RSIC COMPUTER CODE PSR-062

1. NAME AND TITLE

MORN: Calculation of the Response of Sodium Iodide Crystals to Gamma Rays.

MORN is a revised version of the Zerby-Moran code.

2. CONTRIBUTOR

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; IBM 360/370.

4. NATURE OF PROBLEM SOLVED

MORN calculates the response of sodium iodide scintillators to gamma rays of energies up to 10.22 MeV. Output options include 8-1/2 x 11 inch semi-log plots (histograms) of the unbroadened Compton spectrum (without the effects of secondary radiations) and of the total response spectrum (including the effects of detector resolution). A plot of the unbroadened Compton spectrum (with secondaries) with error flags is also available. The printed output includes not only the intrinsic efficiency and the photofraction but also the first and second escape peak efficiencies.

5. METHOD OF SOLUTION

This version of MORN was designed to be used with a master cross-section tape so that the gamma-ray response of any desired material could be obtained by reading the appropriate cross sections from the tape. The code has been modified to include not only cylindrical geometry but also slab geometry (a popular configuration for solid state detectors). MORN was also modified to compute and print out the single and double escape efficiencies and their statistical errors.

6. RESTRICTIONS AND LIMITATIONS

None noted.

7. TYPICAL RUNNING TIME

Computing time varies directly with the number of histories and depends to a lesser extent on source energy and detector size and configuration. An appreciable fraction of the computing time is associated with calculating the effects of secondary radiations.

8. COMPUTER HARDWARE REQUIREMENTS

MORN is operable on the IBM 360/370 computers.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran IV compiler is required.

10. REFERENCES

J. L. Rodda, II, "A Revised Zerby-Moran Code for Calculating the Response of Sodium Iodide Crystals to Gamma Rays," ORNL-TM-2579 (June 1969).

C. D. Zerby and H. S. Moran, "IBM-704 Codes for Predicting the Response of Gamma-Ray Scintillation Counters," CF-60-5-72 (May 1960).

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents and one (1.2MB) DOS diskette which contains the source code and sample problem input.

12. DATE OF ABSTRACT

February 1984.