1. OMC rates in Sm and Kr for 2  -decay V.G. Egorov, A.V. Klinskih, R.V. Vasiliev, M.V.Shirchenko, D.R. Zinatulina 13.06.2007 13.06.2007 MEDEX’07 MEDEX’07

2.  (n,p)-likecharge--exchangereactions

3. 2β-decay 2β-experiments μ - captureStatus 76 Ge Gerda Majorana 76 Se  2004 48 Ca TGV, NEMO3 48 Ti  2002 106 CdTGV 106 Cd  2004 82 Se NEMO3, SuperNEMO 82 Kr  2006 100 MoNEMO3 100 Ru − 116 CdNEMO3 116 Sn  2002 150 NdSuperNEMO 150 Sm  2002,  2006

4. PSI 2006: 150 Sm 2 O 3 (solid target) 150 Sm 2 O 3 (solid target) nat Sm 2 O 3 (solid target) nat Sm 2 O 3 (solid target) nat Kr (gas target) nat Kr (gas target) 82 Kr (gas target) 82 Kr (gas target) 12 C 4 H 10 (gas target) 12 C 4 H 10 (gas target) 232 Th (calibration purpose) 232 Th (calibration purpose) 197 Au (calibration purpose) 197 Au (calibration purpose)

5. Setup (solid target)

6. PSI,2006 Try to find a physicist! An answer

7. To deal with enriched 82 Kr: Keep noble gas (expensive! penetrating!) without loosing Ensure μ-stops in gas ( ⇒ thickness of the entrance window be comparable with the “thickness” of gas ) Ensure detection of low-energy γ-rays without absorption in the target walls ⇒ Special construction was developed.

8. Setup (gas target) Entrance window  C1 & C2 Vessel walls   plastic scintillator C3

9. PSI,2006PMT(C1) PMC(C2) Gas inlet Beam entrance PMT(C3) Gas vessel (C3) covered with black paper

10. PSI,2006 physicist

11. What do we observe?: (Background) radiation not connected directly to muons (uncorrelated spectrum) Cascade of muonic X-rays (prompt spectrum) Nuclear  -rays following  -capture (delayed spectrum)

12. Energy [keV] Time [ns]

13. Spectra with 82 Kr target Spectra with 82 Kr target

15. Time evolution (method) The fragment number (each fragment corresponds to 10 ns time period)

16. Muon life-time in Kr isotopes

17. Our results for Kr and Sm: IsotopeE γ, keVLife-time, nsλ c, 1/μs 82 Kr (isotopic- enriched) 244.8 276.0 649.8 142.89 ± 0.60 142.57 ± 0.33 143.53 ± 1.67 6.54 ± 0.05 6.56 ± 0.01 6.51 ± 0.08 84 Kr (57%)408.2160.14 ± 2.715.79 ± 0.10 86 Kr (17.3%)345.2173.50 ± 2.575.31 ± 0.09 150 Sm (isotopic- enriched) 114.3 198.9 287.2 82.83 ± 0.24 82.65 ± 0.66 83.12 ± 1.02 11.62 ± 0.03 11.64 ± 0.09 11.58 ± 0.14

18. Dependence of λ capt. on (Z,A): Total capture rate reflects the collective properties of the nucleus Primakoff’s rule : λ c =(Z eff ) 4 ∙ X 1 · {1 - X 2 ∙(A-Z)/2A} X 1 = 120..170 X 2 ≈ 3.0

19. Effective Z-values and Huff factors taken from NP 35(1962)295

20. Primakoff’s rule for different isotopes:

21. Conclusions: Some of our results contradict to theory Wrong measurement? Wrong interpretation? Wrong Primakoff rule? Wrong Z eff ? What can we do with this? Any ideas? In any case, our  -values are necessary (and really are used) in extraction of partial capture rates – next talk.

22. Thanks for your attention! Thanks for your attention!