[8p-N403-1~15] CS.1 Code-sharing Session of 2.3&7.4

4:00 PM - 4:15 PM JST(7:00 AM - 7:15 AM UTC)Presentation by Applicant for JSAP Young Scientists Presentation Award

[8p-N403-10] Performance evaluation of ¹²⁹I analysis on the 6MV multi-nuclide AMS system at the University of Tsukuba

〇(M1)Mitsuki Sakuma¹, Masumi Matsumura², Tsutomu Takahashi², Tetsuro Yoshida², Kimikazu Sasa^2,3 (1.Grad. Sch. of Sci. and Tech., Univ. of Tsukuba, 2.AMS Group, UTTAC, Univ. of Tsukuba, 3.Inst. of Pure and Applied Sci., Univ. of Tsukuba)

Keywords:

Facility report,Standard,I-129

¹²⁹I is a long-lived radionuclide and measured by accelerator mass spectrometry (AMS). At the University of Tsukuba, 443 ¹²⁹I samples were measured in FY2024. The background of ¹²⁹I/¹²⁷I was (3.0 ± 1.3) × 10^-14, and the average beam current of ¹²⁷I was 1.5 μA, showing a slight increase from the previous year. NIST (National Institute of Standards and Technology) provides standard samples called SRM (Standard Reference Material) for the calibration of measurements. At the request of NIST, we participated in an interlaboratory comparison of new SRMs for ¹²⁹I and measured ¹²⁹I/¹²⁷I. As a result of the AMS measurements, the results showed no inconsistency with the reference values for samples with ¹²⁹I/¹²⁷I of 10^-13 to 10^-11. However, in samples with ¹²⁹I/¹²⁷I of 10^-14, the measured values differed from reference values by a factor of about two. This discrepancy is thought to be due to the difficulty in preparing samples with low ¹²⁹I/¹²⁷I and the limitations in AMS measurement sensitivity. In this presentation, we will report on the status of AMS measurement performance of ¹²⁹I and the measurement results of NIST SRMs at the University of Tsukuba.