1. Basic Lecture III: Parameter Setting
PHITS
Multi-Purpose Particle and Heavy Ion Transport code System
Basic Lecture III:
Parameter Setting
Mar revised
title 1

2. You will learn how to setup those parameters in this lecture!
Purpose of This Lecture
PHITS simulation is controlled by various parameters defined in [Parameters] section
Every parameter has its default value, and you do not have to change most of them
But you have to change some parameters to obtain appropriate results
You will learn how to setup those parameters in this lecture!
Introduction 2

3. You can obtain this kind of results at the end of this lecture
Goal of This Lecture
Proton (up) and neutron (down) fluences calculated by default settings for homework study
Proton (up) and neutron (down) fluences calculated by appropriate settings for homework study
You can obtain this kind of results at the end of this lecture
Purpose 3

4. Contents of Lecture III
Selection of Calculation Mode
Convenient functions for input
Setting for statistics
Monte Carlo integration
History Number and statistical error
Setting for physics
Cut-off Energy
Nuclear Data Library
Physical Models
Summary
Contents 4

5. Selection of Calculation Mode
Particle Transport Simulation
Checking purpose
Geometry Visualization
Selection of Calculation Mode 5

6. Geometry Visualization
Let’s check the geometry using icntl=11 [3D-show] and icntl=7 [t-gshow]
Geometry Visualization
Geometry Visualization Mode 6

7. Geometry Visualization Mode
[3D-Show] (icntl=11)
lec03.inp
[ T - 3 D s h o w ]
output = 3
material = -1 6
x0 = 0
y0 = 0
z0 = 0
e-the = 70 $ eye
e-phi = 20
e-dst = 80
l-the = 20 $ light
l-phi = 0
l-dst = 100
w-wdt = 50 $ window
w-hgt = 50
w-dst = 25
heaven = z
line = 1
shadow = 2
file = 3dshow.out
title = Check onion structure using [T-3dshow] tally
epsout = 1
・ ・ ・ ・ ・ ・
file = lec03.inp
[ T i t l e ]
・ ・ ・ ・ ・ ・
[ P a r a m e t e r s ]
icntl = 11
maxcas = 100
maxbch = 10
file(6) = phits.out
set: c1[20]
[ S o u r c e ]
infl: {onion.inp}[1-33]
Activate
[t-3dshow]
Onion structure
3dshow.eps
Geometry Visualization Mode 7

8. [T-gshow] (icntl=7) lec03.inp Geometry Visualization Mode 8 Activate
file = lec03.inp
[ T i t l e ]
・ ・ ・ ・ ・ ・
[ P a r a m e t e r s ]
icntl = 7
maxcas = 100
maxbch = 10
file(6) = phits.out
set: c1[20]
[ S o u r c e ]
infl: {onion.inp}[1-33]
file = lec03.inp
[ T i t l e ]
・ ・ ・ ・ ・ ・
[ P a r a m e t e r s ]
icntl = 11
maxcas = 100
maxbch = 10
file(6) = phits.out
set: c1[20]
[ S o u r c e ]
infl: {onion.inp}[1-33]
[ T - G s h o w ]
mesh = xyz
x-type = 2
nx = 100
xmin = -50.
xmax = 50.
y-type = 1
ny = 10
z-type = 2
nz = 100
zmin = -50.
zmax = 50.
axis = xz
output = 6
file = gshow.out
title = Check onion structure using [T-gshow] tally
epsout = 1
Check cell ID and filled materials
Activate
[t-gshow]
gshow.eps
Geometry Visualization Mode 8

9. Check Sources ([t-track])
lec03.inp
Change and Execute
[ T - T r a c k ]
mesh = xyz
x-type = 2
nx = 100
xmin = -50.
xmax = 50.
y-type = 1
ny = 1
z-type = 2
nz = 100
zmin = -50.
zmax = 50.
e-type = 1
ne = 1
unit = 1
axis = xz
file = track_xz.out
title = Check source direction using [T-track] tally
epsout = 1
file = lec03.inp
[ T i t l e ]
・ ・ ・ ・ ・ ・
[ P a r a m e t e r s ]
icntl = 5
maxcas = 100
maxbch = 10
file(6) = phits.out 9

