title: Effects of beta-particles attenuation filter of reference sources and contribution in the calibration of surface contamination monitors.
abstract: If high-energy beta particles are required for the efficiency determination of surface contamination monitors, wide area filtered (90)Sr/(90)Y sources are commonly used instead of short-lived pure (90)Y sources. In this work we show how the instrument efficiencies are dependent on filtering. Significant difference in the instrument efficiencies between filtered (90)Sr/(90)Y and pure (90)Y source was obtained due to spectral degradation of the beta emission spectrum. Changes in the β-particle spectra were investigated by the use of a plastic scintillation spectrometer and the anisotropy of β-particle fluences was examined to clarify the possible reason of such discrepancy.
authors.affiliation: Japan Radioisotope Association, 2-28-45, Hon-komagome, Bunkyo, Tokyo 113-8941, Japan. Electronic address: tyamada@jrias.or.jp.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Yamada
authors.affiliation: Japan Radioisotope Association, 2-28-45, Hon-komagome, Bunkyo, Tokyo 113-8941, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Ohshiro
authors.affiliation: National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 2, 1-1-1 Umezono, Ttsukuba, Ibaraki 305-8568, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kawada
keywords: Angular dependence; Extended sources; ISO 8769; Instrument efficiency; β-Particle spectrum