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Geant4 - Radioprotection example
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README
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0. INTRODUCTION
The Radioprotection example derives from a Geant4 application
( look www.ge.infn.it/geant4/space/remsim for more details ) whose scope
is to evaluate the dose in astronauts, in vehicle concepts and
Moon surface habitat configurations, in a defined interplanetary space
radiation environment.
1. GEOMETRY
The user can calculate the dose in the astronaut (phantom) in the
following set-ups:
- Vehicle configuration
| ||sh| | | | |
|S||ie| |SPE | | |
----> |I||ld| |she | |phantom|
beam |H||in| |lter| | |
| ||g | | | | |
--------------------------------------->
Z axis
- The SIH is the Simplified Inflatable Habitat.
- The shielding is a layer of water, its scope it to protect the astronaut
from Galactic Cosmic Rays (GCR). The user can add, delete this element
in the geometrical configuration, change its thickness through UI comands.
- The SPE shelter is a water layer (thickness = 75.cm along Z axis), its scope
it to protect the astronaut from Solar Particle Events (SPE).
The user can add, delete this element in the geometrical configuration
through UI comands.
- The phantom is the astronaut model; the energy deposit is collected in this
geometrical component. The phantom is a box of water,
it is 30. cm wide along Z axis, it is voxelised in 30 slices along Z axis.
The energy deposit of primary and secondary particles is collected in
each voxel.
- Moon Habitat configuration
_______________________________
| |
/ |Moon Surface |
/ | |
| x | _________ |
|<->|| _____ | |
---->| || |Phan | | <---shelter |
beam | || |thom | | |
| || |_____| | |
\ ||_________| |
\ | |
pyramid |
log| |
|______________________________|
------------------------------------------->
Z axis
- The astronaut/phantom is set in the astronaut habitat (shelter).
- The pyramid log is made of moon soil and protects the astronaut from
GCR and SPE. The user can add, delete this element in the geometrical
configuration, change its thickness (x) through UI comands.
- The phantom is the astronaut model; the energy deposit is collected in this
geometrical component. The phantom is a box of water,
it is 30. cm wide along Z axis, it is voxelised in 30 slices along Z axis.
The energy deposit of primary and secondary particles is collected in
each voxel.
1.1 UI
- The user can change the geometry set-up with the following UI commands:
/configuration/choose vehicle -> choose the Vehicle configuration
/configuration/choose moon -> choose the Moon Habitat configuration
The user can not switch between these two configurations interactively.
- The user can select in the vehicle configuration:
/configuration/AddShielding On -> set the shielding water layer
/configuration/AddShielding Off -> destroy the shielding water layer
/shielding/thickness 30.cm -> set the thickness of the shielding layer
/configuration/AddSPE On -> set the SPE shelter
/configuration/AddSPE Off -> destroy the SPE shelter
- The user can select in the Moon surface habitat configuration:
/configuration/AddRoof On -> set the pyramid log
/configuration/AddRoof Off -> destroy the pyramid log
/roof/thickness 1. m -> set the height (x) of the pyramid log
2. PHYSICS LIST
The user can select the physics processes to activate interactively as
shown in the macro vis.mac.
The example is provided of:
- Low Energy electromagnetic processes for photons, e-
- Standard electromagnetic processes for e+
- Low Energy or Standard electromagnetic processes with ICRU parameterisation
for p, alpha and ions
- Muon electromagnetic processes
- Decay
- Hadronic processes for p and alpha particles as primary particles.
3. PRIMARY PARTICLES
The user can select different set-ups to generate primary particles:
- "Basic": monochromatic particle beam (default configuration)
- "Interplanetary": particle beam with energy derived from a given
energy spectrum.
- "Moon": particles generated with energy derived from a given
energy spectrum; The primary vertex is generated on a given hemisphere.
The default configuration is Basic.
The energy spectrum is written is ASCII file:
first column: energy in MeV
second column: flux
The final two rows must look as follows:
-1 -1
-2 -2
The flux is used as probability of generating a particle with a particular
energy. The sum of the fluxes is normalised to 1 in the RunAction.
Examples of ASCII files --
- Galactic Cosmic Rays fluxes (envelope of CREME96 1977 and CREME86 1975 solar
minimum spectra):
p: gcrZ=1.txt
alpha: gcrZ=2.txt
carbon ion: gcrZ=6.txt
oxygen ion: gcrZ=8.txt
silicon ion: gcrZ=14.txt
iron ion: gcrZ=26.txt
- Solar Particle Events (envelope of CREME96 October 1989 and
August 1972 spectra)
p: speZ=1.txt
alpha: speZ=2.txt
3.1 UI
The user can define primary particles with the following command:
/gun/particle proton
/gun/particle alpha
/gun/particle IonC12
/gun/particle IonO16
/gun/particle IonSi28
/gun/particle IonFe52
The user can select interactively the configuration with the following
UI commands:
/gun/generator Basic
/gun/generator Interplanetary
/gun/generator Moon
In the Basic configuration, the user can change interactively the
energy of primary particles:
example: /gun/energy 1.MeV
4. STEPPING
Available UI command:
/step/hadronicVerbose On -> print the hadronic processes undertaken by
particles during the run
/step/hadronicVerbose Off -> switch off the verbose level
5. ANALYSIS
if ANALYSIS_USE = 1 in the variable environment, the output of
the simulation is remsim.hbk
The file contains histograms:
- 10 (1) Energy Deposit (MeV)in the phantom (astronaut) versus
the depth along Z axis
- 20 (1) Initial energy (MeV) of primary particles
- 30 (1) Energy Deposit (MeV) in the phantom given by secondaries
versus the depth along Z axis
- 40 (1) Initial energy (MeV) of primaries reaching the phantom
- 50 (1) Initial energy (MeV) of primaries ougoing the phantom
- 60 (1) Energy (MeV) of primaries reaching the phantom
- 70 (1) Energy (MeV) of primaries outgoing the phantom
6.SET-UP
- a standard Geant4 example GNUmakefile is provided
setup with:
compiler = gcc-3.2.3
G4SYSTEM = linux-g++
The following environment variables need to be set for the physics packages:
G4LEDATA points to low energy data base - G4EMLOW2.3
G4LEVELGAMMADATA points to PhotoEvaporation data
G4RADIOACTIVEDATA points to Radioactive Decay data
NeutronHPCrossSections points to neutron data - G4NDL3.7
Setup for analysis: AIDA 3.2.1, PI 1.2.1
Users can download the analysis tools from:
http://aida.freehep.org/
http://www.cern.ch/PI
7. HOW TO RUN THE EXAMPLE
example macros are provided:
- vehicle1.mac, vehicle2.mac are examples of simulation in the
vehicle configuration
- moon.mac is an example of simulation in the Moon habitat configuration
- batch mode:
$G4WORDIR/bin/Linux-g++/remsim vehicle1.mac
$G4WORDIR/bin/Linux-g++/remsim vehicle2.mac
$G4WORDIR/bin/Linux-g++/Brachy moon.mac
- Interative mode:
$G4WORDIR/bin/Linux-g++/remsim
-> the vis.mac is loaded automatically |
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Author : Susanna Guatelli
for comments, advices, doubts and questions: guatelli@ge.infn.it
last modified: Susanna Guatelli 27/5/2004
Gabriele Cosmo