The

The reaction data identifier, `I_number`, tells what data
is stored, as given by the following table.

**0:**- This type of data contains pairs (energy, cross section).
For incident photons
`mcfgen`does log-log interpolation onto a fixed set of energy points, and for other incident particles it computes averages over energy groups as described in Section 1.5.3. **1:**- The data consists of pairs (cosine of the collision angle,
probability density) for a sequence of incident energies. This
data may be in the center-of-mass system or the laboratory system,
depending on the kinematics type of the reaction. The code
`mcfgen`converts this data into equiprobable bins. **3:**- The data consists of pairs (energy of secondary particle,
probability density) for a sequence of incident energies and
cosines of the collision angle. This data is in the
center-of-mass system. The probability over cosine and energy of
the secondary is correlated, but the data is not normalized
2-dimensionally. Instead, the integral of the probability density
over the energy of the secondary particle is itself 1.
Consequently, the
= 3 data must be supplemented
by
= 1 data giving the angular distributions.
The output is a collection of equiprobable 2-dimensional (cosine,
energy) bins.
**4:**- The data consists of pairs (energy of secondary particle,
probability density) for a sequence of incident energies. This
data is in the laboratory system. The output of
`mcfgen`in this case is equiprobable energy bins. **7:**- The data consists of pairs (incident energy, multiplicity)
for fission neutrons. These neutrons may be prompt or delayed.
The code
`mcfgen`computes group averages of this data, as described in Section 1.5.3. **9:**- The data consists of pairs (incident energy, multiplicity)
for emitted photons. The treatment of this data is the same as
for
= 7.
**10:**- The data consists of pairs (incident energy, energy of
secondary particle). This data may be in the center-of-mass
system or the laboratory system, depending on the kinematics type
of the reaction. For incident photons
`mcfgen`does linear-linear interpolation onto a fixed set of energy points, and for other incident particles it computes averages over energy groups as described in Section 1.5.3. **11:**- The data consists of pairs (incident energy, energy
deposited to the residual nucleus). This data is not used by
`mcfgen`. **12:**- The data consists of pairs (incident energy,
*Q*), where*Q*denotes the sum of the energies available from the non-elastic reactions. Group averages of this data are calculated as described in Section 1.5.3. **941:**- Coherent scattering form factors for incident photons.
The coherent scattering form factor
*F*_{R}(*E*) specifies the importance of Rayleigh scattering. Specifically, for Rayleigh scattering from a target with atomic number*Z*the cross section is*C*(*Z*)(1 + ), where is the cosine of the collision angle and*C*(*Z*) is a coefficient depending on the target. Then [1, p. 3-23] the angular distribution for coherent scattering for such a target is given by the formula*f*(*E*,) = [*F*_{R}(*E*)]^{2}*C*(*Z*)(1 + ).``mcf.asc'`output file. **942:**- Incoherent scattering form factors for incident photons.
The incoherent scattering form factor
*F*_{C}(*E*) specifies the importance of Compton scattering. Specifically, the Klein-Nishina formula for the Compton scattering cross section is*K*_{N}(*E*,) = ,*E*is the incident energy, is the cosine of the collision angle, is the photon energy in units of electron rest energy, and*x*= 1 - . The angular distribution for incoherent scattering is given by [1, p. 3-23]*f*(*E*,) =*F*_{C}(*E*)*K*_{N}(*E*,).``mcf.asc'`output file. Incidentally, the energy of the secondary photon (in units of electron rest energy, ) is given by /(1 +*x*).