HIRFL-CSR上等时性质量测量进展

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。

Progress of Isochronous Mass Spectrometry at HIRFL-CSR

In recent years, high-precision mass measurements of short-lived nuclides were conducted using isochronous mass spectrometry (IMS) based on the Cooler Storage Ring at the Heavy Ion Research Facility in Lanzhou (HIRFL-CSR). The new data enable us to discuss some related physical problems in the realm of nuclear structure and astrophysics. In this contribution, details of the measurements and data analysis are described. The IMS with two Time-Of-Flight (TOF) detectors is mainly introduced. In order to improve the mass resolving power while preserving the acceptance of the storage ring, additional velocity information beside the revolution time in the ring is obtained for each of the stored ions by using the double TOF detector system. The IMS with two TOF detectors is a brand new concept, and relevant experimental techniques need to be developed. We have established a simulation platform based on CSRe, developed high-performance TOF detectors and installed them in a straight section of the CSRe, performed online beam testing, developed new ion optics and optimized them, and developed data analysis methods and optimized them. Furthermore, planned technical developments are outlined in this contribution.