| Project/Area Number |
63044138
|
|---|
| Research Category |
Grant-in-Aid for international Scientific Research
|
| Allocation Type | Single-year Grants |
|---|
| Section | Joint Research |
|---|
| Research Institution | Science and Engineering Research Laboratory, Waseda University |
|---|
Principal Investigator |
DOKE Tadayoshi Professor, Science and Engineering Research Laboratory, Waseda University, 理工学研究所, 教授 (60063369)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
SUZUKI Satoshi Research Associate, CERN, 準研究員
HARUYAMA Tomiyoshi Assistant, National Laboratory of High Energy Physics, 助手 (90181031)
MASUDA Kimiaki Lecturer, Saitama College of Health, 講師 (40173744)
SHIBAMURA Eido Assistant Professor, Saitama College of Health, 助教授 (30100605)
MURAKI Yasushi Assistant Professor, Institute of Solar and Terrestrial Environments, 太陽地球環境研究所, 助教授 (70013430)
MIYAJIMA Mitsuhiro Assistant Professor, National Laboratory of High Energy Physics, 助教授 (50044756)
YOSHIMURA Yoshio Professor, National Laboratory of High Energy Physics, 教授 (50013397)
HIRABAYASHI Hiromi Professor, National Laboratory of High Energy Physics, 教授 (90013383)
KIKUCHI Jun Professor, Science and Engineering Research Laboratory, Waseda University, 理工学研究所, 教授 (50063665)
|
|---|
| Project Period (FY) |
1988 – 1990
|
| Project Status |
Completed (Fiscal Year 1990)
|
| Budget Amount *help |
¥9,000,000 (Direct Cost: ¥9,000,000)
Fiscal Year 1990: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1989: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1988: ¥3,000,000 (Direct Cost: ¥3,000,000)
|
|---|
| Keywords | liquid argon, / TPC, / solar neutrinos, / proton decay, / inverse beta decay process, / Gran Sasso underground laboratory, / attenuation length of electrons, / scintillation light from liquid argon. |
|---|
| Research Abstract |
In 1985, Professor C. Rubbia proposed to construct 3.3 ktons liquid argon time projection chamber (TPC) for detection of proton decays and solar or cosmic neutrinos, which is called the Icarus project, and he asked Waseda group to join to his project. We agreed to technically help his group. In 1988, the three following steps were considered to realize the 3.3 ktons Liq. Ar TPC,
the first step : two small (2 - 3 tons) Liq. Ar TPCs are constructed as test chambers to get the know-how for construction of large size Liq. Ar TPC,
the second step : a 300 tons Liq. Ar TPC is constructed for observation of solar neutrinos at the Gran Sasso underground laboratory,
the third step : the original large size (3.3 ktons) Liq. Ar TPC is constructed for observation of proton decay events and cosmic neutrinos at the Gran Sasso laboratory.
After that, a test chamber for Liq. A TPC, filled with 2 - 3 tons of liquid argon, was constructed and now its test is being made at CERN. Concerning the future plan as
… More
mentioned above, the construction of 300 tons Liq. Ar TPC in the second step is being changed to that of 1 kton Liq. Ar TPC to be used for observation of solar neutrinos in order to increase the detection sensitivity for neutrinos and to reduce the background level and it seems that the third step completely disappeared.
During three years, in spite of such a change in the project, following excellent results were obtained from the fundamental experiments or the test of the 2 - 3 tons Liq. Ar TPC.
1) We found that ultra high purity liquid argon in which the attenuation length of electrons is longer than 1 meter could easily be obtained by using a simple
2) Using the small test chamber, the test of the readout system for signals from the wire electrodes in the TPC was successfully made at CERN.
3) Use of scintillation lights produced by high energy neutrinos as trigger signals was proposed by the Waseda group in place of that of ionization signals induced at the grid electrode which are very slow. Some fundamental tests for this new technique are being made at Waseda University.
4) New techniques for monitoring the purity of liquid argon were developed at both laboratories of CERN and Waseda.
At present, we hope that such new techniques will be used in the construction of 1 kton Liq. Ar TPC for solar neutrino observation which can solve by itself the neutrino oscillation problem. Less
|
