1. Precision measurement of the half-life and branching ratio of the T=1/2 mirror β decay of 37 K T. Kurtukian-Nieto, P. Ascher, B. Blank, G. Canchel, M. Gerbaux, J. Giovinazzo, S. Grévy Centre d'Etudes Nucléaires de Bordeaux-Gradignan, France A. Bacquias IPHC Strasbourg, France H. Bouzomita, G. F. Grinyer, J. C. Thomas GANIL Caen, France C. Couratin, X. Flechard, E. Lienard LPC-Caen, France I. Matea IPN-Orsay, France J. Liendo Universidad Simon Bolivar, Venezuela Contact person CERN-Isolde: M. Kowalska 41st Meeting of the INTC. CERN, November 3 rd, 2011

2. Teresa Kurtukian NietoNovember 3 rd, 2011 2CERN-INTC-P-311 Measurements needed : Q  value Branching ratio of super-allowed transition  -decay half-life  - angular correlation coefficient Q EC T 1/2 BR  Superallowed Mixed Mirror β decay ft = f(Q ec ) * T 1/2 / BR O. Naviliat-Cuncic and N. Severijns PRL 102, 142302 (2009) consistent test of CVC from a set of nuclear transitions other than super-allowed pure Fermi

3. Teresa Kurtukian NietoNovember 3 rd, 2011 3CERN-INTC-P-311 Introduction: quark-mixing matrix CKM unitarity condition:  O. Naviliat-Cuncic, N. Severijns

4. Teresa Kurtukian NietoNovember 3 rd, 2011 4CERN-INTC-P-311 2011 Least known quantity: Fermi / Gamow-Teller ratio second least known quantity: half-lives Existing measurements 2009 JYFLISOLDE x x xx xx

5. Teresa Kurtukian NietoNovember 3 rd, 2011 5CERN-INTC-P-311 Why to measure 37 K ? T=1/2, decay is predominantly 3/2+ to 3/2 + mixed Fermi/GT decay Correlation measurements to be performed: our collaboration E. Lienard et al. @ GANIL 19 Ne, 35 Ar, 29 P, 37 K, 39 Ca D. Melconian et al. @ TRIUMF 2012 using laser-cooled 37 K (Melconian PhDThesis (2005), AIP C. Proc.1342 (2011) 53 Arxiv: 1108.2530v1 [nucl-ex] 11 Aug 2011) Aim: ΔT 1/2 ~ 0.1 % ΔB.R. ~ 0.1 %

6. Teresa Kurtukian NietoNovember 3 rd, 2011 6CERN-INTC-P-311 Our recent efforts : 38-39 Ca ISOLDE 2007 Blank et al., EPJ A 44,363 (2010) 38 CaT 1/2 = 443.8 ± 1.9 ms

7. Teresa Kurtukian NietoNovember 3 rd, 2011 7CERN-INTC-P-311 Our recent efforts : 38-39 Ca ISOLDE 2007 Blank et al., EPJ A 44,363 (2010) 39 CaT 1/2 = 860.7 ± 1.0 ms

8. Teresa Kurtukian NietoNovember 3 rd, 2011 8CERN-INTC-P-311 Half-life and BR measurement of 37 K radioactive ions detection -  gas counter -  germanium GSI tape system Experimental procedure: production with Ti target separation with HRS/GPS A=37 only 37 Ca T 1/2 =181.1(10) ms accumulation on tape during 1 s tape transport into setup after 2.5 s, measurement for 20T 1/2 tape move and new cycle starts Detection setup at LA1 beamline

9. Teresa Kurtukian NietoNovember 3 rd, 2011 9CERN-INTC-P-311 β detection setup 4π gas counter two single-wire gas counter P5 (95% Ar, 5% CH4) or CF4 moving tape passes through a slit between the two detectors thin aluminised Mylar entrance windows allows to detect low-energy β particles Active volume 2 x 37.4 cm 3 Advantage of using a gas counter: Electronic thresholds: For the gas counter operated in the plateau region, the electronic detection threshold is too low for losses from that source to have any effect on the overall efficiency. Plastic scintillatior and photomultipliers tubes impose a non-negligible low-energy electronic thresholds.

10. Teresa Kurtukian NietoNovember 3 rd, 2011 10CERN-INTC-P-311 Measurements with a fast DAQ system - two electronic chains: 4 μs and 8 μs fixed dead-time a listmode DAQ system - half-life measurement with 100μs DT - γ-ray measurement for branching ratio search for systematic errors: - different CFD thresholds - different detector HV - different gas flow - different cycle times Experimental details beam detection -  gas counter -  germanium GSI tape system Detection setup at LA1 beamline

11. Teresa Kurtukian NietoNovember 3 rd, 2011 11CERN-INTC-P-311 Beam request cycle length:1s + 2.5s + 20T 1/2 = 28 s effective rate: 1000 37 K decays detected/cycle i.e. count rate:few 10 3 37 K per second 3 days of effective counting: ~ 7.7 million 37 K decays 2 days search for systematic errors ~ 13 million 37 K decays (total) ΔT 1/2 < 0.1 % within 5 days (15 shifts)~ 40 000 β-γ for 2796 keV ε=0.3% ΔBR < 0.1 % 1 shift to optimise production -----------------------------------------------------------------------------  Total request:16 shifts Aim:  T 1/2 ~ 0.1 %  BR ~ 0.1 % Accumulation Decay of 37 Ca Measuring time

12. Thank you

13. Teresa Kurtukian NietoNovember 3 rd, 2011 13CERN-INTC-P-311 4π gas counter anode wire Thin windows tape Gas counter halves two single-wire gas counter P5 (95% Ar, 5% CH4) or CF4 moving tape passes through a slit between the two detectors thin aluminised Mylar entrance windows allows to detect low-energy β particles Active volume 2 x 37.4 cm 3

14. Teresa Kurtukian NietoNovember 3 rd, 2011 14CERN-INTC-P-311 Contaminants expected

15. Teresa Kurtukian NietoNovember 3 rd, 2011 15CERN-INTC-P-311 Experimental setup at JYFL

16. Teresa Kurtukian NietoNovember 3 rd, 2011 16CERN-INTC-P-311 preliminary JYFL 2009 T 1/2 = 4123.4(51) ms T 1/2 = 2546.4(18) ms T. Kurtukian Nieto, A. Bacquias et al. Our recent efforts : 29 P and 31 S