10. Check Trajectory of Sources
Track-xz.eps
No reaction and no ionization because all regions are void.
（You can confirm positions and directions of sources.） 10

11. Contents of Lecture III
Selection of Calculation Mode
Convenient functions for input
Setting for statistics
Monte Carlo integration
History Number and statistical error
Setting for physics
Cut-off Energy
Nuclear Data Library
Physical Models
Summary
Contents 11

12. Geometry Visualization Mode
Include File
You can include other files into PHITS input file using “infl” command
lec03.inp
onion.inp
file = lec03.inp
[ T i t l e ]
・ ・ ・ ・ ・ ・
[ P a r a m e t e r s ]
icntl = 7
maxcas = 100
maxbch = 10
file(6) = phits.out
set: c1[20]
[ S o u r c e ]
infl: {onion.inp}[1-33]
file = lec03.inp
[ T i t l e ]
・ ・ ・ ・ ・ ・
[ P a r a m e t e r s ]
icntl = 7
maxcas = 100
maxbch = 10
file(6) = phits.out
set: c1[20]
[ S o u r c e ]
infl: {onion.inp}[1-33]
You have to write “file = input file name”
at the 1st line when you use “infl” command
[ M a t e r i a l ]
・ ・ ・ ・ ・ ・
[ M a t N a m e C o l o r ]
[ S u r f a c e ]
10 so
11 so
12 so
13 so
14 so
15 so
[ C e l l ] e
Replace this line by lines 1 to 33 in “onion.inp”
Geometry Visualization Mode 12

13. How to Use Variables lec03.inp Source Check Mode 13
file = lec03.inp
[ T i t l e ]
・ ・ ・ ・ ・ ・
[ P a r a m e t e r s ]
icntl = 5
maxcas = 100
maxbch = 10
file(6) = phits.out
set: c1[10]
[ S o u r c e ]
s-type = 9
proj = proton
x0 = 0.
y0 = 0.
z0 = 0.
r1 = c1
r2 = c1
dir = 1.0
e0 = 150
s-type=9, 10:　sphere or spherical shell source
（x0, y0, z0）: center of the sphere
r1: inner radius
r2: outer radius Z
You can use variables in PHITS input file.
Format: set: ci[x]
i: integer (1~99)
x: variable
It is effective below the “set” command r1 r2 Y
（x0, y0, z0) X
Source Check Mode 13

14. Mathematical equations
You can use mathematical equations in FORTRAN format in PHITS input file
lec03.inp
Normalization
Results of tally are outputted as values per generated source*.
To compare the results with measured values, the results have to be normalized by a production rate of the source, such as Bq and /cm2/s.
Using a parameter “totfact”, you can directly obtain the results in a unit such as /cm2/s and mGy/h.
In this case, the fluence on the sphere of the source are 1/πr2 (/cm2/source) without normalization. Multiplying a factor of πr2, the fluence on the sphere is 1(/cm2).
set: c1[10]
[ S o u r c e ]
s-type = 9
proj = proton
x0 = 0.
y0 = 0.
z0 = 0.
r1 = c1
r2 = c1
dir = 1.0
e0 = 150
totfact = pi*c1**2
The number π is denoted by pi.
Exponentiation is denoted by **.
Some functions, such as exp and cos, can also be used.
*Precisely, weight of generated source. 14

15. Contents of Lecture III
Selection of Calculation Mode
Convenient functions for input
Setting for statistics
Monte Carlo integration
History Number and statistical error
Setting for physics
Cut-off Energy
Nuclear Data Library
Physical Models
Summary
Contents 15

