cherenkov tracking calorimeters

Cherenkov Tracking Cherenkov Tracking CalorimetersCalorimeters

D. CasperD. CasperUniversity of California, IrvineUniversity of California, Irvine

June 24, 2005June 24, 2005 D. Casper, UC IrvineD. Casper, UC Irvine 22

OutlineOutline OverviewOverview Basic performance around 1 GeVBasic performance around 1 GeV Neutrino responseNeutrino response


Acknowledgements and CaveatsAcknowledgements and Caveats Some work done together with:Some work done together with:

J. Dunmore, C. Regis (UCI)J. Dunmore, C. Regis (UCI) J. Burguet-Castell, E. Couce, J.J. Gomez-Cadenas, J. Burguet-Castell, E. Couce, J.J. Gomez-Cadenas,

P. Hernandez (Valencia)P. Hernandez (Valencia) Thanks to:Thanks to:

M. Fechner (Saclay)M. Fechner (Saclay) Super-Kamiokande and T2K CollaborationsSuper-Kamiokande and T2K Collaborations

DisclaimersDisclaimers Not “official” results of any experiment except where Not “official” results of any experiment except where

notednoted Intended as a generic overviewIntended as a generic overview Hybrid (Cherenkov/Scintillation) detectors not Hybrid (Cherenkov/Scintillation) detectors not

considered explicitlyconsidered explicitly


MotivationsMotivations Fully active targetFully active target

Inexpensive detecting Inexpensive detecting mediummedium

Surface instrumentationSurface instrumentation PMT cost scales like PMT cost scales like

(Mass)(Mass)2/32/3

Long attenuation lengthLong attenuation length Size limited primarily by Size limited primarily by

cavern excavationcavern excavation

Originally designed for Originally designed for proton decay searchesproton decay searches


What Is MeasuredWhat Is Measured PMT timingPMT timing

Coincidence triggerCoincidence trigger Vertex positionVertex position Delayed coincidenceDelayed coincidence

e decaye decay• Nuclear de-excitationNuclear de-excitation• Neutron captureNeutron capture

Cherenkov ringsCherenkov rings Particle directions from angle Particle directions from angle

constraintconstraint Showering/Non-showering Showering/Non-showering

topology for particle IDtopology for particle ID PMT pulse heightsPMT pulse heights

Energies from calorimetry Energies from calorimetry and/or rangeand/or range


Cherenkov DetectorsCherenkov Detectors First Generation (1982-1992)First Generation (1982-1992)

IMB (3.3 kton, 1% IMB (3.3 kton, 1% 4.5%) 4.5%) Kamiokande (0.78 – 1.1 kton, 20%)Kamiokande (0.78 – 1.1 kton, 20%) Harvard-Purdue-WisconsinHarvard-Purdue-Wisconsin

Second Generation (1996-Present)Second Generation (1996-Present) Super-Kamiokande (22.5 kton, 40%)Super-Kamiokande (22.5 kton, 40%) SNO (1.0 kton, 55%)SNO (1.0 kton, 55%) K2K (0.025 kton, 40%)K2K (0.025 kton, 40%)

Next Generation (ca. 2010+)Next Generation (ca. 2010+) T2K 2km (0.025 kton, 40%)T2K 2km (0.025 kton, 40%) Hyper-Kamiokande (~1 Mton, 40%)Hyper-Kamiokande (~1 Mton, 40%) etc…etc…


Basic Performance near 1 GeVBasic Performance near 1 GeV Vertex resolution: ~20-30 cmVertex resolution: ~20-30 cm

Challenge to control the fiducial volume of a small Challenge to control the fiducial volume of a small detectordetector

Direction resolution: 2-3Direction resolution: 2-3°° Negligible compared to neutrino-lepton scattering Negligible compared to neutrino-lepton scattering

angleangle e/e/ mis-ID: ~0.4%/ mis-ID: ~0.4%/ ( (%photocathode)%photocathode)

For equal e/For equal e/ purity and efficiency purity and efficiency Verified in test beamVerified in test beam

Energy resolution: ~2%/(Energy resolution: ~2%/( E Evisvis))1/21/2

Additional energy scale uncertainty: 2-3%Additional energy scale uncertainty: 2-3% Muon decay efficiency: ~95% (Muon decay efficiency: ~95% (++), ~75% (), ~75% ())

22% 22% capture probability in water capture probability in water


Neutrino ResponseNeutrino Response Response (1-ring mu-like sample)Response (1-ring mu-like sample)

Super-beam disappearance signalSuper-beam disappearance signal Super-beam appearance backgroundSuper-beam appearance background Beta-beam appearance signalBeta-beam appearance signal

ee Response (1-ring e-like sample) Response (1-ring e-like sample) Super-beam appearance signalSuper-beam appearance signal Beta-beam disappearance signalBeta-beam disappearance signal Beta-beam appearance backgroundBeta-beam appearance background


Does Size Matter?Does Size Matter? For a given photo-cathode coverage, For a given photo-cathode coverage,

greater pixelization helps reduce greater pixelization helps reduce 00ee For a given photo-cathode coverage, a larger For a given photo-cathode coverage, a larger

detector performs better at e/mu and e/detector performs better at e/mu and e/00 separationseparation


Cross-SectionsCross-Sections


CCQE EfficiencyCCQE Efficiency

Loss of partiallycontained

Fully-contained CCQE 1-ringmu-like efficiency

Losses to 0 cuts

Fully-contained e CCQE 1-ringe-like efficiency


Signal and BackgroundsSignal and Backgrounds

1-ring -like sample 1-ring e-like sample


Contamination vs. SmearingContamination vs. Smearing

1-ring -like sample 1-ring e-like sample


CC Energy Transfer MatricesCC Energy Transfer Matrices

CCQECC1

CC Other


Higher EnergiesHigher Energies Possible to use hadronic calorimetry at Possible to use hadronic calorimetry at

higher energieshigher energies Does not help with particle IDDoes not help with particle ID

Possible to identify clean sample of high-Possible to identify clean sample of high-energy muons from interactions outside energy muons from interactions outside the detectorthe detector ““Upward-going muons”Upward-going muons” May be able to say something about energy May be able to say something about energy

using angle(?)using angle(?)


ConclusionsConclusions A very mature and powerful technologyA very mature and powerful technology Backgrounds to low-medium energy Backgrounds to low-medium energy

super-beams or beta beams are fairly super-beams or beta beams are fairly manageablemanageable Depends on details of beam, baseline, etc.Depends on details of beam, baseline, etc.

Energies above 1.5-2 GeV create Energies above 1.5-2 GeV create difficultiesdifficulties May be mitigated by migrationMay be mitigated by migration

cherenkov tracking calorimeters

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