N. Ya. Osetrova

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

A technique to search for 2K capture of 78Kr with a large low-background proportional counter filled with a sample of krypton enriched in 78Kr up to 99.8% at a pressure of 4.51 atm is described in this paper. The results of first measurements are presented. An analysis of data collected for 159 h yielded a new limit to the half-life of 78Kr with regard to 2K capture (T1/2 ≥ 1.5 × 1021 yr (90% C.L.)). The sensitivity of the facility to the process for one year of measurement was evaluated to be S = 1.0 × 1022 yr (90% C.L.).

New limit on the half-life of 78Kr with respect to the 2K(2ν)-capture decay mode

The features of data accumulated for 1817 h in an experimental search for the 2K(2ν)-capture mode of 78Kr decay are discussed. A new limit on the half-life for this decay is found: T1/2≥2.3×1020 yr (at a 90% C.L.).Features of data accumulated at 1817 hours in the experimental search for 2K(2 \nu)-capture decay mode of Kr-78 are discussed. The new limit for this decay half-life is found to be T_{1/2}>2.3 *10^{20} yr. (90% C.L.).

First results of a search for the two-neutrino double-beta decay of 136Xe with high-pressure copper proportional counters

A description of a low-background installation for a new stage of the experimental search for the 2β(2ν) decay of 136Xe with high-pressure copper proportional counters is presented. The first estimate of the decay half-life limit based on the data measured over 4140 h yields T1/2≥2.4×1021 yr (90% C.L.).

Characteristics of a Proportional Counter Filled with CF4 and Additions of Xe

The performance characteristics of a proportional counter filled with a gas mixture of Freon-14 (CF4) and Xe at pressures of 0.8–14.8 atm were measured. Adding some Xe (a 1–2% concentration is optimal) to CF4 was found to approximately halve the operating high voltage needed for achieving the same gas-amplification factor as in pure CF4, improve the energy resolution, and increase the expected ultimate gas-amplification factor by an order of magnitude.

New stage of search for 2K(2{nu}) capture of {sup 78}Kr

A technique to search for 2K capture of 78Kr with a large low-background proportional counter filled with a sample of krypton enriched in 78Kr up to 99.8% at a pressure of 4.51 atm is described in this paper. The results of first measurements are presented. An analysis of data collected for 159 h yielded a new limit to the half-life of 78Kr with regard to 2K capture (T1/2 ≥ 1.5 × 1021 yr (90% C.L.)). The sensitivity of the facility to the process for one year of measurement was evaluated to be S = 1.0 × 1022 yr (90% C.L.).

Next stage of search for 2K(2

A technique to search for 2K capture of 78Kr with a large low-background proportional counter filled with a sample of krypton enriched in 78Kr up to 99.8% at a pressure of 4.51 atm is described in this paper. The results of first measurements are presented. An analysis of data collected for 159 h yielded a new limit to the half-life of 78Kr with regard to 2K capture (T1/2 ≥ 1.5 × 1021 yr (90% C.L.)). The sensitivity of the facility to the process for one year of measurement was evaluated to be S = 1.0 × 1022 yr (90% C.L.).

\nu

A technique to search for 2K capture of 78Kr with a large low-background proportional counter filled with a sample of krypton enriched in 78Kr up to 99.8% at a pressure of 4.51 atm is described in this paper. The results of first measurements are presented. An analysis of data collected for 159 h yielded a new limit to the half-life of 78Kr with regard to 2K capture (T1/2 ≥ 1.5 × 1021 yr (90% C.L.)). The sensitivity of the facility to the process for one year of measurement was evaluated to be S = 1.0 × 1022 yr (90% C.L.).

)-capture of

The results of amplitude spectrum measurement and data processing of 222Rn and its daughter nucleus decays in a high-pressure copper proportional counter filled with xenon at a pressure of 14.8a tm are given. The preliminary estimates of the α/e ratio for different E/P values are also presented.