The NJOY Nuclear Data Processing System, Volume 1:User's Manual

J. CCCCR
NGGRUP,MAXUP. .. In the current version of the code, these parameters
should both be zero. There is no coding for photon files and no provision for
upscatter.
ICHIX. . . Either a vector x or a matrix x can be produced by isotope; for
vectors, the GROUPR fission matrix can be collapsed with the library flux or an
input flux. There is no provision for a set x vector or x matrix.
IFOPT,NSBLK. .. Several options are available for blocking and subblocking
matrices. For large group structures, IFOPT=l and NSBLK=NGROUP are recommended.
K. MATXSR
NTYPE,NPART. .. A MATXS file can include any or all of four “types” of data;
neutron cross sections and transfer matrices (“NSCAT”), gamma production matri-
ces (“NGAMA”), photon interaction cross sections and transfer matrices (“GSCAT”),
and thermal neutron scattering (“NTHERM”). Depending on which data types are
desired, group structures will be required for neutron (“NEUT”) or photons
(“GAMA”) or both.
HTYPE,HPART,HMAT. .. Data types, particles, materials (and reactions) are
identified by Hollerith names rather than integer flags as in the CCCC formats.
Data type and particle names are left-justified.
*NSCAT *
*NEUT *
The MATXSR user need not be concerned with conventions for naming reactions, as
this is handled automatically.
In a typical MATXS run, the first several cards of input might be these.
-21 -22 23
1 1 *T2LASL NJOY*/
2 3 4
* */
*TYPICAL MATXS RUN WITH THREE DATA TYPES*/
*BASIC DATA FROM ENDF/B-IV*/
* */
*GAMA */
*NEUT *
30 12
*NSCAT* *NGAMA* *GSCAT */
In this example, three data types are requested for a MATXS file on unit 23.
Neutron interaction and gamma production data (in blocked binary) are input from
unit 21 and photon interaction data (in blocked binary) are to be found on unit
22. The code expects to find input data averaged over 30 neutron groups and 12
photon groups. Four cards of Hollerith identification are given.
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