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

1)从日本Suwa矿采集的一种碲矿物中，~(130)Te&gt；的双β衰变的半衰期被确定为(8.5&lt；+！-&gt；1.2)x&lt；10^(20)&gt；年。这一结果与Takaoka和Ogata(1966)报道的半衰期和密苏里州小组(Manuel，1986)给出的半衰期很好地一致，而不同于Heidelberg小组(Kirsten等人，1986)给出的半衰期。2)对于在美国Cash矿山公司采集的碲矿物，我们测定了&lt；^(130)Te&gt；的双β衰变产生的量。其半衰期为(8.6&lt；+！--&gt；2.3)x&lt；10^(20)&gt；年，矿物年龄假设为拉拉酰胺(63&lt；+！-gt；17 Ma)，碲含量为20%，这是根据橄榄石的化学式估计的。3)K-Ar测年给出了日本Suwa和Oya矿采集的含碲钙英岩脉的异常古老的年龄。表观年龄比从地质和地质年代学证据中被认为是正确的年龄早三到八倍。这表明这些矿脉中的矿物含有过量的Ar，因此，方解石和碲矿物等低钾矿物的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.