Alexander, T.

Cortes, M. L.

Gerl, J.

Pietralla, N.

Podolyak, Z.

Reese, M.

Rudolph, D.

Sarmiento, L.

GSI Repository

Evolution of collectivity in the vicinity on 208Pb: Preliminary results∗M. L. Corte´s†1,2, T. Alexander3, L. G. Sarmiento4, M. Reese1, D. Rudolph4, Z. Podolya´k3,N. Pietralla1, J. Gerl2, and the PreSPEC and AGATA Collaborations1TU Darmstadt, Darmstadt, Germany; 2GSI, Darmstadt, Germany; 3University of Surrey, Guildford, United Kingdom;4Lund University, Lund, SwedenKnowledge on the spectroscopic data of nuclei in the re-gion of 208Pb provides key information to probe param-eter sets of nuclear models, both shell-model and mean-field based. It also serves as a basis for the extrapolationof any nuclear model into the area of actinides and super-heavy nuclei. Since 208Pb is the heaviest doubly-magic nu-cleus known to date, it is also the last firm anchor pointfor extrapolations. Within the PreSPEC-AGATA campaignat GSI [1], fragmentation of a 208Pb beam at 1GeV/u on a2.5 g/cm2 Be target was performed to study Pb, Hg andPt isotopes. Charge and mass-to-charge ratio of the in-coming particles were obtained in an event-by-event basisusing the standard FRS detectors [2]. Figure 1 shows theidentification plot obtained for the reference isotope 206Pb.The reducedZ resolution observed is due to the creation ofAoQ2.46 2.48 2.50 2.52 2.54 2.56 2.58Z7879808182838485110210310Figure 1: Incoming particle identification: AoQ vs Z asmeasured in the FRScharge states during the passage of the heavy ions throughthe ionization chambers and other material in the S4 area.The solid line, containing 73% of the events, indicates thegate used to select the isotope of interest and to avoid back-ground events. Incoming particles were focused in a 400mg/cm2 thick Au target to perform relativistic Coulomb ex-citation. Particle identification after the target was obtainedby combining the measurements of energy loss and totalkinetic energy in the LYCCA calorimeter [3] as shown inFigure 2. The solid line indicates the gate used to select Pbions. γ rays emitted after the reaction were detected usingthe AGATA [4] array. Gates on particle-γ time, scatteringangle and crystal multiplicity were applied to observe thedecay of the target nuclei after Coulomb excitation. Fig-∗Work supported by BMBF NuSTAR.DA - TP 6, FKZ: BMBF05P12RDFN8 (TP 6), HGS-HIRe† m.l.cortes@gsi.deEnergy (a. u.)0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6310×Energy Loss (a. u.)2.83.03.23.43.63.8310×1020304050607080Figure 2: Outgoing particle identification: Total kinetic en-ergy vs. Energy loss in the LYCCA calorimeterEnergy (keV)350 400 450 500 550 600 650 700 750Counts050100150200250300350400547.5 keVFigure 3: Energy spectrum measured by AGATA showingthe 547.5 keV 7/2+ → 3/2+ transition in Au.ure 3 shows the energy spectrum obtained using an 10 nstime gate, a scattering angle between 2 mrad and 20 mradand crystal multiplicity lower than 4. The observed peakat 547.5 keV comes from the 7/2+ → 3/2+ transition inAu. The total number of counts observed for this transitionis 66(31). Changes on gates used, as well as backgroundsubtraction will be performed to increase the statistics andto improve the peak-to-total ratio. Doppler correction willbe performed to obtain the projectile de-excitation γ peak.References[1] N. Pietralla et al., EPJ Web of Conferences 66 (2014) 02083.[2] H. Geissel et al., Nucl. Instr. Meth. B 70 (1992) 286.[3] P. Golubev et al., Nucl. Instr. Meth. A 723 (2013) 55.[4] S. Akkoyun et al., Nucl. Instr. Meth. A 668 (2012) 26.GSI SCIENTIFIC REPORT 2014 MU-NUSTAR-GS-02DOI:10.15120/GR-2015-1-MU-NUSTAR-GS-02 153

Evolution of collectivity in the vicinity on $^{208}$Pb: Preliminary results

Sarmiento, Luis

Rudolph, Dirk

Lund University Publications

Evolution of Collectivity in the Vicinity of 208Pb: Preliminary Results

http://repository.gsi.de/record/183911/files/MU-NUSTAR-GS-02.pdf

Evolution of collectivity in the vicinity on $^{208}$ Pb: Preliminary results

Abstract

Similar works

Full text

Available Versions

GSI Repository

Lund University Publications

Evolution of collectivity in the vicinity on 208^{208}208Pb: Preliminary results

Abstract

Similar works

Full text

Available Versions

GSI Repository

Lund University Publications

Evolution of collectivity in the vicinity on $^{208}$ Pb: Preliminary results