[MIS04-P04] Development of Radon Detector and Observation at Okayama
Keywords:Radon detection, atmosphere, earthquake prediction
We had measured radon in a pit of Kurashiki mine, and in the atmosphere in Chiba Prefecture, Chiba. We used a Radon Monitor of SUN NUCLEAR Corporation, Model 1028 in the Kurashiki, and Pylon Trace Environmental Level Radon Gas Detectors (abbreviated to TEL) in Chiba. The TEL is composed of ZnS(Ag) scintillator and a Photomultiplier. However, its count rate decreased due to unknown causes, and stopped in the end.
On the other hand PIN photodiode have been developed for high sensitive radon detector, and used in Super-Kamiokande4. Last year we made a detector to measure atmospheric radon, using PIN photodiode. We use a Si PIN photodiode as detector, S3204-09 (Unsealed), supplied by Hamamatsu Photonics K.K. We constructed a radon detection system, using a stainless pot as air container, H4083 as charge amplifier, C4900-01 as High voltage power supply module, a pulse shape amplifier, a Multi-Channel Analyzer, and a Personal computer as data analysis. Output of the multi-channel analyzer showed clear alpha peaks of 218Po and 214Po of radon daughters from Uranite.
This time we have measured the radon in the atmosphere by the system, for one year at Okayama University of Science, and observed daily variation. We also measured the radon by the system in the pit of Kurashiki mine for about 1 week, and got sensitive data comparing with those by the Radon Monitor, Model 1028. We also plan to substitute the system for the TEL to measure the radon density in the atmosphere in Chiba Prefecture, Chiba.
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