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Measuring octupole collectivity in 221 Rn using Coulomb excitation at MINIBALL, & SPEDE George O’Neill
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Octupole collectivity Certain nucleon configurations have reflection asymmetry Enhanced Schiff moments due to nearly degenerate parity doublets Induce atomic electric-dipole moments Octupole moment measured through E3 transition [1] ‘Octupole collectivity in 220 Rn and 224 Ra’, L. Gaffney, PhD thesis, 2012
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221-Radon Parity doublet splitting only possible in odd mass systems [2] Theoretically, asymmetry strongest @ Z=88, N=134 Good beam achievable at ISOLDE Internal conversion dominates some transitions vs gamma decay 221 Rn, 1x10 5 ion/s 48 hour beam time 120 Sn target, 2 mg/cm 2
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REX-ISOLDE Radioactive ion beam – Radioactive beam EXperiment at ISOLDE Protons incident on UC X target Accelerates up to 3.0 MeV/u
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MINIBALL Coulomb excitation Gamma detector array with DSSSD 144 segments of encapsulated Ge Currently offline for HIE-ISOLDE upgrade
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Results so far 201.0 ↓ 223.5 ↓ 289.3 ↓ Kβ 1 ↓ Kα 1, Kα 2 ↓ 221 Rn, 6x10 3 ion/s 30 hour beam time 120 Sn target, 2 mg/cm 2
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Results so far 201.0 ↓ 223.5 ↓ 289.3 ↓ Kβ 1 ↓ Kα 1, Kα 2 ↓ 7/2+, 0 keV 223.5 keV 22.5 keV 7/2+, 0 keV 201.0 keV 223.5 keV
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SPEDE - motivation SPectrometer for Electron DEtection Si detector in backwards geometry Allows full picture Can also be used for other useful physics
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SPEDE – where we are Beam time applied for at JYFL Detector ordered Preamplifiers tested On track for installation Q4 2014
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Summary Some initial results for 221 Rn SPEDE will enhance knowledge of nucleus Should have first results by 2015 1.‘Octupole collectivity in 220 Rn and 224 Ra’, L. Gaffney, PhD thesis, 2012 2.‘Reflection-asymmetric shapes in odd-A actinide nuclei’, Nucl. Phys. A529 (1991), S. Ćwiok, W. Nazarewicz 3.‘Combined in–beam γ–ray and conversion electron spectroscopy with radioactive ion beams’, P. Papadakis, J. Pakarinen (JYFL proposal)
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221Rn Collaboration CEA Dr Marie-Delphine Salsac, Dr Magda Zielinska Technischen Universität Darmstadt Prof Thorsten Kröll, Dr Marcus Scheck, Sabine Bönig, Michael Thürauf University of Florida Prof C.Y. Wu University of Jyväskylä Dr Tuomas Grahn, Joonas Konki, Sanna Stolze University of Cologne Dr Nigel Warr, Lars Lewandowski, Burkhard Siebeck, Tim Steinbach, Andreas Vogt KVI Groningen Dr Lorenz Willman KU Leuven Dr Liam Gaffney, Dr Kasia Wrzosek-Lipska, Tim De Coster, Nele Kesteloot University of Liverpool Prof Peter Butler, George O'Neill University of Michigan Prof Tim Chupp Yale University Dr Christian Bernards
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Summary Some initial results for 221 Rn SPEDE will enhance knowledge of nucleus Should have first results by 2015 1.‘Octupole collectivity in 220 Rn and 224 Ra’, L. Gaffney, PhD thesis, 2012 2.‘Reflection-asymmetric shapes in odd-A actinide nuclei’, Nucl. Phys. A529 (1991), S. Ćwiok, W. Nazarewicz 3.‘Combined in–beam γ–ray and conversion electron spectroscopy with radioactive ion beams’, P. Papadakis, J. Pakarinen (JYFL proposal)
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