last modified: 11-JUN-1982 | catalog | categories | new | search |

NEA-0660 BOB-7.

BOB-7, Ge(Li) Detector Gamma Spectra Unfolding

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1. NAME OR DESIGNATION OF PROGRAM:  BOB-7.
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2. COMPUTERS
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Program name Package id Status Status date
BOB-7 NEA-0660/01 Tested 11-JUN-1982

Machines used:

Package ID Orig. computer Test computer
NEA-0660/01 IBM 3033 IBM 3033
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3. DESCRIPTION OF PROBLEM OR FUNCTION

The BOB-7 programs analyse Ge(Li) gamma-ray spectra. The BOB-7 series consists of the individual codes BOB-73, BOB-73S and BOB-75.
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4. METHOD OF SOLUTION

The important subroutines and their functions are as follows:



BGSLOP: a subroutine for calculating the slope of the off-peak plateau in the low-energy side (BOB-75 only).



CALAF: a subroutine visualizing the obtained calibration curve in relation to the given standard data in energy calibration and efficiency correction.



DECAY: a function calculating the decay correction factor. It is effective only for the built-in Eu standard sources.



ENGEF: a subroutine for energy calibration and efficiency correction. The calibration can be carried out either by constructing the calibration curve (or the efficiency curve) with the internal or external standard peaks, or by giving the values of  the coefficients of the curve. The calibration curve for the energy  is fitted to a polynomial of the channel number, while the logarithm of the counting efficiency is expressed in a polynomial of the logarithm of the energy.



FINDSK: a subroutine for determining the line shape function of a typical peak in the spectrum; the obtained information is used in the succeeding subprogram, PKFIT, for analysing the rest of the peak groups in the spectrum. The procedure via FINDSK is, however, performed only when the peak shape changes remarkably with each data as in the case of the gamma-scanning of the reactor fuel rod.



FUNX: a function determining the smoothing condition for each peak group, to be used for the NaI(Tl) spectrum or for the spectra given  by the low-energy gamma-ray spectrometer.



GRAFIC: a subroutine visualising the result of the least squares fit.



LINEQ:  a subroutine for calculating the inverse matrix.



LIVET: a subroutine for calculating the live counting time when the  data have been acquired in the clock-time mode.



NLIEQ and NLNIJ: subroutines giving the values of the fitting function with/without tail and its first derivatives with respect to the involved free parameters at given values of the independent variable (the channel number).



NONLIN:  a subroutine for the non-linear least squares fit.



PKFIT: a subroutine for the peak-fitting procedure. The peak shape is approximated by an asymmetric Gaussian curve with/without tail in the low-energy side. The asymmetry factor and/or the shape of the tail are either fixed or unfixed in the least squares fit. The shape of the background level can be chosen among the linear, exponential, and various sigmoid curves.



PKREC:  a subroutine for the peak search.



POLIN: a subroutine for calculating the values of the coefficients of the calibration or efficiency curve and the involved errors.

POLIX: a subroutine for computing the energy and the counting efficiency of a given peak.

SMART: a subroutine for the data-smoothing following Savitzky- Golay's method.

SUBTRAX: a subroutine for detecting a weak peak buried in the natural background spectrum. The background spectrum is smoothed and then subtracted from the smoothed data of the relevant spectrum. The residues are cleared unless positive values continue over one FWHM. The resulting spectrum is smoothed once more and subjected to the succeeding peak-searching procedure.

Note: the program does not correct for the pile-up effect appear- ing in the measurement at a high counting rate, nor does it account  for channel shift during measurement.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Maximum number of channels is 4150 in BOB-73 and BOB-73S and 8200 in BOB-75. Spec- trum data of larger size can be handled using extra (included) subroutines.
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6. TYPICAL RUNNING TIME

For the analysis of the Eu152 spectrum which  consists of 4 partial spectra of 1024-channels measured using digital zero shift - 2 secs. For the analysis of a Pu237 spectrum in the Lx-ray region - 9 secs.
NEA-DB executed the sample case on IBM 3033 in 28 seconds.
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7. UNUSUAL FEATURES OF THE PROGRAM

This code does not require an accurate FWHM value given as input. A rough measure of the peak width is however still required.
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8. RELATED AND AUXILIARY PROGRAMS

BOB-73 and BOB-73S differ from each other mainly in the maximum multiplicity acceptable for a compound of peaks; 18 (with tail) or 19 (without tail) for the former, while 8 (with tail) or 9 (without tail) for the latter. The dis- tinctive feature of BOB-75 lies in the introduction of a taperwise step function as the base line under the peak, which proved to be the most desirable base-line function. The user is recommended to use BOB-75 unless he is content with a rather simplified data analysis with plane Gaussian.
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9. STATUS
Package ID Status date Status
NEA-0660/01 11-JUN-1982 Tested at NEADB
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10. REFERENCES

- H. Baba et al.:
  J. Nucl. Sci. Tech. (Tokyo) 8, 703 (1971).
- H. Baba et al.:
  JAERI 1227 (1973).
NEA-0660/01, included references:
- H. Baba:
  "Usage of the BOB7-Series Programs for the Analysis of Ge(Li)
  Gamma-Ray Spectra"
  JAERI-M 7017 (1977).
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11. MACHINE REQUIREMENTS:  500 kbytes of main storage on IBM 3033.
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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
NEA-0660/01 FORTRAN-IV
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13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:
OS370/033 VS2 03.8G (IBM 3033).
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

Input data may be plotted using the CALCOMP 900 plotter, if desired.
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15. NAME AND ESTABLISHMENT OF AUTHOR

          Hiroshi Baba
          Division of Radioisotope Production
          Radioisotope Center
          JAERI
          Japan.
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16. MATERIAL AVAILABLE
NEA-0660/01
File name File description Records
NEA0660_01.003 BOB-7 INFORMATION FILE 70
NEA0660_01.004 BOB-7, SOURCE CARD IMAGES (FORTRAN-4) 4077
NEA0660_01.006 BOB-7, SAMPLE CASE INPUT DATA FOR FT01 413
NEA0660_01.007 BOB-7, SAMPLE CASE INPUT DATA FOR SYSIN 6
NEA0660_01.008 BOB-7, SAMPLE CASE PRINTED OUTPUT 2484
NEA0660_01.009 BOB-7, JCL TO RUN SAMPLE PROBLEM 107
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17. CATEGORIES
  • O. Experimental Data Processing

Keywords: Gauss function, Li-drifted ge detectors, decay, gamma spectra, least square fit, radiation detectors, spectrometers.