This work analyzed the gamma ray attenuation effect from the self-absorption and shield attenuation per-spectively. An exact mathematical equation was given for the geometric factor of the cylindrical fissile material...This work analyzed the gamma ray attenuation effect from the self-absorption and shield attenuation per-spectively. An exact mathematical equation was given for the geometric factor of the cylindrical fissile material with dual shields. In addition, several approximation approaches suitable for real situation were discussed, especially in the radial and axial directions of the cylinders, since the G-factors have simple forms. Then the space distribution patterns of the G-factor were analyzed based on numerical result and effective ways to solve the geometric informa-tion of the cylindrical fissile material, the radii and the heights, were deduced. This method was checked and verified by numerical calculation. Because of the efficiency of the method, it is ideal for application in real situations, such as nuclear safeguards, which demands speed of detection and accuracy of geometric analysis.展开更多
High-resolution collinear fast-ion-beam-laser spectroscopy has been applied to investigate the optical isotope shifts for transition 4f^(4)5d^(6)K_(11/2)-(24445)°_(11/2) of NdⅡ.From the measured optical isotope ...High-resolution collinear fast-ion-beam-laser spectroscopy has been applied to investigate the optical isotope shifts for transition 4f^(4)5d^(6)K_(11/2)-(24445)°_(11/2) of NdⅡ.From the measured optical isotope shifts,changes in mean-square nuclear charge radiiδ(r^(2))(fm^(2))among five even-even neodymium isotopes have been deduced:(142,144)0.282,(144,146)0.242,(146,148)0.274,(148,150)0.404.The results are in good agreement with experimental data from electronic x-ray spectroscopy and combined optical and x-ray spectroscopy.展开更多
The single-electron detachment cross sections of Cu^(-) in collision with He have been measured in the range of 10-30keV by a growth rate method. The typical value of the cross section is 7.63×10-16 cm^(2) at an ...The single-electron detachment cross sections of Cu^(-) in collision with He have been measured in the range of 10-30keV by a growth rate method. The typical value of the cross section is 7.63×10-16 cm^(2) at an energy of 20 keV. The experimental uncertainty of the results is about ±8%.展开更多
Atomic spectra of singly ionized neodymium have been measured by collinear fast-ion-beam laser spectroscopy.The resonant spectra in the lines of 568.9,570.8,572.7,and 574.1 nm in NdH were obtained and the optical shif...Atomic spectra of singly ionized neodymium have been measured by collinear fast-ion-beam laser spectroscopy.The resonant spectra in the lines of 568.9,570.8,572.7,and 574.1 nm in NdH were obtained and the optical shifts were determined.We obtained the optical shifts of all the five even isotopes(142-150)in Nd IL The accuracy of our results was improved by one order of magnitude compared with other published results.展开更多
基金This research project is supported by the Institute of Applied Physics and Computational Mathematics of Chinathe Foundation of Wang-Dao Scholar Program of Fudan University.
文摘This work analyzed the gamma ray attenuation effect from the self-absorption and shield attenuation per-spectively. An exact mathematical equation was given for the geometric factor of the cylindrical fissile material with dual shields. In addition, several approximation approaches suitable for real situation were discussed, especially in the radial and axial directions of the cylinders, since the G-factors have simple forms. Then the space distribution patterns of the G-factor were analyzed based on numerical result and effective ways to solve the geometric informa-tion of the cylindrical fissile material, the radii and the heights, were deduced. This method was checked and verified by numerical calculation. Because of the efficiency of the method, it is ideal for application in real situations, such as nuclear safeguards, which demands speed of detection and accuracy of geometric analysis.
基金Supported by the National Climbing Project of Chinathe National Natural Science Foundation of China under Grant No.19774016the Doctoral Research Funds of the State Education Commission of China under Grant No.9424626。
文摘High-resolution collinear fast-ion-beam-laser spectroscopy has been applied to investigate the optical isotope shifts for transition 4f^(4)5d^(6)K_(11/2)-(24445)°_(11/2) of NdⅡ.From the measured optical isotope shifts,changes in mean-square nuclear charge radiiδ(r^(2))(fm^(2))among five even-even neodymium isotopes have been deduced:(142,144)0.282,(144,146)0.242,(146,148)0.274,(148,150)0.404.The results are in good agreement with experimental data from electronic x-ray spectroscopy and combined optical and x-ray spectroscopy.
基金Supported by the National Natural Science Foundation of China under Grant No.19874015。
文摘The single-electron detachment cross sections of Cu^(-) in collision with He have been measured in the range of 10-30keV by a growth rate method. The typical value of the cross section is 7.63×10-16 cm^(2) at an energy of 20 keV. The experimental uncertainty of the results is about ±8%.
基金Supported by the National Natural Science Foundation of China under Grant No.19774016.
文摘Atomic spectra of singly ionized neodymium have been measured by collinear fast-ion-beam laser spectroscopy.The resonant spectra in the lines of 568.9,570.8,572.7,and 574.1 nm in NdH were obtained and the optical shifts were determined.We obtained the optical shifts of all the five even isotopes(142-150)in Nd IL The accuracy of our results was improved by one order of magnitude compared with other published results.
