Iodine-129 measurement using JAEA-AMS-MUTSU

Kuwabara, Jun ; Tanaka, Takayuki; Kabuto, Shoji; Kinoshita, Naoki; Seki, Takeo

Increase of the measurement of I/I isotope ratio in various environmental samples using accelerator mass spectrometer (JAEA-AMS-MUTSU) established by the Aomori Research and Development Center JAEA is expected for the purpose of investigating distribution of the iodine isotopes in environment with the release of radioactive materials by the Fukushima first Nuclear Power Plant accident. Background level of JAEA-AMS-MUTSU in iodine measurement was examined by measuring AgI crystal of iodargyrite. Approximately 11 counts per 60 minutes of the I background existed under the condition that there was not iodine in a sample. To reduce the memory effect in the measurement of the sample which has high isotope ratio, establishment of limit of the total counts was considered. The result of a measurement was hardly affected even if the limit of the total counts was made.