Outline of recent ESA-related
developments
Giovanni Santin*, Petteri Nieminen
ESA / ESTEC
*RHEA System SA
GEANT4 – SPENVIS Space Users’ Workshop ‘06
Pasadena, 9-10 November 2006
Geant4
for space environment analyses
Environments – Physics - Geometry - Analysis
ESA involvement in the Geant4 collaboration (since 1997) contributed to


new capabilities in the Geant4 kernel of relevance for space
applications and tools in the space radiation environments and effects domain.
Geometry
modelling
Usability
Applications:
Science mission analyses
Radiation engineering and shielding applications
Planetary environment modelling
Human effects
Physics
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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Physics

New requirements from
–
–
–
–
Science missions
Human space flight
Effects to micro-electronics
Environment modelling
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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Geant4 models
Space environment and Physics models
EM Standard
EM Low Energy
Optical
HAD protons
HAD ions
100 eV
1 keV
10 MeV
100 MeV
100 GeV
100 TeV
100 PeV
Space environment
Plasma
Tr. Electrons
Tr. Protons
Solar protons
Cosmic rays: p,a,ions
Extreme Energy Cosmic Rays
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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Physics developments

Ion physics
–

Very low energy extensions
–

P. Truscott, REAT_MS 1, MARSREM
MG Pia, Geant4-DNA
Physics lists for space applications
–
V. Ivantchenko, REAT_MS 1

Inverse Monte Carlo
–
Laurent Desorgher, REAT_MS 1 & 2
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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Geant4
Reverse MC
“Adjoint” technique [Kalos 1968]

New transport equation, “adjoint” to the conventional “forward”
transport equation

Transport analogous to the forward one, but backward
–



successive points are higher in energy, earlier in time
Suitable for Monte Carlo calculations
Computations start at the detector and score at the source
Possibility of computing doses at a point!
Feasibility study (REAT_MS 1)
Laurent Desorgher

Space IT and Uni. Bern


G4 RMC Prototype for fast e- dose computation
Only continuous energy loss and simple multiple scattering
Completed
Full implementation (REAT_MS 2)


RMC in G4 for fast e- dose computation
Backward simulation of :
–
–

e- ionisation with delta production, continuous energy loss and multiple scattering
Bremstrahlung, compton scattering, photo-electric effect
In development - Release mid 2007
Proposed to be included in Geant4 release
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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Geometry

GDML
– Upgrades
– Developments for CAD I/F

CAD
– Prototype interface through ST-Viewer
– GDML Interface in Space Engineering CAD tools

ESABASE1
– Through ES9 meshing
– Under investigation
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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GDML
Geometry Description Markup Language

Initial frame: XML based geometry description for Geant4 (CERN, ~2000)
Motivation
– move away from hard-coded geometry (C++)
– enable geometry interchange between applications

Presently part of the CERN Simulation Framework (Simulation Project) as
Geometry interchange format
– Actively used at CERN for
Physics comparisons (Geant4 - FLUKA)
Geometry model exchange (Geant4 - ROOT)
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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GDML schema and I/O

GDML is defined through XML Schema (XSD)
• defines document structure and the list of legal
elements (position, rotation, material, solid,…)
• XSD are in XML -> they are extensible

user application (1)
GDML writer
GDML I/O
– C++ implementation of GDML processor
• Input
Xerces-C SAX parser  'in-memory' representation of
the geometry description
• Output
Writing-out GDML data
GDML
Schema
GDML file
GDML reader
– Alternative Python-based processor
• uses xml.sax Python module
• allows very light binding to applications
user application (2)
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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GDML example
<?xml version="1.0" encoding="UTF-8"?>
<gdml xsi:noNamespaceSchemaLocation="GDMLSchema/gdml.xsd">
positions,
rotations
<define>
<position name="TrackerinWorldpos" unit="mm" x="0" y="0"
z="100" />
</define>
<materials>
<material formula=" " name="Air" >
<D value="1.290" unit="mg/cm3"/>
<fraction n="0.7" ref="Nitrogen" />
<fraction n="0.3" ref="Oxygen" />
</material>
</materials>
materials
solids
<solids>
</solids>
geometry
tree
'world'
volume
<box lunit="mm" name="Tracker" x="50" y="50" z="50" />
<structure>
<volume name="World" >
<materialref ref="Air" />
<solidref ref="world" />
<physvol>
 Similar to HTML,
<volumeref ref="Tracker" />
<positionref ref="TrackerinWorldpos"
/> for
explicit tags
<rotationref
ref="TrackerinWorldrot" />
elements, …
</physvol>
</volume>
</structure>

</gdml>
<setup name="Default" version="1.0" >
<world ref="World" />
</setup>
ASCII file: easy to
create, read,
debug, modify,…
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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GDML 2.8 - Status

Solids supported:
–
–
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Boolean solids:
–



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E.g. space electronic components,…
Open source,
collaborative development
–

ConeXpress, ESA, Ronnie Lindberg
Position, rotation and size
Loops, modular models  NEW
–

