1996 Fiscal Year Final Research Report Summary
Radiation imaging by a micro photomultiplier using micromachining thchnique
| Project/Area Number |
07458099
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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 |
エネルギー学一般・原子力学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
NAKAZAWA Masaharu The University of Tokyo, Dept.of Quantum Eng.and Systems Sci., Professor, 大学院・工学系研究科, 教授 (00010976)
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| Co-Investigator(Kenkyū-buntansha) |
KAWARABAYASHI Jun Nagoya University.Dept.of Nuclear Eng., Research assistant, 工学部, 助手 (80283414)
TAKADA Eiji The University of Tokyo, Dept.of Quantum Eng.and Systems Sci., Research assistan, 大学院・工学系研究科, 助手 (00270885)
TAKAHASHI Hiroyuki The University of Tokyo, Dept.of Quantum Eng.and Systems Sci., Assoc.Professor, 大学院・工学系研究科, 助教授 (70216753)
IGUCHI Tetsuo The University of Tokyo, Dept.of Quantum Eng.and Systems Sci., Assoc.Professor, 大学院・工学系研究科, 助教授 (60134483)
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| Project Period (FY) |
1995 – 1996
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| Keywords | Photomultiplier / Micromachining / Etching / LIGA / Electron Multiplier / Silicon / PMT |
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| Research Abstract |
We have investigated a new position sensitive array type photomultiplier which can be used for a radiation imaging detector operated at very high counting rate such as in SR facilities. This idea is based on miniaturizing a standard photomultiplier tube (PMT). Many miniature holes are formed on the dynode using micromachining technique. These dynode plates are layred with insulators, and bias voltages are applied among plates. Incident electrons to the first dynode plate make secondary electrons on the dynode hole, and these emitted electrons are attracted to the next layred dynode plate. The successive secondary electron emissions occur in each pixel that works like an independent photomultiplier. As to the structure of this dynode hole, two different types of plate dynodes were designed. One had many pyramid shape penetrating holes (100mum*100mum size) which were formed by anisotropic Si etching, and the other had many slanting holes (100mum*80mum size) which were molded by a LIGA like process. Calculated maximum multiplication factors after 12 stages were 10^5 for the pyramid type and 10^7 for the slanting hole type. Both type of dynode plates are fabricated. The electron multiplication factor per one dynode was measured using two dynode plates of each hole configuration. It was 1.62 at the bias voltage of 150V in pyramid hole type, and 2.14 at 400V in slanting hole type. These values agreed with 1.7 (pyramid) and 2.19 (slanting) obtained by Monte Carlo simulation. In order to study the feasibility of a multi-layred device, four pyramid dynodes are stacked in one device. Unfortunately, a charge-up effect was found for the silicon multilayred device which extremely lowers the multiplication facotor. Although this effect must be investigated and overcome, we ensured the feasibility of multilayred devices.
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Research Products
(2 results)
