Ultrafast imaging tools are of great importance for determining the dynamic density distribution in high energy density(HED)matter.In this work,we designed a high energy electron radiography(HEER)system based on a lin...Ultrafast imaging tools are of great importance for determining the dynamic density distribution in high energy density(HED)matter.In this work,we designed a high energy electron radiography(HEER)system based on a linear electron accelerator to evaluate its capability for imaging HED matter.40 MeV electron beams were used to image an aluminum target to study the density resolution and spatial resolution of HEER.The results demonstrate a spatial resolution of tens of micrometers.The interaction of the beams with the target and the beam transport of the transmitted electrons are further simulated with EGS5 and PARMELA codes,with the results showing good agreement with the experimental resolution.Furthermore,the experiment can be improved by adding an aperture at the Fourier plane.展开更多
In noncommutative space, we examine the problem of a noninteracting and harmonically trapped Bose- Einstein condensate, and derive a simple analytic expression for the effect of spatial noncommutatlvity on energy spec...In noncommutative space, we examine the problem of a noninteracting and harmonically trapped Bose- Einstein condensate, and derive a simple analytic expression for the effect of spatial noncommutatlvity on energy spectrum of the condensate, it indicates that the ground-state energy incorporating the spatial noncommutativity is reduced to a lower level, which depends upon the noncommutativity parameter 8. The gap between the noncommutative space and commutative one for the ground-state level of the condensate should be a signal of spatial noncommutativity.展开更多
Traditional plastic scintillator has respectively low gamma energy resolution.Space radiation detection need the plastic scintillator to keep a relatively better energy resolution for gamma.Thus we did experiments to ...Traditional plastic scintillator has respectively low gamma energy resolution.Space radiation detection need the plastic scintillator to keep a relatively better energy resolution for gamma.Thus we did experiments to study how to get it enhanced by adding light guider and chamfer.A 9000 Bq radioactive source 60 Co has been utilized to make the experiment and results came that when keeping other conditions same,the height of poly methyl methacrylate(PMMA)light guider changes from 12 mm to 40 mm and the energy resolutions varied from 72.3%to63.5% respectively.Furthermore,another contrast experiment was made to decide whether plastic scintillator with light guiders or integrated chamfer can get better energy resolution.In conclusion the plastic scintillator with integrated chamfer got 55.0%.Through the study of adding light guider or chamfer to plastic scintillator,the gamma energy resolution has been improved greatly from 72.3%to 55.0%.展开更多
Compared to the rank reduction estimator （RARE） based on second-order statistics （called SOS-RARE）, the RARE employing fourth-order cumulants （referred to as FOC-RARE） is capable of dealing with more sources and...Compared to the rank reduction estimator （RARE） based on second-order statistics （called SOS-RARE）, the RARE employing fourth-order cumulants （referred to as FOC-RARE） is capable of dealing with more sources and mitigating the negative influences of the Gaussian colored noise. However, in the presence of unexpected modeling errors, the resolution behavior of the FOC-RARE also deteriorate significantly as SOS-RARE, even for a known array covariance matrix. For this reason, the angle resolution capability of the FOC-RARE was theoretically analyzed. Firstly, the explicit formula for the mathematical expectation of the FOC-RARE spatial spectrum was derived through the second-order perturbation analysis method. Then, with the assumption that the unexpected modeling errors were drawn from complex circular Gaussian distribution, the theoretical formulas for the angle resolution probability of the FOC-RARE were presented. Numerical experiments validate our analytical results and demonstrate that the FOC-RARE has higher robustness to the unexpected modeling en＇ors than that of the SOS-RARE from the resolution point of view.展开更多
The response functions of a 4π summing BGO detector were established using extensive experimental measurements and GEANT4 simulation. The partial and total efficiencies for all components of the γ-ray interaction wi...The response functions of a 4π summing BGO detector were established using extensive experimental measurements and GEANT4 simulation. The partial and total efficiencies for all components of the γ-ray interaction with the BGO detector were also measured. These response functions and efficiencies will be used in the β-Oslo method experiments to study the neutron capture cross sections of radioactive heavy ions. The application of the response functions of the BGO detector under simulated continuum γ-rays and source measurement γ-rays proves that the method and response functions are reliable.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11435015 and 11505251)the Ministry of Science and Technology of China(Grant No.2016YFE0104900)the Chinese Academy of Sciences(Grant Nos.28Y740010 and 113462KYSB20160036)
文摘Ultrafast imaging tools are of great importance for determining the dynamic density distribution in high energy density(HED)matter.In this work,we designed a high energy electron radiography(HEER)system based on a linear electron accelerator to evaluate its capability for imaging HED matter.40 MeV electron beams were used to image an aluminum target to study the density resolution and spatial resolution of HEER.The results demonstrate a spatial resolution of tens of micrometers.The interaction of the beams with the target and the beam transport of the transmitted electrons are further simulated with EGS5 and PARMELA codes,with the results showing good agreement with the experimental resolution.Furthermore,the experiment can be improved by adding an aperture at the Fourier plane.
