| Co-Investigator(Kenkyū-buntansha) |
NUMAJIRI Masaharu Applied Research Laboratory, Research Associate, 放射線科学センター, 助手 (20189385)
MIURA Taichi Applied Research Laboratory, Associate Professor, 放射線科学センター, 助教授 (80209717)
KONDO Kenjiro Applied Research Laboratory, Professor, 共通研究施設, 教授 (20004434)
何 春清 高エネルギー加速器研究機構, 放射線科学センター, COE研究員
HE Chun-Qing Applied Research laboratory ; COF Scientist
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| Research Abstract |
In order to study the surface of polymers, a pulsed slow positron beam (PSPB) is necessary to determine the injection time in the investigated polymer. Commonly PSPB is made using a linear accelerator, which need large facility. In this project, a small apparatus desk-top size has been built using radio isotopes. The bunched and pulsing beam was obtained by the RF method, in which RF field is applied on a Al tube with 2cm diameter and 5cm length. The length is determined by the flight time of positions through the tube. Thus 40 MHz RF is used to bunch the rundum beam to a bunched beam. The width is 500 to 600ps, which is enough to study polymer samples, which have lifetimes longer than 1.5ns to 2 ns. In order to get a beam with 300pswidth, it is required another main buncher.
In this project, the apparatus to obtain a pulsed and bunched beam has been successfully built and applied to measure lifetimes of polymers : polyethylene, epoxy resin, epoxy composite, epoxy coated films on a Silicon metal.
In this application, the heat expansion coefficient of the surface and the bulk of epoxy resin was obtained. The increase in the positronium formation with increasing the depth was observed in polyethylene. The skin layer of the composite materials was observed by a non destructive method. Low K films on Silicon plate, which are extensively used in 1C and electric industry has been studied. Large holes with about 50 ns positron lifetime hasbeen successfully observed
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