Discovery of Beta Decay for Neutral Kaon

Research Project

Project/Area Number	23654087
Research Category	Grant-in-Aid for Challenging Exploratory Research
Allocation Type	Multi-year Fund
Research Field	Particle/Nuclear/Cosmic ray/Astro physics
Research Institution	Kyoto University
Principal Investigator	NANJO Hajime 京都大学, 理学(系)研究科(研究院), 助教 (40419445)
Project Period (FY)	2011 – 2013
Project Status	Completed (Fiscal Year 2013)
Budget Amount *help	¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000) Fiscal Year 2013: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000) Fiscal Year 2012: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000) Fiscal Year 2011: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Keywords	KLベータ崩壊 / thin gap chamber / ガス検出器 / チェレンコフ検出器 / ベータ崩壊 / CP非保存
Research Abstract	A detector which enables the KL beta decay search experiment has been developed.A thin gap chamber is constructed with cathodes of 12-um thick aluminized mylar film and a 1.6-mm-thick gas volume of CF4 and n-pentane gas mixture. In spite of its thickness of 5mg/cm2, it can be operated in high-flux neutron and gamma beam line with 99% charged particle efficiency. It was tested in the actual high intensity KL beam line and was proved to be operated stably in it with an allowable hit rate.