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Identification of isotopes of 1 Ge V/n heavy ions using liquid argon calorimeters

使用液氩量热仪鉴定 1 Ge V/n 重离子同位素

基本信息

批准号：
09554013
负责人：
MASUDA Kimiaki
金额：
$ 6.85万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09554013/
关键词：
Particle detector Rare gas liquids Energy loss Heavy ion calorimeter Isotope identification 光電離

项目摘要

This research project aims to study the performance of liquid argon calorimeter with photoionization process in order to investigate the energy resolution and isotopes identification for high energy heavy ions.We have measured responses of an allene-doped liquid argon calorimeter to heavy ions from HIMAC of NIRS, Japan. Electrodes of the calorimeter are made of thin G10 plates which are mechanically precise and form multi-parallel-plate ionization chambers. For measurement of position of incident ions and study of the effect of multiple scattering, two sets of strip electrodes are inserted to the electrode system. These give information of track of the particles.Accelerator beams were 500〜650 MeV/n Ne, Ar and Fe ions and the beam intensity was 100〜200 counts per spill. In ionization chambers, induced charge signals are affected by space charge of positive ions. In general, the time structure of beam spills at HIMAC is not uniform. We used beams of more uniform structure and minimized the effect of space charge.By adding allene, recombination of electron-ion pairs decreased and signal size increased. This led the improvement of energy resolution, but the resolution was still worse than that expected from calculation. This is the same if a specific scattering angle is selected.This means that the scattering is not a main cause of degradation of resolution. This fact suggests that one must consider another effect such as density fluctuation of liquid. A scatter plot of signals of stopping cell and those of the preceding cell shows a clear separation of element but the isotope separation is critical. Further analysis will be done.

本研究旨在研究光电离过程的液氩量热计的性能，以研究高能重离子的能量分辨率和同位素鉴别，我们测量了日本NIRS HIMAC的一个Allene掺杂液氩量热计对重离子的响应。量热计的电极由薄的G10板制成，这些板具有机械精度并形成多个平行板电离室。为了测量入射离子的位置和研究多次散射的影响，在电极系统中插入两组条形电极。加速器束流为500 ~ 650 MeV/nNe、Ar和Fe离子，束流强度为100 ~ 200计数/次溢出。在电离室中，感生电荷信号受正离子空间电荷的影响。在一般情况下，在HIMAC的束流溢出的时间结构是不均匀的。我们使用了结构更均匀的电子束，并将空间电荷的影响降到最低。通过加入丙二烯，电子-离子对的复合减少，信号尺寸增加。这导致能量分辨率的提高，但分辨率仍然比从计算预期的差。如果选择了特定的散射角，这也是一样的。这意味着散射不是分辨率下降的主要原因。这一事实表明，必须考虑另一种效应，如液体的密度波动。停止细胞的信号和前一细胞的信号的散点图显示了元素的明显分离，但同位素分离是关键的。将进行进一步分析。