5.2.17. Options for Coulomb diffusion, gravitational field, and electromagnetic field

Table 5.2.138 nspred

Value

Explanation
(D=0)
Options for Coulomb diffusion (angle straggling) [1] . Note that this option is not applicable for electrons and positrons.
=0
Without Coulomb diffusion.
=1
With Coulomb diffusion by the original NMTC model.
=2
(Recommended) With Coulomb diffusion by the Lynch’s formula based on the Moliere theory [2] .
You can also set nspred=-1, -2. When it is specified as a negative value, Coulomb scattering is always taken into account; when specified as a positive value, Coulomb scattering is taken into account until a source particle occurs the first reaction. To reduce calculation time, setting 0 or positive values is recommended for usual calculations. For transport calculations of charged particles in a large scale with very low density or highly transparent charged particles such as muons, please set the negative values.
Table 5.2.139 ascat1

Value

Explanation
(D=13.6)
Parameter \(A\) in the Lynch’s formula (see below) for nspred=2.
Table 5.2.140 ascat2

Value

Explanation
(D=0.038)
Parameter \(B\) in the Lynch’s formula (see below) for nspred=2.
Table 5.2.141 nedisp

Value

Explanation
(D=0)
Energy straggling option for charged particle and nuclei. Note that this option is not applicable for electrons and positrons.
=0
Without energy straggling.
=1
(Recommended) With Landau Vavilov energy straggling [3] .
Table 5.2.142 gravx

Value

Explanation
(D=0)
x-component of gravity direction.
Table 5.2.143 gravy

Value

Explanation
(D=0)
y-component of gravity direction.
Table 5.2.144 gravz

Value

Explanation
(D=0)
z-component of gravity direction.

gravx, gravy, gravz represent the directions of gravity; the gravitational force is effective for neutrons at energies below 1 eV. For example, if gravx=1, gravy=0, gravz=0, the direction of the gravitational force is negative along the x-axis. imagnf is a parameter equivalent to ielctf which enables both [magnetif field] and [electro magnetic field]. From Ver.3.36, imagnf and [magnetif field] are deprecated because they were merged to ielctf and [electro magnetic field], respectively.

Table 5.2.145 usrmgt

Value

Explanation
(D=1)
Options for user subroutine of time dependent magnetic field defined in [electro magnetic field].
= 1
usrmgt1.f, which includes Wobbler magnet, is used.
= 2
usrmgt2.f, which includes Pulse magnet, is used.
Table 5.2.146 usrelst

Value

Explanation
(D=1)
Options for [elastic option].
= 1
usrelst1.f, for Bragg scattering, is used.
= 2
usrelst2.f, a sample program, is used.
Table 5.2.147 ielctf

Value

Explanation
(D=0)
Options for electromagnetic field.
= 0
Without electromagnetic field.
= 1
With electromagnetic field. If you want to precisely calculate the trajectory of charged particles (except electrons and positrons) under a strong electromagnetic field that significantly bends their trajectories within a short distance (less than a few cm), set the maximum flight mesh size ( deltg ) in the electromagnetic field to a smaller value.