CCC-0156 MECC-7.

1. NAME OR DESIGNATION OF PROGRAM:  MECC-7

3. DESCRIPTION OF PROGRAM OR FUNCTION

MECC-7 calculates the results of nuclear reactions caused by a medium-high energy particle colliding with a nucleus. The incident particles may be protons or neutrons with energies from about 100 to 2500 MeV or charged pions with energies from about 100 to 1500 MeV. Target nuclei may be any element heavier than carbon. MECC-7 writes a history tape containing data on the properties of the particles escaping from the nucleus as a result of the particle-nucleus collision. The data consist of the type of escaping particles, their energies, and angles of emission.

I4C utilizes the data on the MECC-7 history tape to calculate particle multiplicities and various cross sections, such as the nonelastic cross section or the doubly-differential cross section for energy-angle correlated distributions. I4C also carries the nuclear reaction through an additional phase, that of evaporation, and calculates evaporation residual nuclei (radiochemical) cross sections and the particle multiplicities and energy spectra of particles
"boiled off" from the nucleus after the cascade has stopped.

4. METHODS

The code system is based on the assumption that nuclear reactions involving high-energy particles can be described in terms of particle-particle collisions within the nucleus. The life history of each individual particle is traced as the incident particle, and the subsequent generations of particles involved in collisions, wind their way through the nucleus. The point of collision, the type of collision, the momentum of the struck nucleon, and the scattering angles for each collision are determined by statistical sampling techniques. Free-particle experimental data are used whenever cross-section data are required. Cross sections and distributions resulting from the nuclear reaction are calculated in I4C by taking the average value of many results.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

There are no known restrictions implied by storage allocation. Target nuclei may be any element from 4He to 239Pu. Incident particle energies must be 1
MeV or greater. Incident nucleon energies must be less than 3500 MeV, and incident pion energies must be less than 2500 MeV. The results are expected to be valid only over the ranges described in section 4. The maximum possible number of incident particle histories is 999,999.

6. TYPICAL RUNNING TIME

The approximate running times on the IBM 360/91 per 1000 incident particles ranged from 0.26 minutes for a 1-GeV particle on oxygen to 3.3 minutes for the same energy particle on lead, and from 0.4 minutes for a 2.5-GeV particle on oxygen to 6.2 minutes for the same energy particle on lead. The I4C analysis with all options takes approximately 1/5 of the MECC-7 running time.

8. RELATED OR AUXILIARY PROGRAMS

AUXILIARY ROUTINES:

MECC-7 Cascade data generator.
I4C: Cascade Data Analysis, combined form of 4 routines: Analysis I, Analysis II, Evaporation, and Angular Momentum.
NUCON: CS update code.
CONV: BCD-to-binary converter for data libraries.
ANG: Angular momentum distribution calculation.
Non-standard library subroutines.

DATA LIBRARIES:
CS: Nuclear Configuration Data and Cross Sections for MECC-7.
ET: Evaporation Table for EVAP.

Originally packaged as MECC-3 (1971), MECC-7 is the latest in this series of ORNL intranuclear cascade code development.

- H.W. Bertini, M.P. Guthrie and O.W. Hermann
"Instructions for the Operation of Codes Associated with
MECC-7, A Preliminary Version of an Intranuclear-Cascade
Calculation for Nuclear Reactions".
ORNL-4564 (May 1971), (updated code version 1973).
-R.L.Hahn and O.W. Hermann
"Inclusion of Fission and Charged-Particle Emission in
Calculations of Nuclear Reactions; Computer Energies
Angles, and Ranges of Recoil Nuclei,"
ORNL-TM-3179 (April 1971)
- Miriam P.Guthrie:
"EVAP-4: Another Modification of a Code to Calculate
Particle Evaporation from Excited Compound Nuclei",
ORNL-TM-3119 (September 1970)
- Contents of MECC Primary Output Tape
- Contents of Nuclear Configuration Tape
- Hugo W.Bertini and Miriam P.Guthrie;
"Results from Medium-Energy Intranuclear-Cascade Calculation"
Nucl.Phys. A169, (1971) 670-672
- Hugo W.Bertini;
"Nonelastic Interactions of Nucleons and Mesons with Complex
Nuclei at Energies Below 3 GeV"
Phys.Rev.C Vol.6, No.2 (August 1972), 631-659
- Hugo W.Bertini;
"Intranuclear-Cascade Calculation of the Secondary Nucleon
Spectra from Nucleon-Nucleus Interactions in the Energy Range
240 to 2900 MeV and Comparisons with Experiment",
Phys.Rev. Vol.188, No.4 (December 1969) 1711-1730
- Hugo W.Bertini;
"Low-Energy Intranuclear Cascade Calculation",
Phys.Rev. Vol. 138, No. 7AB, AB2 (June 1965)
- Hugo W.Bertini;
"Low-Energy Intranuclear Cascade Calculation"
Phys.Rev. Vol 131, No.4 (August 1963) 1801-1821

11. HARDWARE REQUIREMENTS

The codes were designed for the IBM 360/75/91 with standard I-O and a maximum of 6 tape units or direct access devices. Maximum core size required ~ 1020K.

13. SOFTWARE REQUIREMENTS

The packaged codes were run on the IBM 360/75/91 Operating System using OS-360 FORTRAN H Compiler.
I4C uses the overlay feature and was compiled with OPT = 2.

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

Non-standard library subroutines are in Assembly Language.

15. NAME AND ESTABLISHMENT OF AUTHOR

Contributed by: Radiation Safety Information Computational Center
                Oak Ridge National Laboratory
                Oak Ridge, Tennessee, USA
Developed by:   Oak Ridge National Laboratory
                Oak Ridge, Tennessee, USA

Readme.rsi  readme file
Mecc7.exe  Compressed file