简介:SpokecavitieshavebeendevelopedandhaveapparentadvantagesforhighcurrentprotonacceleratorbasedonFig.1(coloronline)Theelectromagneticfielddistribution.superconductivityatlowandmediumenergyregion.Astheresearchandthetechnicalreserve,InstituteofModernPhysics(IMP)hasstartedtheR&Dprogramofadoublespokecavity(operatingfrequency325MHz,0=0.52),withintheframeworkofChinaAcceleratorDrivenSystem(C-ADS)project.TheRFdesignandmechanicalstructuredesignhavebeenfinished,andtwoprototypecavitiesweremanufacturedinHarbin.
简介:Wehaveinvestigatedthephysicalproperties,includingthemorphology,texture,adhesionandchemicalquality,ofhigh-frequencychemicalvapourdepositeddiamondcoatingsonWC-6%Cosubstrates,whichwerepre-treatedbyatwo-stepetchingmethod.TheresultsindicatethattheincreasingCocontentfrom0.12to3.05%withintheetchingdepthof5μmcausedamorphologytransformationfromprismdiamondtospheruliticdiamond,andatexturetransformationfroma{111}orientationtoa{110}orientation.TheRamanspectrumshowsthatthespheruliticdiamondfilmcontainsmorenon-diamondphases(graphite,amorphouscarbonanddiamond-likecarbon,etc)andhaslowerchemicalqualitythandiamondfilmsonaWC-6%Cosubstrate.Thediamondcoatinggrainsizesbecameaboutfourtimessmallerwhenthedepositiontemperaturesonthesubstratesurfacewerereducedfrom1000to900℃.Comparedwithspheruliticdiamondfilms,theprismdiamondfilmsexhibitbetteradhesionontheWC-6%Cosubstrate.
简介:Thesymmetryenergy,whichgovernsmanyphysicalphenomenafromthestructureofexoticnucleitoastrophysicalprocesses,hasmanyramificationsinbothnuclearphysicsandastrophysics.Althoughnuclearsymmetryenergyanditsslopeatthenormaldensityofnuclearmatterhavebeenroughlypinneddown,recentinterpretationsofFOPIandFOPI-LANDdatabydifferenttransportmodelsleadtodivergentconclusionsonthedensity-dependentsymmetryenergyatsupradensities.
简介:Numericalsimulationofthemixedconvectioninducedbybuoyancy,crystalrotation,andalsounbalancedsurfacetensionatthemelt-gasinterfaceisconductedbymeansofthefinitevolumemethodinthemodeloftheCzochralskicrystalgrowth.TheroleofMarangoniconvectionintheheatandmasstransferisinvestigatedbythecomparisonofthemodelswithandwithoutsurfacetensionincluded,andourresultsindicatethatMarangoniconvectionplaysanimportantroleintheheatandmasstransferneartheinterfaceofmeltandcrystal,andalsotheconvectionstructure.
简介:Withabout20permanentstaffandseveralgraduatestudents,IonSourceGroupisdoingpioneeringworkinhighperformanceECRandLaserionsourcedevelopment,ionsourceplasmastudy,ionsourceapplicationandroutineoperationfornationallaboratory.In2016,withthegreatcontributionsoftheteammembers,manyverypromisingresultsandachievementshavebeenmade.FortheroutineoperationofHIRFLfacility,threeionsources,i.e.
简介:InstitutionofModernPhysics(IMP)hasdesigned,fabricatedandinstalledthefirstSRFcavityelectropolishingsystemofChina.It’ssizedfor1.3GHzSRFcavities,andalsocanworksformultiplecellcavitieswithfurtherupgradeofstructure.
