title: Development of a windowless multi-wire proportional chamber (MWPC) counting system for measuring extended-area beta source.
abstract: A windowless MWPC counting system has been developed to measure surface emission rate of extended-area sources. A new anode and guard plane design gives better electric-field uniformity in the (250×200)mm2sensitive volume relative to a previous-generation MWPC at KRISS, which has been used as a national standard with uncertainty <1%. The conditions of stable operation for the new MWPC system were studied, and the uncertainty was estimated with an extended-area36Cl source. The relative combined standard uncertainty was evaluated to be 0.23%, a 50% improvement over the previous-generation MWPC counting system.
authors.affiliation: Korea Research Institute of Standards and Science (KRISS), Daejeon 34113, Republic of Korea. Electronic address: shhwang@kriss.re.kr.
authors.forename: S H
authors.initials: SH
authors.lastname: Hwang
authors.affiliation: Korea Research Institute of Standards and Science (KRISS), Daejeon 34113, Republic of Korea.
authors.forename: J M
authors.initials: JM
authors.lastname: Lee
authors.affiliation: Korea Research Institute of Standards and Science (KRISS), Daejeon 34113, Republic of Korea.
authors.forename: K B
authors.initials: KB
authors.lastname: Lee
authors.affiliation: Korea Research Institute of Standards and Science (KRISS), Daejeon 34113, Republic of Korea.
authors.forename: T S
authors.initials: TS
authors.lastname: Park
keywords: Extended-area source; Multi-wire proportional chamber; Surface emission rate