基金The project supported in part by National Natural Science Foundation of China under Grant No. 10174086. Luo greatly appreciates Prof. J.Z. Zhang for valuable discussions.
文摘In noncommutative space, we examine the problem of a noninteracting and harmonically trapped Bose- Einstein condensate, and derive a simple analytic expression for the effect of spatial noncommutatlvity on energy spectrum of the condensate, it indicates that the ground-state energy incorporating the spatial noncommutativity is reduced to a lower level, which depends upon the noncommutativity parameter 8. The gap between the noncommutative space and commutative one for the ground-state level of the condensate should be a signal of spatial noncommutativity.
基金supported by the National Natural Science Foundation of China including Research on the Technology of Fast Neutron Location Sensitive Detector Based on GEM and Data Acquisition(No.11575073)the Space Neutron Telescope Detection Technology(No.11775114)
文摘Traditional plastic scintillator has respectively low gamma energy resolution.Space radiation detection need the plastic scintillator to keep a relatively better energy resolution for gamma.Thus we did experiments to study how to get it enhanced by adding light guider and chamfer.A 9000 Bq radioactive source 60 Co has been utilized to make the experiment and results came that when keeping other conditions same,the height of poly methyl methacrylate(PMMA)light guider changes from 12 mm to 40 mm and the energy resolutions varied from 72.3%to63.5% respectively.Furthermore,another contrast experiment was made to decide whether plastic scintillator with light guiders or integrated chamfer can get better energy resolution.In conclusion the plastic scintillator with integrated chamfer got 55.0%.Through the study of adding light guider or chamfer to plastic scintillator,the gamma energy resolution has been improved greatly from 72.3%to 55.0%.
基金Project(61201381)supported by the National Nature Science Foundation of ChinaProject(YP12JJ202057)supported by the Future Development Foundation of Zhengzhou Information Science and Technology College,China
文摘Compared to the rank reduction estimator （RARE） based on second-order statistics （called SOS-RARE）, the RARE employing fourth-order cumulants （referred to as FOC-RARE） is capable of dealing with more sources and mitigating the negative influences of the Gaussian colored noise. However, in the presence of unexpected modeling errors, the resolution behavior of the FOC-RARE also deteriorate significantly as SOS-RARE, even for a known array covariance matrix. For this reason, the angle resolution capability of the FOC-RARE was theoretically analyzed. Firstly, the explicit formula for the mathematical expectation of the FOC-RARE spatial spectrum was derived through the second-order perturbation analysis method. Then, with the assumption that the unexpected modeling errors were drawn from complex circular Gaussian distribution, the theoretical formulas for the angle resolution probability of the FOC-RARE were presented. Numerical experiments validate our analytical results and demonstrate that the FOC-RARE has higher robustness to the unexpected modeling en＇ors than that of the SOS-RARE from the resolution point of view.
基金supported by the National Key Research and Development Program of China(Nos.2016YFA0400502,2018YFA0404404)the National Natural Science Foundation of China(Nos.U1867211,11490563,12005304,12125509,11961141003 and U1332129)。
文摘The response functions of a 4π summing BGO detector were established using extensive experimental measurements and GEANT4 simulation. The partial and total efficiencies for all components of the γ-ray interaction with the BGO detector were also measured. These response functions and efficiencies will be used in the β-Oslo method experiments to study the neutron capture cross sections of radioactive heavy ions. The application of the response functions of the BGO detector under simulated continuum γ-rays and source measurement γ-rays proves that the method and response functions are reliable.
