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1 Next stage of a search for 2K(2 )-capture of 78 Kr Valery V. Kuzminov Baksan Neutrino Observatory INR RAS NON-ACCELERATOR NEW PHYSICS Dubna, Russia,

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Presentation on theme: "1 Next stage of a search for 2K(2 )-capture of 78 Kr Valery V. Kuzminov Baksan Neutrino Observatory INR RAS NON-ACCELERATOR NEW PHYSICS Dubna, Russia,"— Presentation transcript:

1 1 Next stage of a search for 2K(2 )-capture of 78 Kr Valery V. Kuzminov Baksan Neutrino Observatory INR RAS NON-ACCELERATOR NEW PHYSICS Dubna, Russia, June , 2005

2 2 Ju. Gavriljuk, V. Gavrin, A. Gangapshev, V. Kazalov, V. Kuzminov, N. Osetrova Institute for Nuclear Research of the Russian Academy of Sciences, Moscow Russia A. Shubin, G. Skorynin, I. Pul`nikov, A.Ryabukhin FSUE PA “Electrochemical Plant”, Zeleznogorsk, Krasnoyarsk Region, 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 №

3 3 2ek2ek (2.88 MeV) Theory: Experiment: N 2k =0.786N ee M. Doi … 1992y

4 4 2. Se** > Se*+ Se* K ab = keV, 2K ab =25.3 keV K  1 = keV 1.00 K  2 = keV 0.52 K  1 = keV 0.21 K  2 = keV 0.01  k =0.596 x-ray  e =0.404 e-Auger Se* = } = = еаеаккеаеакк еакеакеакеак assumption

5 5 Schematic diagram of 2k-capture event 78 Se **  78 Se

6 6 Parameters of the counter 1. Body’s materialCu 2. Total length, mm Fiducial length, mm Outer diameter, mm Inner diameter, mm Central anode material, mmg.p.tan., Total volume, l Fid. Volume, l Pressure, at Capacity, pF Anode wire resistance, Ohm613  140  150 Cross-section of the counter + - anode

7 7 Low background shield  1760 mm   970 mm 15 cm lead 8 cm borated polyethylene 18 cm copper

8 8

9 9 View of installation

10 10 Isotopes Content (atomic percents) < Isotopes Content (atomic percents) < Kr – sumple 1. Old 78 Kr – sumple, (48.64 l) 2. New 78 Kr – sumple, (47.65 l) 85 Kr – activity  1.8· Bk/l Preliminary measurements: Bkg. (20  100 keV) = 67 h -1 (V=9.16 l, p=4.55 at) Bkg. = Bkg. own + Bkg. Kr-85 |  ? 85 Kr – activity  0.1Bk/l Preliminary measurements: Bkg. (20  100 keV) = 3700 h-1 (V=9.16 l, p=4.55 at)

11 11 Electric scheme of the setup PA1 & PA2 – preamplifiers A1 & A2 – amplifiers CS – coincidence scheme DO – digital oscilloscope

12 12 Real pulse sample

13 13 Spectrum of 109 Cd (88 keV) Energy, keV R=6% R=6.5% R=15.9%

14 14 Background (T=159 h)

15 15 Values of parameters for useful events with 3( ) ionizations E, keVN, chan.R,% 2 , chan. (95% C.L.)  N, chan. 1.6E1aE1a  E2aE2a  EkEk  EkEk  EE  450

16 16 Events in the region 25.3±2.5 keV (95% C.L.) №, eventEE E 1, chan.E 2, chan.E 3, chan Effect = 0   2.44 (90% С.L.) Probability (p): E 1 a ; E k  ; E k    E 2 a ; E k  ; E k    0.985

17 17 Results: 1. Number of Kr-78 atoms · Registration efficiency for 3(·)-events Probability for 3(·)-events


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