16. Volume and Area Calculation
Monte Carlo Integration is numerical integration using random number. Using this concept, the volume of each cell can be calculated from the average track length divided by the average flux inside the cell, by setting icntl = 5. =
Volume of a cell [cm3]
Total track length in a cell [cm]
=　average track length [cm/source]
x #Line [source]
Density of line [1/cm2]
= average flux [1/cm2/source]
　x #Line [source] =
Track length [cm/source] of particles calculated by [t-track] by setting icntl = 5
You can obtain better statistics by increasing the history number
Expected flux [1/cm2/source]
No Reaction, No Ionization Mode 16

17. Volume and Area Calculation
Monte Carlo Integration is numerical integration using random number. Using this concept, the volume of each cell can be calculated from the average track length divided by the average flux inside the cell, by setting icntl = 5.
Volume of a cell [cm3]
by using isotropic irradiation source
and
You can obtain better statistics by increasing the history number
Expected flux in the sphere is 1/πr2 (/cm2/source)
No Reaction, No Ionization Mode 17

18. No Reaction, No Ionization Mode
Exercise 1
Volume and area calculation
lec03.inp
[ P a r a m e t e r s ]
icntl = 5
maxcas = 100
maxbch = 10
file(6) = phits.out
set: c1[30]
[ S o u r c e ]
s-type = 9
proj = proton
x0 = 0.
y0 = 0.
z0 = 0.
r1 = c1
r2 = c1
dir = -all
e0 = 150
totfact = pi*c1**2
[ T - T r a c k ]
mesh = reg
reg =
・ ・ ・ ・ ・ ・
file = volume.out
[ T - C r o s s ]
reg = 5
r-in r-out area
( ) ( ) 1.0
( ) ( ) 1.0
( ) ( ) 1.0
( ) ( ) 1.0
( ) ( ) 1.0
file = area.out
Change &
Execute
To calculate volumes and areas of the geometry:
icntl=5,
s-type=9,
r1=r2（size including the whole of the geometry）
dir=-all
No Reaction, No Ionization Mode 18

19. Results of Calculation
volume.out
area.out
・ ・ ・ ・ ・ ・
#num reg volume flux r.err
E E
E E
E E
E E
E E
・ ・ ・ ・ ・ ・
#num area flux 　　　　r.err
E E
E E
E E
E E
E E
Volume of each cell is…
4π(5)3/3=524 cm3
4π(10)3/ =3665 cm3
4π(15)3/ =9948 cm3
4π(20)3/ =19373 cm3
4π(25)3/ =31940 cm3
Area of each surface is…
4π(5)2=314 cm2
4π(10)2=1257 cm2
4π(15)2=2827 cm2
4π(20)2=5027 cm2
4π(25)2=7854 cm2
Differences become larger for inner spheres
→ Statistics are not enough !!
No Reaction, No Ionization Mode 19

20. Contents of Lecture III
Selection of Calculation Mode
Convenient functions for input
Setting for statistics
Monte Carlo integration
History Number and statistical error
Setting for physics
Cut-off Energy
Nuclear Data Library
Physical Models
Summary
Contents 20

21. Change History Number
The accuracy of Monte Carlo simulation depends on the history number of the simulation
You can obtain results with better statistics by increasing the history number
maxcas
(D=10)
History number per 1 batch
maxbch
Number of batch
rseed
(D=0.0)
rseed < 0
rseed = 0
rseed > 0
Initial random number option
Get initial random number from starting time
Default value
Value of rseed is used as initial random number
irskip
(D=0)
irskip > 0
irskip < 0
Random number control
Begin calculation after skipping histories by irskip
Begin calculation after skipping random number by Irskip
maxcas ×maxbch ＝total history number
The same initial random number is used in default setting.
If you want to obtain different results whenever you execute PHITS, set rseed < 0. 21

