α(PS)-γ(Ge) digital anti-coincidence spectroscopy and its application to activity measurement of 225Ac

Ken-Ichi Mori; Takahiro Yamada; Yasushi Sato; Kotaro Nagatsu; Hidetoshi Kikunaga

doi:10.1016/j.apradiso.2023.111061

α(PS)-γ(Ge) digital anti-coincidence spectroscopy and its application to activity measurement of ²²⁵Ac

Appl Radiat Isot. 2023 Dec:202:111061. doi: 10.1016/j.apradiso.2023.111061. Epub 2023 Sep 29.

Authors

Ken-Ichi Mori¹, Takahiro Yamada², Yasushi Sato³, Kotaro Nagatsu⁴, Hidetoshi Kikunaga⁵

Affiliations

¹ Sector of Nuclear Science Research, Japan Atomic Energy Agency, Japan.
² Atomic Energy Research Institute, Kindai University, Japan. Electronic address: tyamada@kindai.ac.jp.
³ Research Institute for Measurement and Analytical Instrumentation, National Metrology Institute of Japan, Japan.
⁴ Department of Advanced Nuclear Medicine Sciences, National Institutes for Quantum and Radiological Science and Technology, Japan.
⁵ Research Center for Electron Photon Science, Tohoku University, Japan.

PMID: 37793241
DOI: 10.1016/j.apradiso.2023.111061

Abstract

Activity of ²²⁵Ac was measured by the digital anti-coincidence spectroscopy technique using a 4πα-γ detector configuration, composed of a sandwich type 4π plastic scintillator and Ge detectors. Ultrathin plastic scintillators were used for selective detection of α-particles emitted from ²²⁵Ac and its progenies, and the α-counting efficiencies of a 4π plastic scintillation detector for individual nuclides in the decay chain were determined as well. A list-mode multichannel analyzer was employed to record coincidence/anti-coincidence events for off-line analyses. The time difference distribution spectra revealed α-particle emission following ²¹³Po decay without β-particle interference from ²¹³Bi.

Keywords: (225)Ac; Activity standardization; Targeted α therapy; Ultrathin plastic scintillator; α–β discrimination.