First result of the experimental search for the 2K-capture of Xe-124 with the copper proportional counter

TL;DR

This paper reports the first experimental search for 2K-capture in Xe-124 using a copper proportional counter, setting a new lower limit on its half-life and outlining plans for increased sensitivity in future measurements.

Contribution

It presents the first experimental limit on Xe-124 2K-capture half-life and describes an improved setup for future, more sensitive searches.

Findings

Half-life limit for Xe-124 2K-capture: > 4.67 x 10^{20} years

Use of a 52 L sample to enhance detection sensitivity

Projected sensitivity of 1.46 x 10^{21} years for future measurements

Abstract

First result of experiment for searching of 2K-capture of Xe-124 with the large-volume copper proportional counter is given. The 12 litre sample with 63.3% (44 g) of Xe-124 was used in measurements. The limit on the half-life of Xe-124 with regard to 2K(2\nu)-capture for the ground state of Te-124 has been found: T_{1/2} > 4.67x10^{20} y (90% C.L.). A sample with volume 52 L comprising of Xe-124 (10.6 L - 58.6 g) and Xe-126 (14.1 L - 79.3 g) will used at the next step of the experiment to increase a sensitivity of 2K-caption of Xe-124 registration. In this case sensitivity to the investigated process will be at the level of S=1.46 x 10^{21} y (90% C.L.) for 1 year measurement.