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Title: Isomer Tagging with a Dual Multi-Wire Proportional Counter and a Differential Plunger

Abstract

This report details the status of an experimental research programme which has studied isomeric states in the mass 130-160 region of the nuclear chart. Several new isomers have been established and characterised near the proton drip line using a recoil isomer tagging technique at the University of Jyvaeskylae, Finland. The latest experiments have been performed with a modified setup where the standard GREAT focal-plane double-sided silicon-strip detector was changed to a dual multi-wire proportional-counter arrangement. This new setup has improved capability for short-lived isomer studies where large focal-plane rates can be tolerated. The results of key recent experiments for nuclei situated above ({sup 153}Yb, {sup 152}Tm) and below ({sup 144}Ho, {sup 142}Tb) the N = 82 shell gap were presented. These studies have charted the evolution of isomeric states across the neutron shell from K-Isomers at N = 74, to shape isomers at N = 77 and shell-model isomers at N = 82, 83. The excitation energies for some of the lowest-lying excited states in these isomeric nuclei show behaviour which is characteristic of an X(5) symmetry falling midway between the limits expected for pure vibrational and rotational behaviour. The future prospects for studies of these nuclei were discussed usingmore » an isomer-tagged differential-plunger setup. This technique will be capable of establishing the deformation of the states above the isomers and will aid in determining whether their behaviour is indeed well described by the X(5) symmetry limit.« less

Authors:
; ; ; ;  [1];  [1]; ; ; ; ; ; ; ; ; ;  [2]; ;  [2];  [2]
  1. School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom)
  2. Department of Physics, University of Jyvaeskylae, Jyvaeskylae, FIN-40014 (Finland)
Publication Date:
OSTI Identifier:
21143350
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 1012; Journal Issue: 1; Conference: FINUSTAR: 2. conference on Frontiers In NUclear STructure, Astrophysics and Reactions, Crete (Greece), 10-14 Sep 2007; Other Information: DOI: 10.1063/1.2939299; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-243X
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; EXCITATION; EXCITED STATES; GAMMA RADIATION; HOLMIUM 144; ISOMERIC NUCLEI; MULTIWIRE PROPORTIONAL CHAMBERS; NEUTRONS; NUCLEAR STRUCTURE; PROTONS; RECOILS; SHELL MODELS; SI MICROSTRIP DETECTORS; SYMMETRY; TERBIUM 142; THULIUM 152; YTTERBIUM 153

Citation Formats

Cullen, D M, Mason, P J. R., Khan, S, Kishada, A M, Varley, B J, Rigby, S V, Oliver Lodge, Lab., University of Liverpool, Liverpool, L69 7ZE, Scholey, C, Greenlees, P, Rahkila, P, Jones, P M, Julin, R, Juutinen, S, Leino, M, Leppaenen, A P, Nyman, M, Uusitalo, J, Grahn, T, Pakarinen, J, Oliver Lodge, Lab., University of Liverpool, Liverpool, L69 7ZE, Nieminen, P, and Department of Nuclear Physics, Australian National University, Canberra, ACT 0200. Isomer Tagging with a Dual Multi-Wire Proportional Counter and a Differential Plunger. United States: N. p., 2008. Web. doi:10.1063/1.2939299.
Cullen, D M, Mason, P J. R., Khan, S, Kishada, A M, Varley, B J, Rigby, S V, Oliver Lodge, Lab., University of Liverpool, Liverpool, L69 7ZE, Scholey, C, Greenlees, P, Rahkila, P, Jones, P M, Julin, R, Juutinen, S, Leino, M, Leppaenen, A P, Nyman, M, Uusitalo, J, Grahn, T, Pakarinen, J, Oliver Lodge, Lab., University of Liverpool, Liverpool, L69 7ZE, Nieminen, P, & Department of Nuclear Physics, Australian National University, Canberra, ACT 0200. Isomer Tagging with a Dual Multi-Wire Proportional Counter and a Differential Plunger. United States. https://doi.org/10.1063/1.2939299
Cullen, D M, Mason, P J. R., Khan, S, Kishada, A M, Varley, B J, Rigby, S V, Oliver Lodge, Lab., University of Liverpool, Liverpool, L69 7ZE, Scholey, C, Greenlees, P, Rahkila, P, Jones, P M, Julin, R, Juutinen, S, Leino, M, Leppaenen, A P, Nyman, M, Uusitalo, J, Grahn, T, Pakarinen, J, Oliver Lodge, Lab., University of Liverpool, Liverpool, L69 7ZE, Nieminen, P, and Department of Nuclear Physics, Australian National University, Canberra, ACT 0200. 2008. "Isomer Tagging with a Dual Multi-Wire Proportional Counter and a Differential Plunger". United States. https://doi.org/10.1063/1.2939299.
@article{osti_21143350,
title = {Isomer Tagging with a Dual Multi-Wire Proportional Counter and a Differential Plunger},
author = {Cullen, D M and Mason, P J. R. and Khan, S and Kishada, A M and Varley, B J and Rigby, S V and Oliver Lodge, Lab., University of Liverpool, Liverpool, L69 7ZE and Scholey, C and Greenlees, P and Rahkila, P and Jones, P M and Julin, R and Juutinen, S and Leino, M and Leppaenen, A P and Nyman, M and Uusitalo, J and Grahn, T and Pakarinen, J and Oliver Lodge, Lab., University of Liverpool, Liverpool, L69 7ZE and Nieminen, P and Department of Nuclear Physics, Australian National University, Canberra, ACT 0200},
abstractNote = {This report details the status of an experimental research programme which has studied isomeric states in the mass 130-160 region of the nuclear chart. Several new isomers have been established and characterised near the proton drip line using a recoil isomer tagging technique at the University of Jyvaeskylae, Finland. The latest experiments have been performed with a modified setup where the standard GREAT focal-plane double-sided silicon-strip detector was changed to a dual multi-wire proportional-counter arrangement. This new setup has improved capability for short-lived isomer studies where large focal-plane rates can be tolerated. The results of key recent experiments for nuclei situated above ({sup 153}Yb, {sup 152}Tm) and below ({sup 144}Ho, {sup 142}Tb) the N = 82 shell gap were presented. These studies have charted the evolution of isomeric states across the neutron shell from K-Isomers at N = 74, to shape isomers at N = 77 and shell-model isomers at N = 82, 83. The excitation energies for some of the lowest-lying excited states in these isomeric nuclei show behaviour which is characteristic of an X(5) symmetry falling midway between the limits expected for pure vibrational and rotational behaviour. The future prospects for studies of these nuclei were discussed using an isomer-tagged differential-plunger setup. This technique will be capable of establishing the deformation of the states above the isomers and will aid in determining whether their behaviour is indeed well described by the X(5) symmetry limit.},
doi = {10.1063/1.2939299},
url = {https://www.osti.gov/biblio/21143350}, journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 1012,
place = {United States},
year = {Mon May 12 00:00:00 EDT 2008},
month = {Mon May 12 00:00:00 EDT 2008}
}