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NEA-0892 ESTIMA.

ESTIMA, Neutron Width Level Spacing, Neutron Strength Function of S- Wave, P-Wave Resonances

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1. NAME OR DESIGNATION OF PROGRAM:  ESTIMA.
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2. COMPUTERS
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Program name Package id Status Status date
ESTIMA NEA-0892/01 Tested 04-NOV-1982

Machines used:

Package ID Orig. computer Test computer
NEA-0892/01 IBM 3033 IBM 3033
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3. DESCRIPTION OF PROBLEM OR FUNCTION

ESTIMA calculates level spacing and neutron strength function of a mixed sequence of s- and p-wave resonances given a set of neutron widths as input parameters. Three  algorithms are used, two of which calculate s-wave average parameters and assume that the reduced widths obey a Porter-Thomas distribution truncated by a minimum detection threshold. The third performs a maximum likelihood fit to a truncated chi-squared distribution of any specified number of degrees of freedom, i.e. it  can be used for calculating s-wave or p-wave average parameters. Resonances of undeclared angular orbital momentum are divided into groups of probable s-wave and probable p-wave by a simple application of Bayes' Theorem.
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4. METHOD OF SOLUTION

Three algorithms are used:
i)  GAMN method, based on simple moments properties of a Porter-
    Thomas distribution.
ii) Missing Level Estimator, a simplified version of the algorithm
    used by the program BAYESZ.
iii) ESTIMA, a maximum likelihood fit.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

A maximum of 400 resonances is allowed in the version available from NEADB, however this restriction can be relaxed by increasing array dimensions.
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6. TYPICAL RUNNING TIME

12 seconds of IBM 3033-11 CP time were required for three analyses, using each of the above three methods,  on 275 resonances.
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7. UNUSUAL FEATURES OF THE PROGRAM

The program requires a certain amount of user judgement to select the best average parameters from  the set of calculated estimates.
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8. RELATED AND AUXILIARY PROGRAMS:
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9. STATUS
Package ID Status date Status
NEA-0892/01 04-NOV-1982 Tested at NEADB
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10. REFERENCES:
NEA-0892/01, included references:
- E. Fort and J.P. Doat:
  ESTIMA - A Code to Calculate Average Parameters from Sets of
  Resolved Resonance Parameters.
  NEANDC-161-U  (June 1983)
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11. MACHINE REQUIREMENTS

190 Kbytes on an IBM 3033-11, excluding graphics routines.
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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
NEA-0892/01 FORTRAN-IV
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13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  OS/VS2.
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

The program was written to make use of the graphics routines available on the CISI system at Saclay, France. To obtain such output elsewhere, routines will have to be written to interface with the local computer graphics environment.
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15. NAME AND ESTABLISHMENT OF AUTHOR

E. Fort
CEN Cadarache
Boite postale no 1
Saint-Paul-Lez-Durance (France)
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16. MATERIAL AVAILABLE
NEA-0892/01
File name File description Records
NEA0892_01.003 ESTIMA INFORMATION FILE 170
NEA0892_01.004 ESTIMA SOURCE PROGRAM (FORTRAN-4) 1517
NEA0892_01.005 ESTIMA JCL TO COMPILE + LINKEDIT 7
NEA0892_01.006 ESTIMA JCL TO RUN TEST CASES 10
NEA0892_01.007 ESTIMA INPUT FOR TEST CASE 1 227
NEA0892_01.008 ESTIMA INPUT FOR TEST CASE 2 218
NEA0892_01.009 ESTIMA OUTPUT OF TEST CASE 1 638
NEA0892_01.010 ESTIMA OUTPUT OF TEST CASE 2 400
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17. CATEGORIES
  • A. Cross Section and Resonance Integral Calculations
  • B. Spectrum Calculations, Generation of Group Constants and Cell Problems

Keywords: porter-thomas distribution, resonance, unresolved region.