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PeV Cosmic Neutrinos from the Mountains. Ping Yeh ( 葉平 ) National Taiwan University November 15, 2002 CosPA 2003 @ NTU, Taipei. Today is the 75th Birthday of NTU!. Ultra-High Energy Cosmic Rays. Origin. Anisotropy. Fly’s Eye P(fluct) < 0.07. - PowerPoint PPT Presentation
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PeV Cosmic Neutrinos from the MountainsPing Yeh ()National Taiwan University November 15, 2002 CosPA 2003 @ NTU, TaipeiToday is the 75th Birthday of NTU!
Ultra-High Energy Cosmic RaysOriginD.J. Bird et al., Ap. J. 511, 738 astro-ph/9806096AGASA4% excessM. Teshima et al., 27th ICRC p337, 2001AnisotropyFlys EyeP(fluct) < 0.07
High Energy Cosmic NeutrinosProduction presumably dominated by nm and neHadronic
Transportation & Oscillation: 1:1:1
Cosmic Rays and NeutrinosCosmic Ray Spectrum Not Well UnderstoodCR + X e2e~ 0.1 /EeV/year/km2/srGZK Firm!~ 1.2 x 103 /PeV/year/km2/srAGN ?
Observing High Energy Cosmic NeutrinosPrinciple: convert neutrinos to observablesLow cross section: need large target volumeSignals development: need large detection volumeMostly use H2O as target and detection volume (Bikal, AMANDA, ANTARES, IceCube)Energy coverage: H2O, air fluorescence, and the hole
Conventional n Detectors: Atm/SolarShield from CR & Atmospheric s: Underground Under Water/IceVery Large Target Volume = Detection VolumeSuperKsolar deficit/ & SNO
Conventional High Energy n DetectorsLimited by Target Volume: Maximum Energy ~ 1015 eVDeployment: 2003 - 2009ExistingYoshidas talk
IceCube: 1 PeV Limit for nt
UHECR DetectorsDetect -induced Air ShowersConversion Efficiency in Atmosphere Small AugerFluorescence Energy Threshold High > 1018 eVReflected
Window of OpportunityConventional n DetectorUHECR n Detector?
AGN Jets, CRs and Protons??
Earth SkimmingEarth Skimming + Mountain PenetratingCherenkov vs. fluorescenceTelescopeCross Section ~ E1.4Sensitive to nt ne: electron energy mostly absorbed in mountain nm: no extensive air shower t appearance experiment!
CollaborationItaly: IASF, CNR, PalermoN. La Barbera, O. Catalano, G. Cusumano, T. Mineo, B. SaccoFrance: Paris, France F. Vannucci, S. BouaissiUSA: Hawaii J.G. LearnedJapan: ICRR M. SasakiTaiwan: NCTS/CosPA3 G.L. Lin, H. Athar, NTUHEP/CosPA2PIs: W.S. Hou & Y.B. HsiungHardware Team: K. Ueno (Faculty)Y.K. Chi (Electronics)Y.S. Velikzhanin (Electronics)M.W.C. Lin (Technician)Simulation Team:M.Z. Wang (Faculty)P. Yeh (Faculty)H.C. Huang (Postdoc)C.C. Hsu (Ph.D. student)
NUUM.A. Huang (Faculty)
Formed in Spring 2002
Rates, Rates? Rates!Figure of merit for the experimentDiffused source vs point source Flux: different sources, different modelsAcceptance: Maximizing A(E) within the budget constraint is the design goal
FeasibilityFeasibility study was done in 2002 (Alfred Huang)Assume: aperture = 1 m2, light collection efficiency = 10%, ~ 40 km wide valley, ~ 2 km high mountainConclusion was O(1) events per yearDeemed feasible, more attractive with a small budget, and was funded that wayMore detailed study in 2003, will be shown
AcceptanceFigure of merit of the telescope designA = integration of detection efficiency in the phase space (x, y, theta, phi) Detection efficiency depends on aperture & field of viewlight collection efficiencytrigger logic
Factors for AcceptanceThe chain of conversions
nt to t conversion rate: ~ O(10-5) - O(10-4)Expect O(10) /year/km2/sr t flux> O(1) km2 sr acceptance desired t decay: ~ 82% branching fraction for showersLight collection (baseline design): 1 m2 aperture, 8o x 16o field of view, ~ 10% efficiencyTrigger: position dependent
The Signal and Background PatternCherenkov: ns pulse, angular span ~ 1.5 degreesNight Sky Background (mean)Measured at Lulin observatory: 2.0 x103 ph/ns/m2/srA magnitude 0 star gives 7.6 ph/m2/ns in (290,390) nmCosmic Ray background very small
Cluster-based trigger algorithmRandom Background with NSB flux1 km away from a 1 PeV e- shower
Trigger StudyBackground Rates vs Signal Efficiency1PeV, 30 km, normal incidence1PeV, 30 km, 10 incidenceH-L TriggerSingle TriggerH-H Trigger (Dual trigger)H threshold Trigger Rate (Hz)XYLocal coincidence necessaryto kill the background!
