在核工业的一些工作场所中往往同时存在β射线和γ射线,准确测量β粒子和γ粒子能谱对于相关工作人员的辐射防护十分重要。本文利用Geant4模拟了β粒子和γ粒子在叠层闪烁体探测器中的能量沉积,研究了材料和结构对叠层闪烁体探测器甄别...在核工业的一些工作场所中往往同时存在β射线和γ射线,准确测量β粒子和γ粒子能谱对于相关工作人员的辐射防护十分重要。本文利用Geant4模拟了β粒子和γ粒子在叠层闪烁体探测器中的能量沉积,研究了材料和结构对叠层闪烁体探测器甄别性能的影响。模拟结果显示,对于双层结构的闪烁体探测器,第1层和第2层选用不同材料的闪烁体对β粒子的甄别影响不大,主要影响对γ粒子的甄别。γ粒子的误甄别率和识别率分别随第1层和第2层材料原子序数的增加而增加。3层结构闪烁体探测器对于γ粒子的误甄别率明显低于双层结构,并且γ粒子的误甄别率随第1层闪烁体厚度的增加而增加。经过对模拟结果分析,采用0.2 mm BC-444+17.8 mm BC-444+25 mm BaF_(2)的3层闪烁体结构甄别性能较好,对β粒子和γ粒子的平均识别率和误甄别率分别为96.7%、41.1%和<0.001%、0.16%。展开更多
In this study, the activation cross-sections were measured for ^(232)Th(n,2n)^(231)Th reactions at neutron energies of 14.1 and 14.8 MeV, which were produced by a neutron generator through a T(d,n)~4He reaction. Induc...In this study, the activation cross-sections were measured for ^(232)Th(n,2n)^(231)Th reactions at neutron energies of 14.1 and 14.8 MeV, which were produced by a neutron generator through a T(d,n)~4He reaction. Induced gamma-ray activities were measured using a low background gamma ray spectrometer equipped with a high resolution HPGe detector. In the cross-section calculations, corrections were made regarding the effects of gamma-ray attenuation, dead-time, fluctuation of the neutron flux, and low energy neutrons. The measured cross-sections were compared with the literature data, evaluation data(ENDF-B/VII.1, JENDL-4.0 and CENDL-3.1), and the results of the model calculation(TALYS1.6).展开更多
利用中子活化法,精确地测量了14 Me V能区中子诱发的232Th(n,f)138Xe裂变截面.在测量中用27Al(n,α)24Na反应出射的α射线监督中子通量,中子的能量由90Zr(n,2n)89Zr反应与93Nb(n,2n)92mNb反应的截面之比给出.在中子能量为14.1±0.3...利用中子活化法,精确地测量了14 Me V能区中子诱发的232Th(n,f)138Xe裂变截面.在测量中用27Al(n,α)24Na反应出射的α射线监督中子通量,中子的能量由90Zr(n,2n)89Zr反应与93Nb(n,2n)92mNb反应的截面之比给出.在中子能量为14.1±0.3和14.7±0.3 Me V下,其裂变截面分别为12.72±1.24和11.82±1.13 mb.展开更多
In order to understand the dnve-in target in a D-D type neutron generator,it is essential to study the mechanism of the interaction between hydrogen ion beams and the hydrogenabsorbing metal film.The present research ...In order to understand the dnve-in target in a D-D type neutron generator,it is essential to study the mechanism of the interaction between hydrogen ion beams and the hydrogenabsorbing metal film.The present research concerns the nucleation of hydride within zirconium film implanted with hydrogen ions.Doses of 30 keV hydrogen ions ranging from 4.30×10^（17） to1.43×10^（18） ions cm^（-2） were loaded into the zirconium film through the ion beam implantation technique.Features of the surface morphology and transformation of phase structures were investigated with scanning electron microscopy,atomic force microscopy and x-ray diffraction.Confirmation of the formation of 5 phase zirconium hydride in the implanted samples was first made by x-ray diffraction,and the different stages in the gradual nucleation and growth of zirconium hydride were then observed by atomic force microscope and scanning electron microscopy.展开更多
The D（d,p）T reaction in Be metal environments has been measured to investigate the electron screening effect in metals in an energy region of from 5.5 keV to 10 keV in a center of mass system （CMS） at a temperatur...The D（d,p）T reaction in Be metal environments has been measured to investigate the electron screening effect in metals in an energy region of from 5.5 keV to 10 keV in a center of mass system （CMS） at a temperature of 121 K. The depth distribution of deuteron density in Be metals has an impact on the observed reaction yields. A model of deuteron density distribution in metal has been proposed to obtain the original yields. A screening energy of （116±46） eV has been obtained with the assumed deuteron density distribution model.展开更多