22. Adjust maxcas and maxbch in accordance with your situation
History and batch
Q. What is history number?
　　Number of generated source specified in [source] section → number of grapes
Q. What is number of batch?
　　A constant history number (maxcas) is taken as a batch. maxbch is the number of running PHITS calculations. →　maxcas: number of grapes per a bunch　　maxbch：number of bunch
Q. What does PHITS do at the end of each batch?
　　PHITS calculates results of tally and statistical errors, and outputs them (by setting itall=1).
　　→tasting harvested grapes
Q. Why does PHITS divide all calculations into some batch?
　　In the case that you run all calculations at once, their results may come to nothing if parameters in the calculations were wrong. →In the case that a farmer harvests all grapes without tasting them, he may get a great damage if he took a wrong time to do it.
　　If the above processing is performed each history, it spends a computational time wastefully. →If he harvests with tasting each grapes, it takes a very long time.
Adjust maxcas and maxbch in accordance with your situation
e.g. set a computational time per one batch to be 2 or 3 minutes 22

23. Volume and Area Calculation
lec03.inp
volume.out
file = lec03.inp
[ T i t l e ]
・ ・ ・ ・ ・ ・
[ P a r a m e t e r s ]
icntl = 5
maxcas = 10000
maxbch = 10
file(6) = phits.out
set: c1[30]
[ S o u r c e ]
s-type = 9
proj = proton
x0 = 0.
y0 = 0.
z0 = 0.
r1 = c1
r2 = c1
dir = -all
e0 = 150
file = lec03.inp
[ T i t l e ]
・ ・ ・ ・ ・ ・
[ P a r a m e t e r s ]
icntl = 5
maxcas = 1000
maxbch = 10
file(6) = phits.out
set: c1[30]
[ S o u r c e ]
s-type = 9
proj = proton
x0 = 0.
y0 = 0.
z0 = 0.
r1 = c1
r2 = c1
dir = -all
e0 = 150
file = lec03.inp
[ T i t l e ]
・ ・ ・ ・ ・ ・
[ P a r a m e t e r s ]
icntl = 5
maxcas = 100
maxbch = 10
file(6) = phits.out
set: c1[30]
[ S o u r c e ]
s-type = 9
proj = proton
x0 = 0.
y0 = 0.
z0 = 0.
r1 = c1
r2 = c1
dir = -all
e0 = 150
・ ・ ・ ・ ・ ・
#num reg volume flux r.err
E E
E E
E E
E E
E E
・ ・ ・ ・ ・ ・
#num reg volume flux r.err
E E
E E
E E
E E
E E
・ ・ ・ ・ ・ ・
#num reg volume flux r.err
E E
E E
E E
E E
E E
Volume of each cell is…
4π(5)3/3=524 cm3
4π(10)3/ =3665 cm3
4π(15)3/ =9948 cm3
4π(20)3/ =19373 cm3
4π(25)3/ =31940 cm3
area.out
・ ・ ・ ・ ・ ・
#num area flux 　　　　r.err
E E
E E
E E
E E
E E
・ ・ ・ ・ ・ ・
#num area flux 　　　　r.err
E E
E E
E E
E E
E E
・ ・ ・ ・ ・ ・
#num area flux 　　　　r.err
E E
E E
E E
E E
E E
Area of each surface is …
4π(5)2=314 cm2
4π(10)2=1257 cm2
4π(15)2=2827 cm2
4π(20)2=5027 cm2
4π(25)2=7854 cm2
History Number 23

24. Restart Calculation mode
lec03.inp
volume.out
file = lec03.inp
[ T i t l e ]
・ ・ ・ ・ ・ ・
[ P a r a m e t e r s ]
icntl = 5
maxcas = 10000
maxbch = 10
file(6) = phits.out
set: c1[30]
[ S o u r c e ]
s-type = 9
proj = proton
x0 = 0.
y0 = 0.
z0 = 0.
r1 = c1
r2 = c1
dir = -all
e0 = 150
・ ・ ・ ・ ・ ・
#num reg volume flux r.err
E E
E E
E E
E E
E E
・ ・ ・ ・ ・ ・
#num reg volume flux r.err
E E
E E
E E
E E
E E
・ ・ ・ ・ ・ ・
#num reg volume flux r.err
E E
E E
E E
E E
E E
istdev = -1
area.out
・ ・ ・ ・ ・ ・
#num area flux 　　　　r.err
E E
E E
E E
E E
E E
・ ・ ・ ・ ・ ・
#num area flux 　　　　r.err
E E
E E
E E
E E
E E
・ ・ ・ ・ ・ ・
#num area flux 　　　　r.err
E E
E E
E E
E E
E E
History Number 24