Acceptance DeterminationIntegration of efficiencies in phase space Three independent methods for cross-checking
Results are consistent with each other!
Method
Efficiency
Integration
Investigator
MIR
Range determined from Simulation
Monte Carlo
Alfred
MIME
Modelled Curve
Monte Carlo
Minzu
NISE
Detailed Simulation
Numerical
Ping
Acceptance CurveEstimated with an idealistic vertical plane mountain surfaceAcceptance starts at Et ~ 1 PeVGradually levels off near 1 EeV (t decay length = 50 km @ 1 EeV)
Preliminary ReconstructionReconstruction: Minimize 2 for x,y,,, and ETwo Detectors Separated by a few 100m
Reconstruction ErrorPossible to Reconstruct Events Angular Error within 1Energy Error ~ 40%Reconstruction Efficiency 30% ~ 70%
SensitivitySensitivity : 1 event/year/decade of energyGreat Chance to See fromAGNTDGC Attenuation is an Issue
Requirements on the InstrumentFind signal on top of background!Rate >= 0.5 events/yearaperture, light collection efficiency, triggerAngular resolution: 0.5 degrees or smallerTiming (ns pulse)Low budget
Prototype TelescopePurpose:Proof of ConceptMeasure BackgroundTelescopeCommercial Fresnel Lens (NTK-F300, f30cm, size=30cm, pitch=0.5mm, PMMA UV), UV Filter (BG3)Hamamatsu 4x4 (H6568) MAPMTReadout Electronics: Preamp, Receiver, Trigger, ADC and DAQ
Field Test at Lulin Observatory (2900m)E (Mt. Jade)03715Sirius3 elevation angles: 3, 7, 152 conditions: w/o BG3 filter
Cosmic RaysCR tracks seen by prototype telescopeSystem functions properlyPotential Use: Monitor System HealthCalibration by CR events
SiriusStudy:Effective field of viewLens transmittance as function of off-axis angle.In the future, Calibrate the pointing accuracyMonitoring telescope health
The OpticsWant to utilize existing mirrors or lensesFirst concept: EUSO-type Fresnel lensNote that EUSO is years awayTimely readiness and cost!
The Optics - revisedCurrent direction: ASHRA-type Mirror + correction lensPhoton Sensor: Multi-Anode PhotomultiplierDont need arc-min resolution: optics is basically ready NOWSasakis talk
The ElectronicsDynamic Range x4
Schematics of the ElectronicsUV filterHamamatsu8x8 MPMT16-channelspreamplifierUV filterDetector pairStart readout32 channels DCM(Data Collection Module) in cPCI10 bit x40 MHzPipelinedADC16 RAM x 256 x 16 per 8 channelsMirrorTrigger FPGAADC controlFPGA (x4)To/fromAnother DCMStart readout10 bit x40 MHzPipelinedADCTo/fromAnother DCMSignal-sharing plateFront-end electronics box 8x8 pixels(1 MPMT, 1 SSP, 4 preamplifiers)
Calibration: PointingCrab Nebula as the standard candleCan we see it? d J / d E = 0.28 * ( E / 1TeV ) -2.6 km-2 s-1 TeV-1 Integrated flux is not small: 0.3 /km2 /sRandom background > 10 times higher in stary stary nights Use neutral density filter + tighter trigger
Acceptance to the CrabAcceptance ~ around O(0.1) km2 srRate ~ 6 events/hrExposure of several nights would be usefulPhoton density (1/m2 )log E (TeV) Trigger Range (m)
SitePrimary Site: Mt. Hualalai looking at Mauna LoaGood weather condition, less background, GC in FOVNo electricity, no water, no communicationPrototype Site: Mauna Loa looking at Mauna KeaInfrastructure ready, on-site help from CosPA1!No GC observationMt. HualalaiMauna KeaMauna LoaStill looking forpossible sites!
ScheduleDetector DesignConstruct1024 Ch. Prototype200320042005Prototype OperationConstruct Full-size TelescopeSite Survey / PreparationInstallation & CalibrationFull Telescope OperationCrabs itinerary dictates October - December
ConclusionNuTel is the first experiment dedicated to Earth skimming / mountaing watchingThe PeV cosmic nt rate is a few events/yearThe cost is low: O(1) million US dollars to build itThe time is short: prototype deployment in 2004The window of opportunity is good, both in energy and time (Hmm the uncertainty principle?) Ashra is a natural continuation for NuTelSite coincidesPhysics complimentarySchedule looks promising