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Coulomb Excitation of 140 Nd (and 140 Sm) Experiment IS496 MINIBALL@REX-ISOLDE. ENSAR. B(E2) of first 2 + state A twofold motivation. Systematics. Mixed-symmetry. Knowledge of B(E2) as basis for observation of mixed-symmetry state Future possibility with HIE-ISOLDE. A~140 region
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Coulomb Excitation of 140Nd(and 140Sm)Experiment IS496MINIBALL@REX-ISOLDE ENSAR 07.12.2011 | ISOLDE workshop | Christopher Bauer - TU Darmstadt
B(E2) of first 2+ stateA twofold motivation Systematics Mixed-symmetry Knowledge of B(E2) as basis for observation of mixed-symmetry state Future possibility with HIE-ISOLDE • A~140 region • N=80 isotones • Comparison with QPM 07.12.2011 | ISOLDE workshop | Christopher Bauer - TU Darmstadt
Experimental Setup01.07. – 04.07.2011 • Projectile: 140Nd • Contaminant: 140Sm, ... ? • Ion source: RILIS • Current: I ~ 1-2 pA • Ebeam = 399 MeV (2.85 MeV/u) • Targets: 1. 48Ti (1.4 mg/cm2) 2. 64Zn (1.55 mg/cm2) 07.12.2011 | ISOLDE workshop | Christopher Bauer - TU Darmstadt
Principles of MeasurementTarget normalization • Unstable nuclei of interest provided as beam • Normalization to well-known target excitation • Choice of target • Excitation cross-section (depending on beam energy E, proton number Z and B(E2) value) • Kinematics (geometry, particle detector) • Uncertainty of parameter for normalization M22 2+ 0+ M20 07.12.2011 | ISOLDE workshop | Christopher Bauer - TU Darmstadt
Particle identificationEnergy distribution over CD Cut on detected scattered target nuclei 07.12.2011 | ISOLDE workshop | Christopher Bauer - TU Darmstadt
Gamma spectraDominated by 140Nd and 140Sm Laser on Laser off 140Sm 531 keV 140Nd 774 keV 48Ti 984 keV 07.12.2011 | ISOLDE workshop | Christopher Bauer - TU Darmstadt
Laser ON/OFF comparisonNormalized to 140Sm excitation Laser on Laser off 140Sm 531 keV 140Nd 774 keV Laser ionisation + Surface ionisation 07.12.2011 | ISOLDE workshop | Christopher Bauer - TU Darmstadt
Result of Coulex calculationsUsing CLX and DCY Conditions Map of matrix elements • Contaminants subtracted by 140Sm comparison • Only excitation of first 2+ taken into account (projectile and target) • Normalization to target excitation of 48Ti • B(E2; ) = 30(5) W.u. • QPM value: 17 W.u. 07.12.2011 | ISOLDE workshop | Christopher Bauer - TU Darmstadt
140Nd and isotopic chain 07.12.2011 | ISOLDE workshop | Christopher Bauer - TU Darmstadt
N=80 isotones 07.12.2011 | ISOLDE workshop | Christopher Bauer - TU Darmstadt
Summary Outlook / To do Results Conclusions B(E2) larger than expected from various predicitions, need further interpretation • 140Nd Coulex evaluation • B(E2) = 30(5) W.u. • 140Sm Coulex limit • B(E2) < XXX W.u. • Detailed analysis of 140Sm fraction in beam composition • Handling of Coulex calculations with Gosia2 • 142Sm experiment in 2012? • First identification of a MSS in a radioactive isotope @HIE-ISOLDEin 2014/2015? 07.12.2011 | ISOLDE workshop | Christopher Bauer - TU Darmstadt
Thank you for your attention! 07.12.2011 | ISOLDE workshop | Christopher Bauer - TU Darmstadt