1999 Fiscal Year Final Research Report Summary
Study of High Energy Cosmic Particles in Tibet
| Project/Area Number |
10044063
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (A).
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
素粒子・核・宇宙線
|
|---|
| Research Institution | The University of Tokyo |
|---|
Principal Investigator |
YUDA Toshinori ICRR, Univ. of Tokyo, Prof., 宇宙線研究所, 教授 (60092368)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
MIZUTANI Kohei Fac. of Sci., Saitama Univ., Prof., 理学部, 教授 (60008844)
HOTTA Naoki Fac. of Ed. Utsunomiya Univ., Assoc. Prof., 教育学部, 助教授 (60157039)
OHNISHI Munehiro ICRR, Univ. of Tokyo, Ass., 宇宙線研究所, 助手 (10260514)
TORII shoji Fac. of Eng. Kanagawa Univ., Assoc. Prof., 工学部, 助教授 (90167536)
SAITO Toshiharu Tokyo Metr. College, Assoc. Prof., 助教授 (40259833)
|
|---|
| Project Period (FY) |
1998 – 1999
|
| Keywords | Tibet / Yangbajing / Air shower array / Gamma-ray point source / Burst detector / Primary proton component / Crab Nebulad / Mrk501 |
|---|
| Research Abstract |
Since 1995, an air shower array (Tibet-II) has been operating at Yangbajing (4,300m above sea level) in Tibet to search for 10 TeV gamma-ray point sources, as well as to study the primary cosmic rays at high energies. In 1996, a high density air shower array whose detectors are placed on a 7.5 m grid was also set up inside the Tibet-II to detect shower events with energy above 3 TeV. With the advent of this high density air shower array, a signal from the Crab Nebula has been detected for the first time with a conventional air shower array. Furthermore, we also succeeded to detect signals from the nearby AGN Mrk501 which was in a very high state in 1997.
A hybrid experiment of air shower array and core detector (consisting of emulsion chambers and burst detector) was done during the period from 1996 summer through 199g summer. The total area of the core detector is 80 m2. Observation of a bundle of high energy particles contained in the air shower provides a direct information about the proton component in the primary particles. Applying an artificial neural network method to the data set obtained from the burst detectors, we obtained the energy spectrum of protons between 200 TeV and 1000 TeV.
In the fall of 1999, we constructed a new air shower array consisting of 545 detectors which are placed on a 7.5 m square grid. The effective area covering the detector array is about 22,000 m2. The threshold energy of showers is about 3 TeV and the trigger rate is about 700 Hz. The array has been operated since the middle of November 1999.
|
Research Products
(8 results)
