Results of In-Depth Analysis of Data Obtained in the Experimental Search for 2K(2ν)-Capture in ⁷⁸Kr

Abstract

A brief description of the results of joint analysis of data obtained in long-term measurements of krypton samples differing in ⁷⁸Kr content is presented. Low-background high-pressure proportional gas counters were used as detectors. The comparative analysis of experimental data on single and double K-capture provided the first estimate of the probability of production of a double K-shell vacancy in the process of K-shell electron capture in ⁸¹Kr: ${{P}_{{KK}}} = \left[ {5.7 \pm 0.8\,\,({\text{stat}}{\text{.}}) \pm 0.4\,\,({\text{syst}}{\text{.}})} \right] \times {{10}^{{ - 5}}}$. A new result for the half-life of ⁷⁸Kr with respect to the 2K(2ν)-mode was also obtained: ${{T}_{{1/2}}} = \left[ {1.9_{{ - 0.7}}^{{ + 1.3}}\,\,({\text{stat}}{\text{.}}) \pm 0.3\,\,({\text{syst}}{\text{.}})} \right] \times {{10}^{{22}}}$ years (90% CL).