权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Development of Pestov Time-of-Flight Counter for Quark-Gluon-Plasma Experiment

用于夸克-胶子-等离子体实验的佩斯托夫飞行时间计数器的研制

基本信息

批准号：
10640247
负责人：
MIAKE Yasuo
金额：
$ 2.11万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640247/
关键词：
Pestov Spark Counter Planar Narrow Gap Relativistic Heavy Ion Collisions High Resolution TOF Counters Particle Identification 飛行時間測定器放電

项目摘要

Pestov Spark Counter is expected to provide good timing resolution (<100ps) and good position resolution (<2mm) in an environment of high particle densities such as in ultra-relativistic heavy ion collisions. However, this counter is known to show double structure in timing distributions, which is a serious problem for the particle identification with this counter. Also an aging effect is known to prevent a long term stability of this counter.To understand the nature of this problem, we have developed a cascade simulation code for narrow gap discharge, in which Townsend/Streamer discharge process and UV emission/absorption processes are implemented. It turns out that statistical fluctuation of initial electrons dominates the primary component and its width, while the UV emission/absorption is the main cause of the second component of the timing distributions. It is understood that wider gap reduces the strength of the second component but the timing resolution becomes worse.We have built a prototype counter and observed the aging effect of this counter. Major cause of the effect is found to be due to a polymer layer built on the surface of the cathode. It is chemically formed from the quencher gas for the absorption of UV photons. We have come up with ideas to improve the aging effect, which might improve the double structure of the timing distribution also.

Pestov Spark 计数器有望在高粒子密度环境（例如超相对论重离子碰撞）中提供良好的定时分辨率（<100ps）和良好的位置分辨率（<2mm）。然而，众所周知，该计数器在时间分布上显示出双重结构，这对该计数器的粒子识别来说是一个严重的问题。此外，众所周知，老化效应会阻碍该计数器的长期稳定性。为了了解该问题的本质，我们开发了用于窄间隙放电的级联模拟代码，其中实施了 Townsend/Streamer 放电过程和 UV 发射/吸收过程。事实证明，初始电子的统计涨落主导着主成分及其宽度，而紫外发射/吸收是时序分布的第二成分的主要原因。据了解，较宽的间隙会降低第二个组件的强度，但计时分辨率会变差。我们构建了一个原型计数器并观察了该计数器的老化效果。发现这种效应的主要原因是阴极表面上形成的聚合物层。它是由吸收紫外光子的淬灭气体化学形成的。我们提出了改善老化效果的想法，这也可能改善时序分布的双重结构。