~1.02MeV(25°~90°)范围内任意能量的系列单能γ射线;采用辐射屏蔽技术和提高能量分辨率方法对γ射线探测器进行了该能区的能量响应标定;通过MCNP程序对探测器的能量沉积趋势和不同散射角散射γ射线的能量分布进行模拟计算。结果表明:该标定系统信噪比达到了20∶1左右,能量分辨率约为6%,0.66MeV的灵敏度与标准137Cs源直照标定的灵敏度基本一致。 相似文献
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使用~(137)Cs、~(60)Co和~(22)Na三种点射线源,分别探讨了由不同体积闪烁晶体组成的探测器对不同能量γ射线的峰效率、能谱响应及有效中心的影响。实验结果表明:随着闪烁晶体体积的不同,不同能量γ能谱光电峰的峰位及其能量分辨率都发生了变化。还发现探测器有效中心点的位置依赖于闪烁晶体的体积,其峰效率的倒数与探测器有效距离平方成反比。此实验结果可为改善不同体积NaI(Tl)闪烁探测器的能谱响应和高精度测量提供参考。 相似文献
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利用蒙特卡罗方法模拟研究NaI和BGO晶体探测器对不同γ射线的响应。模拟结果表明,BGO晶体的光电峰和第一逃逸峰对计数贡献大,而NaI晶体的逃逸峰贡献大。对于井眼和地层流体分别为油和水砂岩地层,模拟改变NaI和BGO晶体探测器的直径和长度时的非弹性散射γ射线响应能谱,采用不同能窗处理方法对地层流体的分辨能力不同,选取光电峰和第一、第二逃逸峰对应的能量窗时,BGO晶体探测器比NaI晶体探测器测量的C/O(C与O的元素含量比)差值大,但受尺寸的影响不大;采用光电峰对应的能量窗时,BGO晶体探测器测量的C/O差值比NaI的大得多,且随尺寸的增加差值增大;能量道的漂移对C/O值影响较大,而能量分辨率对差值影响相对较小。 相似文献
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PENGTai-Ping YANGHong-Qiong YANGJian-Lun YANGGao-Zhao LILin-Bo SONGXian-Cai 《核技术(英文版)》2005,16(1):40-42
We develop a kind of neutron detector, which consists of a polyethylene thin film and two PIN semiconductors connected face-to-face. The detector is insensitive to γ-rays. Its sensitivity to neutron has been calculated with MCNP program and calibrated by experiments, and the results indicate that the neutron sensitivity of the compensation detector will vary with polyethylene convel‘ter. The compensation PIN detector can be employed to measure pulse neutron in neutron and gamma mixture radiation field. 相似文献