文摘在核工业的一些工作场所中往往同时存在β射线和γ射线,准确测量β粒子和γ粒子能谱对于相关工作人员的辐射防护十分重要。本文利用Geant4模拟了β粒子和γ粒子在叠层闪烁体探测器中的能量沉积,研究了材料和结构对叠层闪烁体探测器甄别性能的影响。模拟结果显示,对于双层结构的闪烁体探测器,第1层和第2层选用不同材料的闪烁体对β粒子的甄别影响不大,主要影响对γ粒子的甄别。γ粒子的误甄别率和识别率分别随第1层和第2层材料原子序数的增加而增加。3层结构闪烁体探测器对于γ粒子的误甄别率明显低于双层结构,并且γ粒子的误甄别率随第1层闪烁体厚度的增加而增加。经过对模拟结果分析,采用0.2 mm BC-444+17.8 mm BC-444+25 mm BaF_(2)的3层闪烁体结构甄别性能较好,对β粒子和γ粒子的平均识别率和误甄别率分别为96.7%、41.1%和<0.001%、0.16%。
基金Supported by National Natural Science Foundation of China(No.11205076)
文摘In this study, the activation cross-sections were measured for ^(232)Th(n,2n)^(231)Th reactions at neutron energies of 14.1 and 14.8 MeV, which were produced by a neutron generator through a T(d,n)~4He reaction. Induced gamma-ray activities were measured using a low background gamma ray spectrometer equipped with a high resolution HPGe detector. In the cross-section calculations, corrections were made regarding the effects of gamma-ray attenuation, dead-time, fluctuation of the neutron flux, and low energy neutrons. The measured cross-sections were compared with the literature data, evaluation data(ENDF-B/VII.1, JENDL-4.0 and CENDL-3.1), and the results of the model calculation(TALYS1.6).
文摘利用中子活化法,精确地测量了14 Me V能区中子诱发的232Th(n,f)138Xe裂变截面.在测量中用27Al(n,α)24Na反应出射的α射线监督中子通量,中子的能量由90Zr(n,2n)89Zr反应与93Nb(n,2n)92mNb反应的截面之比给出.在中子能量为14.1±0.3和14.7±0.3 Me V下,其裂变截面分别为12.72±1.24和11.82±1.13 mb.
基金Financial support from National Natural Science Foundation of China(nos 11205136 and 11505145)the Research Fund for Doctoral Program of Southwest University of Science and Technology(no.l4zx7166)
文摘In order to understand the dnve-in target in a D-D type neutron generator,it is essential to study the mechanism of the interaction between hydrogen ion beams and the hydrogenabsorbing metal film.The present research concerns the nucleation of hydride within zirconium film implanted with hydrogen ions.Doses of 30 keV hydrogen ions ranging from 4.30×10^（17） to1.43×10^（18） ions cm^（-2） were loaded into the zirconium film through the ion beam implantation technique.Features of the surface morphology and transformation of phase structures were investigated with scanning electron microscopy,atomic force microscopy and x-ray diffraction.Confirmation of the formation of 5 phase zirconium hydride in the implanted samples was first made by x-ray diffraction,and the different stages in the gradual nucleation and growth of zirconium hydride were then observed by atomic force microscope and scanning electron microscopy.
基金Supported by National Natural Science Foundation of China (10675056)
文摘The D（d,p）T reaction in Be metal environments has been measured to investigate the electron screening effect in metals in an energy region of from 5.5 keV to 10 keV in a center of mass system （CMS） at a temperature of 121 K. The depth distribution of deuteron density in Be metals has an impact on the observed reaction yields. A model of deuteron density distribution in metal has been proposed to obtain the original yields. A screening energy of （116±46） eV has been obtained with the assumed deuteron density distribution model.
