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Isospin impurity of the Isobaric Analogue State of super-allowed beta decay

Isospin impurity of the Isobaric Analogue State of super-allowed beta decay. experimental technique isospin impurity determination. Bertram Blank, CEN Bordeaux-Gradignan ESNT, Saclay, April, 26-29, 2011. The idea:. T, T z. Super-allowed b decay. T, T z - 1. Proton emission.

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Isospin impurity of the Isobaric Analogue State of super-allowed beta decay

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  1. Isospin impurity of the Isobaric Analogue State of super-allowed beta decay • experimental technique • isospin impurity determination Bertram Blank, CEN Bordeaux-Gradignan ESNT, Saclay, April, 26-29, 2011

  2. The idea: T, Tz Super-allowed b decay T, Tz- 1 Proton emission Gamma decay T-3/2, Tz-3/2 T - 1, Tz- 1

  3. The idea: 52Ni: T=2, Tz=-2 Super-allowed b decay 52Co: T=2, Tz=-1 Proton emission: T=1/2, Tz = -1/2 Gamma decay 51Fe: T=1/2, Tz=-1/2 T= ½ + ½ T = 1, Tz = -1 T = 2 Can one determine the isospin impurity of the IAS?

  4. Proton-rich nuclei in the region of Ca to Ni • Mass region (20  Z  28 et Tz  -3/2) • 5 experiments at GANIL • 23 isotopes studied (39Ti au 53Ni) • Calcium: 37,36Ca • Titanium: 41,40,39Ti • Vanadium: 43V • Chromium: 45,44,43,42Cr • Manganese : 47,46Mn • Iron: 49,48,47,46,45Fe • Cobalt: 51,50Co • Nickel: 53,52,51,50,49,48Ni • Copper: 55Cu • Zinc: 56,55,54Zn

  5. GANIL / LISE3 2000 Primary beam: 58Ni @ 75 MeV/A intensity: 3 - 4 mAe spectrometer LISE3 : degrader Be (50 mm) Wien filter detection setup SISSI target: natNi 200 mg/cm2 silicon telescope identification of implanted fragments DSSSD (X-Y): 2 x 16 x 3 mm - veto for light particles - residual energy, x-y position - energy loss - time of flight: micro-channel plate detectors RF cyclotron

  6. Identification projectile fragments 7 to 8 identification parameters

  7. Radioactivity of 41Ti Radioactivity of 49Fe 41Ti 41Ti Correlation time  41Ti T 41Ti A Contaminant from 49Fe and 45Cr B1 B2  Protons Proton and gamma branching ratios and energies

  8. Background subtraction for  rays Before After 49Fe 49Fe Decay of 49Fe Contaminants Decay of 49Fe C. Dossat et al., NPA 792 (2007) 18

  9. Spectroscopy of 52Ni T1/2 = (40.8 ± 0.2) ms Pp = (31.4 ± 1.5) % • Ep = (1349 ± 10) keV • Ip = (9.4 ± 1.3) % • Ep = (1057 ± 11) keV • Ip = (2.9± 0.3) % • Ep = (2815 ± 23) keV • Ip = (0.9 ± 0.4) % C. Dossat et al., NPA 792 (2007) 18

  10. Ep = (1013 ± 12) keV • Ip = (1.8± 0.3) % • Ep = (1500-1900) keV • Ip = (2.0 ± 0.4) % • Ep = (2000-3000) keV • Ip = (1.4 ± 0.5) % Spectroscopy of 48Fe T1/2 = (40.8 ± 0.2) ms Pp = (31.4 ± 1.5) % C. Dossat et al., NPA 792 (2007) 18

  11. X Isospin impurities • Proton emission from the IAS is isospin forbidden • Comparison of , and of for IAS : • 48Fe : =2.1 % - = 30%=42 % • 52Ni : =10 % - = 38%=64 % • Determination of isospin impurities with these experimental data: • (experimental, theory) • ’p : Coulomb and centrifugal barrier penetration • Sp = 1

  12. Isospin impurity:example of 48Fe Shell model (48Mn) IAS • = 2.1 % • = 42 % • II = 0.52 % W.A. Richter, B.A. Brown

  13. Isospin impurity: example of 52Ni Shell model (52Co) IAS • = 10 % • = 64 % • II = 19 % W.A. Richter, B.A. Brown

  14. Isospin impurity of IAS • neighboring nuclei: surprising… • however: • shell-model study: • II(36Ca) = 0.4 %, II (40Ti) = 17.3 % (Theory Jyväskylä in sd shell) • similar treatment possible for many other nuclei: 45,44Cr, 46Mn, 49Fe, 53,51Ni…. II(48Fe) = 0.52 %, II (52Ni) = 19 % B.A. Brown, N. Smirnova….

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