Measurements of the total reaction cross section for^(12-16)C,^(14-17)N and^(16-18)O on carbon target at intermediate energies were performed on RIBLL of HIRFL.A larger enhancement ofσR for^(15)C was observed than th...Measurements of the total reaction cross section for^(12-16)C,^(14-17)N and^(16-18)O on carbon target at intermediate energies were performed on RIBLL of HIRFL.A larger enhancement ofσR for^(15)C was observed than that for its neighbors.The analysis of these data indicates possible existence of an anomalous nuclear structure in^(15)C.A new quantity was suggested as the criterion to distinguish anomalous structure nuclei from normal nuclei.展开更多
Fragments produced in the reaction of 60 MeV/n^(18)O on Be have been measured experimentally.The isotopic distribution of fragmentation reaction is well reproduced by a modified statistical abrasion-ablation model It ...Fragments produced in the reaction of 60 MeV/n^(18)O on Be have been measured experimentally.The isotopic distribution of fragmentation reaction is well reproduced by a modified statistical abrasion-ablation model It is predicted that the isotopic distribution shifts toward the neutron rich side for neutron rich projectile,but this isospin effect decreases with the increase of the atomic number difference Z-Z_(A)and disappears at last,where Z and Z_(A)are atomic numbers of the isotopic distribution and the projectile respectively.展开更多
The experimental measurement of the total interaction cross sections of N,C,B,and Be isotopes on 12C target at medium energies is described.A new formula that gives a good description of the energy-range relationship ...The experimental measurement of the total interaction cross sections of N,C,B,and Be isotopes on 12C target at medium energies is described.A new formula that gives a good description of the energy-range relationship of energetic ions over a wide energy range is presented.The energy calibration of detectors is made by a Monte Carlo simulation method based on this new formula.展开更多
The angular distributions of intermediate mass fragments with charge numbers from 3 to 24 emitted in 30 MeV/u 40Ar+58,64Ni and 115In reactions over an angular range of 5o-140ohave been measured.In different angular re...The angular distributions of intermediate mass fragments with charge numbers from 3 to 24 emitted in 30 MeV/u 40Ar+58,64Ni and 115In reactions over an angular range of 5o-140ohave been measured.In different angular region an exponential distribution function dσ/dΩ=N exp(-θ/α)was used to fit the measured angular distributions.The decay factor a which can be connected with the interaction time T and the factor N which is related to the intensity of the emission sources have been extracted.The relationship ofα(Z)and N(Z)with Z for different reaction systems and different angular regions has been discussed.The different behavior of dσ/dΩ,α(Z),and N(Z)for the three studied reaction systems exists mainly in the middle and backward angular regions.The dependencies of angular distributions on isospin and the size of reaction systems have also been discussed.展开更多
Two low-lying isomeric states in 169Ta have been identified via ^(159)Tb(l6O,6nγ)^(169)Ta reaction.Their half-lives are measured to be 28±5ns for the 9/2^(-)level and 17±4 ns for the 5/2^(-)level by using t...Two low-lying isomeric states in 169Ta have been identified via ^(159)Tb(l6O,6nγ)^(169)Ta reaction.Their half-lives are measured to be 28±5ns for the 9/2^(-)level and 17±4 ns for the 5/2^(-)level by using the delayedγ-γcoincidence method.These two isomeric states are considered to be the bandheads with 9/2-[514]and 1/2-[541]configurations,respectively.Possible neutron quasiparticle configuration for the ground state of ^(169)W is discussed.展开更多
文摘HADAR(High Altitude Detection of Astronomical Radiation)是一个基于大气切伦科夫成像技术的地面望远镜阵列,其采用大口径折射式水透镜系统来收集大气切伦科夫光,以实现对10 GeV—10 TeV能量段的伽马射线和宇宙线的探测.HADAR具有低阈能和大视场的优势,因此可以对天区进行连续扫描和观测,在观测活动星系核(Active Galactic Nuclei,AGN)等银河系外伽马射线源方面具有明显优势.本文研究了HADAR实验对AGN的探测能力.基于费米望远镜(Fermi Large Area Telescope,Fermi-LAT)的AGN源能谱信息,将观测能量外推至甚高能能段,同时加入河外背景光的吸收效应,以计算HADAR对AGN源观测的统计显著性.研究结果显示,HADAR运行一年时间,预计将有31个Fermi-LAT AGN源以高于5倍显著性被观测到,其中大部分为蝎虎状天体类型.
基金Supported by the National Natural Science Foundation of China for Distinguished Young Scholar under Grand No.19625513National Natural Science Foundation of China under Grant No.19675059+1 种基金Shanghai Science,Technology Development Fund under Grant No.96XD14011Major State Basic Research Development Program(G200077400).
文摘Measurements of the total reaction cross section for^(12-16)C,^(14-17)N and^(16-18)O on carbon target at intermediate energies were performed on RIBLL of HIRFL.A larger enhancement ofσR for^(15)C was observed than that for its neighbors.The analysis of these data indicates possible existence of an anomalous nuclear structure in^(15)C.A new quantity was suggested as the criterion to distinguish anomalous structure nuclei from normal nuclei.
基金Supported by the National Natural Science Foundation of China for Distinguished Young Scholar under Grand No.19625513National Natural Science Foundation of China under Grant No.19675059Shanghai Science and Technology Development Fund under Grant No.96XD14011.
文摘Fragments produced in the reaction of 60 MeV/n^(18)O on Be have been measured experimentally.The isotopic distribution of fragmentation reaction is well reproduced by a modified statistical abrasion-ablation model It is predicted that the isotopic distribution shifts toward the neutron rich side for neutron rich projectile,but this isospin effect decreases with the increase of the atomic number difference Z-Z_(A)and disappears at last,where Z and Z_(A)are atomic numbers of the isotopic distribution and the projectile respectively.
基金Supported by the National Science Foundation of China for Distinguished Young Scholar under Grand No.19625513.
文摘The experimental measurement of the total interaction cross sections of N,C,B,and Be isotopes on 12C target at medium energies is described.A new formula that gives a good description of the energy-range relationship of energetic ions over a wide energy range is presented.The energy calibration of detectors is made by a Monte Carlo simulation method based on this new formula.
基金Supported by the National Natural Science Foundation of China under Grant No.19235012the Foundation of Chinese Academy of Sciences。
文摘The angular distributions of intermediate mass fragments with charge numbers from 3 to 24 emitted in 30 MeV/u 40Ar+58,64Ni and 115In reactions over an angular range of 5o-140ohave been measured.In different angular region an exponential distribution function dσ/dΩ=N exp(-θ/α)was used to fit the measured angular distributions.The decay factor a which can be connected with the interaction time T and the factor N which is related to the intensity of the emission sources have been extracted.The relationship ofα(Z)and N(Z)with Z for different reaction systems and different angular regions has been discussed.The different behavior of dσ/dΩ,α(Z),and N(Z)for the three studied reaction systems exists mainly in the middle and backward angular regions.The dependencies of angular distributions on isospin and the size of reaction systems have also been discussed.
基金Supported by the State Education Committee of Chinathe National Natural Science Foundation of China under Grant No.19605008.
文摘Two low-lying isomeric states in 169Ta have been identified via ^(159)Tb(l6O,6nγ)^(169)Ta reaction.Their half-lives are measured to be 28±5ns for the 9/2^(-)level and 17±4 ns for the 5/2^(-)level by using the delayedγ-γcoincidence method.These two isomeric states are considered to be the bandheads with 9/2-[514]and 1/2-[541]configurations,respectively.Possible neutron quasiparticle configuration for the ground state of ^(169)W is discussed.
