1999 Fiscal Year Final Research Report Summary
Development of Pestov Time-of-Flight Counter for Quark-Gluon-Plasma Experiment
| Project/Area Number |
10640247
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
素粒子・核・宇宙線
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| Research Institution | University of Tsukuba |
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Principal Investigator |
MIAKE Yasuo University of Tsukuba, Institute of Physics, Professor, 物理学系, 教授 (10157422)
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| Co-Investigator(Kenkyū-buntansha) |
SATO Susumu University of Tsukuba, Institute of Physics, Assistant Professor, 物理学系, 助手 (70302346)
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| Project Period (FY) |
1998 – 1999
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| Keywords | Pestov Spark Counter / Planar Narrow Gap / Relativistic Heavy Ion Collisions / High Resolution TOF Counters / Particle Identification |
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| Research Abstract |
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.
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