25. Restart Calculation mode
lec03.inp
In the restart calculation mode, a message is shown in the console screen.
file = lec03.inp
[ T i t l e ]
・ ・ ・ ・ ・ ・
[ P a r a m e t e r s ]
icntl = 5
maxcas = 10000
maxbch = 10
file(6) = phits.out
set: c1[30]
[ S o u r c e ]
s-type = 9
proj = proton
x0 = 0.
y0 = 0.
z0 = 0.
r1 = c1
r2 = c1
dir = -all
e0 = 150
istdev = -1
Information on each batch is also outputted.
History Number 25

26. Concept of Batch
“Batch” is a set of sources to be simulated in a single program run
When the simulation of one batch is finished
You can output the results still in progress by setting “itall=1” in the [parameters] section
You can terminate the job manually by editting “batch.now” file
batch.now
If you change “1” to “0” at the first line and save it,
PHITS execution will be terminated
when the simulation of current batch is finished
1 <--- 1:continue, 0:stop
bat[ ] ncas = : rijk =
low neutron = : ncall/s = E+00
cpu time = s.
date =
time = 15h 08m 25
History Number 26

27. Exercise 2 Job Termination by “batch.now” lec03.inp History Number 27
file = lec03.inp
[ T i t l e ]
・ ・ ・ ・ ・ ・
[ P a r a m e t e r s ]
icntl = 5
itall = 1
maxcas = 10000
maxbch = 100
file(6) = phits.out
$ istdev = -1
Execute a long calculation with a large maxbch.
Set itall=1 to check the intermediate result.
Terminate the job by batch.now.
track_xz.eps
batch.now
0 <--- 1:continue, 0:stop
1 <--- 1:continue, 0:stop
Check whether the job is properly terminated or not by seeing “phits.out”
History Number 27

28. Contents of Lecture III
Selection of Calculation Mode
Convenient functions for input
Setting for statistics
Monte Carlo integration
History Number and statistical error
Setting for physics
Cut-off Energy
Nuclear Data Library
Physical Models
Summary
Contents 28

29. Cut-off Energy Cut-off Energy 29
You can reduce your computational time by killing the particles in which you are not interested, by setting “cut-off energy” parameters
particle ID
Cut-off energy
proton
emin(1)
1 MeV
neutron
emin(2)
π，μ
emin(3~8)
electron・positron
emin(12,13)
109 MeV
photon
emin(14)
nucleus
emin(15~19)
1 MeV/u
Particles with energy below their emin parameters are NOT traced by PHITS simulation
Cut-off Energy 29

30. Cut-off Energy lec03.inp Cut-off Energy 30
Mono-energetic proton 150MeV incidence
[ P a r a m e t e r s ]
icntl = 0
　itall = 1
maxcas = 1000
maxbch = 10
file(6) = phits.out
$ istdev = -1
set: c1[30]
[ S o u r c e ]
s-type = 9
proj = proton
・ ・ ・ ・ ・ ・
dir = -all
e0 = 150
[ P a r a m e t e r s ]
icntl = 5
　itall = 1
maxcas = 10000
maxbch = 100
file(6) = phits.out
$ istdev = -1
set: c1[30]
[ S o u r c e ]
s-type = 9
proj = proton
・ ・ ・ ・ ・ ・
dir = -all
e0 = 150
Change &
Execute
[ T - C r o s s ] off
mesh = reg
reg = 5
r-in r-out area
e-type = 2
ne = 100
emin = 0.
emax = 200.
axis = eng
unit = 1
output = flux
file = cross.out
epsout = 1
[ T - C r o s s ]
mesh = reg
reg = 5
r-in r-out area
e-type = 2
ne = 100
emin = 0.
emax = 200.
axis = eng
unit = 1
output = flux
file = cross.out
epsout = 1
source-energy.eps
Tally inward fluxes between the constitution cells of onion
gshow.eps
Cut-off Energy 30

