Common analysis of background spectra of proportional counter filled with krypton enriched with 78Kr and natural krypton

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Common analysis of background spectra of
proportional counter filled with krypton enriched
with 78Kr and natural krypton
Vladimir Kazalov Baksan Neutrino Observatory INR
RAS
"PARTICLES and COSMOLOGY, April 16 - 21 , 2007,
Baksan Valley
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• Ju. Gavriljuk, V. Gavrin, A. Gangapshev,
• V. Kazalov, V. Kuzminov, N. Osetrova
• Institute for Nuclear Research of the Russian
  Academy of Sciences, Moscow Russia
• S. Panasenko, S. Ratkevich
• Karazin Kharkiv National University, Kharkiv,
  Ukraine

The work is performing in the frames of a
Presidium RAS Fundamental Research Program
Neutrino Physics and Supported by RFBR grant
?04-02-16037
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2ek
2? (2.88 MeV)

Theory
Experiment
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assumption
Se-----------------gt SeSe Kab12.652
keV, 2Kab25.3 keV Ka111.221 keV
1.00 Ka211.181 keV 0.52 Kb112.491 keV
0.21 Kb212.651 keV 0.01 wk0.596
x-ray we0.404 e-Auger
Se Se 0.4042 0.163 0.481 0.5962 0.355
?? ?? ? ? ?? ? ?? ? 0.4042 0.163 0.481 0.5962 0.355
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Schematic diagram of 2k-capture event
78Se ? 78Se
78Se ? 78Se
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Parameters of the counter
1. Bodys material Cu
2. Total length, mm 1160
3. Fiducial length, mm 595
4. Outer diameter, mm 150
5. Inner diameter, mm 140
6. Central anode material, mm g.p.tan., 0.010
7. Total volume, l 11.0
8. Fid. Volume, l 9.16
9. Pressure, at 4.51
10. Capacity, pF 31
11. Anode wire resistance , Ohm 613
Æ140
Æ150
Cross-section of the counter - anode
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Low background shield
? 1760 mm
?
? ?
970 mm
15 cm lead 8 cm borated polyethylene 18 cm
copper
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(No Transcript)
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View of installation
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Electric scheme of the setup
PA1 PA2 preamplifiers A1 A2
amplifiers CS coincidence scheme DO digital
oscilloscope
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Real pulse sample
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Spectrum of 109Cd (88 keV)
Events / keV
Energy, keV
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Background of 78Kr(T8400 h)
Events / keV
Energy, keV
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Background of Krnat (T3039 h)
Events / keV
Energy, keV
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Comparison of 78Kr with Krnat
Events / keV
Energy, keV
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Comparison of 78Kr with Krnat
Events / keV
Energy, keV
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Three point pulse
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Results
Events / keV
Energy, keV
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1. Number of Kr-78 atoms - 1,081024
2. Registration efficiency for 3()-events
   - 0,809
3. Probability for 3()- events - 0,3550,985
4. Effectiveness of selection for 3()- events -
   0,43