5.2.13. Parameters for EGS5¶
Value |
Explanation |
(D=0)
|
Options for controlling PEGS5 (invalid when negs \(\ne1,2\) ).
|
=-1
|
Output PEGS5.inp: Yes, Execute PEGS5: Yes, Execute PHITS: No.
|
=0
|
Output PEGS5.inp: Yes, Execute PEGS5: Yes, Execute PHITS: Yes.
|
=1
|
Output PEGS5.inp: No, Execute PEGS5: Yes, Execute PHITS: Yes.
|
=2
|
Output PEGS5.inp: No, Execute PEGS5: No, Execute PHITS: Yes.
|
Value |
Explanation |
(D=1)
|
Options for treating multiple scatterings in EGS5.
|
=0
|
Original EGS5 method. With this option, the starting scattering strength is used only when the electron is generated as a source particle. After several steps, the maximum scattering strength is used.
|
=1
|
Original PHITS-EGS5 method. Use starting scattering strength whenever an electron enters a new material. This option enables transporting electrons in thin foils without changing the chard parameter; the computational time becomes slightly longer.
|
Value |
Explanation |
(D=0)
|
Options for controlling EGS5 output files.
|
=0
|
Delete all EGS5 output files when PHITS calculation is finished. Some files remain when the user self-terminates the PHITS calculation.
|
=1
|
Keep egs5.inp, pegs5.dat and pegs5.msfit and delete the others.
|
=2
|
Keep all EGS5 output files. See EGS5 manual [1] for details on each file.
|
Value |
Explanation |
(D=-1)
|
Options for random number used in EGS5. Setting parameter to 0 or to a positive value hides the MPI parallelization and the restart-calculation function.
|
< 0
|
Use random number generated by PHITS.
|
=0
|
Use random number generated by EGS5 with the default initial random seed (314159265).
|
> 0
|
Use random number generated by EGS5 with the initial random seed \(=\) iegsrand.
|
PEGS is the prepocessor for EGS. It contains a set of fortran subprograms, which negerate material data for the use of EGS5. It is needed to change the parameter ipegs in order to change the input file of PEGS5 (pegs5.inp). Note that, to retain PEGS5-related files after executing PHITS, iegsout automatically becomes 1 (or greater) when ipegs is set \(\geq1\) .
When using EGS5 (negs=1,2), the default values of the minimum energies for electron, positron, and photon transports are changed to emin(12,13)=0.1, emin(14)=0.001. The maximum energies are set to dmax(12-14)=1,000.0 (1 GeV) for negs=1,2 and dmax(12-14)=1e+7 (10 TeV) for negs=2 respectively. These values can also be changed by explicitly setting the related parameters. Note that the default values of several EGS5 parameters differ from those employed in the original EGS5 code.
From ver. 2.76, photo-nuclear reactions can be considered in EGS5. Thus, input files with negs=1 and ipnint=1 produce results that differ from those calculated by the previous version of PHITS.
Value |
Explanation |
(D=1)
|
Option for K and L-edge fluorescent photons.
|
=0
|
Do not explicitly treat K and L-edge fluorescent photons.
|
=1
|
Explicitly treat K and L-edge fluorescent photons.
|
Value |
Explanation |
(D=1)
|
Option for K and L-edge Auger electrons.
|
=0
|
Do not explicitly treat K and L-edge Auger electrons.
|
=1
|
Explicitly treat K and L-edge Auger electrons.
|
Value |
Explanation |
(D=1)
|
Option for coherent (Rayleigh) scattering.
|
=0
|
Do not consider coherent scattering.
|
=1
|
Consider coherent scattering.
|
Value |
Explanation |
(D=0)
|
Option for linearly polarized photon scattering (not available in the PHITS code at this moment).
|
=0
|
Do not consider linearly polarized photon scattering.
|
=1
|
Consider linearly polarized photon scattering.
|
Value |
Explanation |
(D=0)
|
Option for outputting stopping powers by PEGS5. When this parameter is changed, ipegs must be set to \(-1\) to not to execute PHITS calculations, and to prevent obtaining incorrect results.
|
=1
|
Unrestricted collisional stopping power only.
|
=2
|
Unrestricted collisional and radiative stopping power.
|
=3
|
Unrestricted collisional and restricted radiative stopping power.
|
=4
|
Restricted collisional and unrestricted radiative stopping power.
|
=5
|
Unrestricted radiative stopping power only.
|
=6
|
Restricted radiative stopping power only.
|
=7
|
Restricted collisional stopping power only.
|
Value |
Explanation |
(D=0.1)
|
Array of 'characteristic dimensions,' or representative size (in units of cm) of each material. This parameter controls the electron step-size in each material. The value must be decreased when simulating electron scattering in thin foils by setting imsegs=0. When a negative value is set for this parameter, the actual chard values used in EGS5 are adjusted to their absolute values divided by the material density in g/cm \(^3\) . This option is useful for simulating electrons in huge objects (of km order).
|
Value |
Explanation |
(D=0)
|
Option for using density correction factors used in the evaluation of ICRU90.
|
=0
|
Do not use ICRU90 density correction factors.
|
=1
|
Use ICRU90 density correction factors. In this case, PHITS automatically find liquid water, graphite, and dry air from the [material] section based on the compositions and densities of each material. The criterions for the material judgement are as follows:
Liquid water: A material composed of H and O with density between 0.9 and 1.1 g/cm \(^3\)
Graphite: A material composed of C with density between 1.55 and 2.40 g/cm \(^3\)
Dry air: A material composed of C, N, O, and Ar with density below 0.03 g/cm \(^3\) . This threshold density can be changed by gasegs parameter.
|
Value |
Explanation |
(D=0.03)
|
A material with density below this value is automatically regarded as gas in PEGS.
|
Value |
Explanation |
(D=1)
|
Option for incoherent scattering function.
|
=0
|
Do not use incoherent scattering function for Compton scattering.
|
=1
|
Use incoherent scattering function for Compton scattering (ibound is automatically set to 1).
|
Value |
Explanation |
(D=1)
|
Option for Doppler broadening of Compton scattering energies.
|
=0
|
Do not consider Doppler broadening.
|
=1
|
Consider Doppler broadening (incohr and ibound are both automatically set to 1).
|
Value |
Explanation |
(D=1)
|
Option for electron-impact ionization (EII).
|
=0
|
Do not consider EII.
|
=1
|
Consider EII.
|
Value |
Explanation |
(D=0)
|
Option for split of X-rays generated by electron-impact ionization.
|
=0
|
No splitting.
|
=1
|
Splitting.
|
Value |
Explanation |
(D=0)
|
Number of electron-impact ionization X-rays for splitting when ieispl=1.
|
Value |
Explanation |
(D=1)
|
Option for determination of bremsstrahlung polar angle.
|
=0
|
Angle given by \(m/E\) .
|
=1
|
Sampling.
|
Value |
Explanation |
(D=1)
|
Option for determination of polar angles of pair electrons.
|
=0
|
Angle given by \(m/k\) .
|
=1
|
Sampling.
|
Value |
Explanation |
(D=1)
|
Option for determining angular distributions of photoelectrons.
|
=0
|
Emission in the direction of incident photon.
|
=1
|
Sampling.
|
Value |
Explanation |
(D=1)
|
Option for Compton cross section.
|
=0
|
Use free Compton cross section.
|
=1
|
Use bound total Compton cross section.
|
Value |
Explanation |
(D=1)
|
Option for correcting bremsstrahlung cross section.
|
=0
|
Use Motz et al. empirical.
|
=1
|
Normalize integrated cross section to ICRU-37 radiative stopping power.
|
=2
|
No correction.
|