Geant4 in Space selected recent investigations Giovanni Santin, Petteri Nieminen European Space Agency Giovanni.Santin@esa.int Geant4 ‘07 Hebden Bridge, 13-19 Sep 2007

Outline Planetary exploration Looking outside the solar system Geant4 usability: Tools and Engineering aspects Space Users’ community Giovanni Santin - Geant4 in Space - Geant4 '07, Hebden Bridge, Sep 2007

2. Planetary exploration Physics models Scientific Exploration: Low En EM Manned space flight: Even Lower En EM and physics for hadrons Interfaces (Engineering) Tools Giovanni Santin - Geant4 in Space - Geant4 '07, Hebden Bridge, Sep 2007

Solar event gamma-rays Electron Bremsstrahlung – induced gammas in solar flares Compton back-scattering  observable gamma-ray spectrum much softer than predicted by simple analytic calculations Giovanni Santin - Geant4 in Space - Geant4 '07, Hebden Bridge, Sep 2007

Mercury surface ? Bepi Colombo: X-Ray Mineralogical Survey of Mercury Fluorescence development in Geant4 Giovanni Santin - Geant4 in Space - Geant4 '07, Hebden Bridge, Sep 2007

PlanetoCosmics Mercury soil and magnetic field + Dipole B0 = 300 nT Giovanni Santin - Geant4 in Space - Geant4 '07, Hebden Bridge, Sep 2007

Detectors for Mercury (and Mars) High-Purity Germanium detectors (HPGe) used in astrophysics / planetary exploration gamma-ray spectrometers GCR and secondary fast neutrons  degradation of energy resolution, normally recovered by annealing (e.g. Mars Odyssey, INTEGRAL) For missions to inner solar system (Mars Observer, Messenger, BepiColombo) solar protons becoming major source of degradation (NIEL) Giovanni Santin - Geant4 in Space - Geant4 '07, Hebden Bridge, Sep 2007

PlanetoCosmics Geant4 simulation of Cosmic Rays in planetary Atmo- / Magneto- spheres Laurent Desorgher, University of Bern http://reat.space.qinetiq.com/septimess/magcos/ Giovanni Santin - Geant4 in Space - Geant4 '07, Hebden Bridge, Sep 2007

DESIRE Dose Estimation by Simulation of the ISS Radiation Environment http://www.particle.kth.se/desire/ T. Ersmark1, P. Carlson1, E. Daly2, C. Fuglesang3, I. Gudowska4, B. Lund-Jensen1, R. Nartallo2, P. Nieminen2, M. Pearce1, G. Santin2, N. Sobolevsky5 1Royal Institute of Technology (KTH) (Stockholm), 2ESA-ESTEC (Noordwijk), 3EAC/JSC (Cologne/Houston), 4Karolinska Institutet (Stockholm), 5Institute for Nuclear Research (Moscow) DESIRE Dose Estimation by Simulation of the ISS Radiation Environment GOAL Accurate Monte Carlo calculations (Geant4) of the radiation fields and doses to astronauts inside the European Columbus module of the International Space Station. ISS AND COLUMBUS INCIDENT RADIATION Trapped protons Galactic cosmic rays Solar particle events Earth albedo neutrons SPELLCHECK! Circular orbit 400 km altitude 51.6º inclination 370 tons (14A) 110 by 75 m Giovanni Santin - Geant4 in Space - Geant4 '07, Hebden Bridge, Sep 2007 Courtesy NASA

Solar event of 13 December 2006 Giovanni Santin - Geant4 in Space - Geant4 '07, Hebden Bridge, Sep 2007

STS-116 mission to ISS Giovanni Santin - Geant4 in Space - Geant4 '07, Hebden Bridge, Sep 2007

Life on Mars? Giovanni Santin - Geant4 in Space - Geant4 '07, Hebden Bridge, Sep 2007

