Geant4 in JAXA Masanobu Ozaki (JAXA/ISAS)
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. Lunar exploration mission 3. Inter-planetary missions 4. Automated ISS mission This presentation will introduce them briefly.
X- and Gamma-ray astronomy Suzaku Observatory (ISAS/JAXA and many universities) The 5th Japanese X-ray astronomy satellite Launched on 2005-07-10 High-precision and Low-noise detector systems XIS (X-ray CCD camera) [0.3 12 kev] HXD (Hard X-ray Detector) [10 600 kev]
Background-event spectrum of XIS Primary events from 4π Sr Geant4 simulation (energy deposition) + charge-diffusion simulation in CCD Physics 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 ParentIDTrackID StepNumber Succeeded in representing the BGD spectrum and resolving the BGD generation mechanism
Suzaku Hard X-ray Detector (HXD) BGO PIN*64 (1060keV) GSO*16 (30600keV) Si-PIN [2mm thick](10 60 kev) GSO [5mm thick](30 600keV) BGO: Shield + Phoswitch BGO well + Fine Collimator: narrow FOV as a non-imaging detector -> Low Background -> High Sensitivity Complex Response for incident photons Performance Key: Monte Carlo simulator
NeXT New exploration X-ray Telescope Experience of Suzaku simulation will be included from the design phase. The focusing feature of the X-ray telescope (XRT) will be simulated by Geant4 (NEW!)
Prototype of NeXT XRT Mirror for balloon experiment Geantr4 geometry
Point Spread Function
Effective Area
Response for offset incident 6 measured H=+6.28 H=0 H=-6.28 Detector-V [arcmin] V=+8.74 V=0 4 2 0-2 -4 6-6 10 5 0 SPring-8 30keV log scale -5 Detector-V [arcmin] V offset angle [arcmin] simulated -5 0 5 10 H offset angle [arcmin] 2 0-2 -4 30keV log scale -10-10 4-6 -6-4 -2 0 2 4 6 Detector-H [arcmin]
Kaguya (a.k.a. SELENE) JAXA s Lunar explorer Launched on 2007-09-14 100km altitude from Moon in the observation phase
Kaguya Gamma-Ray Spectrometer (GRS) Ge detector with BGO active shield Many simulations with Geant4 from the development phase (3 talks)
Future Space Plasma Missions at JAXA ~2020 s Planetary Magnetospheres The Plasma Universe Geospace Exploration SCOPE/CrossScale ESA/JAXA Multiscale at the same time in Earth magnetosphere ~2016 ESA/JAXA mission to Jupiter in 2020 s (to be proposed to ESA CosmicVision) (to be proposed to ESA CosmicVision) BepiColmbo L2013 ESA/JAXA mission to Mercury ERG A small explorer into the inner-magnetosphere and relativistic particle acceleration processes ~2011
BepiColombo: Mission to Mercury MPO[ESA] Complete study of Mercury MMO[JAXA] The 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. First Full-Scale Euro-Japan joint mission C. Noshi/RISH, Kyoto Univ. Two orbiters (MPO & MMO) will observe Mercury simultaneously with instruments developed by Euro-Japan joint research teams. Design & Development by JAXA MMO (Mercury Magnetospheric Orbiter) MPO Mercury Planetary Orbiter) MPO [2.3h / orbit] 400km x 1500km 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. - High temperature materials & technologies. - Best scientific instruments from Japan-Euro collaboration. MMO Mercury Magnetospheric Orbiter MMO [9.3h / orbit] 400km x 12,000km 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. Baseline Schedule 2012 Launch 2017 Mercury Arrival Orbit / Mercury Magnetosphere (model) Mercury Project Office: http://www.stp.isas.jaxa.jp/mercury/
Using Geant4 in future space plasma missions Calculation of Radiation Dose in Spacecraft 1. Solar array 2. Electric parts ( including SEU/SEL ) 3. Sensors ( CCD/SSD/MCP ) Estimation of Radiation Background in each Scientific & System Instruments 1.Using Geant4 for development of plasma instruments in order to obtain high quality scientific data under strong radiation environment (Mercury, Radiation Belt, Jupiter etc )
ISS mission: GSC/MAXI by JAXA and universities Monitor of All-sky X-ray Image of 2-30 kev (GSC) 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. 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
Detector Response Matrix (DRM) builder for GSC/MAXI 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
Comparison between ground calibration and DRM output :Calibration data (X=5mm,Y=80mm) Target Cu-K line (8.1keV) :DRM simulations(8kev) (X=5mm,Y=80mm)
Conclusion Several Japanese space science mission use or will use Geant4 1.To construct the detector response to the incident photons. 2.To simulate the detector outputs due to the environment radiation.