5.2.8. Event generator mode and kerma approximation

Table 5.2.82 e-mode [1]

Value	Explanation
(D=0)
=0	Simple sampling mode (non event generator mode).
=1	Event generator mode Ver.1 (simple sampling + evaporation model).
=2	Event generator mode Ver.2 (Ver.1 + accurate charged particle yields + accurate neutron energy distribution).
=3	Event generator mode Ver. 3 (Ver. 2 + excitation states of residual nuclei)

When e-mode \(\ne\) 0 and high-energy nuclear data libraries [2] are used, PHITS determines the reaction point using the total cross section contained in the high-energy nuclear data libraries while the information on secondary particles is evaluated using the nuclear reaction models. Even in this case, the event-generator mode ver. 1 or 2 is still used for neutrons below 20 MeV.

[1]

Including charged-particle and photo-nuclear data libraries.

Table 5.2.83 ikerman

Value	Explanation
(D=0)	Control parameters for the use of kerma approximation for neutrons in [t-deposit].
=0	Automatic selection. Kerma approximation is not used when event generator mode is activated (e-mode \(\ge\) 1).
=1	Kerma approximation for neutrons is always not used.

Table 5.2.84 ikermap

Value	Explanation
(D=0)	Control parameters for the use of kerma approximation for photons in [t-deposit].
=0	Automatic selection. Kerma approximation is not used when EGS5 mode is activated (negs=1,2), or when emin(12) and emin(13) are set below 10 MeV.
=1	Kerma approximation for photons is always not used.

The event generator mode (e-mode=1,2) is essential for calculation of event-by-event quantities, such as detector signals, residual recoiled nuclides, lineal energies, attributed to neutrons below 20 MeV. The simple sampling mode (e-mode=0) reproduces secondary neutron spectra given by the nuclear data library better than e-mode=1,2. Note that e-mode=0 does not consider the conservation of energy and momentum. See Section 5.2.27 for further discussion of the use.

[2]

Until ver. 2.73, file(14)=trxcrd.dat is required for e-mode=1,2.