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

In order to process reaction “vectors” (as opposed to group-to-group trans-
fer matrices), one inputs data cards such as
3 103 *(N,P)*/
3 105/ .
Here MFD=3 specifies a vector, MTD=103 is the section to be processed, and
“(N,P)” is the user-supplied name for the reaction. This name is only used to
label the listing and is optional as shown by the second line. There are sev-
eral special MT-numbers recognized by NJOYwhile processing vectors.
MT Meaning
252 ~ (average scattering cosine)
253 ~ (average log decrement)
258 mean lethargy
259 mean reciprocal velocity
452 total fission yield
455 delayed fission yield
456 prompt fission yield
The first three are computed from fundamental definitions, not file 3. The last
three are computed using MF1 yields and MF3 fission cross sections.
To process one matrix reaction (that is, group-to-group scattering),
use MFD=6 as
The reaction
dictionary.
in this example:
6 16 *(N,2N)*/.
types with scattering data are most easily found under
Caution: MF4, MT103-15O are charged particle angular d
and should not be requested as matrices.
use
MF=4 in the
stribut ons
As a convenience feature, a consecutive sequence of MTDs can be specified
as follows.
3 51 *FIRST INELASTIC LEVEL*/
3 -76 *HIGHER INELASTIC LEVELS*/
6 51 *FIRST INELASTIC LEVEL*/
6 -76 *HIGHER INELASTIC LEVELS*/
All values of MTD from 51 through 76 will then be processed into both vectors and
matrices.
Fissionable materials introduce some additional complexity. GROUPR pro-
duces a prompt fission group-to-group matrix that can be converted into the
traditional &Jf and x vectors by later modules (for example, DTFR). For simple
evaluations, it is only necessary to make this request.
10
3 18 ‘FISSION XSEC*/
6 18 *FISSION MATRIX*/
.
r
*
8