There are a large number of nuclides with unknown mass in heavy neutron-rich region, which urgently need to be measured. We propose to measure the mass of 204Pt and other heavy neutron-rich nuclides by using the isochronous mass spectrometry (IMS) at the research facility HIRFL-CSR. In the IMS experiments, the nuclides of interest are produced by using projectile fragmentation and stored in the storage ring CSRe. The revolution times of the stored ions are measured, from which the nuclear masses are extracted. To obtain high-precision results from the IMS experiments, it is required that several ions are stored in the Experimental Cooling Storage Ring(CSRe) simultaneously to correct for the effect of the magnetic-field instability. However, the production cross sections of the heavy neutron-rich nuclides are very small, so that the number of ions that can be stored in the CSRe is too low to fulfill the requirement. To solve this problem, it is proposed to use a production target with two different thicknesses at different areas. In this way, a sufficiently large number of ions can be produced and stored in the CSRe at the same time without reducing the yield of the target nucleus significantly. The simulations show that it is feasible to measure the masses of heavy neutron-rich nuclides at CSRe. The experimental settings are recommended.

基于兰州重离子研究装置冷却储存环（HIRFL-CSR）发展了等时性质谱术（Isochronous mass spectrometry,IMS）,高精度测量了一批短寿命原子核的质量并研究了核结构和核天体领域的相关物理问题。本文综述了IMS实验的原理和步骤,重点介绍了目前正在发展的双TOF探测器谱仪。利用双TOF质量谱仪在测量离子回旋周期的同时测量了离子的速度,用来修正实验结果,可以在很宽的动量接收度内实现高质量分辨,并消除离子动量分散带来的系统误差。双TOF等时性质谱术是全新的概念,需要针对性开发相关实验技术。我们建立了基于CSRe的模拟平台,研制了高性能TOF探测器并安装在CSRe直线段,进行了在线束流测试,发展了新的束流光学设置并进行优化,开发了实验数据处理方法并在做进一步优化,并对下一步工作进行了展望。