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The following is a typical first line of the file `mcfgen.input',
0 1 1 6 1 33 2 0 0 00
(In practice several of the zeros are usually replaced by spaces,
but these spaces are read as zeros.) The spacing is rigidly
prescribed by the format,
READ(iocins,'(i6,1x,6(i2,1x),3x,i2, i3, 17x, 2i1)',
& nnzab, iyi, iyo, ngpi, nflx, nppbe, ntmp,
& idum, nclibtyp, nfiss, nsup
The meanings of these values is as follows.
- The atomic number and mass number (
1000*Z + A)
for this target. The value
= 0 is most common, and
it serves as a flag indicating that nnzab is overwritten by
the next line in the `mcfgen.input' file. A value of A = 0 denotes the natural element, so that
ZA = 28000 represents
natural nickel. The special values
ZA = 99120 and 99125 denote,
respectively, short-lived and long-lived fission fragments.
- The identifier for the incident particle. See
Section 2.1. In the example above the `1' denotes a
- The identifier for the secondary particle. In the
example line we have a neutron,
= 1. This parameter
is not used.
> 0, it identifies which energy
group bounds are to be read from the `bdfls' file. In the
instance above we have
= 6, so we take the collection
of energy groups labeled `6' (175 groups with 20 Mev maximum).
Note that for incident charged particles we usually have
= 71 giving 63 energy groups with 20 Mev maximum, and
for incident photons the standard value is
= 80 for
175 groups with 30 Mev maximum. In order to specify the energy
group boundaries from the `mcfgen.input' file, one sets
- A flux identifier. This is the flag specifying
flux data in the `bdfls' file. The value
gets an energy-independent flux. In order to get a non-constant
flux, one may specify one of the other flux identifiers in the
`bdfls' file, or one may set
= 0, denoting that
flux is given in the `mcfgen.input' file.
- The number of equiprobable angular bin
boundaries (33 here) for data type
= 3. This is
reset to 17 if it is 0 here. The number of equiprobable angular
bins is one less.
- The temperature identifier. Usually,
> 0 and it is the flag for temperature data in the `bdfls'
file. In the example it is
= 2, giving the set `2'
of temperatures. If
= 0, we get the temperatures
from the `mcfgen.input' file. In fact, there is to be
only one temperature because Doppler broadening is not done
- Unused (an old debug option).
- Defines the data type:
- The output is in terms of bin averages.
- The output is grid based. This option
is used only for incident photons.
- Not used by mcfgen.
- The temperature or level range request sentinel.
- No special excitation levels or range of
temperatures. This is the usual choice.
- Read in the range of excitation levels from
the input file `mcfgen.input'.
- Get the range of temperatures from the
`mcfgen.input' file. But note again that there can
be only one temperature because mcfgen does not handle
- Read in the ranges of excitation levels
and temperatures from the `mcfgen.input' file.
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