skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Level structure of {sup 26}Si and its implications for the astrophysical reaction rate of {sup 25}Al(p,{gamma}){sup e26}Si.

Abstract

No abstract prepared.

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC); Engineering and Physical Sciences Research Council (EPSRC); National Science Foundation (NSF)
OSTI Identifier:
914914
Report Number(s):
ANL/PHY/JA-58348
Journal ID: ISSN 0556-2813; PRVCAN; TRN: US200817%%12
DOE Contract Number:
DE-AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Phys. Rev. C; Journal Volume: 75; Journal Issue: 2007
Country of Publication:
United States
Language:
ENGLISH
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; NUCLEAR REACTION KINETICS; SILICON 26; ALUMINIUM 25; ELECTRONIC STRUCTURE

Citation Formats

Seweryniak, D., Woods, P. J., Carpenter, M. P., Davinson, T., Janssens, R. V. F., Jenkins, D. G., Lauritsen, T., Lister, C. J., Shergur, J., Sinha, S., Woehr, A., Physics, Univ. of Edinburgh, Univ. of York, Univ. of Maryland, and Univ. of Notre Dame. Level structure of {sup 26}Si and its implications for the astrophysical reaction rate of {sup 25}Al(p,{gamma}){sup e26}Si.. United States: N. p., 2007. Web.
Seweryniak, D., Woods, P. J., Carpenter, M. P., Davinson, T., Janssens, R. V. F., Jenkins, D. G., Lauritsen, T., Lister, C. J., Shergur, J., Sinha, S., Woehr, A., Physics, Univ. of Edinburgh, Univ. of York, Univ. of Maryland, & Univ. of Notre Dame. Level structure of {sup 26}Si and its implications for the astrophysical reaction rate of {sup 25}Al(p,{gamma}){sup e26}Si.. United States.
Seweryniak, D., Woods, P. J., Carpenter, M. P., Davinson, T., Janssens, R. V. F., Jenkins, D. G., Lauritsen, T., Lister, C. J., Shergur, J., Sinha, S., Woehr, A., Physics, Univ. of Edinburgh, Univ. of York, Univ. of Maryland, and Univ. of Notre Dame. Mon . "Level structure of {sup 26}Si and its implications for the astrophysical reaction rate of {sup 25}Al(p,{gamma}){sup e26}Si.". United States. doi:.
@article{osti_914914,
title = {Level structure of {sup 26}Si and its implications for the astrophysical reaction rate of {sup 25}Al(p,{gamma}){sup e26}Si.},
author = {Seweryniak, D. and Woods, P. J. and Carpenter, M. P. and Davinson, T. and Janssens, R. V. F. and Jenkins, D. G. and Lauritsen, T. and Lister, C. J. and Shergur, J. and Sinha, S. and Woehr, A. and Physics and Univ. of Edinburgh and Univ. of York and Univ. of Maryland and Univ. of Notre Dame},
abstractNote = {No abstract prepared.},
doi = {},
journal = {Phys. Rev. C},
number = 2007,
volume = 75,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • A study of the level structure of {sup 26}Si using in-beam {gamma}-ray spectroscopy is presented. A full level scheme is derived incorporating all states lying below the proton threshold energy. The results are in good agreement with shell model predictions and one-to-one correspondence is found with states in the mirror nucleus {sup 26}Mg. Additionally, a {gamma}-decay branch is observed from a state at 5677.0(17) keV, which is assigned to a 1{sup +} resonance important in the astrophysical reaction {sup 25}Al(p,{gamma}){sup 26}Si. The newly derived resonance energy, E{sub r}=159.2(35) keV, has the effect of decreasing the reaction rate at the novaemore » ignition temperature of {approx_equal}0.1 GK by a factor of {approx_equal}2 when compared with the previous most precise measurement of this state.« less
  • Several resonances in {sup 25}Al(p,{gamma}){sup 26}Si have been studied via the {sup 28}Si(p,t){sup 26}Si reaction. Triton energies and angular distributions were measured using a segmented annular detector array. An additional silicon detector array was used to simultaneously detect the coincident protons emitted from the decay of states in {sup 26}Si above the proton threshold in order to determine branching ratios. A resonance at 5927{+-}4 keV has been experimentally confirmed as the first l=0 state above the proton threshold, with a proton branching ratio consistent with one.
  • We present theoretical results for the {sup 25}Al(p,{gamma}){sup 26}Si resonance-capture rate. The isobaric mass multiplet equation is used to determine the energies and J{sup {pi}} values of states in {sup 26}Si based upon those observed in {sup 26}Mg and {sup 26}Al together with sd shell calculations for the c coefficients. Three Hamiltonians for the sd shell, USD, USDA and USDB, are used to estimate the theoretical uncertainties in the {gamma}-decay and proton-decay widths that go into the resonance-capture rate.
  • The nuclear physics uncertainty associated with the production of the Galactic {beta}-delayed {gamma}-ray emitter {sup 26}Al in classical novae is currently dominated by the uncertainty in the thermonuclear {sup 25}Al(p,{gamma}){sup 26}Si reaction rate. By combining the results of recent experiments with past work, the center-of-mass energy of the key J{sup {pi}}=3{sup +}, {sup 25}Al(p,{gamma}){sup 26}Si resonance is determined to be 412(2) keV, and a lower limit of {gamma}{sub p}/{gamma}{sub {gamma}}>5.6 is set for this resonance. The resulting large reduction in the {sup 25}Al(p,{gamma}){sup 26}Si rate uncertainty is expected to constrain uncertainties in the nova contribution to Galactic {sup 26}Al.
  • The first in-beam {gamma}-ray spectroscopy study of {sup 24}Al is presented. A complete level structure of {sup 24}Al incorporating all states below the proton-emission threshold, has been constructed. The first excited state above the proton threshold has also been identified as a 3{sup +} state at 2345.1 {+-} 1.4 keV. This state, corresponding to a resonance energy of 473 {+-} 3 keV, has been suggested to be the dominant resonance contributing to the {sup 23}Mg(p,{gamma}){sup 24}Al stellar reaction rate. The improved precision of the level energy and unambiguous assignment of the state has reduced the uncertainty of the {sup 23}Mg(p,{gamma}){supmore » 24}Al stellar reaction rate, which constrains the production of A > 20 nuclei in ONe novae.« less