CCC-0361: SANDYL, 3-D Time-Dependent and Space-Dependent Gamma Electron Cascade Transport by Monte-Carlo

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CCC-0361 SANDYL. (Abstract last modified 01-OCT-1980)

SANDYL, 3-D Time-Dependent and Space-Dependent Gamma Electron Cascade Transport by Monte-Carlo

Abstract Table of Contents:

1. NAME OR DESIGNATION OF PROGRAM - SANDYL.

2. COMPUTER FOR WHICH PROGRAM IS DESIGNED AND OTHER MACHINE VERSION PACKAGES AVAILABLE -

To request or retrieve programs click on the one of the active versions below. A password and special authorization is required.

Explanation of the status codes.

Program-name Package-ID Status SANDYL CCC-0361/01 Tested

Machines used: Package-ID Orig.Computer Test Computer CCC-0361/01 CDC CYBER 173 CDC CYBER 173

3. DESCRIPTION OF PROBLEM OR FUNCTION - SANDYL performs three- dimensional, time and space dependent Monte Carlo transport calculations for photon-electron cascades in complex systems.

4. METHOD OF SOLUTION - The problem geometry is divided into zones of homogeneous atomic composition bounded by sections of planes and quadrics. The material of each zone is a specified element or combination of elements.
For a photon history, the trajectory is generated by following the photon from scattering to scattering using the various probability distributions to find distances between collisions, types of collisions, types of secondaries, and their energies and scattering angles. The photon interactions are photoelectric absorption (atomic ionization), coherent scattering, incoherent scattering, and pair production. The secondary photons which are followed include bremsstrahlung, fluorescence photons, and positron-electron annihilation radiation.
The condensed-history Monte Carlo method is used for the electron transport. In a history, the spatial steps taken by an electron are precomputed and may include the effects of a number of collisions. The corresponding scattering angle and energy loss in the step are found from the multiple scattering distributions of these quantities. Atomic ionization and secondary particles are generated with the step according to the probabilities for their occurrence.
Electron energy loss is through inelastic electron-electron collisions, bremsstrahlung generation, and polarization of the medium (density effect). Included in the loss is the fluctuation due to the variation in the number of energy-loss collisions in a given Monte Carlo step (straggling). Scattering angular distributions are determined from elastic nuclear-collision cross sections corrected for electron-electron interactions. The secondary electrons which are followed included knock-on, pair, Auger (through atomic ionizations), Compton, and photoelectric electrons.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM - The energy range is generally limited to 1 keV-1 GeV by the information in the electron data files EXSEC. The photon data file PXSEC contains cross sections in the range 10 eV to 1 GeV.
The code deals with a maximum of 110 zones, specified by maxima of 100 conic surfaces and 75 planes.

6. TYPICAL RUNNING TIME - 12 seconds on a CDC 6600 for a sample problem consisting of 9 zones.

7. UNUSUAL FEATURES OF THE PROGRAM - To obtain generality, sacrifices are made in efficiency. A user may be able to achieve significant economies in computer run time either by programming modifications or by the judicial use of the zoning and variance reduction techniques available in the code and discussed in the main reference.

8. RELATED AND AUXILIARY PROGRAMS -

9. STATUS
CCC-0361/01: 01-OCT-1980 Tested at NEADB

10. REFERENCES  -
- H.M. Colbert:
  SANDYL - A Computer Program for Calculating Combined Photon-
  Electron Transport in Complex Systems.
  SLL-74-0012 (May 1974).
CCC-0361/01:

11. MACHINE REQUIREMENTS - The largest overlay requires 330,000 octal words. In addition to the card image input, the program requires disc or tape input files for the electron and photon cross section data.

12. PROGRAMMING LANGUAGE(S) USED -
CCC-0361/01: FORTRAN-IV

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED - SCOPE 3.3.

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS -
SANDYL is a FORTRAN computer program coded to run on the CDC 6600. It consists of card input, a photon data file, an electron data file and the transport program TMAPQ which, in turn, consists of a resident program and four overlays.
The program is written in FORTRAN IV and is in a form compatible with the requirements of the CDC 6600 FORTRAN EXTENDED compiler (FTN 3.0). The program can be run on the CDC 6600 RUN compiler with minor modifications; i.e., the form of the IF UNIT and IF EOF checks must be revised and the 1P specification must be removed from those output format specifications where it appears.

15. NAME AND ESTABLISHMENT OF AUTHOR -
          L.G. Haggmark
          Analytical Division 8341
          Sandia Laboratories
          Livermore
          California 94550
          USA

16. MATERIAL AVAILABLE -
CCC-0361/01:
CCC0361_01.001    SOURCE                                          12429 records
CCC0361_01.002    PHOTON DATA FILE                                12759 records
CCC0361_01.003    ELECTRON DATA FILE                               6802 records
CCC0361_01.004    INPUT DATA FOR S.P.                                38 records
CCC0361_01.005    PRINTED OUTPUT OF S.P.                           6811 records

17. CATEGORIES -

- F. Space
Time Kinetics, Coupled Neutronics Hydrodynamics Thermodynamics
- J. Gamma Heating and Shield Design

Keywords: ELECTRONS, GAMMA RADIATION, MONTE CARLO METHOD, PHOTON TRANSPORT, PHOTONS, TRANSPORT THEORY