Study on double beta-decays of <^(128)Te> and <^(130)Te> .

1)从日本水和矿收集的一种碲矿物中，确定了<^(130)Te>双β衰变的半衰期为(8.5 <+！- >.2) x <10^(20)>年。这一结果与Takaoka和Ogata（1966）报告的半衰期以及Missouri小组（Manuel, 1986）给出的半衰期吻合良好，而与Heidelberg小组（Kirsten et al., 1986）给出的半衰期不同。2)对采自美国Cash矿的一种碲矿物（<Ag_3> AuTe），测定了<^(130)Te>双β衰变产生的<^(130)Xe>的量。半衰期为(8.6 <+！-> 2.3) x <10^(20)>年，假设矿物年龄为Laramide (63 <+！-> - 17ma)，碲的含量为20%，这是由petite的化学式估算出来的。3) K-Ar测年对日本Suwa和Oya矿采集的含碲方解石脉进行了异常的年龄测定。表面年龄比地质学和地质年代学证据所认为的正确年龄要大3到8倍。这表明这些矿脉中的矿物含有过量的Ar，因此，低钾矿物如方解石和碲矿物的K-Ar定年可能给出不正确的，可能更古老的碲矿石形成年龄。

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.