PlanetoCosmics Mars field and atmosphere MGS observation Br @ 400 km Connerney et al., Geophys.Res.Let. 28, 21, 4015-4018, 2001 Cain 50-degree spherical harmonic model (2003) Geant4 implementation courtesy L. Desorgher, University of Bern NASA Mars-GRAM2001 model p,n, T in function of : Lat., long. (topography from MOLA) Altitude, season, local time, F10.7 Dust models Based on : Nasa MGCM 0-80 km Univ. of Arizona MTGCM 80-170 km Mars Global Surveyor (MGS): ●Aerobraking orbits (alt >101.6km) ●Science phasing orbits (alt >170. km) ●Mapping orbit (alt ~400 km) MGS Magnetic field measurement : ●No global field (dipole at equator <0.5 nT) ●Strong crustal field in the southern high lands : 1600 nT at 100 km over some regions 10x higher than on Earth Signature of an old global magnetic field ●Interaction of the solar wind with Mars ionosphere and crustal field Crustal magnetization seems to follow the topographical dichotomy of Mars: – low lands B weak, high lands B strong – north lands were probably formed after the cessation of the Mars dynamo •East-west band of inverse polarity in high lands at ~180 lon: – possible signature of early sea floor spreading –change of the polarity of Mars global field in the past •No magnetization over large impact basins of Hellas and Argyre: –Large impact did remove the crustal field in these regions MGS observation Interpretation Mars Crustal field models Cain et al., J. Geophys. Res. 108, E2, 5008, 2003: 90 and 50- degree spherical harmonic model 90 degree model developed to best-fit all MGS data 50 degree model developed to best fit the MGS mapping orbit data (~400 km) The 90 degree model is needed to match the smaller scale structure Probably the best one Available and implemented in PLANETOCOSMICS Giovanni Santin - Geant4 in Space - Geant4 '07, Hebden Bridge, Sep 2007

MarsREM See dedicated talk on Friday afternoon Models for Mars, Phobos and Deimos Surface topology and composition, subsurface, atmospheric composition and density (including diurnal and annual variations), local magnetic fields Active magnetic shielding: review and development of a G4 tool User-friendly engineering tool (QARM) New ion physics Consortium led by QinetiQ. ESA funding See dedicated talk on Friday afternoon Parallel Session 2- Aero/Space Applications Giovanni Santin - Geant4 in Space - Geant4 '07, Hebden Bridge, Sep 2007

No humans on Jupiter Laurent Desorgher et al, Planetocosmics tool Environments and doses on Jupiter Europa ESA / ESTEC, GRAS tool JURA Jupiter mission feasibility study focusing on radiation Giovanni Santin - Geant4 in Space - Geant4 '07, Hebden Bridge, Sep 2007

Looking outside GRB X-ray sources GLAST-LAT / GBM SWIFT XMM from ICATPP Japanese missions These images, taken by the Optical Monitor on board ESA's XMM-Newton observatory on 3 and 4 July 2005, show a comparison between the states of the comet before and just after impact. The images were taken in the blue (top) and ultraviolet channels (bottom) of the instrument. The ultraviolet images show the emissions of hydroxyl ions, the direct decay product of water. About 1.5 hours after the impact, the brightness of hydroxyl groups is increased by a factor of about five. Later, about 4.5 hours after the impact the ultraviolet emission is decreased again which indicates that the peak has passed. The presence of water in Tempel 1 is consistent with preliminary measurements of the composition of the comet made last week by the ALICE instrument on ESA's Rosetta spacecraft. For more information on this story please visit the ESA website. XMM-Newton probes formation of galaxy clusters Wednesday, August 31 2005 ESA's X-ray observatory, XMM-Newton, has for the first time allowed scientists to study in detail the formation history of galaxy clusters, not only with single arbitrarily selected objects, but with a complete representative sample of clusters. Knowing how these massive objects formed is a key to understanding the past and future of the Universe. Scientists currently base their well-founded picture of cosmic evolution on a model of structure formation where small structures form first and these then make up larger astronomical objects. Galaxy clusters are the largest and most recently formed objects in the known Universe, and they have many properties that make them great astrophysical 'laboratories'. For example, they are important witnesses of the structure formation process and important 'probes' to test cosmological models. To successfully test such cosmological models, we must have a good observational understanding of the dynamical structure of the individual galaxy clusters from representative cluster samples. For example, we need to know how many clusters are well evolved. We also need to know which clusters have experienced a recent substantial gravitational accretion of mass, and which clusters are in a stage of collision and merging. In addition, a precise cluster mass measurement, performed with the same XMM-Newton data, is also a necessary prerequisite for quantitative cosmological studies. The most easily visible part of galaxy clusters, i.e. the stars in all the galaxies, make up only a small fraction of the total of what makes up the cluster. Most of the observable matter of the cluster is composed of a hot gas (10-100 million degrees) trapped by the gravitational potential force of the cluster. This gas is completely invisible to human eyes, but because of its temperature, it is visible by its X-ray emission. This is where XMM-Newton comes in. With its unprecedented photon-collecting power and capability of spatially resolved spectroscopy, XMM-Newton has enabled scientists to perform these studies so effectively that not only single objects, but also whole representative samples can be studied routinely. Giovanni Santin - Geant4 in Space - Geant4 '07, Hebden Bridge, Sep 2007

