In this paper full-energy peak (photopeak) efficiency and photopeak attenuation coefficient of 3'' × 3'' NaI(Tl) well-type scintillation detector were calculated using gamma-rayisotropic radiating...In this paper full-energy peak (photopeak) efficiency and photopeak attenuation coefficient of 3'' × 3'' NaI(Tl) well-type scintillation detector were calculated using gamma-rayisotropic radiating point sources (with photon energy: 0.245, 0.344, 0.662, 0.779, 0.964, 1.1732, 1.333 and 1.408 MeV) placed outside the detector well. These energies were obtained from <sup>152</sup>Eu, <sup>137</sup>Cs and <sup>60</sup>Co. The relations between the full energy peak efficiency and photopeak attenuation coefficients, were plotted vs. photon energy at different sources to detector distance, and it found that the full energy peak efficiency decreased by increasing the distance between the source and the detector.展开更多
有源效率刻度需要使用多种能量不同的源,并且要求样品源与标准源的测量条件一致,对于一般的实验室,由于实验条件的限制,并不能有效地对探测器进行效率刻度。为了解决此类问题,针对地层元素测井中使用的溴化镧探测器(LaBr3:Ce晶体,ø...有源效率刻度需要使用多种能量不同的源,并且要求样品源与标准源的测量条件一致,对于一般的实验室,由于实验条件的限制,并不能有效地对探测器进行效率刻度。为了解决此类问题,针对地层元素测井中使用的溴化镧探测器(LaBr3:Ce晶体,ø3.18 cm×10.16 cm),首先用蒙特卡罗软件MCNP(Monte Carlo N Particle Transport Code)研究了影响探测效率的因素,主要包括探测器Al壳厚度、MgO反射层厚度、晶体尺寸大小;其次,进行了无源全能峰效率刻度,并与理论计算结果和实测结果进行了对比。结果表明:端面Al壳和MgO反射层厚度的增加都会降低全能峰探测效率,侧面Al壳厚度变化对全能峰探测效率的影响较小;晶体长度、半径的增加会提高全能峰探测效率,且半径的变化对全能峰效率的影响较大。全能峰效率的模拟结果与理论计算结果和实测结果之间的误差分别在7%和6%以内,这表明模拟结果是准确的,为实验室进行无源效率刻度提供了一定的参考。展开更多
In this work we calibrated the NaI(Tl) scintillation detectors (5.08 × 5.08 cm2 and 7.62 × 7.62 cm2) and the Full Energy Peak Efficiency (FEPE) for these detectors have been calculated for point sources plac...In this work we calibrated the NaI(Tl) scintillation detectors (5.08 × 5.08 cm2 and 7.62 × 7.62 cm2) and the Full Energy Peak Efficiency (FEPE) for these detectors have been calculated for point sources placed at different positions on the detector axis using the analytical approach of the effective solid angle ratio. This approach is based on the direct mathematical method reported by Selim and Abbas [1,2] and has been used successfully before to calibrate the cylindrical, parallelepiped, and 4π NaI(Tl) detectors by using point, plane and volumetric sources. In addition, the present method is free of some major inconveniences of the conventional methods.展开更多
文摘In this paper full-energy peak (photopeak) efficiency and photopeak attenuation coefficient of 3'' × 3'' NaI(Tl) well-type scintillation detector were calculated using gamma-rayisotropic radiating point sources (with photon energy: 0.245, 0.344, 0.662, 0.779, 0.964, 1.1732, 1.333 and 1.408 MeV) placed outside the detector well. These energies were obtained from <sup>152</sup>Eu, <sup>137</sup>Cs and <sup>60</sup>Co. The relations between the full energy peak efficiency and photopeak attenuation coefficients, were plotted vs. photon energy at different sources to detector distance, and it found that the full energy peak efficiency decreased by increasing the distance between the source and the detector.
文摘有源效率刻度需要使用多种能量不同的源,并且要求样品源与标准源的测量条件一致,对于一般的实验室,由于实验条件的限制,并不能有效地对探测器进行效率刻度。为了解决此类问题,针对地层元素测井中使用的溴化镧探测器(LaBr3:Ce晶体,ø3.18 cm×10.16 cm),首先用蒙特卡罗软件MCNP(Monte Carlo N Particle Transport Code)研究了影响探测效率的因素,主要包括探测器Al壳厚度、MgO反射层厚度、晶体尺寸大小;其次,进行了无源全能峰效率刻度,并与理论计算结果和实测结果进行了对比。结果表明:端面Al壳和MgO反射层厚度的增加都会降低全能峰探测效率,侧面Al壳厚度变化对全能峰探测效率的影响较小;晶体长度、半径的增加会提高全能峰探测效率,且半径的变化对全能峰效率的影响较大。全能峰效率的模拟结果与理论计算结果和实测结果之间的误差分别在7%和6%以内,这表明模拟结果是准确的,为实验室进行无源效率刻度提供了一定的参考。
文摘In this work we calibrated the NaI(Tl) scintillation detectors (5.08 × 5.08 cm2 and 7.62 × 7.62 cm2) and the Full Energy Peak Efficiency (FEPE) for these detectors have been calculated for point sources placed at different positions on the detector axis using the analytical approach of the effective solid angle ratio. This approach is based on the direct mathematical method reported by Selim and Abbas [1,2] and has been used successfully before to calibrate the cylindrical, parallelepiped, and 4π NaI(Tl) detectors by using point, plane and volumetric sources. In addition, the present method is free of some major inconveniences of the conventional methods.
