[21a-E303-1~12] 2.4 Accelerator Mass Spectrometry, Accelerator Beam Analysis

[21a-E303-1] Development of the Ultrasensitive Detection Method for ⁴¹Ca by means of Accelerator Mass Spectrometry

〇Kimikazu Sasa¹, Yuta Ochiai¹, Tsutomu Takahashi¹, Masumi Matsumura¹, Keisuke Sueki¹ (1.AMS, Univ. Tsukuba)

Keywords:41Ca, Accelerator Mass Spectrometry, 6 MV tandem accelerator

We have developing the ultrasensitive detection method for ⁴¹Ca using the 6 MV AMS system at the University of Tsukuba. The ion source can extract CaF₃^- beams up to 500 nA from CaF₂ materials. In this study, we tried to detect a charge state of ⁴¹Ca⁵⁺ with a total energy of 32.5 MeV. The beam transmission of ⁴¹Ca⁵⁺ is improved to about 7 %. A multi-plate gas-ionization detector is employed to separate ⁴¹Ca spectrum from isobaric interferences of ⁴¹K. We obtain a background level of ⁴¹Ca/Ca ratio to about 3 × 10⁻¹⁵ and a measurement precision of about 3% for 10^-10.