核素等时性质量测量实验中一种基于离子速度纯化次级束的方法  

A Method of Purifying the Secondary Beam Based on the Ions Velocities in Isochronous Atomic Mass Measurements

作　　者：刘大委 王猛[1] 徐星[1,2] 颜鑫亮[1] 帅鹏[1,3] 涂小林[1] 张玉虎[1] 陈瑞九 邢元明[1,2] 原有进[1] 杨建成[1] 徐瑚珊[1] 夏佳文[1] 

机构地区：[1]中国科学院近代物理研究所,兰州730000 [2]中国科学院大学,北京100049 [3]中国科学技术大学,合肥230026

出　　处：《原子核物理评论》2016年第3期302-307,共6页Nuclear Physics Review

基　　金：国家自然科学基金资助项目(U1232208;U1432125;11205205);国家重点基础研究发展计划(973计划)资助项目(2013CB-834401);亥姆霍兹-中科院联合研究小组(HCJRG-108)~~

摘　　要：等时性质量谱仪(Isochronous Mass Spectrometry,IMS)是测量短寿命核素质量的有效实验装置。在IMS核素质量测量实验过程中,目标核素通过弹核碎裂反应产生,并被次级束流线分离、传输后注入到储存环内。由于远离稳定线的目标核素产额非常低,经常伴随大量杂质核素产生,这些杂质离子会加重飞行时间探测器(Time of Flight,TOF)系统的工作负担。在HIRFL-CSR利用IMS进行核素质量测量实验过程中,发展了一种进一步纯化筛选次级离子的方法,以减轻TOF系统的工作负担。基于次级离子在束流线中飞行速度的差异性,利用HIRFL-CSR踢轨磁铁(Kicker)系统,调节次级束流注入CSRe的时间,使次级离子得到进一步筛选和纯化后注入到CSRe内。在实验中,我们测试并验证了该方法的可行性,并讨论了它在纯化次级束流方面的作用。The isochronous Mass Spectrometry（IMS） is a powerful experimental instrument for measuring masses of short-lived nuclides. In the IMS, the nuclides of interest are produced via the projectile fragmentation reaction, then injected into the storage ring after the in-flight separation with beam line. The yields of the nuclides of interest are usually very small accompanying a huge amount of contaminant nuclides, aggravating the load of time-of-flight（TOF） detector. In the IMS nuclear mass measurement experiment conducted at the HIRFL-CSR, we developed a method of purifying the secondary beam fragments to ease the burden of the TOF detector, which is based on the differences of the ions′velocities in the beam line and realized by adjusting the injection time of secondary fragments using the Kicker system of the HIRFL-CSR. We tested and verified the method in an online experiment, and its performance is discussed in this paper.

关 键 词：核素质量 速度 注入时间 纯化次级束 

分 类 号：TL67[核科学技术—核技术及应用]