XMM Firsov + multiple scattering H. Winter et al., NIM(B) vol 125, p124-127, 1997 DD induced CCD CTE loss observed on ACIS instrument on board Chandra Radiation belt low-energy protons scattering off X-ray mirrors Surface scattering: new physics in Geant4: proton scattering at very small angles Proton efficiency to reach the detector Experimental data show : Scattered protons suffer little energy loss: ~3 keV for protons in energy range 30 – 710 keV Energy loss independent of incidence angle (for angles <1 degree) Largely independent of surface material Multiple scattering alone cannot account for the behaviour of protons scattering at grazing incidence angles Song & Wang [NIM B153 (1999)] proved that low-angle incident protons only interact with the electron plasma cloud without entering the surface Giovanni Santin - Geant4 in Space - Geant4 '07, Hebden Bridge, Sep 2007

X- and Gamma-ray “Suzaku” Observatory JAXA / NASA-GSFC, launched July 2005 High-precision and Low-noise detector systems XIS: X-ray [0.3—12 keV] imaging spectrometer, 4 CCD HXD: Hard X-ray [10—600 keV] GSO-BGO phoswich, embedded CCD Geant4 simulation: Energy deposition + Charge-diffusion in CCD Courtesy of Masanobu Ozaki (ISAS/JAXA and JST/CREST) XIS HXD Succeeded in representing the BGD spectrum and resolving the BGD generation mechanism Giovanni Santin - Geant4 in Space - Geant4 '07, Hebden Bridge, Sep 2007

Gamma-rays from neutron stars December 27, 2004 One of the biggest explosions ever observed by humans Saturation in Konus-Wind direct observation Compton gammas from Moon surface detected by Helicon-Corona-F response matrix computed with Geant4 Direct Conus-Wind gamma ray spectrometer Giovanni Santin - Geant4 in Space - Geant4 '07, Hebden Bridge, Sep 2007

LISA JWST INTEGRAL ACE LISA Pathfinder RHESSI Herschel Cassini GLAST Messenger Bepi Colombo GAIA SWIFT SOHO SELENE Astro-E2 XMM-Newton ConeXpress EUSO AMS MAXI ISS Columbus

Geant4 usability Developments oriented to both science and engineering Interfaces / Geometry Formats, interfaces: Geometry: GDML, STEP-SPE CAD Geometry modelling: FASTRAD, ESABASE2 Geometry model database Tools Detector / Shielding :SSAT, MULASSIS, GRAS Planetary environments: PLANETOCOSMICS Microdosimetry: GEMAT (QinetiQ), RADSAFE (Vanderbilt) Reverse MC Prototype successful implementation - ongoing Laurent Desorgher, ESA REAT-MS project See talks by Fan Lei - Friday Plenary session TRAD – Aerospace Parallel session Giovanni Santin - Geant4 in Space - Geant4 '07, Hebden Bridge, Sep 2007

CAD geometry interface (and 3D modelling GUI) ESA REAT-MS contract CAD Using G4TessellatedSolid by P.Truscott (ESA REAT_MS1) Prototype used to require ST-Viewer commercial S/W (~300 USD) GDML module reads ST-Viewer files New: Direct GDML output from 3D modelling tools tools (ESA REAT_MS2) CAD STEP interface (and normal 3D models) FASTRAD and ESABASE2 GDML (Witek Pokorski) Tessellated shape, modular (multi-file) models, loops FASTRAD, ESABASE2 GUI for 3D modelling GDML output See FASTRAD talk in Aerospace parallel session Giovanni Santin - Geant4 in Space - Geant4 '07, Hebden Bridge, Sep 2007

Geant4 Reverse MC Full implementation (REAT_MS 2) “Adjoint” technique [see e.g. Kalos, 1968] Transport analogous to the forward one, but backward successive points are higher in energy, earlier in time Feasibility study (REAT_MS 1) Only continuous energy loss and simple multiple scattering Laurent Desorgher Space IT and Uni. Bern 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 Ongoing development Proposed to be included in Geant4 release Giovanni Santin - Geant4 in Space - Geant4 '07, Hebden Bridge, Sep 2007

Space community Geant4 Space Users’ web page Space Users’ Workshop Users, publications, news http://geant4.esa.int Feedback appreciated Space Users’ Workshop Tokyo University, Japan, 12-15 Feb 2008 Giovanni Santin - Geant4 in Space - Geant4 '07, Hebden Bridge, Sep 2007