geant4 application for japanese space science missions from 2006 to future
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Geant4 Application for Japanese Space Science
Missions from 2006 to Future
Masanobu Ozaki
(ISAS/JAXA and JST/CREST)
Japanese Space Science Missions
In Japan, most of fundamental researches relating to the on-orbit radiation environment are carried out for non-commercial (i.e. scientific) missions.
1. X-ray and Gamma-ray astronomy
2. Inter-planetary missions
3. Balloon missions
4. Automated ISS mission
This presentation will introduce them briefly.
X- and Gamma-ray astronomy
“Suzaku” Observatory (ISAS/JAXA and many universities)
Launched on July 10, 2005
•XIS (X-ray CCD camera) [0.3—12 keV]•HXD (Hard X-ray Detector) [10—600 keV]
High-precision and Low-noisedetector systems
The 5th Japanese X-ray astronomy satellite
Suzaku X-ray Imaging Spectrometer (XIS)
XIS camera bodySuzaku satellite
X-ray telescope(XRT)
Readouts
2.5cm
1.4c
m2.
5cm
4.75mFocal length
15cmIm
agin
g re
gion
Fra
me-
stor
e re
gion
CCD chip
Background-event spectrum of XISPhysics processes
•Electromagnetic Interaction(down to 250eV)
•Hadronic Interaction
Used Geant4 outputs:
•Physics process of particle generation, position, energy, solid-ID•Energy deposition and its physics process•ParentID 、 TrackID 、 StepNumber
Succeeded in representing the BGD spectrum and resolving the BGD generation mechanism
Geant4 simulation (energy deposition) + charge-diffusion simulation in CCD
Primary events from 4 Sr
Suzaku Hard X-ray Detector (HXD)
PIN*64
BGO
GSO*16
(10 ~ 60keV)
(30 ~ 600keV)
Si-PIN [2mm thick](10—60 keV)GSO [5mm thick](30—600keV)BGO: Shield + PhoswitchBGO well + Fine Collimator: narrow FOV as a non-imaging detector
-> Low Background-> High Sensitivity
Complex Response for incident photons
Performance Key: Monte Carlo simulator
simHXD: full simulator of HXD
Mass Model
(energy, direction)
MC simulationbased on Geant4
energy deposit-> signal
simAE
simDE
pipeline processingsimulation data
mass model
HXD responses:based on simHXD outputs
Crab Nebula (a standard candle) -> well-studied emission spectrum
HXD-PIN(10-70 keV) HXD-GSO(40-600 keV)
BLACK: real data, RED: emission model x response
These responses are used by all the Suzaku Observers.
HXD WAM: Wide All-sky MonitorBGO anti-co units around HXD:Not only for active shielding, but also all-sky detector for• Gamma-ray burst spectroscopy• Bright source monitor• …
Astro-E2 Mass Model
We must take into account of the absorption and scattering of full-satellite components such as• Solid-Ne dewar• satellite-structure panels• solar array panels• .......
Future Space Plasma Missions at JAXA ~2020’s
Planetary Magnetospheres The Plasma Universe Geospace Exploration
BepiColmbo L2013ESA/JAXA mission to Mercury
ESA/JAXA missionto Jupiter in 2020’s(to be proposedto ESA CosmicVision)
SCOPE/CrossScale ESA/JAXAMultiscale at the same timein Earth magnetosphere ~2016(to be proposed to ESA CosmicVision)
ERGA small explorer intothe inner-magnetosphere and relativistic particle acceleration processes~2011
BepiColombo: Mission to Mercury
First Full-Scale Euro-Japan joint mission
Two orbiters (MPO & MMO) will observe Mercury simultaneously with instruments developed by Euro-Japan joint research teams.
Complete study of MercuryThe innermost planet Mercury was already known in the ancient days, but it was visited only by the Mariner 10 spacecraft 3 decades ago. Mercury is still “unknown” and provides important keys to the solar system science.
MPO ( Mercury Planetary Orbiter)is a three-axis stabilized spacecraft. It studies geology, composition, inner structure and the exosphere. Abnormal structure and composition of Mercury will provide the keys for the planetary formation in the inner solar system.
