title: Characteristic of thoron (220Rn) in environment.
abstract: This paper describes importance of220Rn (hereafter thoron) progeny measurement for the dose estimation. Although the spatial distribution of thoron activity concentration strongly depends on the distance from wall surface as an indoor thoron source), a homogeneous distribution was expected to be observed for212Pb activity concentration which was one of thoron progeny. Furthermore, the mean equilibrium factor for thoron obtained by the recent measurements in several countries widely ranged from 0.008 to 0.07. Therefore the bronchial dose evaluated using the equilibrium factor and activity concentration of thoron instead of thoron progeny activity concentration may have a large uncertainty. Thus, the thoron progeny measurement should be investigated at each measurement point for the dose estimation for thoron.
authors.affiliation: Hirosaki University Graduate School of Health Science, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hosoda
authors.affiliation: Hirosaki University Graduate School of Health Science, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kudo
authors.affiliation: Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Iwaoka
authors.affiliation: Hirosaki University Graduate School of Health Science, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan.
authors.forename: Ryohei
authors.initials: R
authors.lastname: Yamada
authors.affiliation: Hirosaki University Graduate School of Health Science, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan.
authors.forename: Takahito
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Hirosaki University Graduate School of Health Science, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Tamakuma
authors.affiliation: Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan. Electronic address: tokonami@hirosaki-u.ac.jp.
authors.forename: Shinji
authors.initials: S
authors.lastname: Tokonami
keywords: Dose estimation; Equilibrium factor; Passive-type radon-thoron discrimination monitor; Spatial distribution; Thoron