We have developed MGGPOD, a user-friendly suite of Monte Carlo codes built around the widely used GEANT (Version 3.21) package. The MGGPOD Monte Carlo suite and documentation are publicly available for download. MGGPOD is an ideal tool for supporting the v

MGGPOD:AMONTECARLOSUITEFORGAMMA-RAYASTRONOMYG.Weidenspointner1,2,M.Harris1,2,C.Ferguson3,S.Sturner2,B.Teegarden4,and

C.Wunderer5

1´Centred’EtudeSpatialedesRayonnements,BP4346,31028ToulouseCedex4,France2

NASAGoddardSpaceFlightCenter,Code661&USRA,Greenbelt,MD20771,USA

3

UniversityofSouthampton,Southampton,SO171BJ,UK

4

NASAGoddardSpaceFlightCenter,Code661,Greenbelt,MD20771,USA5

SpaceScienceLaboratory,UniversityofCaliforniaBerkeley,CA94720,USA

arXiv:astro-ph/0406159v1 7 Jun 2004

ABSTRACT

WehavedevelopedMGGPOD,auser-friendlysuiteofMonteCarlocodesbuiltaroundthewidelyusedGEANT(Version3.21)package.TheMGGPODMonteCarlosuiteanddocumentationarepubliclyavailablefordownload.MGGPODisanidealtoolforsupportingthevariousstagesofgamma-rayastron-omymissions,rangingfromthedesign,development,andperformancepredictionthroughcalibrationandresponsegenerationtodatareduction.Inparticu-lar,MGGPODiscapableofsimulatingabinitiothephysicalprocessesrelevantfortheproductionofin-strumentalbackgrounds.Theseincludethebuild-upanddelayeddecayofradioactiveisotopesaswellasthepromptde-excitationofexcitednuclei,bothofwhichgiverisetoaplethoraofinstrumentalgamma-raybackgroundlinesinadditiontocontinuumback-grounds.

Keywords:gamma-rayastronomy;MonteCarlosimulation;instrumentation.

1.INTRODUCTION

Intenseandcomplexinstrumentalbackgrounds,againstwhichthemuchsmallersignalsfromcelestialsourceshavetobediscerned,areanotoriousprob-lemforlowandintermediateenergygamma-rayas-tronomy(～50keV–10MeV).Thereforeadetailedqualitativeandquantitativeunderstandingofinstru-mentallineandcontinuumbackgroundsiscrucialformoststagesofgamma-rayastronomymissions,rang-ingfromthedesignanddevelopmentofnewinstru-mentationthroughperformancepredictiontodatareduction.Apromisingapproachforobtainingquan-titativeestimatesofinstrumentalbackgroundsisabinitioMonteCarlosimulation(seee.g.Deanetal.,2003).