PSR-0261 MICAP.

1. NAME OR DESIGNATION OF PROGRAM:  MICAP.

3. DESCRIPTION OF PROGRAM OR FUNCTION

MICAP has been developed to determine the response of a gas-filled cavity ionization chamber or  other detector type (plastic scintillator, calorimeter) in a mixed neutron and photon radiation environment. In particular, MICAP determines the neutron, photon, and total response of the detector system. The applicability of MICAP encompasses all aspects of mixed  field dosimetry analysis including detector design, pre-experimental planning and post-experimental analysis. MICAP is a modular code system developed to be general with respect to problem applicability The transport modules utilize combinatorial geometry to accurately model the source/detector geometry and also use continuous energy and angle cross section and material data to represent the materials for a particular problem.

4. METHOD OF SOLUTION

The calculational scheme used in MICAP follows  individual radiation particles incident on the detector wall material. The incident neutrons produce photons and heavy charged particles, and both primary and secondary photons produce electrons  and positrons. As these charged particles enter or are produced in the detector material, they lose energy and produce ion pairs until  their energy is completely dissipated or until they escape the detector. Ion recombination effects are included along the path of each charged particle rather than applied as an integral correction  to the final result. The neutron response is determined from the energy deposition resulting from the transport of the charged particles and recoil heavy ions produced via the neutron interactions with the detector materials. The photon response is determined from the transport of both the primary photon radiation incident on the detector and also the secondary photons produced via the neutron interactions. MICAP not only yields the energy deposition by particle type and total energy deposited, but also the particular type of reaction, i.e. elastic scattering, inelastic scattering, (n,p), (n,alpha), etc., which produced the particle depositing the energy. Physics to handle ENDF/B-V partial cross section data have been incorporated in the neutron transport module  to account for all processes which may contribute to the output signal. The transport modules utilize continuous angular distribution and secondary energy distribution data when selecting the emergent direction and energy of a particle. Furthermore, reactions are treated as discrete and are allowed to occur with any  of the constituent nuclides comprising a mixture. Finally, MICAP incorporates a combinatorial geometry package and input cross section processors to eliminate restrictions in the modeling capability of the code system with respect to geometry, physical processes, nuclear data and sources.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Present dimensions limit the number of media to 10 in PHOTON. Dimensions restrict the number of media to 15 and the number of nuclei per medium to 11 in the RECOMB module. The RDNDF module is currently configured to process one nuclide at a time.

6. TYPICAL RUNNING TIME

Running time is problem dependent. The sample problem requires no more than 25 seconds in any individual module.

7. UNUSUAL FEATURES OF THE PROGRAM:

8. RELATED AND AUXILIARY PROGRAMS

ENDF/B-V data pre-processed through the RESEND5-LINEAR/SIGMA1 programs so that all cross section data are linearly interpolable over the entire energy range have been included in the package for the following nuclides: hydrogen, carbon, nitrogen, oxygen, fluorine, aluminum, argon and calcium. Pair production data is also included for input to PESCP.

RDNDF Reads and processes ENDF/B-formatted x-sec files MICRO               Manipulates the microscopic x-sec datasets
MACRO               Creates macroscopic x-sec data sets
NEUTRON             Neutron transport module
RECOMB              Calculates the saturation effects corrections
PECSP               Generates photon and electron x-sec and
                    material data
PHOTPREP            Generates photon source input for PHOTON
PHOTON              Photon and electron transport module

10. REFERENCES

- J.O. Johnson and T.A. Gabriel:
  Development and Evaluation of a Monte Carlo Code System for
  Analysis of Ionization Chamber Responses
  ORNL/TM-10196 (July 1987)

- J.O. Johnson and T.A. Gabriel:
  A User's Guide to MICAP - A monte Carlo Ionization Chamber
  Analysis Package
  ORNL/TM-10340 (January 1988).

11. MACHINE REQUIREMENTS

MICAP is operable on the IBM3033 computer. Core storage required varies among modules. Typical problems require approximately 1000 Kbytes of memory.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED

The FORTRAN H-Exetended Enhanced compiler was used under MVS.

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:

15. NAME AND ESTABLISHMENT OF AUTHORS

      Oak Ridge National Laboratory,
      Oak Ridge, Tennessee
      United States

source program   mag tapeRDNDF Fortran IV source file               SRCTP
source program   mag tapeMICRO Fortran IV source file               SRCTP
source program   mag tapeMACRO Fortran IV source file               SRCTP
source program   mag tapeNEUTRON Fortran IV source file             SRCTP
source program   mag tapeRECOMB Fortran IV source file              SRCTP
source program   mag tapeHEAVY Fortran IV source file               SRCTP
source program   mag tapePESCP Fortran IV source file               SRCTP
source program   mag tapePHOTREP Fortran IV source file             SRCTP
source program   mag tapePHOTON  Fortran IV source file             SRCTP
source program   mag tapeNEUTRON Assembler source file              SRCTP
source program   mag tapeHEAVY Assembler source file                SRCTP
source program   mag tapePTOTREP Assembler source file              SRCTP
source program   mag tapePHOTON Assembler source file               SRCTP
symb data lib    mag tapeHYDROGEN ENDF/B-V data library             LBSTP
symb data lib    mag tapeCARBON ENDF/B-V data library               LBSTP
symb data lib    mag tapeNITROGEN ENDF/B-V data library             LBSTP
symb data lib    mag tapeOXYGEN ENDF/B-V data library               LBSTP
symb data lib    mag tapeFLUORINE ENDF/B-V data library             LBSTP
symb data lib    mag tapeALUMINUM ENDF/B-V data library             LBSTP
symb data lib    mag tapeARGON ENDF/B-V data library                LBSTP
symb data lib    mag tapeCALCIUM ENDF/B-V data library              LBSTP
test-case data   mag tapePHPRNM.DAT PECSP pair production data      DATTP
test-case data   mag tapeRDNDF JCL and sample input data            DATTP
test-case data   mag tapeMICRO JCL and sample input data            DATTP
test-case data   mag tapeMACRO JCL and sample input data            DATTP
test-case data   mag tapeNEUTRON JCL and sample input data          DATTP
test-case data   mag tapeRECOMB JCL and sample input data           DATTP
test-case data   mag tapeHEAVY JCL and sample input data            DATTP
test-case data   mag tapePECSP JCL and sample input data            DATTP
test-case data   mag tapePHOTPREP JCL and sample input data         DATTP
test-case data   mag tapePHOTON JCL and sample input data           DATTP
test-case output mag tapeRDNDF sample output                        OUTTP
test-case output mag tapeMICRO sample output                        OUTTP
test-case output mag tapeMACRO sample output                        OUTTP
test-case output mag tapeNEUTRON sample output                      OUTTP
test-case output mag tapeRECOMB sample output                       OUTTP
test-case output mag tapeHEAVY sample output                        OUTTP
test-case output mag tapePECSP sample output                        OUTTP
test-case output mag tapePHOTPREP sample output                     OUTTP
test-case output mag tapePHOTON sample output                       OUTTP
report                   ORNL/TM-10340 (January 1988)               REPPT