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Title: Energy levels of {sup 251}Cf populated in the {alpha} decay of {sub 100}{sup 255}Fm and EC decay of {sub 99}{sup 251}Es

Abstract

Gamma-ray singles spectra of extremely pure (chemically and isotopically) samples of {sup 255}Fm, with strengths of {approx}1 mCi, have been measured with a high-resolution 2-cm{sup 2}x10-mm germanium LEPS detector and with a 25% Ge spectrometer. Gamma rays with intensities as low as 1.0x10{sup -6}% per {sup 255}Fm {alpha} decay have been identified. The electron spectrum of a mass-separated {sup 251}Es source was measured with a cooled Si(Li) electron spectrometer. The spectrum provided the conversion coefficients of low-energy transitions in {sup 251}Cf and thereby their multipolarities. The present measurements confirm the previous assignments of single-particle states in {sup 251}Cf. These include 1/2{sup +}[620], 0.0 keV; 7/2{sup +}[613], 106.30 keV; 3/2{sup +}[622], 177.59 keV; 11/2{sup -}[725], 370.47 keV; 9/2{sup -}[734], 433.91 keV; 5/2{sup +}[622], 543.98 keV; 1/2{sup -}[750], 632.0 keV; 9/2{sup +}[615], 683 keV; and 9/2{sup +}[604], 974.0 keV. A vibrational band was identified in previous studies at 981.4 keV and given an assignment of {l_brace}7/2{sup +}[613]x2{sup -}{r_brace}3/2{sup -}. Three new vibrational bands are identified in the present work at 942.5, 1086.5, and 1250.0 keV with tentative assignments {l_brace}7/2{sup +}[613]x1{sup -}{r_brace}5/2{sup -},{l_brace}7/2{sup +}[613]x1{sup -}{r_brace}9/2{sup -}, and {l_brace}7/2{sup +}[613]x0{sup +}{r_brace}7/2{sup +}, respectively. A level was identified at 1185.5 keV with spin of 5/2more » or 7/2 but it was not given any configuration assignment. Another level was identified at 1077.5 keV and given a spin of 9/2. Again, no configuration could be assigned to this level.« less

Authors:
; ; ; ; ; ;  [1];  [2]
  1. Argonne National Laboratory, Argonne, Illinois 60439 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
20699113
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 72; Journal Issue: 5; Other Information: DOI: 10.1103/PhysRevC.72.054308; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ALPHA DECAY; ALPHA PARTICLES; CALIFORNIUM 251; CONVERSION; EINSTEINIUM 251; ELECTRON SPECTRA; ENERGY-LEVEL TRANSITIONS; FERMIUM 255; GAMMA SPECTRA; KEV RANGE; L-S COUPLING; MULTIPOLARITY; SPIN; VIBRATIONAL STATES

Citation Formats

Ahmad, I., Greene, J.P., Moore, E.F., Kondev, F.G., Chasman, R.R., Porter, C.E., Felker, L.K., and Nuclear Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831. Energy levels of {sup 251}Cf populated in the {alpha} decay of {sub 100}{sup 255}Fm and EC decay of {sub 99}{sup 251}Es. United States: N. p., 2005. Web. doi:10.1103/PhysRevC.72.054308.
Ahmad, I., Greene, J.P., Moore, E.F., Kondev, F.G., Chasman, R.R., Porter, C.E., Felker, L.K., & Nuclear Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831. Energy levels of {sup 251}Cf populated in the {alpha} decay of {sub 100}{sup 255}Fm and EC decay of {sub 99}{sup 251}Es. United States. doi:10.1103/PhysRevC.72.054308.
Ahmad, I., Greene, J.P., Moore, E.F., Kondev, F.G., Chasman, R.R., Porter, C.E., Felker, L.K., and Nuclear Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831. Tue . "Energy levels of {sup 251}Cf populated in the {alpha} decay of {sub 100}{sup 255}Fm and EC decay of {sub 99}{sup 251}Es". United States. doi:10.1103/PhysRevC.72.054308.
@article{osti_20699113,
title = {Energy levels of {sup 251}Cf populated in the {alpha} decay of {sub 100}{sup 255}Fm and EC decay of {sub 99}{sup 251}Es},
author = {Ahmad, I. and Greene, J.P. and Moore, E.F. and Kondev, F.G. and Chasman, R.R. and Porter, C.E. and Felker, L.K. and Nuclear Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831},
abstractNote = {Gamma-ray singles spectra of extremely pure (chemically and isotopically) samples of {sup 255}Fm, with strengths of {approx}1 mCi, have been measured with a high-resolution 2-cm{sup 2}x10-mm germanium LEPS detector and with a 25% Ge spectrometer. Gamma rays with intensities as low as 1.0x10{sup -6}% per {sup 255}Fm {alpha} decay have been identified. The electron spectrum of a mass-separated {sup 251}Es source was measured with a cooled Si(Li) electron spectrometer. The spectrum provided the conversion coefficients of low-energy transitions in {sup 251}Cf and thereby their multipolarities. The present measurements confirm the previous assignments of single-particle states in {sup 251}Cf. These include 1/2{sup +}[620], 0.0 keV; 7/2{sup +}[613], 106.30 keV; 3/2{sup +}[622], 177.59 keV; 11/2{sup -}[725], 370.47 keV; 9/2{sup -}[734], 433.91 keV; 5/2{sup +}[622], 543.98 keV; 1/2{sup -}[750], 632.0 keV; 9/2{sup +}[615], 683 keV; and 9/2{sup +}[604], 974.0 keV. A vibrational band was identified in previous studies at 981.4 keV and given an assignment of {l_brace}7/2{sup +}[613]x2{sup -}{r_brace}3/2{sup -}. Three new vibrational bands are identified in the present work at 942.5, 1086.5, and 1250.0 keV with tentative assignments {l_brace}7/2{sup +}[613]x1{sup -}{r_brace}5/2{sup -},{l_brace}7/2{sup +}[613]x1{sup -}{r_brace}9/2{sup -}, and {l_brace}7/2{sup +}[613]x0{sup +}{r_brace}7/2{sup +}, respectively. A level was identified at 1185.5 keV with spin of 5/2 or 7/2 but it was not given any configuration assignment. Another level was identified at 1077.5 keV and given a spin of 9/2. Again, no configuration could be assigned to this level.},
doi = {10.1103/PhysRevC.72.054308},
journal = {Physical Review. C, Nuclear Physics},
number = 5,
volume = 72,
place = {United States},
year = {Tue Nov 01 00:00:00 EST 2005},
month = {Tue Nov 01 00:00:00 EST 2005}
}