Union, subtraction, intersection
Assembly of volumes
Replicas and divisions
Parameterized volumes
–

box, sphere (G4Sphere and G4Orb), tube, cone, polycone,
parallepiped, trapezoid (G4Trap and G4Trd), torus,
polyhedron, hype (tube with hyperbolic profile), elliptical tube
Tetrahedron, tessellated, ellipsoid, twisted solids  NEW
http://cern.ch/gdml
Stable, mature
Main G4 geometry format at ESA
LHCB, CERN, R.Maunder
Antropomorphic Phantom, INFN,
Giorgio Guerrieri, Maria Grazia
Pia, Susanna Guatelli
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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Geant4
CAD interface
–
–
–
CAD
model
STEP


StepTools
OpenCascade
library
CAD-GDML interfaces in engineering tools
ESABASE2 (eta_max)
FASTRAD (TRAD)
CAD tool
model
ST-Viewer
Uses G4TessellatedSolid (P.Truscott)
Requires auxiliary files created with ST-Viewer
commercial S/W
Based on GDML (v 2.8)
Future contract to integrate GEANT4 in CAD
GUI framework
Geant4
10 GeV proton in wood
LHEP_BIC_HP
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
ESABASE 2
GDML
FASTRAD
External
CAD tool
Prototype by ESA REAT_MS contract
(QinetiQ+sub.)

12
Sector Shielding Analysis Tool
SSAT
DOSE



Ray tracing: from a user-defined point
within a Geant4 geometry
NORM, SLANT and MIXED tracing
SHIELDING

Estimate of the dose at a point
–
Based on external Dose-Depth curve
•
–

E.g. SHIELDOSE-2 curve [rad VS g/cm2]
Ray-by-ray dose calculation
Results:
–
–
–
Total dose
Dose-Depth profile
Dose directionality
shielding levels
fraction of solid angle for which the
shielding is within a defined interval
global and from single materials

shielding distribution
the mean shielding level as a function
of look direction

It utilizes geantinos
ConeXpress model: R.Lindberg, ESA
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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MULASSIS
and GEMAT
Layer Geometry
Physics list choice
Analysis options



–
–
–
–
–
Dose
Pulse Height Spectrum
Ion. dose
NIEL
Dose Equivalent
Primary particle spectrum and fluences from
SPENVIS

–
–
–
–
Trapped protons
Solar protons
Trapped electrons
…
Geant4-based Microdosimetry Tool

Microdosimetry in geometries representing
features of a semiconductor device
(transistor/junction geometries)

Analysis includes
–
–
single event effects (SEE)
simultaneous energy deposition in several
sensitive regions (MBU)
Web interface

z
y
x
Trajectory average spectra
Contacts
Differential flux (/cm2/s/MeV)
1.00E+05
1.00E+04
1.00E+03
electrons
protons
1.00E+02
1.00E+01
0.01
0.1
1.00E+00
1
1.00E-01
10
1.00E-02
Energy (MeV)
100
1000
Depleted regions
non-depleted active or
inactive regions
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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GRAS
Geant4 Radiation Analysis for Space

Detector / Component effects
–

Human dosimetry
–


GDML format, or existing C++ class, …
Ready-To-Use tool
–

Dose Equivalent, Equivalent Dose,… for ESA exploration initiative
3D geometry
–

Dose, Fluence, NIEL, LET… for support to engineering and scientific design
Different analyses set without re-compilation
Modular / extendable design
Is being integrated into SPENVIS
Santin et al, IEEE Trans. Nucl. Sci. 52, 2005
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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GRAS components
Geometry
1
Santin et al, RADECS, 2005
Source
- GDML
- Used also for STEP CAD models
Also provided:
- MULASSIS – like
- Interface to ESABASE (in progress)
- C++ model
2
RADIATION
ENVIRONMENT
/gps/pos/type Surface
/gps/pos/shape Sphere
...
/gps/ang/type cos
/gps/particle e...
/gras/geometry/type gdml
/gdml/file geometry/conexpress.gdml
Analysis
4
Physics
3
Geant4 physics models
through script commands
/gras/phys/addPhysics
/gras/phys/addPhysics
/gras/phys/addPhysics
/gras/phys/addPhysics
em_standard
binary
binary_ion
lowe_neutron
/gras/physics/setCuts 0.1 mm
/gras/physics/stepMax 0.01 mm
GEAN
T4
- NIEL
- Fluence
- Charging
- LET
- Path-length
Anal
ysis
Man
ager
D
DD
os
osos
e
e
e
A
AA
na D Fl
na
na D ue
ly
ly ly osos nc
si
si si e e e
s
s s AA A
M na
M
M na
D NIna
D
od
odod os
ly lyE ly
os ul
ul ul si
e siL si
e es
sA
eses A
A sM s
DD
M na M
… nana
osos
od
ly od
od
ly
A ly
e e
si ulsi ul
na si ul
AA
ess es
es
s
ly s
nana
si M M M
ly ly
s odod od
si si
ul
M
ul ul
s s
od eses es
MM
ul
odod
es
ul ul
eses
- Dose (TID)
- Dose equivalent
- Equivalent dose
- Source monitoring
- Detector analysis
In progress:
Activation
more SEE
/gras/analysis/dose/addModule doseB12
/gras/analysis/dose/doseB12/addVolume b1
/gras/analysis/dose/doseB12/addVolume b2
/gras/analysis/dose/doseB12/setUnit rad
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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GRAS
Lindberg et al, accepted, IEEE Trans. Nucl. Sci.
Shielding assessment
Comparison to ray-tracing
Geant4 v7.1 Dose for Particle Energy of 1.75 MeV
Avr. Dose per Event (MeV)
0.02


