1993 Fiscal Year Final Research Report Summary
Research for development of a large spectrometer for Quark Gluon Plasma search
| Project/Area Number |
04044031
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Institution | Institute of Physics, University of Tsukuba |
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Principal Investigator |
YAGI Kousuke Institute of Physics, University of Tsukuba, Professor, 物理学系, 教授 (60028107)
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| Co-Investigator(Kenkyū-buntansha) |
NAYAK T Institute of Physics, Columbia University, Assistant, 物理学科, 助手
ZAJC W.A. Institute of Physics, Columbia University, Associate Professor, 物理学科, 助教授
NAGAMIYA S. Institute of Physics, Columbia University, Professor, 物理学科, 教授
富沢 和之 筑波大学, 物理学系, 助手 (50241782)
KURITA Kazuyoshi Institute of Physics, University of Tsukuba, Assistant, 物理学系, 助手 (90234559)
ARAI Ichirou Institute of Physics, University of Tsukuba, Assistant Professor, 物理学系, 講師 (50134440)
MIAKE Yasuo Institute of Physics, University of Tsukuba, Associate Professor, 物理学系, 助教授 (10157422)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Quark Gluon Plasma / Relativistic Heavy Ion Collisions / Large Spectrometer / Particle Identification / High Resolution TOF / Plastic Scintillator / Electromagnetic Calorimeter |
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| Research Abstract |
At very early stage of our Big Bang Universe, it is believed to have existed a hot and highly exited state of matter, called "Quark Gluon Plasma(QGP)". The goal of this research is to design a large spectrometer to detect QGP which is assumed to be recreated in high energy heavy ion collisions. At 100GeV/c per nucleon in collider mode, Au-Au collisions create over 5000 charged particles.
We focused on the hadron channel as signatures of QGP and designed a time of flight(TOF) which is best suited for particle identification in the momentum region between 0.5 and 2.5 GeV/c. To separate pions and kaons well at 5m away from collision point, we need to achieve time resolution less than 100 ps. The shape of the scintillator was determined from the particle density to be a square rod whose width and thickness are about 1 cm and the length is 1-3 m. To accomplish the time resolution(less than 100 ps), we performed the following tests.
*To avoid degradation of rise time of PMT signals through signal cables, we invented a discriminator which is mounted directly on a PMT. We found that rise time was shortened by 30%.
*Selection of scintillator material and shape.
*Position dependence of pulse height and time resolution was measured. We found pulse attenuation length is larger than time resolution degradation length by factor of 2. It means that time resolution of scintillation counter solely depends on photon statistics.
*We constructed 100 array of TOF and obtained time resolution of 55ps. It gave us the basis of the PHENIX TOF construction. Our technique developed in this research opened possibility of utilizing an electromagnetic calorimeter as a particle identification device.
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