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NEA-0834 DEEBAR.

DEEBAR, Resonance Level Spacing Calculation by Dyson-Metha Optimum Statistics

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1. NAME OR DESIGNATION OF PROGRAM:  DEEBAR.
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2. COMPUTERS
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Program name Package id Status Status date
DEEBAR NEA-0834/03 Report 26-JUL-1988

Machines used:

No item found

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3. DESCRIPTION OF PROBLEM OR FUNCTION

Calculates the mean spacing D
of the first, second, third, etc. resonances using the Dyson-Mehta optimum statistic.
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4. METHOD OF SOLUTION

The code is run interactively and the user examines the output and chooses what he feels to be the best values  for the number of resonances to be considered and for D noting for example that at the higher energies resources may have been missed through lack of resolution, which leads to a steady increase in successive values of D.
The program goes on to calculate the value of the level density parameter which corresponds to the chosen value of D, using a back-  shifted Fermi-gas model, and to calculate the values of D for dif- ferent spin states of the compound nucleus. Finally the observed resonance energies are compared with an energy ladder whose rungs are uniformly spaced; the deviations of the resonance from the lad-  der energies are tabulated, and their standard deviation. This com-  parative table indicates roughly just where resonances may have been missed, supposing the value of D well-chosen. Most probable values are given for the energies of the top bound resonances, these are estimated by use of Dyson's Coulomb gas model.
For materials such as iron the resolved resonances extend nearly to 1 MeV, and over so wide a range D must be expected to decrease steadily by a factor of two. If the resonance energies are input in keV units, DEEBAR uses the level density formalism to allow for the expected energy dependence, both in calculation of D values for  zero neutron energy and in the energy ladder.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM:
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6. TYPICAL RUNNING TIME:
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7. UNUSUAL FEATURES OF THE PROGRAM:
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8. RELATED AND AUXILIARY PROGRAMS:  LJPROB program to distinguish s-, p- and d-waves.
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9. STATUS
Package ID Status date Status
NEA-0834/03 26-JUL-1988 Report Only
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10. REFERENCES:
NEA-0834/03, included references:
- M. Booth, A.L. Pope, R.W. Smith and J.S. Story:
  DEEBAR - A Basic Interactive Computer Programme for Estimating
  Mean Resonance Spacings.
  AEEW-R 2003  (February 1988)
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11. MACHINE REQUIREMENTS:
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12. PROGRAMMING LANGUAGE(S) USED

No item found

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13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:
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15. NAME AND ESTABLISHMENT OF AUTHOR

          J. S. Story
          Reactor Physics Division
          Atomic Energy Establishment Winfrith
          Dorchester, Dorset DT2 8DH
          United Kingdom
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16. MATERIAL AVAILABLE
NEA-0834/03
report                   AEEW-R 2003  (February 1988)               REPPT
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17. CATEGORIES
  • A. Cross Section and Resonance Integral Calculations

Keywords: resolved region, resonance, spectra.