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Title: Proton scattering on radioactive proton sd-shell nuclei and comparison to Coulomb excitation

Abstract

Systematic measurements of the first excited states in neutron-rich nuclei in the {pi}(sd)-shell have been performed in the last two years using the technique of intermediate energy Coulomb excitation. These experiments were designed to study the evolution of nuclear shell structure as the neutron-dripline is approached and to provide experimental data which can be easily compared to nuclear model predictions. These measurements indicated a breakdown of the N=20 shell closure for {sup 32}Mg and a weakening of the N=28 shell closure below {sup 48}Ca, as well as a region of moderate collectivity around {sup 40,42}S. However, this experimental technique is sensitive only to the electromagnetic response of the nucleus. To probe the neutron distributions we performed a series of proton scattering experiments in inverse kinematics on neutronrich sulfur and argon isotopes. Proton scattering at energies of about 30 MeV/nucleon is more sensitive to neutrons than to protons by about a factor of three. The combination of the proton scattering results with the Coulomb excitation measurements allows a determination of the ratio of the neutron transition matrix element M{sub n} to the proton transition matrix element M{sub p}. Deviations from the homogeneous collective model expectation M{sub n}/M{sub p}=N/Z can be indicativemore » of isovector deformation predicted to occur for neutron-rich sulfur isotopes. Proton scattering experiments and Coulomb excitation experiments on the same isotopes have been performed at the NSCL with radioactive beams produced in the A1200 fragment separator and protons detected in an array of Si strip-Si-CsI telescopes.« less

Authors:
; ;  [1]; ; ;  [2]; ; ; ;  [3];  [2];  [4]
  1. Department of Physics and Astronomy and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan, 48824 (United States)
  2. Institut de Physique Nucleaire, IN2P3-CNRS, 91406 Orsay (France)
  3. Department of Physics, Florida State University, Tallahassee, Florida 32306 (United States)
  4. (United States)
Publication Date:
OSTI Identifier:
21208224
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 481; Journal Issue: 1; Conference: Nuclear structure 98 conference, Gatlinburg, TN (United States), 10-15 Aug 1998; Other Information: DOI: 10.1063/1.59552; (c) 1999 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; ARGON ISOTOPES; COLLECTIVE MODEL; COMPARATIVE EVALUATIONS; COULOMB EXCITATION; EXCITED STATES; GAMMA SPECTROSCOPY; MAGNESIUM 32; MATRIX ELEMENTS; MEV RANGE; NEUTRONS; NUCLEAR STRUCTURE; PROTON DETECTION; PROTON REACTIONS; PROTON-NUCLEON INTERACTIONS; PROTONS; RADIOACTIVE ION BEAMS; SHELL MODELS; SI MICROSTRIP DETECTORS; SULFUR ISOTOPES

Citation Formats

Glasmacher, T., Ibbotson, R. W., Scheit, H., Blumenfeld, Y., Kelley, J. H., Suomijaervi, T., Cottle, P. D., Kemper, K. W., Jewell, K., Riley, L., Marechal, F., and Department of Physics, Florida State University, Tallahassee, Florida 32306. Proton scattering on radioactive proton sd-shell nuclei and comparison to Coulomb excitation. United States: N. p., 1999. Web. doi:10.1063/1.59552.
Glasmacher, T., Ibbotson, R. W., Scheit, H., Blumenfeld, Y., Kelley, J. H., Suomijaervi, T., Cottle, P. D., Kemper, K. W., Jewell, K., Riley, L., Marechal, F., & Department of Physics, Florida State University, Tallahassee, Florida 32306. Proton scattering on radioactive proton sd-shell nuclei and comparison to Coulomb excitation. United States. doi:10.1063/1.59552.
Glasmacher, T., Ibbotson, R. W., Scheit, H., Blumenfeld, Y., Kelley, J. H., Suomijaervi, T., Cottle, P. D., Kemper, K. W., Jewell, K., Riley, L., Marechal, F., and Department of Physics, Florida State University, Tallahassee, Florida 32306. Thu . "Proton scattering on radioactive proton sd-shell nuclei and comparison to Coulomb excitation". United States. doi:10.1063/1.59552.
@article{osti_21208224,
title = {Proton scattering on radioactive proton sd-shell nuclei and comparison to Coulomb excitation},
author = {Glasmacher, T. and Ibbotson, R. W. and Scheit, H. and Blumenfeld, Y. and Kelley, J. H. and Suomijaervi, T. and Cottle, P. D. and Kemper, K. W. and Jewell, K. and Riley, L. and Marechal, F. and Department of Physics, Florida State University, Tallahassee, Florida 32306},
abstractNote = {Systematic measurements of the first excited states in neutron-rich nuclei in the {pi}(sd)-shell have been performed in the last two years using the technique of intermediate energy Coulomb excitation. These experiments were designed to study the evolution of nuclear shell structure as the neutron-dripline is approached and to provide experimental data which can be easily compared to nuclear model predictions. These measurements indicated a breakdown of the N=20 shell closure for {sup 32}Mg and a weakening of the N=28 shell closure below {sup 48}Ca, as well as a region of moderate collectivity around {sup 40,42}S. However, this experimental technique is sensitive only to the electromagnetic response of the nucleus. To probe the neutron distributions we performed a series of proton scattering experiments in inverse kinematics on neutronrich sulfur and argon isotopes. Proton scattering at energies of about 30 MeV/nucleon is more sensitive to neutrons than to protons by about a factor of three. The combination of the proton scattering results with the Coulomb excitation measurements allows a determination of the ratio of the neutron transition matrix element M{sub n} to the proton transition matrix element M{sub p}. Deviations from the homogeneous collective model expectation M{sub n}/M{sub p}=N/Z can be indicative of isovector deformation predicted to occur for neutron-rich sulfur isotopes. Proton scattering experiments and Coulomb excitation experiments on the same isotopes have been performed at the NSCL with radioactive beams produced in the A1200 fragment separator and protons detected in an array of Si strip-Si-CsI telescopes.},
doi = {10.1063/1.59552},
journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 481,
place = {United States},
year = {1999},
month = {9}
}