31. Cut-off Energy lec03.inp Cut-off Energy 31 Change & Execute cross.eps
[ P a r a m e t e r s ]
icntl = 0
　itall = 1
maxcas = 1000
maxbch = 10
file(6) = phits.out
$ istdev = -1
set: c1[30]
[ S o u r c e ]
s-type = 9
proj = proton
・ ・ ・ ・ ・ ・
dir = -all
e0 = 150
[ P a r a m e t e r s ]
icntl = 0
　itall = 1
maxcas = 1000
maxbch = 10
emin(2) = 50
file(6) = phits.out
$ istdev = -1
set: c1[30]
[ S o u r c e ]
s-type = 9
proj = proton
・ ・ ・ ・ ・ ・
dir = -all
e0 = 150
Change & Execute
cross.eps
Neutron fluxes below 50 MeV disappears.
Cut-off Energy 31

32. Contents of Lecture III
Selection of Calculation Mode
Convenient functions for input
Setting for statistics
Monte Carlo integration
History Number and statistical error
Setting for physics
Cut-off Energy
Nuclear Data Library
Physical Models
Summary
Contents 32

33. What is data libraries?
Because reaction cross sections of photons, electrons, positrons, and low-energy neutrons (below 20 MeV) have complex structures, normal reaction models cannot describe their behaviors. → Data libraries are required.
Cut-off energies of photons, electrons, and positrons are set to be high in default setting, because it may take a long time to execute PHITS considering their transports.
Some parameters ,such as emin, should be set in [parameters] section to use data libraries.
Neutron reaction cross section on 113Cd target（JENDL-4.0） 33

34. How to Use Data Libraries
Check nuclear data
c:/phits/XS/neu
Check address (xsdir) file
c:/phits/data/xsdir.jnd
Check 1st line of the address file
datapath=c:/phits/XS
Set “emin(i)”, “dmax(i)” and “file(7)” in the [Parameters] section
Neutron data library
Folder name where data libraries are included
Nuclear Data Library 34

35. Exercise 3 Use neutron data library lec03.inp Nuclear Data Library 35
phits.out
[ P a r a m e t e r s ]
icntl = 0
　itall = 1
maxcas = 1000
maxbch = 10
emin(1) = 50
emin(2)= 1.0e-10
dmax(2) = 20
file(6) = phits.out
file(7) = c:/phits/data/xsdir.jnd
$ istdev = -1
CPU Summary
・ ・ ・ ・ ・ ・
dklos =
hydro =
n-data =
h-data =
p-data =
e-data =
p-egs5 =
e-egs5 =
Use data library for neutrons below 20 MeV
(Check emin < dmax)
Folder & file name of the address file
Nuclear Data Library 35

36. Exercise 4 Use photon & electron data libraries
Set cut-off energies of electron, positron and photon:
emin(12~14) = 1.0 → in order to avoid long computational time
Set their maximum energies for using their data libraries:
dmax(12~14) = → enough high for most cases
Execute PHITS
Check ‘e-data’ and ‘p-data’ written in ‘phits.out’
Exercise
Visualize electron, positron and photon fluences by changing ‘part’ parameter in [t-track]
Nuclear Data Library 36

37. Exercise 5 Use EGS5 for photon & electron transport lec03.inp 37
phits.out
[ P a r a m e t e r s ]
icntl = 0
　itall = 1
maxcas = 1000
maxbch = 10
emin(2)= 1.0e-10
dmax(2) = 20
emin(12) = 1.0
emin(13) = 1.0
emin(14) = 1.0
dmax(12) =
dmax(13) =
dmax(14) =
file(6) = phits.out
file(7) = c:/phits/data/xsdir.jnd
file(20) = c:/phits/XS/egs
negs = 1
$ istdev = -1
CPU Summary
・ ・ ・ ・ ・ ・
dklos =
hydro =
n-data =
h-data =
p-data =
e-data =
p-egs5 =
e-egs5 =
Folder for data library for EGS5
Use EGS5 37

