1990 Fiscal Year Final Research Report Summary
Beam Quality Determination of Ultra High Energy Neutrons
| Project/Area Number |
63480248
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Radiation science
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| Research Institution | University of Tsukuba |
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Principal Investigator |
INADA Tetsuo Univ. of Tsukuba, Inst. Basic Med. Sci., Prof., 基礎医学系, 教授 (50114038)
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| Co-Investigator(Kenkyū-buntansha) |
TADA Junichiro Univ. of Tsukuba, Inst. Basic Med. Sci., Assiatant, 基礎医学系, 助手 (40163464)
HAYAKAWA Yoshinori Univ. of Tsukuba, Inst. Basic Med. Sci., Assiat. Prof., 基礎医学系, 講師 (90101740)
MARUHASHI Akira Univ. of Tsukuba, Inst. Clin. Med. Sci., Assistant, 臨床医学系, 講師 (30114135)
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| Project Period (FY) |
1988 – 1990
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| Keywords | High energy neutrons / Dose distribution / RBE / 50% dose depth / Multicell spheroid / 細胞致死効果 / RBE / スフェロイド細胞 |
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| Research Abstract |
As ultra high energy neutron facility was constructed at PARMS, University of Tsukuba, to produce a neutron beam superior to an X ray beam generated by a modern linac in terms of dose distribution. This has been achieved using the reaction on a thick uranium target struck by 500 MeV proton beam from the booster-synchrotron of High Energy Physics Laboratory. The percent depth dose of this neutron beam is nearly equivalent to that of X-rays at around 20 MV and the dose rate of 15cGy per minute. Relative biological effectiveness of this neutron beam has been estimated on the cell killing effect by the use of HMV-I cell line. Resultant survival curve of cells after the neutron irradiation shows the shoulder with n and Dq of 8 and 2.3 Gy, respectively. RBE value at 10 ^2 survival level for the present neutron, compared with ^<137> Cs gamma -rays is 1.24. The result suggests that the biological effects of high energy neutrons are not practically large enough whenever the depth dose distri bution of neutrons becomes superior to high energy linac X-rays.
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