NESC0742 CASIM

1. NAME OR DESIGNATION OF PROGRAM:  CASIM

3. DESCRIPTION OF PROBLEM OR FUNCTION

CASIM   is  a   Monte   Carlo
program to study  the average development of  high energy cascades
in large targets (shields) of  arbitrary geometry and composition.
The program  is best  suited for  incident energies  in the  range
20-1000 GeV.

4. METHOD OF SOLUTION

The   simulation  makes   extensive  use   of
weighting techniques to avoid difficulties encountered in sampling
complicated distributions and to allow  the user to introduce bias
in the sampling.   The program uses the  particle production model
(in the form  of a set of inclusive distributions)  to compute (a)
star densities (i.e. nuclear interaction  densities) as a function
of location and  particle type throughout the  target.  From these
star  densities,   estimates  of   a  number   of  quantities   of
radiobiological interest can be obtained;  (b) momentum spectra of
particles interacting in the shield also as a function of location
and type; (c) energy deposited by the cascade.  This quantity is a
useful  measure   of  target  heating   embedded  in   the  target
(ionization calorimeter).

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

The  program  does
not study transport of low momentum  particles (less than or equal
to 0.3 GeV/c).

6. TYPICAL RUNNING TIME

Running time is highly problem dependent. The NESC executed the sample problem in 35 CPU minutes and the modification problem (see item 14) in 15 CPU minutes on an IBM370/195.

NEA-DB executed the test cases included in this package on an IMB 3084 computer. The more general case required 19 minutes of CPU time.

7. UNUSUAL FEATURES OF THE PROGRAM:

8. RELATED AND AUXILIARY PROGRAMS:

10. REFERENCES:

- A. Van Ginneken:
  CASIM - Program to Simulate Transport of Hadronic Cascades in Bulk
  Matter
  FN-272 (January 1975).
- K. Hillstrom:
  DSIN/DCOS, OS/360-FORTRAN IV Compatible Routine for the Sine and
  Cosine Function
  B158S (October 1969) Revised by J. Wang (July 1975 and August
  1977).
- J. Wang:
  EXP - Exponential Function (single precision)
  B356S (October 1977).
- Donald F. Jordan:
  ARGPOWER, IBM S/360 FORTRAN IV Single-precision Power Function
  B457S (January 1968) Revised by W.J. Cody (February 1969 and
  October 1974) and by J. Wang (October 1977).

11. MACHINE REQUIREMENTS:  350K of memory, tape drives, line printer

The test cases ran on IBM 3084 in 316K bytes of main storage.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:   OS/370,360.

MVS-SP (IBM 3084).

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

   The
star  (or   energy)  densities   and  momentum   spectra  normally
calculated by CASIM are not always  the information best suited to
the user.  As an example of how the program can be modified by the
user, the  application of  CASIM to a  highly specific  problem is
included.   Also included  in  this  package are  three  Assembler
routines (DSIN,  ESP, FRXPR)  from a  library at  Argonne National
Laboratory.  If the program is run  without these routines, a vast
number of underflows  may appear, affecting the  efficiency of the
program.  There  will also be a  slight difference in  the answers
from those provided by the author.

15. NAME AND ESTABLISHMENT OF AUTHOR

                 A. Van Ginneken
                 Fermi National Accelerator Laboratory
                 P. O. Box 500
                 Batavia, Illinois  60510

File name	File description	Records
NESC0742_01.001	Information file	65
NESC0742_01.002	CASIM source program (fortran IV)	3049
NESC0742_01.003	CASIM source program for biased problem	3210
NESC0742_01.004	ARGONNE mathematical routines (assembler)	735
NESC0742_01.005	CASIM input data for general problem	6
NESC0742_01.006	CASIM output printing for general problem	5060
NESC0742_01.007	CASIM input for biased problem	5
NESC0742_01.008	CASIM output printing for biased problem	560