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Title: Higher-spin structures in F 21 and Na 25

Abstract

We investigated excited states in F-21 and Na-25 using the Be-9(C-14, pn gamma) reaction at 30, 35, and 45 MeV and the Be-9(O-18, pn gamma) reaction at 35 MeV. We also detected protons and identified in an E-Delta E telescope at 0 degrees in coincidence with one or more gamma radiations in the FSU Compton-suppressed Ge detector array. Many new levels and electromagnetic decays were observed, especially among the higher spin states. Angular distributions and mean lifetimes were measured wherever possible in both nuclei. The energy levels of the positive-parity states in the two nuclei agree rather well with shell model calculations using both the USDA and WBP interactions up to the highest spins observed of 13/2 h. Both a weak coupling approximation and shell model calculations using the WBP interaction generally reproduce the negative-parity states in F-21. Finally, the shell model calculations reproduce relatively well the measured M1 and E2 transitions in both nuclei, but overpredict the parity-changing E1 transitions in F-21, the only nucleus in which negative-parity states were observed in the present experiment.

Authors:
 [1];  [2];  [2];  [2];  [2];  [3];  [2];  [2];  [2];  [2];  [2];  [2];  [2];  [2]
  1. Florida State Univ., Tallahassee, FL (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Florida State Univ., Tallahassee, FL (United States)
  3. Florida State Univ., Tallahassee, FL (United States); National Superconducting Cyclotron Lab., East Lansing, MI (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE; National Science Foundation (NSF)
OSTI Identifier:
1287013
DOE Contract Number:  
AC05-00OR22725; 1064819; 1401574
Resource Type:
Journal Article
Journal Name:
Physical Review. C, Nuclear Physics
Additional Journal Information:
Journal Volume: 92; Journal Issue: 3; Journal ID: ISSN 0556-2813
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS

Citation Formats

VonMoss, J. M., Tabor, S. L., Tripathi, Vandana, Volya, A., Abromeit, B., Bender, P. C., Caussyn, D. D., Dungan, R., Kravvaris, K., Kuchera, M. P., Lubna, R., Miller, S., Parker, J. J., and Tai, P. -L. Higher-spin structures in F21 and Na25. United States: N. p., 2015. Web. doi:10.1103/PhysRevC.92.034301.
VonMoss, J. M., Tabor, S. L., Tripathi, Vandana, Volya, A., Abromeit, B., Bender, P. C., Caussyn, D. D., Dungan, R., Kravvaris, K., Kuchera, M. P., Lubna, R., Miller, S., Parker, J. J., & Tai, P. -L. Higher-spin structures in F21 and Na25. United States. doi:10.1103/PhysRevC.92.034301.
VonMoss, J. M., Tabor, S. L., Tripathi, Vandana, Volya, A., Abromeit, B., Bender, P. C., Caussyn, D. D., Dungan, R., Kravvaris, K., Kuchera, M. P., Lubna, R., Miller, S., Parker, J. J., and Tai, P. -L. Thu . "Higher-spin structures in F21 and Na25". United States. doi:10.1103/PhysRevC.92.034301.
@article{osti_1287013,
title = {Higher-spin structures in F21 and Na25},
author = {VonMoss, J. M. and Tabor, S. L. and Tripathi, Vandana and Volya, A. and Abromeit, B. and Bender, P. C. and Caussyn, D. D. and Dungan, R. and Kravvaris, K. and Kuchera, M. P. and Lubna, R. and Miller, S. and Parker, J. J. and Tai, P. -L.},
abstractNote = {We investigated excited states in F-21 and Na-25 using the Be-9(C-14, pn gamma) reaction at 30, 35, and 45 MeV and the Be-9(O-18, pn gamma) reaction at 35 MeV. We also detected protons and identified in an E-Delta E telescope at 0 degrees in coincidence with one or more gamma radiations in the FSU Compton-suppressed Ge detector array. Many new levels and electromagnetic decays were observed, especially among the higher spin states. Angular distributions and mean lifetimes were measured wherever possible in both nuclei. The energy levels of the positive-parity states in the two nuclei agree rather well with shell model calculations using both the USDA and WBP interactions up to the highest spins observed of 13/2 h. Both a weak coupling approximation and shell model calculations using the WBP interaction generally reproduce the negative-parity states in F-21. Finally, the shell model calculations reproduce relatively well the measured M1 and E2 transitions in both nuclei, but overpredict the parity-changing E1 transitions in F-21, the only nucleus in which negative-parity states were observed in the present experiment.},
doi = {10.1103/PhysRevC.92.034301},
journal = {Physical Review. C, Nuclear Physics},
issn = {0556-2813},
number = 3,
volume = 92,
place = {United States},
year = {2015},
month = {9}
}

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