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Neutron capture cross sections of 70,72,73,74,76 Ge at n_TOF EAR-1. C. Lederer, Goethe University Frankfurt
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Neutron capture cross sections of 70,72,73,74,76Ge at n_TOF EAR-1 C. Lederer, Goethe University Frankfurt J. Andrzejewski, M. Barbagallo, E. Chiaveri, C. Domingo-Pardo, R. Dressler, P. Ferreira, I.F. Goncalves, C. Guerrero, F. Gunsing, F. Käppeler, J.Neuhausen, C. Massimi, J. Perkowski, R. Reifarth, D. Schumann, G. Tagliente, J.L. Tain, P. Vaz, A. Wallner, C. Weiß, and the n_TOF Collaboration 23rd October 2013 INTC Meeting,CERN INTC-P-381
Nucleosynthesis above Fe Se rp, p-process (~1%) Proton number Ge Zn r-process (~50%) Ni Fe s-process (~ 50% of abundances) Neutron number October 23, 2013 Claudia Lederer INTC Meeting, CERN
s process Se Proton number Ge Zn • Nuclear Physics Input: • b decay half lives • <s>…. Maxwellian Averaged Cross Section MACS Ni Fe s-process Neutron number October 23, 2013 Claudia Lederer INTC Meeting, CERN
s process Se Proton number Ge Zn • Nuclear Physics Input: • b decay half lives • <s>…. Maxwellian Averaged Cross Section MACS Ni Fe s-process kT=8 – 90 keV Neutron number October 23, 2013 Claudia Lederer INTC Meeting, CERN
s process October 23, 2013 Claudia Lederer INTC Meeting, CERN
s process 72Ge(n,g)x2 Rel. Abundance Change MassNumber October 23, 2013 Claudia Lederer INTC Meeting, CERN
Motivation • Neutron capturecrosssectionsofGecrucialfor • understandingelementalabundancesfromGetoSr • Low backgroundexperiments: • - GERDA (neutrinoless double bdecayof76Ge) • - Dark matter experiments, e.g. CDMS-II (Gedetectors) October 23, 2013 Claudia Lederer INTC Meeting, CERN
Available Data Good et al (1966): Gnfor En<40 keV Maletski et al (1968): Gnfor En<30 keV Ggfor En<4 keV 72Ge(n,g) October 23, 2013 Claudia Lederer INTC Meeting, CERN
Available Data Good et al (1966): Gnfor En<40 keV Maletski et al (1968): Gnfor En<30 keV Ggfor En<4 keV 72Ge(n,g) Good et al (1966): Gnfor En<22 keV Maletski et al (1968): Gnfor En<60 keV Ggfor En<3 keV 74Ge(n,g) October 23, 2013 Claudia Lederer INTC Meeting, CERN
Experimental Setup • n_TOF EAR-1 – highneutronenergyresolution, highneutronflux • C6D6Detectionsystem – lowneutronsensitivity • Samples: enriched GeO2pelletsfrom ISOFLEX preparedat PSI, cylindrical form, 2 cm diameter October 23, 2013 Claudia Lederer INTC Meeting, CERN
Countrate Estimate 72Ge 70Ge 74Ge 73Ge
Countrate Estimate 72Ge 70Ge 76Ge 74Ge 73Ge
Beam Time Request • n_TOF EAR-1 – highneutronenergyresolution, highneutronflux • C6D6Detectionsystem – lowneutronsensitivity • Samples: enriched GeO2pelletsfrom ISOFLEX preparedat PSI, cylindrical form, 2 cm diameter • splitmeasurementover 2 experimental campaigns October 23, 2013 Claudia Lederer INTC Meeting, CERN
Summary • (n,g) crosssections on Ge isotopes arecrucialforunderstanding s processnucleosynthesisandareimportantforestimatingbackgrounds in dark matter and double bdecayexperiments • Few experimental data on Ge in thekeVneutronenergyregion • Goal: • measurecrosssectionandanalyzeresonancesfrom thermal uptoabout 200 keV • MACSs from 10-100 keVwithuncertainties <5% • Measurement: • enriched GeO2samplesof 2 g • Measurement atn_TOFEAR-1 - highneutronenergyresolution, highneutronflux • C6D6capturesetup - lowneutronsensitivity • 12x1018protons on target, splitover 2 experimental campaigns October 23, 2013 Claudia Lederer INTC Meeting, CERN
Additional Slides October 23, 2013 Claudia Lederer INTC Meeting, CERN
Experimental Data 70Ge(n,g) Good et al (1966): Gnfor En<40 keV Maletski et al (1968): Gnfor En<30 keV Ggfor En<4.5 keV October 23, 2013 Claudia Lederer INTC Meeting, CERN
Experimental Data 73Ge(n,g) Maletski et al (1968): Gnfor En<9 keV Ggfor En<2 keV October 23, 2013 Claudia Lederer INTC Meeting, CERN
Experimental Data 76Ge(n,g) Good et al (1966): Gnfor En<30 keV Maletski et al (1968): Gnfor En<50 keV Ggfor En<5 keV October 23, 2013 Claudia Lederer INTC Meeting, CERN
Neutron scattering October 23, 2013 Claudia Lederer INTC Meeting, CERN