New stage of search for 2K(2ν) capture of 78Kr

Abstract

A technique to search for 2K-capture of 78 Kr with large low-background proportional counter filled with an enriched in 78 Kr up to 99.8% sample of Krypton at a pressure of 4.51 is described in this paper. The results of first measurements are presented. Analysis of data collected during 159 hours yielded new limit to the half-life of 78 Kr with regard to 2K-capture (T 1/2 ≥ 6 · 10 21 yr (90% C.L.)). Sensitivity of the facility to the process for one year of measurement was evaluated to be S = 1.0 · 10 22 yr (90% C.L.).

Double beta decay searches of134Xe,126Xe and124Xe with large scale Xe detectors

“…The predictions for 2ν ECEC half-lives span a range of two orders of magnitude, experimentally a lower half-life limit for the 124 Xe decay of 1.1 ×10 17 yr is given [35]. No experimental limit exists for 126 Xe and only one prediction is available for a half-life value between 4.7-12 ×10 25 yrs [38].…”

Deformed shell model results for two-neutrino positron double-βdecay ofSe74

“…However, in the past few years, serious attempts have been made using direct counting methods to measure half-lives for 2ν e + DBD modes in the upper (pf g 9/2 ) shell nuclei 78 Kr [13], 64 Zn [14], and 74 Se [15]. In the past, attempts have also been made for 106,108 Cd [16] and 130,132 Ba [17] nuclei.…”

Improving Calibration of the Large Low-Background Proportional Counter

“…Recording the response of the relaxation of atomic processes after the capture of orbital electrons in a gaseous medium provides essential advantages over liquid and solid-state detectors. The interaction of radiation with gas atoms makes it possible to reveal the topological signature of a rare event, which was demonstrated in our previous works [1,2]. When the source is a part of the detection medium, it is possible to measure the total energy release except for a neutrino emission.…”