RSIC COMPUTER CODE PSR-082

1. NAME AND TITLE

DENIS: Monte Carlo Simulation of the Capture and Detection of Neutrons with Large Liquid Scintillators.

2. CONTRIBUTOR

Departement de Physique Nucleaire, CEA Centre d'Etudes Nucleaires de Saclay, Gif-sur-Yvette, France.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; IBM 360/370.

4. NATURE OF PROBLEM SOLVED

DENIS follows one neutron, given at zero time with a certain initial location energy and direction, in its interactions with a gadolinium-loaded liquid scintillator.

5. METHOD OF SOLUTION

DENIS Follows the neutron until it escapes from the assembly, it is captured by a nucleus of hydrogen or gadolinium, or the time limit for the experimental counting of this neutron is exceeded.

If the neutron has been captured in the specified time-gate,, the capturing nucleus de-excites with one or more gammas which again interact with the scintillator. The total amount of energy deposited by the gammas is calculated.

In order to obtain directly useful results, a loop is done over a given number of neutrons and the statistics over these neutrons are printed. For given initial conditions, one obtains the capture probability of the neutrons and their detection probability as a function of the threshold introduced by the detecting system.

6. RESTRICTIONS OR LIMITATIONS

The initial conditions concerning the neutrons must be introduced in the MAIN routine. The neutron energy in Mev, its location in cm, and its direction cosines must be known before statement MAIN 0024.

The geometrical routine GEOM deals with a sphere having a diametrical hole. GEOM must be replaced by another routine if the detector is not a sphere.

7. TYPICAL RUNNING TIME

No study has been made by RSIC of typical running times for DENIS.

8. COMPUTER HARDWARE REQUIREMENTS

DENIS is operable on the IBM 360/370 computers.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran IV compiler is required.

10. REFERENCES

J. Poitou, "DENIS: Detection Efficiency of Neutrons in Scintillators."

J. Poitou and C. Signarbieux, "A Monte-Carlo Simulation of the Capture and Detection of Neutrons with Large Liquid Scintillators," Nucl. Instr. and Meth. 114 (1974) 113-119.

11. CONTENTS OF CODE PACKAGE

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

12. DATE OF ABSTRACT

February 1984, updated December 1991.