Technical Improvements in the Experiment of Isochronous Mass Measurement of 58Ni Projectile Fragments
The combination of in-flight fragment separator and the isochronous mass spectrometry(IMS) in storage rings have been proven to be a powerful tool for the precision mass measurements of short-lived exotic nuclei.In IMS, the mass-over-charge ratio is only related to the revolution period of stored ions, and the relative mass resolution can reach up to the order of 10-6.However, the instability of the magnetic field of storage ring deteriorates the resolution of revolution period, making it very difficult to distinguish the ions with very close mass-over-charge ratio via their revolution periods.To improve the resolution of revolution periods, a new method of weighted shift correction (WSC) has been developed to accurately correct the influence of the magnetic field instabilities in the isochronous mass measurements of 58Ni projectile fragments.By using the new method, the influence of unstable magnetic fields can be greatly reduced, and the mass resolution can be improved by a factor up to 1.7.Moreover, for the ions that still cannot be distinguished after correcting the magnetic field instabilities, we developed a new method of pulse height analysis for particle identification.By analyzing the mean pulse amplitude of each ion from the timing detector, the stored ions with close mass-over-charge ratios but different charge states such as 34Ar and 51Co can be identified, and thus the mass of 51Co can be determined.The charge-resolved IMS may be helpful in the future experiments of isochronous mass measurement even for N =Z nuclei.
nuclear mass storage ring isochronous mass spectrometry mass measurement
帅鹏 涂小林 张玉虎 王猛 徐星 颜鑫亮 陈相成
国际会议
The Fifth International Conference on Proton-emitting Nuclei(第五届原子核质子发射国际会议)(PROCON2015)
兰州
英文
173-179
2015-07-06（万方平台首次上网日期，不代表论文的发表时间）