MMO ( Mercury Magnetospheric Orbiter )is a spin-stabilized spacecraft. It studies magnetic field, atmosphere, Magnetosphere, and inner interplanetary space. Comparison of magnetic field & Magnetosphere with Earth will provide the new vision for space physics.
MMO [9.3h / orbit]400km x 12,000km
MPO [2.3h / orbit]400km x 1500km
Design & Development by JAXA
MMO (Mercury Magnetospheric Orbiter)
- High temperature materials & technologies.- Best scientific instruments from Japan-Euro collaboration.
Design & Development by JAXA
MMO (Mercury Magnetospheric Orbiter)
- High temperature materials & technologies.- Best scientific instruments from Japan-Euro collaboration.
Orbit / Mercury Magnetosphere (model)
Orbit / Mercury Magnetosphere (model)
C. Noshi/RISH, Kyoto Univ.
Baseline Schedule2012 Launch2017 Mercury Arrival
MMO[JAXA]MPO[ESA]
Mercury Project Office: http://www.stp.isas.jaxa.jp/mercury/
Using Geant4 in future space plasma missions
• Calculation of Radiation Dose in Spacecraft– Solar array– Electric parts ( including SEU/SEL )– Sensors ( CCD/SSD/MCP …)
• Estimation of Radiation Background in each Scientific & System Instruments– Using Geant4 for development of plasma instruments
in order to obtain high quality scientific data under strong radiation environment (Mercury, Radiation Belt, Jupiter etc )
Balloon mission: PoGOLite by Hiroshima-U, TiTech, Yamagata-U, SLAC and others
•Compton Polarimeter made of plastic scintilatorHigh modulation factorOptimized for Hard X-ray (25-100keV)
Balloon Flight!
•Japanese Consortium :•PMT 、 Beam test, DAQ, Performance modeling
•Stanford University: Detector array, DAQ, Gondola and attitude control system, Payload integration and testing
•Swedish Consortium:Side-anticoincidence Shield, Observation planning
•Ecolo Polytechnique:Scintillator and crystal reflective material
2003 2005 2006 2007 2008
Proposal to NASASpring8/Argonne
Beam Test
KEKBeam Test
KEKBeam Test
Proton Beam Test (Osaka)
2004
Second Proposal to NASA
Sensor Complete
Gondola Ready
Flight Instrument Integration
Schedule
(b)
Slow Plastic Scint.Collimator (FOV:5 deg2)
Fast Plastic Scint.(Pol. measurement)
Bottom BGOPMT assembly(low noise)
Side BGO Scint.Shield (BG rejection.)
1st prototype(fast scinti. 7 units)
2nd prototype(fast/slow 19 units+anti)
Flight Instrument Integration and Test
-- Geant4 (original) : MF=12.4%-- Geant4 (with fix) : MF=22.2%-- EGS4 : MF=21.8%
Modulation Curve for CrabPoGOLite Geant4 simulation
•Polarized Compton ScatteringPoGO-fix process
•Rayleigh ScatteringImplement Pol. dependence
ISS mission: GSC/MAXIby JAXA and universities
FOV : 1.5deg ×160deg
The FOVs sweep almost the entire sky during one ISS orbital period of 90 minutes. A point source stays in the FOV for 45 seconds.
Monitor of All-sky X-ray Image of 2-30 keV (GSC)
The collimator:
Material : phosphor bronze
Thickness: 0.1 mm, Height: 118.4 mm
The interval between slats: 0.1 mm
128 slats for one GSC unit
Ground calibration:• Energy-PH relation, position-PH relation, energy resolution, position resolution• The collimator response based on design value
Geant4 simulation• geometry from design sheet• photoelectric absorption, energy deposition, multiple scattering• considering L-escape
Detector Response Matrix (DRM) builder for GSC/MAXI
:Calibration data
:DRM simulations(8keV)(X= - 5mm,Y= - 80mm)
(X= - 5mm,Y= - 80mm)Target Cu-K line (8.1keV)
Comparison between ground calibration and DRM output
Conclusion
• Several Japanese space science mission use or will use Geant4– To construct the detector response to the
incident photons.– To simulate the detector outputs due to the
environment radiation.
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