G4 v7.1,Cuts=0.10 mm
G4 v7.1,Cuts=100.00 mm
G4 v8.0, cuts 0.1 mm
G4 v8.0, cuts 100 mm
0.016
0.012
0.008
0.004
0.01

G4 v7.1, Cuts= 0.01 mm
G4 v7.1,Cuts=1.00 mm
G4 v8.0, cuts. 0.01 mm
G4 v8.0, cuts 1 mm
0.1
1
StepMax (mm)
10
100
Comparison of transmission (p, e-)
Parametric study: stability of Geant4
dose estimates after transmission VS
tracking parameters
Dose comparison in simple and realistic
satellite geometries
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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GRAS
Status and plans

Current release V1.3
–

SREM radiation monitor (calibration)
HERSCHEL (glitch studies)
ConeXpress (dosimetry)
GAIA (dosimetry, transients)
RF filters (surface effects)
Neutron
production
TOF
Upgrades
–
–
–
–

Using Geant4 8.0.p01, GDML 2.5
Ongoing studies using GRAS
–
–
–
–
–

JWST
NIRSpec
New analysis modules
Review of uncertainties  to Geant4 release
Interface to PHITS (T. Koi)
Upgrade of physics list
Coming release V1.4
–
–
–
HERSCHEL
Glitch study
Using Geant4 8.1.p01, GDML 2.8
Next weeks
Software Installation & User Manual  NEW
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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Planetary exploration
Robotic and human missions

Long interplanetary journey

Long permanence with scarce natural
shielding
New user requirements include:
 planetary models
e.g. scaling of SPE fluence to other
planets, magnetic field description,
crustal maps

ion physics
electromagnetics / hadronics for HZE

biological effects
macroscopic / microscopic models
very low energy physics
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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Geant4
DNA


Damage mechanisms

Interactions of Radiation with Biological
Systems at the Cellular and DNA Level


Human phantom library
Applications in radiation
protection, therapy protocol
studies
Analytical model
INFN Genova

Geant4 extension to simulate electromagnetic interactions in liquid water down to ~7.5 eV
–

e-, p, H, He
Processes for cell survival
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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DESIRE
DESIRE (cont)
Dose Estimation by Simulation of the ISS Radiation Environment
GEANT4 GEOMETRY
 ISS configuration 14A, 400 volumes
 Columbus, 800 volumes
CALCULATED DOSE RATES
INSIDE COLUMBUS
 Trapped protons: 2.0 Gy/h
SPENVIS, AP8-min
 Model available for collaborations
from Tore Ersmark (KTH)
 GCR protons: 3.3 Gy/h
CREME96, solar minimum
Example
spectra of
penetrating
trapped protons
and secondary
particles.
Courtesy: T. Ersmark, KTH Stockholm
DESIRE
The DESIRE project is funded by ESA (15613/NL/LvH)
and the Swedish National Space Board.
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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REMSIM

Simulation and Analysis of Vehicle Concepts and Surface Habitat Designs

Quantitative dosimetry
 Evaluation of interplanetary transfer vehicle concepts and habitat
 Interplanetary space radiation environment
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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IEEE Trans Nucl Sci
52, No. 6, Dec 2005
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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Laurent Desorgher
PLANETOCOSMICS

Interactions of cosmic rays with planets
–



Space IT and Uni. Bern
Mars, Mercury, Earth
Propagation in magnetosphere
Interactions with atmosphere and soil

Flux of shower particles in atmosphere and soil (new)
Energy deposited in atmosphere and soil (new)

In development
–
Jupiter case
Available at
http://cosray.unibe.ch/~laurent/planetocosmics
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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Active Shielding
Laurent Desorgher
Space IT and Uni. Bern

MarsREM project

Literature review on active magnetic shielding

Development of a G4 magnetic shielding tool for computing shielding of
space radiation by artificial magnetic fields

Comparative study of active and passive shielding by using this tool

In progress – release end 2007
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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Tools for the
Space Users’ community
http://geant4.esa.int

Geant4 Space Users’
web page
– Users
– ~100 publications
– News

Feedback appreciated
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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To do
Giovanni Santin - Recent ESA-related developments - Pasadena, Nov 2006
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