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$Id: README,v 1.8 2008/06/02 10:00:40 sincerti Exp $
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Geant4 - Nanobeam example
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README file
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CORRESPONDING AUTHOR
S. Incerti (a, *) et al.
a. Centre d'Etudes Nucleaires de Bordeaux-Gradignan
(CENBG), IN2P3 / CNRS / Bordeaux 1 University, 33175 Gradignan, France
* e-mail:incerti@cenbg.in2p3.fr
Last modified by S. Incerti, 10/04/2008
---->1. INTRODUCTION.
The nanobeam example simulates the beam optics of the nanobeam line installed
on the AIFIRA electrostatic accelerator facility located at CENBG,
Bordeaux-Gradignan, France. For more information on this facility,
please visit :
http://www.cenbg.in2p3.fr/
The code can be used to calculate :
1) intrinsic aberration coefficients of the nanobeam line
2) beam image from a relasitic primary emittance distribution
3) grid shadow images
Three quadrupole field models can be used :
- a simple square field model
- a 3D mesh field model computed from OPERA3D
- an analytical model based on Enge's model
---->2. GEOMETRY SET-UP.
The full magnetic configuration of the nanobeam line is simulated.
This configuration is made of a combination of a doublet and triplet of
5 Oxford Microbeams Ltd. OM50 quadrupoles.
More details on the experimental setup and its simulation with Geant4 can
be found in the following papers, which may be found on the SLAC-SPIRES
online database (http://www.slac.stanford.edu/spires/) :
- A DETAILED RAY-TRACING SIMULATION OF THE HIGH RESOLUTION MICROBEAM AT THE
AIFIRA FACILITY
F. Andersson, Ph. Barberet, S. Incerti, Ph. Moretto (CENBG, Gradignan) . Dec 2007.
In press in Nucl.Instrum.Meth.B266:1653-1658, 2008
- MONTE CARLO SIMULATION OF THE CENBG MICROBEAM AND NANOBEAM LINES WITH THE
GEANT4 TOOLKIT
By S. Incerti, Q. Zhang, F. Andersson, Ph. Moretto, G.W. Grime,
M.J. Merchant, D.T. Nguyen, C. Habchi, T. Pouthier and H. Seznec
In press in Nucl.Instrum.Meth.B260:20-27, 2007
- GEANT4 SIMULATION OF THE NEW CENBG MICRO AND NANO PROBES FACILITY
By S. Incerti, C. Habchi, Ph. Moretto, J. Olivier and H. Seznec. May 2006. 5pp.
Published in Nucl.Instrum.Meth.B249:738-742, 2006
- A COMPARISON OF RAY-TRACING SOFTWARE FOR THE DESIGN OF QUADRUPOLE MICROBEAM
SYSTEMS
By S. Incerti et al.,
Published in Nucl.Instrum.Meth.B231:76-85, 2005
---->3. SET-UP
- a standard Geant4 example GNUmakefile is provided
setup with:
compiler = gcc-3.4.6
G4SYSTEM = linux-g++
The following section gives the necessary environment variables.
------->>3.1 ENVIRONMENT VARIABLES
All variables are defined with their default value.
- G4SYSTEM = Linux-g++
- G4INSTALL points to the installation directory of GEANT4;
- G4LIB point to the compiled libraries of GEANT4;
- G4WORKDIR points to the work directory;
- CLHEP_BASE_DIR points to the installation directory of CHLEP;
- G4LEDATA points to the low energy electromagnetic libraries;
- LD_LIBRARY_PATH = $CLHEP_BASE_DIR/lib
- G4LEVELGAMMADATA points to the photoevaporation library;
- G4NEUTRONHPDATA points to the neutron data files;
- G4RADIOACTIVEDATA points to the libraries for radio-active decay
hadronic processes;
- G4ABLADATA points to the libraries fo ablation processes;
However, the
$G4LEDATA,
$G4LEVELGAMMADATA,
$G4NEUTRONHPDATA,
$G4RADIOACTIVEDATA
and $G4ABLADATA
variables do not need to be defined for this example.
Once these variables have been set, simply type gmake to compile the Nanobeam
example.
------->>3.2 VISUALIZATION
Visualization has not been implemented.
All results are stored in text files and can be displayed with the provided
ROOT macro file plot.C.
This macro file shows :
- the beam profile along the nanobeam line (only for the computation of intrinsic
coefficients)
- the beam image (Y vs X) on target
- the beam emittance (THETA vs X) and (PHY vs Y) on target
- the grid shadow image
---->4. HOW TO RUN THE EXAMPLE
The code can be run with :
> $G4WORDIR/bin/$G4SYSTEM/Nanobeam
The macro file default.mac is read by default.
It can be one of the following macro files :
1) for the computation of intrinsic aberration coefficients :
coef-square.mac : using square magnetic field model (=default.mac)
coef-map.mac : using 3D map magnetic field model
coef-enge.mac : using Enge's analytical field model
2) for the simulation of the beam image with a realistic emittance :
image-square.mac : using square magnetic field model
image-map.mac : using 3D map magnetic field model
image-enge.mac : using Enge's analytical field model
3) for the simulation of grid shadow images
grid-square.mac : using square magnetic field model
grid-map.mac : using 3D map magnetic field model
grid-enge.mac : using Enge's analytical field model
These macros files are stored in the ./macros directory.
---->5. PHYSICS
The example runs with protons with fluctuationg energies around 3 MeV.
Standard electromagnetic processes are activated by default.
---->6. SIMULATION OUTPUT AND RESULT ANALYZIS
The output results consists in several .txt files.
These files can be easily analyzed using for example the provided ROOT macro
file plot.C; to do so :
* be sure to have ROOT installed on your machine
* be sure to be in the nanobeam directory
* launch ROOT by typing root
* under your ROOT session, type in : .X plot.C to execute the macro file
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Should you have any enquiry, please do not hesitate to contact:
incerti@cenbg.in2p3.fr
Gabriele Cosmo