Massenspektrometrischer Nachweis von ββ-Zerfallsprodukten

Abstract

The principles and methods of mass-spectrometric detection ofββ-decay products and the theoretical purposes for such studies are discussed in detail.

We report also the results of our new measurements on two tellurides, one native tellurium sample and one selenide. Concerning the decay$Te^{130} \underrightarrow {\beta - \beta - }Xe^{130}$, we have found that Xe¹³⁰ in a native tellurium sample amounts to 67% of the total xenon with an absence of any other anomaly, which is an important improvement over previous measurements. —For the first time the decay$Se^{82} \underrightarrow {\beta - \beta - }Kr^{82}$ was studied by massspectrometry. A Kr⁸²-excess was positively found in an copper selenide. A detailed discussion of all processes other than doubleβ-decay which might contribute to the Xe¹³⁰ and Kr⁸²-anomalies is undertaken. It can be shown that these effects are small compared to theββ-decay process. It can be said now positively thatββ-decay occurs in nature. Discussing all available data we obtained the effective half-life of Te¹³⁰ to be 6×10^20±0.3 y and that of Se⁸² equals to 6 × 10^19±0.3 y. The results are in agreement with the theoretical predictions for the 2ν-ββ-decay. Nevertheless, no-neutrinoββ-decay is still possible. However, from the data we calculated that the leptonnonconservation is at most 0.7%.