38. Contents of Lecture III
Selection of Calculation Mode
Convenient functions for input
Setting for statistics
Monte Carlo integration
History Number and statistical error
Setting for physics
Cut-off Energy
Nuclear Data Library
Physical Models
Summary
Contents 38

39. g-decay option Recommended value is igamma=2 from version 2.64. 39
igamma: Activate g-decay from residual nuclides produced by nuclear reaction. (Default setting does NOT produce g-rays)
igamma
(D=0)
= 0
= 1
= 2
= 3
g-decay option for residual nuclei
Without g-decay
With g-decay
With g-decay based on EBITEM model
With g-decay and isomer production based on EBITEM model
Recommended value is igamma=2 from version 2.64. 39

40. Option for beam transport analysis
nspred and nedisp: Consider angular and energy straggling of charged particle, respectively (Important for beam transport analysis)
nspred
(D=0)
= 0
= 1
= 2
= 10
Option for Coulomb diffusion (angle straggling)
Without Coulomb diffusion
With Coulomb diffusion by the NMTC model
With Coulomb diffusion by Lynch’s formula
With Coulomb diffusion by ATIMA
nedisp
Energy straggling option for charged particle
Without energy straggling
With energy straggling by Landau Vavilov model
With energy straggling by ATIMA
Recommended values are nspred = 2 & nedisp = 1. 40

41. Nuclear Reaction Model
Switching Energy
Several nuclear reaction models are implemented in PHITS
You can switch the models in the [parameters] section
inclg
(D=1)
Control parameter for use of INCL
ejamnu
(D=20.)
Switching energy of nucleon-nucleus reaction calculation to JAM model (MeV)
ejampi
Switching energy of pion-nucleus reaction calculation to JAM model (MeV)
eqmdnu
Switching energy of nucleon-nucleus reaction calculation to JQMD model (MeV)
eqmdmin
(D=10.)
Minimum energy of JQMD calculation (MeV/u)
ejamqmd
(D=3500.)
Switching energy of nucleus-nucleus reaction from JQMD to JAMQMD (MeV/u)
incelf
(D=0)
Control parameter for use of INC-ELF
dmax(i)
(D=emin(i))
Maximum energy of library use for i-th particle
Nuclear Reaction Model 41

42. Map of Nuclear Reaction Models
(1MeV)
emin(i)
(=emin)
dmax(i)
(3.0GeV)
einclmax
Nucleon Library INCL (inclg=1) JAM
(1MeV)
emin(i)
(3.0GeV)
einclmax
Pion INCL (inclg=1) JAM
(10MeV/u)
eqmdmin
(3.5GeV/u)
ejamqmd
Nucleus JQMD JAMQMD
(d, t, 3He, α) INCL (inclg=1)
Kaon, Hyperon JAM
Nuclear Reaction Model 42

43. Event Generator Mode Event generator mode is effective in the case
A nuclear reaction model for low-energy neutron interaction using nuclear data library combined with a special evaporation model
Determine all ejectiles emitted from low-energy neutron interaction, considering the energy and momentum conservation
Event generator mode is effective in the case
to know spectra of proton or alpha particles from reactions of low-energy neutrons.
to obtain information on residual nuclei (e.g. recoil energies).
to perform event-by-event analysis (e.g. response function calculation).
Event generator mode is NOT effective in the case
to know information only on neutrons and photons (e.g. shielding).
to calculate transmittance of neutrons.
to know accurate behaviors of thermal-neutrons. 43

