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SUMMARY:Improving the precision of calibrating a large low-background prop
 ortional counter
DTSTART;VALUE=DATE-TIME:20201008T091500Z
DTEND;VALUE=DATE-TIME:20201008T093000Z
DTSTAMP;VALUE=DATE-TIME:20261014T221124Z
UID:indico-contribution-2280@cern.ch
DESCRIPTION:Speakers: V.V. Kazalov (INR RAS)\nThe fundamental difference b
 etween low-background nuclear-physical measurements and other types of stu
 dies of the characteristics of ionizing radiation sources is the extremely
  low total event count rate. Therefore\, all recording devices in such exp
 eriments are oriented to work with individual signals. Spectrometric measu
 rements of low-energy ionizing radiation using gas detectors are mainly ca
 rried out in the proportional amplification mode. The proportional counter
  is an excellent detector for the soft x-ray region because it is saturabl
 e\, energy selective and has high-absorption efficiency as well as a very 
 good signal to noise ratio. The search for such a rare nuclear decay as th
 e simultaneous capture of two orbital electrons by the same noble gas isot
 ope nucleus by recording x-rays and Auger electrons is possible using larg
 e proportional counters. The characteristics of these counters must satisf
 y a number of conditions\, since the intrinsic radiation\, a background of
  the detectors must be ultra-low and the spectrometric characteristics mus
 t be stable during sufficiently long measurements. \n\nModern equipment al
 lows us to record the full shape of the signals in digital form from sever
 al channels simultaneously. Subsequent analysis with specially developed s
 oftware algorithms allows obtain the desired dependencies and divide event
 s into separate groups. Such information is of particular value when condu
 cting low-background measurements\, in which the useful effect is a small 
 fraction of the total count rate. In this case\, the selection of events w
 ith parameters corresponding to the effect can significantly increase the 
 effect/background ratio. The quality of such a selection depends on the co
 mpleteness of taking into account the features of the response function to
  the desired events inherent in a particular operating mode of the gas det
 ector.\n\nExperiments on the study of double decay processes with the capt
 ure of electrons of the inner atomic shell in different isotopes of high-p
 urity noble gases are ongoing for a long time at the Baksan Neutrino Obser
 vatory of the INR RAS using several 10.93-liter copper proportional counte
 rs. The experience of long-term measurements related to a search of 2$\\nu
 $2K capture with samples of different enriched for $^{78}$Kr and $^{124}$X
 e using large proportional counters with a casing made of M1-grade copper 
 showed that the spectrometric properties of the detector quite noticeably 
 degrade over time.\n\nIn this report\, we will focus on the analysis of ch
 anges in spectrometric properties overtime of a detector filled with xenon
  during long measurements\, in contrast to krypton\, which does not have l
 ong-lived radioactive isotopes that allow enough proper calibration from i
 nternal sources.\n\nhttps://indico.particle.mephi.ru/event/35/contribution
 s/2280/
LOCATION:Zoom Facilities
URL:https://indico.particle.mephi.ru/event/35/contributions/2280/
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