5.2.7. Decays and de-excited process models

Table 5.2.76 nevap

Value

Explanation
(D=3)
Options for evaporation model.
=0
Without evaporation model.
=3
Using GEM model.
Table 5.2.77 ngem

Value

Explanation
(D=1)
Options for the version of the GEM model.
=0
Use the default version (currently ver.1).
=1
Use Ver.1.
=2
Use Ver.2 (including nucleon-gamma emission competition、KTUY data [1] for shell correction).
Table 5.2.78 ifission

Value

Explanation
(D=1)
Options for fission reaction model.
=1
Use the default version (currently Ver.1).
=2
Apply Iwamoto’s model [2] to nuclei with charge less than 89, for proton- or neutron-induced reaction.
Table 5.2.79 igamma

Value

Explanation
(D=2)
\(\gamma\) decay options for residual nuclei [3] .
=0
Without \(\gamma\) decay.
=1
With \(\gamma\) decay.
=2
With \(\gamma\) decay based on the EBITEM model.
=3
With \(\gamma\) decay and isomer production based on the EBITEM model.
=-1,-2,-3
Same as 1, 2, 3, except that Doppler effect owing to the motion of excited nuclei is disregarded. Do not use unless necessary, as it distorts physical reaction processes.
Table 5.2.80 ismm

Value

Explanation
(D=0)
Control parameter of Statistical Multi-fragmentation Model (SMM).
=0
SMM is not used.
=1
SMM is used. When a JQMD calculation is performed, switching time from JQMD to GEM changes from the default value of 150 fm/c to 75 fm/c.
Table 5.2.81 irelax

Value

Description

(D=0)

Option to control the generation of characteristic X-rays and Auger electrons induced by charged particles such as protons and heavy ions.

0

Do not generate characteristic X-rays or Auger electrons.

>0

Generate characteristic X-rays and Auger electrons according to their production probabilities. The absolute value specifies the range of electron shells included (1: K shell only, 2: K and L shells, …, 7: all electron shells).

<0

Forcibly generate characteristic X-rays and Auger electrons, and adjust their weights according to the production probabilities. The absolute value specifies the range of electron shells included (-1: K shell only, -2: K and L shells, …, -7: all electron shells).

Setting igamma=3 enables obtaining information on isomer production using [t-yield] with axis=chart or dchain: see reference [4] for details.

With the Statistical Multi-fragmentation Model (SMM), PHITS improves the accuracy of calculating the production cross sections of light and medium-heavy fragments for collisions of heavy ions such as Pb or Hg or for incident energies over 100 MeV/n. It should be noted that the computational time becomes long when using this model: see the references [5] [6] for details.