title: Production of a positron microprobe using a transmission remoderator.
abstract: A production method for a positron microprobe using a beta+-decay radioisotope (22Na) source has been investigated. When a magnetically guided positron beam was extracted from the magnetic field, the combination of an extraction coil and a magnetic lens enabled us to focus the positron beam by a factor of 10 and to achieve a high transport efficiency (71%). A 150-nm-thick Ni(100) thin film was mounted at the focal point of the magnetic lens and was used as a remoderator for brightness enhancement in a transmission geometry. The remoderated positrons were accelerated by an electrostatic lens and focused on the target by an objective magnetic lens. As a result, a 4-mm-diameter positron beam could be transformed into a microprobe of 60 microm or less with 4.2% total efficiency. The S parameter profile obtained by a single-line scan of a test specimen coincided well with the defect distribution. This technique for a positron microprobe is available to an accelerator-based high-intensity positron source and allows 3-dimensional vacancy-type defect analysis and a positron source for a transmission positron microscope.
authors.affiliation: Department of Applied Chemistry, Chiba University, 1-33 Yayoi, Inage, Chiba 263-8522, Japan. fujinami@faculty.chiba-u.jp
authors.forename: Masanori
authors.initials: M
authors.lastname: Fujinami
authors.forename: Satoshi
authors.initials: S
authors.lastname: Jinno
authors.forename: Masafumi
authors.initials: M
authors.lastname: Fukuzumi
authors.forename: Takumi
authors.initials: T
authors.lastname: Kawaguchi
authors.forename: Koichi
authors.initials: K
authors.lastname: Oguma
authors.forename: Takashi
authors.initials: T
authors.lastname: Akahane