| Budget Amount *help |
¥7,500,000 (Direct Cost: ¥7,500,000)
Fiscal Year 1986: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1985: ¥7,100,000 (Direct Cost: ¥7,100,000)
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| Research Abstract |
1) From a tellurium mineral collected at the Suwa mine, Japan, a half-life for double beta-decay of <^(130)Te> has been determined to be (8.5 <+!-> 1.2) x <10^(20)> years. This result is in good agreement with the half-life reported by Takaoka and Ogata (1966) and that given by the Missouri group (Manuel, 1986), and different from the half-life given by the Heidelberg group (Kirsten et al., 1986).
2) For a tellurium mineral (petzite, <Ag_3> AuTe) collected at the Cash mine, Co. USA, we have determined the amount of <^(130)Xe> produced by double beta-decay of <^(130)Te> . The half-life is (8.6 <+!-> 2.3) x <10^(20)> years with assumptions of a mineral age of Laramide (63 <+!-> 17 Ma) and of a tellurium content of 20% that was estimated from the chemical formula of petzite.
3) K-Ar dating gives extra-ordinarily old ages for tellurium-bearing calcitequartz veins collected at the Suwa and Oya mines, Japan. The apparent ages are three to eight times older than the ages which have been considered to be correct from geological and geochronological evidence. This indicates that minerals in these veins contain excess Ar, and hence that the K-Ar dating of low potassium minerals such as calcite and tellurium minerals may give incorrect, possibly older ages for the formation of tellurium ores.
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