File 6 - Discrete Two-Body Scattering (LAW=2)

This law is used to describe the distribution in energy and angle of particles described by two-body kinematics. It is very similar to File 4, except its use in File 6 allows the concurrent description of the emission of positrons, electrons, photons, neutrons, charged particles, residual nuclei, and isomers. Since the energy of a particle emitted with a particular scattering cosine μ is determined by kinematics, it is only necessary to give

where the P_l are the Legendre polynomials with the maximum order NL. Note that the angular distribution p_i is normalized.

The following quantities are defined for LAW=2:

LANG: flag that indicates the representation:
LANG=0, Legendre expansion;
LANG=12, tabulation with p_i(μ) linear in μ
LANG=14, tabulation with lnp_i(μ) linear in μ.
NR,NE,EINT: standard TAB2 parameters
NL: for LANG=0, NL is the highest Legendre order used,
for LANG>0, NL is the number of cosines tabulated.
NW: number of parameters given in the LIST record:
for LANG=0, NW=NL;
for LANG>0, NW=2*NL.
AL: for LANG=0, the Legendre coefficients,
for LANG>0, the μ,p_i pairs for the tabulated angular distribution.

The format for a subsection with LAW=2 is

     [MAT, 6, MT/ 0.0, 0.0, 0, 0, NR, NE/ EINT] TAB2
     [MAT, 6, MT/ 0.0, E1, LANG, 0, NW, NL/ AL(E1)] LIST
                  --------------------
                  continue with LIST records for the
                  rest of the incident energies
                  --------------------

Note that LANG=0 is very similar to File 4 with LTT=1 and LVT=0. The tabulated option is similar to File 4 with LTT=2 and LVT=0, except that a LIST record is used instead of TAB1. The kinematical equations require AWR and AWP from File 6 and QI from File 3.

LAW=2 can be used in sections with MT=50-90, 600-648, 650-698, etc. only, and the center-of-mass system must be used (LCT=2).

23 January 1998

T-2 Nuclear Information Service

ryxm@lanl.gov