1997 Fiscal Year Final Research Report Summary
Developement of Water Cherenkov Detector for the Giant Air Shower Array(Pierre Auger Project)
| Project/Area Number |
08454061
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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 | The University of Tokyo |
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Principal Investigator |
NAGANO Motohiko The University of Tokyo, ICRR,Professor, 宇宙線研究所, 教授 (00013384)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIDA Shigeru The University of Tokyo, ICRR,Assistant, 宇宙線研究所, 助手 (00272518)
HAYASHIDA Naoaki The University of Tokyo, ICRR,Assistant, 宇宙線研究所, 助手 (50114616)
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| Project Period (FY) |
1996 – 1997
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| Keywords | cosmic rays / extremely high energy / water cherenkov / AGASA / Auger Project / lateral distribution / extensive air shower / calibration |
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| Research Abstract |
The Pierre Auger project will construct two large observatories to study cosmic rays with energies in excess of 10^<20>eV.Two detectors will be built of 3000km^2 each in Utah, USA and Mendoza Provence, Argentina. The choice of the surface detector is a water tank of 10 m^2 area and 1.2 m deep. Each array will consist of about 1600 such tanks. In order to study how effectively we can achieve muon-electromagnetic separation, two water tanks were deployed at the Akeno Giant Air Shower Array (AGASA) which is the only operational array in the world. The first tank, installed in fall of 1996 has all surfaces covered with diffuse reflector. The second tank, installed in summer 1997, has diffuse reflector on all surfaceas except the top which is a light absorbing black. The second tank has a much faster response which may permit better muon-electromagnetic separation. The results so far are as follows :
A.Lateral Distribution : Knowledge of the lateral distribution function (1df) of shower particles is crucial in the determination of the shower energy in surface arrays with a wide separation of detectors. Thus we aim to derive an experimental 1df from the tanks at AGASA and compare it to the 1df of the Haverah Park experiment which used very similar detector units. The result is in consistent with the expected density distribution from the Haverah Park experiment.
B.Self Caliburation of the Water Cherenkov Detectors (WCD) : The Auger Observatory plans to deploy 3200 detector stations. It is not practical to have a scintillation counter telescope attached to each station to calibrate the sensitivity of each detector in VEQ.we have demonstrated the abaility to calibrate and monitor a WCD without additional equipment.
C.Comparison of Black-Top and White-Top WDC's : The differences of the white-top and black-top WCD's have been studied for standard muon signals and agree with expectations based on simulation.
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