title: Solving the charging effect in insulating materials probed by a variable monoenergy slow positron beam.
abstract: A variable monoenergy slow positron beam (VMSPB) operating at a high vacuum on insulating materials encounters a problem of significant surface charging effect with time. As a result, positronium formation is inhibited, and the positron annihilation radiation counting rate is reduced; these consequently distorted the experimental positron annihilation and results. To solve such problems, a technique of depositing an ultrathin layer of sputtering noble metals on insulators is developed. We report a successful method of sputtering a few atomic layers of platinum (∼1 nm) on a polyamide membrane to completely remove the charging effect for VMSPB applications in insulators.
authors.affiliation: R&D Center for Membrane Technology, Department of Chemical Engineering, Chung Yuan University , Chung-Li, 32023, Taiwan.
authors.forename: Wei-Song
authors.initials: WS
authors.lastname: Hung
authors.forename: Manuel
authors.initials: M
authors.lastname: De Guzman
authors.forename: Quanfu
authors.initials: Q
authors.lastname: An
authors.forename: Kueir-Rarn
authors.initials: KR
authors.lastname: Lee
authors.forename: Yan-Ching
authors.initials: YC
authors.lastname: Jean
authors.forename: Juin-Yih
authors.initials: JY
authors.lastname: Lai