2003 Fiscal Year Final Research Report Summary
R&D on detector components for rare K+ decay experiment in high intensity beam environment
| Project/Area Number |
12440070
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | High Energy Accelerator Research Organization (KEK) |
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Principal Investigator |
SUGIMOTO Shojiro KEK, Institute of Particle and Nuclear Studies(IPNS), Professor, 素粒子原子核研究所, 教授 (20044753)
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| Co-Investigator(Kenkyū-buntansha) |
NOMURA Tadashi Kyoto University, Graduate School of Science, Research Associate, 大学院・理学研究所, 助手 (10283582)
KOMATSUBARA Takeshi IPNS, associate Professor, 素粒子原子核研究所, 助教授 (30242168)
KOBAYASHI Masaaki IPNS, Professor, 素粒子原子核研究所, 教授 (40013388)
TAMAGAWA Yoichi Fukui University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (40236732)
NOMACHI Masaharu Osaka University, Graduate School of Science, Professor, 大学院・理学研究所, 教授 (90208299)
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| Project Period (FY) |
2000 – 2003
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| Keywords | K meson / rare decay / high intensity beam / Cherenkov counter / Silicon-strip detector |
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| Research Abstract |
We have developed new detector components for rare K+ decay experiment to cope with high beam background environment:
1)A new programmable trigger board and digital mean-timer modules using complex programmable logic device have been introduced to the trigger system of the BNL-E949 experiment. The online dead time was reduced from 4.0% to 1.7% by introducing an on-chip prescaler to the programmable trigger board. The acceptance loss of the online photon veto was reduced from 4.9% to 1.8% by introducing the mean-timer modules.
2)We have developed a new heavy (XO=0.89cm) and radiation-hard (10**8 rad) Cherenkov radiators based on lead tungstate PbWO4 (PWO). We have found that doping PWO with trivalent rare-earth ions (La3+,Gd3+,Y3+,etc.) improves the characteristics of PWO dramatically including the transmittance, radiation-hardness and mechanical quality. In the course of studying the effects of trivalent ions, it has been found that heavy doping of these ions quenches the scintillation, thereby creating a new Cherenkov radiator by keeping good transmittance, excellent radiation-hardness, etc.
3)We have developed a new monitoring system based on blue LED's. The system was introduced, to the E949 experiment, and enabled us to observe a variation within the beam spill. The kinetic-energy resolution of pi(+) in Kpi2 decay was improved from sigma=3.246MeV to sigma= 3.042MeV by using information of the new monitoring system.
4)We have developed a single-sided silicon strip detector with a sensitive area of 92 x 92 mm**2 as a real-time, fast and medium-segmented hodoscope for rare kaon decay experiments in high beam background environment. The Equivalent Noise Charge(ENC, 1 sigma) at the preamplifier input was ~1600e (6% of the signal for single minimum ionizing particle ~27000e).
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