微波技术对ECR离子源性能的影响

󰀁󰀁󰀁󰀁󰀁󰀁󰀁󰀁

HIGH

ENERGY

PHYSICS

AND

NUCLEAR

PHYSICS

Vol.31,Supp.󰀁

Jul.,2007

ImpactofMicrowaveTechnologyonECRISPerformances*

L.Celona1;1)

F.Consoli1F.Maimone3

S.Barbarino1,2

D.Mascali1,2

G.Ciavola1L.Tumino3

S.Gammino1

1(IstitutoNazionalediFisicaNucleare–LaboratoriNazionalidelSud,ViaS.Sofia62,95123Catania,Italy)2(Universit`adegliStudidiCatania,DipartimentodiFisicaeAstronomia,ViaS.Sofia,95123Catania,Italy)

3(Universit`adegliStudidiCatania,DipartimentodiIngegneriaInformaticaedelleTelecomunicazioni,

VialeA.Doria6,95123Catania,Italy)

AbstractThecouplingbetweenmicrowavegeneratorsandECRionsources(ECRIS)isakeypointforthedesignofthenewgenerationECRISaswellasfortheoptimizationoftheexistingones.Theelectromagneticcharacterizationoftheplasmachamberwheretheionizationphenomenatakeplaceisafundamentalstartingpointtounderstandandmodelsuchprocess.Insucheffortthecomplexstructuresoftheinjectionandextractionflangestogetherwiththelargedimensionsofthechamberandthehighfrequenciesthataretypicallyusedmakeimpossibleananalyticalsolutionandalsocreategreatdifficultiesinthemodellingevenwithstate-of-artelectromagneticsimulators(CST,HFSS).InthefollowingpapertheresultsofsomenumericalcalculationsfortheoptimumplasmachamberexcitationwillbepresentedalongwiththeexperimentalmeasurementscarriedoutwiththeSERSEionsourceatINFN-LNS.Acampaignofmeasurementsisalsoplannedtofurtherinvestigatethemicrowavecouplingandthemodeexcitation,whichdeterminestheefficiencyoftheECRplasmaheating.

Keywordsplasma,ionsources,ECRheating

1Introduction

TheElectronCyclotronResonanceionsources

provementwasstrictlylinkedtotheimprovementofthemagneticconfinementandtotheincreaseofthefrequencywhich,undergoodconfinementcondi-tions,takestohigherplasmadensity.Infact,thenewECRISgenerationwillfeatureboostedperfor-mancesbyshiftingupthechargestatedistributionandtheproducedionbeamcurrent.Theoptimiza-tionofthefirstofthepreviousitemsisdonebyusingpowerfulmagnetictrapsfortheaxialandradialcon-finementtogetherwiththeuseoffrequenciesrangingbetween28and37GHzaccordingtotheECRISstan-dardmodel

[1,2]

(ECRIS)arewidelyusedintheacceleratorfacilities,increasingthebeamenergyandintensity,aswellasformanyindustrialapplications,makingmoreeffi-cienttheindustrialprocesses.Therearesomefun-damentalprocessesandparametersinthedesignofsuchsourcesandtheoptimizationcriteriachangesde-pendingfromthefinalgoal:

•Magneticfieldprofileandworkingfrequency•Microwavecoupling•ECRheating

•Beamextractionandtransport

Uptorecenttimes,theECRISperformancesim-

.Thestrongmagneticfieldneeded

fortheplasmaconfinementoriginatesahighstrayfielddetrimentalforbeamoptics,whichmakescom-plicatethebeamextractionatransportprocessesinpresenceofspacechargeeffects;fortheseproblem

148󰀁󰀁󰀂󰀂󰀂󰀁󰀂󰀂(HEP&NP)󰀃31󰀁

󰀁󰀁󰀁L.Celona󰀂󰀂󰀁󰀁󰀁󰀁󰀄ECR󰀁󰀁󰀂󰀁󰀁󰀁󰀁󰀁149

150󰀁󰀁󰀂󰀂󰀂󰀁󰀂󰀂(HEP&NP)󰀃31󰀁

󰀁󰀁󰀁L.Celona󰀂󰀂󰀁󰀁󰀁󰀁󰀄ECR󰀁󰀁󰀂󰀁󰀁󰀁󰀁󰀁151

References

1GellerR.Proc.of10thInt.Work.onECRIonSources,1990,1

2GamminoSetal.PlasmaSourceSci.Technol.,1996,5:19

3CelonaLetal.RadiationEff.&Def.inSolids,2005,160:457

4CelonaLetal.AIPConf.Proc.,2005,749:99

5KawaiYetal.Rev.Sci.Instrum.,2006,77:03A3316GamminoSetal.Nucl.Instrum.Methods,2002,A491:342