简介:TheprecursoryprojectofADSprotonlinearacceleratoristhedevicetoprovideintenseprotonbeamsfortheentiretransmutationsystem,whichhasthefiguresofintensebeamandhighenergy.Asaresult,acontinuousdeflectedbeamwithacertainintensitywoulddeclinetheperformanceoftheacceleratordevicesorevenmakedamageswithin20s.Inordertopreventthiskindofproblem,anintegratemachineprotectionsystemwithfunctionsofstatemonitoringandtimelybeamcuttingisrequiredtoprotectacceleratordevices.
简介:Ithasbeensuggestedthathydrogen-richsystemsathighpressuremayexhibitnotablyhighsuper-conductingtransitiontemperatures.Oneofthemoreinterestingtheoreticalpredictionswasthathydrogensulfidecanbemetallizedandthehigh-temperaturesuperconductingstatecanbeinduced.Arecordcriticaltemperature(203K)waslaterconfirmedforH3Sinanexperiment.Inthispaper,weinvestigated,withintheframeworkoftheEliashbergformalism,thepropertiesofcompressedMgH6,whichisexpectedtobeaverygoodcandidateforroom-temperaturesuperconductivity.Thisappliesparticularlytothepressurerangefrom300to400GPa,wherethetransitiontemperatureiscloseto400K.Moreover,theestimatedthermodynamicpropertiesandtheresultingdimensionlessratiosexceedthepredictionsoftheBardeen-Cooper-Schrieffertheory.Thisbehaviorisattributedtothestrongelectron-phononcouplingandretardationeffectsexistinginhydrogen-dominatedmaterialsunderhighpressure.
简介:In2016,theresearchanddevelopmentoflaserionsourcesweremainlycontributedtopromotetheperformanceoftheionsource,suchastoprolongthepulsedurationoftheionbeam,torealizetherepetitionrateoperationmodeoftheionsource.Inaddition,theproductionofhighlychargedmetallicionbeamsfromanECRionsourcewithlaserablationplasmainjectionwasalsoinvestigatedpreliminarily.Theconfinementoflaserproducedplasmawithasolenoidwasstudied.Forthispurpose,a1.5m-longsolenoidwasinstalledontheexpansionstageofthelaserionsource.
简介:ThedevelopmentoftheHalfWaveResonator(HWR010)isbasedontheChinaADSproject.TheHWR010operatesat162.5MHzandcanprovidemorethan0.78MVofacceleratingvoltagepercavityforprotonwithopt=0.10.ThegoaloftheRFpropertiesistogetalowerheatloadandahigheracceleratinggradient,whicharedeterminedbyahigherR/Q0andlowerpeaksurfacefields(Bpk/EaccandEpk/Eacc).InordertooptimizetheHWRgeometryparameters,CST-MWSisusedtoconducttheRFsimulation.TheoptimizedRFparametersareshowinTable1.
简介:Fieldemissionoccurredinsuperconductingradio-frequency(SRF)cavitiesisthemajorobstacleoftheacceleratorsoperatingathighgradient,whichpartlycausedbytheinnersurfacecontamination,suchasthehydrocarbonsandtheabsorbedresidualgas.Theplasmaprocessingcanbeaneffectivemethodtosolvethefieldemissionissues.Thepropertiesoflowtemperatureglowdischarge,whichwasargonplasmawiththechemicallyreactiveoxygen,wereinvestigatedfortheSRFcavitiesusedforCADSproject.
简介:HIRFL-CSRacceleratorfacilityhasbeenoperatingwith3ionsources,whichareLAPECR1,LECR3andSECRAL.Theseionsourcescanprovidedifferentkindsofionswithdifferentenergy.Forexample,LAPECR1mainlyprovidesH+andHe+witheextractionvoltageabove25keV,LECR3canprovidetheionbeamswithlowtomediumchargestates,includingthemetallicionswithlowmass,suchasC^4+,Ar^11+,B^3+,Mg^7+,etc.,whileSECRALaimstoproduceintenseandhighlychargedionbeams,especiallymetallicones,suchlikeKr^19+,Xe^31+,Ni^19+,Bi^31+,U^33+,andsoon.