ISOLDE Workshop and Users meeting 2014 "50th Anniversary Edition"

Results from the recent 207Tl experiment using the ISOLDE Decay Station with triggerless data acquisition.

16 Dec 2014, 14:40

15m

503/1-001 - Council Chamber (CERN)

Submitted Ground States and Decays

Speaker

Robert John Carroll (University of Surrey (GB))

Description

Results from the recent 207Tl experiment using the ISOLDE Decay Station with triggerless data acquisition. R. J. Carroll1, Zs. Podolyák1, E. Rapisarda2, T. Alexander1, A. Algora3, A. Andreyev4, S. Ansari5, F. Browne6, A. Bruce6, B. Cheal7, T. E. Cocolios8, J. Cubriss4, Zs. Dombrádi9, P. Van Duppen10, K. Flanagan8, L. M. Fraile11, C. Fahlander12, W. Gelletly1, R.-B. Gerst5, M. Gorska13, H. Grawe13, A. Gredley7, P. Greenlees14, M. Huyse10, L. Harkness-Brennan7, D. Jenkins4, D. T. Joss7, S. Judge15, U. Koester16, J. Konki14, M. Kowalska2, I. Kuti9, S. Lalkovski1, I. Lazarus17, R. Lică18, G. Lotay1, M. V. Lund, M. Madurga2, N. Marginean18, R. Marginean18, C. Mihai18, R. E. Mihai18, A. Negret18, C. Nobs6, S. Noe18, C. Nita6,18, R. D. Page7, S. Pascu18, Z. Patel1, V. Pucknell17, P. H. Regan1,15, R. Raabe10, C. M. Shand1, D. Sohler9, T. Storra2, H. Stroke19, S. Stegmann5, Ch. Sotty10, V. Vedia11, R. Wadsworth4, P. M. Walker1, F. Wearing7, E. Wilson1, G. Wilson4, H. De Witte10. 1Department of Physics, University of Surrey, Guildford, GU2 7XH, United Kingdom 2CERN, Physics Department, 1211 Geneva 23, Switzerland 3IFIC, CSIC-Universidad de Valencia, 46071, Spain 4Department of Physics, University of York, Heslington, York YO10 5DD, UK 5Institut für Kernphysik der Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany 6University of Brighton, Brighton BN2 4GJ, United Kingdom 7Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool, UK 8Department of Physics and Astronomy, The University of Manchester, M13 9PL Manchester, United Kingdom 9Institute of Nuclear Research of the Hungarian Academy of Sciences, 4026 Debrecen, Hungary 10KU Leuven, Instituut voor Kern- en Stralingsfysica, Celestijnenlaan 200D, 3001 Leuven, Belgium 11Grupo de Física Nuclear, FAMN, Universidad Complutense, CEI Moncloa, 28040 Madrid, Spain 12Department of Physics, Lund University, S-22100, Lund, Sweden 13GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstrasse 1, 64291 Darmstadt, Germany 14Department of Physics, PO Box 35 (YFL), FI-40014 University of Jyväskylä, Finland 15National Physical Laboratory, Teddington, Middlesex, TW11 0LW, UK 16Institut Laue-Langevin, 6 rue J. Horowitz, F-38042 Grenoble, France 17STFC, Daresbury Laboratory, Warrington, WA4 4AD, United Kingdom 18H. Hulubei National Institute for Physics and Nuclear Engineering, Bucharest, Romania 19Department of Physics, New York University, New York, New York 10003, USA A recent experiment was performed using the ISOLDE Decay Station to measure low-lying states in 207Tl populated via the β decay of 207Hg, produced using a molten lead target. The 207Tl nucleus has one proton less than 208Pb, which is a classic shell model core. Above the lowest-lying states, structure is likely based on the coupling of the proton hole to either a broken proton or neutron pair, which would require excitation across a shell closure, or to a collective octupole excitation. The observation of these states will reveal information on the single-particle orbitals near the shell closures at Z = 82 and N = 126, which will be valuable for the improvement of the predictive power of nuclear models. An additional objective of the experiment was to test the feasibility of producing a 208Hg beam from a molten lead target with the intention of studying states in 208Tl populated via the β decay of 208Hg. Such a study is crucial for the understanding of the proton-hole neutron-particle interactions in this region as information is scarce. The ISOLDE Decay Station consisted of a four HPGe Clover detectors and a MINIBALL cluster for high-resolution γ-ray spectroscopy, in addition to three plastic scintillator detectors for observing radioactive β-decay events. Beams of 207Hg and 208Hg were implanted onto a tape from which subsequent radioactive decays could be observed. Data were recording using a triggerless data acquisition system in which every signal was recorded with a time stamp, enabling coincident signals to be correlated in software. Preliminary results from the early analysis of this experiment, showing many promising new γ rays associated with 207Tl, will be presented for both the 207Tl and 208Tl objectives.

Presentation materials

Slides

Carroll.pdf