44. How to Use EG Mode Set “e-mode = 2” in the [Parameters] section
(“igamma” is automatically set to 2 when you activate the event generator mode)
e-mode
(D=0)
= 0
= 1
= 2
Option for event generator mode
Normal mode
Event generator mode version 1
Event generator mode version 2 44

45. Exercise 6 Use event generator mode lec03.inp 45
Change & Execute
[ P a r a m e t e r s ]
icntl = 0
itall = 1
maxcas = 1000
maxbch = 10
emin(2)= 1.0e-10
dmax(2) = 20
emin(12) = 1.0
emin(13) = 1.0
emin(14) = 1.0
dmax(12) =
dmax(13) =
dmax(14) =
file(6) = phits.out
file(7) = c:/phits/data/xsdir.jnd
...
e-mode = 0
[ S o u r c e ]
s-type = 9
proj = neutron
x0 = 0.
y0 = 0.
z0 = 0.
r1 = c1
r2 = c1
dir = -all
e0 = 20.0
totfact = pi*c1**2
[ T - T r a c k ]
mesh = reg
reg = ( )
e-type = 2
ne = 100
emin = 0
emax = 20.
axis = eng
unit = 1
part = proton neutron photon alpha
file = track_eng.out
epsout = 1
If you want to output sum of results in several regions, use ( ).
First, execute PHITS not activating event generator mode.（default setting）
Set source particles to be 20 MeV neutrons.
Confirm proton and alpha spectra by tallying particle fluences in the whole sphere. 45

46. Proton and alpha spectra are shown!
Exercise 6
Use event generator mode
lec03.inp
Change & Execute
[ P a r a m e t e r s ]
icntl = 0
itall = 1
maxcas = 1000
maxbch = 10
emin(2)= 1.0e-10
dmax(2) = 20
emin(12) = 1.0
emin(13) = 1.0
emin(14) = 1.0
dmax(12) =
dmax(13) =
dmax(14) =
file(6) = phits.out
file(7) = c:/phits/data/xsdir.jnd
...
e-mode = 2
Track_eng.eps
Proton and alpha spectra are shown! 46

47. Important “file” Parameters
(D=phits.out)
Summary output file name. If not specified, standard output.
File(7)
(D=c:/phits/data/xsdir.jnd)
Address file for cross section data library.
File(15)
(D=dumpall.dat)
Dump file name for dumpall=1 option.
File(18)
(D=voxel.bin)
Binary file name for ivoxel=1,2.
File(20)
(D=c;/phits/XS/egs/)
Directory containing the library data for EGS5
File(21)
(D=c:/phits/dchain-sp/data/)
Directory containing the library data for DCHAIN-SP 47

48. Contents of Lecture III
Selection of Calculation Mode
Convenient functions for input
Setting for statistics
Monte Carlo integration
History Number and statistical error
Setting for physics
Cut-off Energy
Nuclear Data Library
Physical Models
Summary
Contents 48

49. Summary
[Parameters] section is used for controlling PHITS simulation procedure.
You can select the calculation modes such as particle transport simulation, geometry and source check using “icntl” parameter.
Statistical uncertainty of PHITS simulation depends on the history number (“maxcas” & “maxbch”)
You have to set cut-off energy “emin” of each particle to obtain good statistical data within a reasonable computational time
Low-energy neutrons, as well as photons, electrons and positron must be transported using nuclear and atomic data libraries by setting “dmax” and “file(7)” parameter.
You have to carefully select the physical models used in your simulation, such as the event generator mode
If you feel difficulties by selecting these parameters, see “recommendation” folder and find appropriate setting for your simulation
Summary 49

50. Homework
Based on the homework condition …
Transport neutrons down to 10-10MeV using nuclear data library up to 20 MeV
Activate event generator mode
Obtain depth-dose distribution with relative error less than 2%, by changing maxcas, istdev, batch.now etc.
宿題（3次元体系）
Homework 50

51. Depth-dose distribution inside (up) and outside (down) beam radius
Example Answer
Proton (up) and neutron (down) fluences
Depth-dose distribution inside (up) and outside (down) beam radius
Homework 51