S. P. Yakimenko

Pulse shape analysis and identification of multipoint events in a large-volume proportional counter in an experimental search for 2K capture of 78Kr

Abstract57-69A pulse shape analysis algorithm and a method for suppressing the noise component of signals from a large copper proportional counter in the experiment aimed at searching for 2K capture of 78Kr are described. These signals correspond to a compound event with different numbers of charge clusters from primary ionization. A technique for separating single-and multipoint events and determining the charge in individual clusters is presented. Using the Daubechies wavelets in multiresolutional signal analysis, it is possible to increase the sensitivity and the resolution in extraction of multipoint events in the detector by a factor of 3–4.A pulse shape analysis algorithm and a method for suppressing the noise component of signals from a large copper proportional counter in the experiment aimed at searching for 2K capture of Kr are described. These signals correspond to a compound event with different numbers of charge clusters due to from primary ionization is formed by these signals. A technique for separating singleand multipoint events and determining the charge in individual clusters is presented. Using the Daubechies wavelets in multiresolutional signal analysis, it is possible to increase the sensitivity and the resolution in extraction of multipoint events in the detector by a factor of 3÷ 4.

New experiment on search for the resonance absorption of solar axion emitted in the M1 transition of 83Kr nuclei

Axions with an energy of 9.4 keV emitted in the M1 transition of 83Kr nuclei in the Sun have been sought in the resonance absorption reaction A + 83Kr → 83Kr* → 83Kr + γ, e (9.4 keV). A proportional gas chamber filled with krypton and placed in a low-background setup at the underground laboratory of the Baksan neutrino observatory was used to detect γ-ray photons and electrons appearing after the decay of a nuclear level. As a result, a new constraint has been determined on the isoscalar and isovector coupling constants of the axion with nucleons: |gAN3– gAN0| ≤ 1.29 × 10–6. This constraint results in the following new bound on the mass of the axion in the hadronic axion model: mA ≤ 100 eV (95% C.L.).

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

First result of experiment for searching of 2K-capture of 124Xe with the large-volume copper proportional counter (LPC) is given. The 12 liters sample with 63.3% (44 g) of 124Xe was used in measurements. The limit on the half-life of 124Xe with regard to 2K(2ν)-capture for the ground state of 124Te (0+ → 0+, g.s.) has been found: T1/2 ≥ 4.67 × 1020 yr (90% C.L.). A sample with volume 52 liters comprising of 124Xe (10.6L - 58.6 g) and 126Xe (14.1L - 79.3 g) will used at the next step of the experiment to increase a sensitivity of 2K-caption of 124Xe registration. In this case sensitivity to the investigated process will be at the level of S = 1.46 × 1021 yr (90% C.L.) for 1 year measurement.

A technique for searching for the 2K capture in 124Xe with a copper proportional counter

An experimental technique for searching for the 2K capture in 124Xe with a large low-background copper proportional counter is described. Such an experiment is conducted at the Baksan Neutrino Observatory of the Institute for Nuclear Research of the Russian Academy of Sciences. The experimental setup is located in the Low-Background Deep-Level Laboratory at a depth of 4900 m.w.e., where the flux of muons of cosmic rays is suppressed by a factor of 107 relative to that at the Earth’s surface. The setup incorporates a proportional counter and low-background shielding (18 cm of copper, 15 cm of lead, and 8 cm of borated polyethylene). The results of processing the data obtained in 5 months of live measurement time are presented. A new limit on the half-life of 124Xe with respect to the 2K capture is set at the level of 2.5 × 1021 years.

Comparative study of the double- K -shell-vacancy production in single- and double-electron-capture decay

We carried out the comparative study of the signal from the decay of double

Investigating 2K-capture in 78Kr with a large-volume copper proportional counter

K

Search for resonant absorption of solar axions emitted in M 1-transitions in 83 Kr nuclei: Second stage of the experiment

-shell vacancy production that follows after single

Search for 2K(2ν)-capture of 124Xe

K

Results of Searching for Solar Hadronic Axions Emitted in the M1 Transition in 83Kr Nuclei

-shell electron capture of

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

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