Super Fine-Grained Detector for improved neutrino interaction measurements in T2K

SuperFine-GrainedDetectorfor improvedneutrinointeraction measurementsinT2K WataruOkinagaforT2KSuperFGDgroup NeutrinoTelescopes2025 T2Kexperiment 2 •ALongbaselineneutrinooscillationexperimentinJapan •beamfromJ-PARC,measuredatanearandfardetector •Fardetector:Super-Kamiokande •Measuresdisappearanceandappearance •CPconservationwasrejectedata90%C.L. νμ/ ¯νμ νμ/ ¯νμνe/ ¯νe Super-Kamiokande(SK) J-PARCMainRing Neardetectors TalkbySophieKing NeardetectorND280 •FGDs(scintillatortrackers)surroundedbyTPCsandECals •Constrainstheneutrinofluxandinteractionuncertainties •Limitations: •Lowsensitivityforshortrangeparticles(mainlyprotons) •Difficulttotrackparticleswithlargescatteringangle •Anupgradewasdonetofurtherconstrainuncertainties 3 w/oND280 w/ND280 1ringmuon ν 13.0% 3.0% ν 12.0% 4.0% 1ringelectron ν 13.8% 4.7% ν 12.7% 5.9%   EventnumberuncertaintyatSK TheEuropeanPhysicalJournalC,83(9) •ReplacedtheupstreampartofND280withthreenewsub-detectors •SuperFGD(thistalk) •2tonactiveneutrinotargetmadeofscintillatorcubes •High-angleTPC(TalkbyMatteoFeltre,StefanoLevorato) •Measureparticleswithlargescatteringangle •Time-of-Flightdetectors •Timinginformationtorejectbackgrounds •150pstimingresolution ND280upgrade 4 ExistingTPC TalkbyGioeleReina FGDtoSuperFGD 5 Scintillator cube WLS fibers 192 182 56 •ClassicFGD(184x1x1cm3scintillatorbars) •Readoutfrom2directions •Requires6hitsfortrackreconstruction(range>6cm) •Cannottrackparticlesparalleltothebars •SuperFGD(1cm3scintillatorcubes,192x182x56) •Readoutof2Dx3directions(X,Y,andZplanes) •3hitsneededfortracking •4πacceptance •Total55,888channels ScintillatorcubesandWLSfibers •2millionscintillatorcubesmadebyinjectionmolding •Reflectinglayersformedbychemicaletching •ManufacturedbyUNIPLASTCo. •3holestoinsertwavelengthshifting(WLS)fibers •Propagatethelighttophoto-sensors •Y11producedbyKuraray 6 1cm Photo-sensorsanddetectorbox •HamamatsuMulti-PixelPhotonCounter(S13360-1325PE) •8x8MPPCsaremountedonaprintedcircuitboard •Afirmyetlightboxwasdesignedtoholdthecubes 7 1.3mm MPPC MPPCsmountedonaPCBDetectorbox Attach LEDcalibrationmodules •LEDcalibrationmodulesareattachedontheoppositesideofthebox •InjectlightfromtheoppositesideoftheWLSfiberstotheMPPCs •Asetoflightguideplate(LGP)anddiffuserprovidesuniformlight 8 Cubes Boxwall ToMPPCs Notch •Front-EndBoards(FEBs)digitizethesignalfromtheMPPCs •8CITIROCchipsmountedoneachFEB •OpticalConcentratorBoards(OCBs)buildeventsandsendtoaDAQPC •AMasterClockBoard(MCB)providesclocktimingandtrigger Electronics 9 MPPC-PCB FEB OCB MCB LEDdriver DAQPC x881(64ch/PCB) x221(4PCB/FEB) x16(14FEB/OCB) LEDmodule Clock,trigger Synchronized data LEDtriggerLEDsignal Analog signal Digital data Muonandprotonanalysis •A4πacceptancewasachievedwithSuperFGD •Systematicerrorsfromlargeangleeventscanbereduced. •AclearprotonBraggpeakwasseeninrealdata. •Protonscanbetaggedforeventcategorization 16 T2Kworkinprogress Neutronanalysis •SuperFGDiscapableofmeasuring •Neutronsaredetectedwithscatteredprotons •Theneutronenergy(=speed)canbecalculatedfromthetime-of-flight 17 T2Kworkinprogress ¯νμ+p→μ++n Aneutroneventcandidate TalkbyAsitSrivastava Electronneutrinoanalysis •cross-sectionerrorisconstrainedonlybyatheoreticalprediction •AimingtomeasurecrosssectionwithSuperFGD •~1%ofthebeamcomponent •Electron/gammacanbedistinguishedinSuperFGD •Measuretheenergydepositatthee+e-overlapregion 18 T2Kworkinprogress Conversionpoint νe eventcandidate νe eventcandidate γ νe Summary •T2KaimstofindCPviolationintheleptonsector •Weupgradedtheneardetectortofurtherconstrainuncertainties •Anewneutrinotarget,SuperFGDwasinstalled •Composedof1cm3scintillatorcubes •Capableoftrackingparticlesin3D •Lowenergyprotons,high-anglemuonscanbeanalyzed •BeamdatawastakeninJune2024 •Staytunedforourfirstphysicsresults! 19 Backup CP δ 3−2−1−0 1 2 3 2 χ∆ 0 5 10 15 20 25 Normal ordering Inverted ordering CLσ1 90% CL CLσ2 CLσ3 CLσ1 90% CL CLσ2 CLσ3 T2Klatestresultandprospect •CPconservationisexcludedata90%C.L. •Statisticalerroristhedominantuncertainty. •Nowincreasingthebeampower(upto1.3MW) •Systematicerrorwillbedominantinafewyears •ND280wasupgradedtofurtherreducetheinteractionuncertainty 21 (δCP = 0, π) distributionfor(Bestfit) δCP =−π/2 δCP Δχ2 Achieved800kW SuperFGDdynamicrange •Threechargereadouts:Highgain,lowgain,time-over-threshold •Cover3.5peto~2000pe •HGcalibratedwithLEDdata •LGandToTarecrosscalibratedintheoverlapregion •Cosmicandbeamdataareused 22 T2Kworkinprogress