1. 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!

2. Ultra-High Energy Cosmic Rays Origin D.J. Bird et al., Ap. J. 511, 738 astro-ph/9806096 AGASA 4% excess M. Teshima et al., 27th ICRC p337, 2001 Anisotropy Fly’s Eye P(fluct) < 0.07

3. High Energy Cosmic Neutrinos Production presumably dominated by  and e Hadronic Transportation & Oscillation: 1:1:1

4. Cosmic Rays and Neutrinos Cosmic Ray Spectrum Not Well Understood CR + X     e   2   e UHECR +  CMB  N +   GZK ~ 0.1 /EeV/year/km 2 /sr GZK Firm! ~ 1.2 x 10 3 /PeV/year/km 2 /sr AGN ?

5. Observing High Energy Cosmic Neutrinos Principle: convert neutrinos to observables Low cross section: need large target volume Signals development: need large detection volume Mostly use H 2 O as target and detection volume (Bikal, AMANDA, ANTARES, IceCube) Energy coverage: H 2 O, air fluorescence, and the “hole”

6. Conventional Detectors: Atm/Solar Shield from CR & Atmospheric  ’s: Underground  Under Water/Ice Very Large Target Volume = Detection Volume SuperK solar deficit/ &    SNO

7. Conventional High Energy Detectors Limited by Target Volume: Maximum Energy ~ 10 15 eV Deployment: 2003 - 2009 Existing Yoshida’s talk

8. IceCube: 1 PeV Limit for 

9. UHECR Detectors Detect -induced Air Showers Conversion Efficiency in Atmosphere Small Auger Fluorescence  Energy Threshold High > 10 18 eV Reflected

10. Window of Opportunity Conventional  Detector UHECR  Detector ?

11. AGN Jets, CRs and    Protons? ?

12. Earth Skimming   Telescope Cross Section ~ E 1.4 ~ E 1.4   Earth Skimming + Mountain Penetrating Cherenkov vs. fluorescence Sensitive to  e : electron energy mostly absorbed in mountain  : no extensive air shower  appearance experiment!

13. Collaboration Italy: IASF, CNR, Palermo –N. La Barbera, O. Catalano, G. Cusumano, T. Mineo, B. Sacco France: Paris, France F. Vannucci, S. Bouaissi USA: Hawaii J.G. Learned Japan : ICRR M. Sasaki Taiwan: –NCTS/CosPA3 – G.L. Lin, H. Athar, … NTUHEP/CosPA2 PIs: W.S. Hou & Y.B. Hsiung Hardware 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) NUU M.A. Huang (Faculty) Formed in Spring 2002

14. Rates, Rates? Rates! Figure of merit for the experiment Diffused source vs point source Flux: different sources, different models Acceptance: Maximizing A(E) within the budget constraint is the design goal

15. Feasibility Feasibility study was done in 2002 (Alfred Huang) Assume: aperture = 1 m 2, light collection efficiency = 10%, ~ 40 km wide valley, ~ 2 km high mountain Conclusion was O(1) events per year Deemed feasible, more attractive with a small budget, and was funded that way More detailed study in 2003, will be shown

16. Acceptance Figure of merit of the telescope design A = integration of detection efficiency in the phase space (x, y, theta, phi) Detection efficiency depends on aperture & field of view light collection efficiency trigger logic

17. Factors for Acceptance The chain of conversions  to  conversion rate: ~ O(10 -5 ) - O(10 -4 ) Expect O(10) /year/km 2 /sr  flux > O(1) km 2 sr acceptance desired  decay: ~ 82% branching fraction for showers Light collection (baseline design): 1 m 2 aperture, 8 o x 16 o field of view, ~ 10% efficiency Trigger: position dependent

18. The Signal and Background Pattern Cherenkov: ns pulse, angular span ~ 1.5 degrees Night Sky Background (mean) Measured at Lulin observatory: 2.0 x10 3 ph/ns/m 2 /sr A magnitude 0 star gives 7.6 ph/m 2 /ns in (290,390) nm Cosmic Ray background very small Cluster-based trigger algorithm Random Background with NSB flux1 km away from a 1 PeV e - shower

19. Trigger Study Background Rates vs Signal Efficiency 1PeV, 30 km, normal incidence 1PeV, 30 km, 10° incidence H-L Trigger Single Trigger H-H Trigger (Dual trigger) H threshold Trigger Rate (Hz) X Y Local coincidence necessary to kill the background!

20. Acceptance Determination Integration of efficiencies in phase space Three independent methods for cross-checking Results are consistent with each other!

21. Acceptance Curve Estimated with an idealistic vertical plane mountain surface Acceptance starts at E  ~ 1 PeV Gradually levels off near 1 EeV (  decay length = 50 km @ 1 EeV)

22. Preliminary Reconstruction Reconstruction: Minimize  2 for x,y, , , and E –Two Detectors Separated by a few 100m E, x, y, ,  1 2 N 1, T 1, x 1, y 1,  1,  1 N 2, T 2, x 2, y 2,  2,  2

23. Reconstruction Error Possible to Reconstruct Events –Angular Error within 1 ° –Energy Error ~ 40% –Reconstruction Efficiency 30% ~ 70%

24. Sensitivity Sensitivity : 1 event/year/decade of energy Great Chance to See from –AGN –TD –GC Attenuation is an Issue

25. Requirements on the Instrument Find signal on top of background! Rate >= 0.5 events/year aperture, light collection efficiency, trigger Angular resolution: 0.5 degrees or smaller Timing (ns pulse) Low budget

26. Prototype Telescope Purpose: –Proof of Concept –Measure Background Telescope –Commercial Fresnel Lens (NTK-F300, f30cm, size=30cm, pitch=0.5mm, PMMA UV), –UV Filter (BG3) –Hamamatsu 4x4 (H6568) MAPMT –Readout Electronics: Preamp, Receiver, Trigger, ADC and DAQ

27. Field Test at Lulin Observatory (2900m) E 玉山 (Mt. Jade) 0° 3° 7° 15° Sirius 3 elevation angles: 3°, 7°, 15° 2 conditions: w/o BG3 filter

28. Cosmic Rays CR tracks seen by prototype telescope –System functions properly Potential Use: –Monitor System Health –Calibration by CR events

29. Sirius Study: –Effective field of view –Lens transmittance as function of off-axis angle. In the future, –Calibrate the pointing accuracy –Monitoring telescope health

30. The Optics Want to utilize existing mirrors or lenses First concept: EUSO-type Fresnel lens Note that EUSO is years away Timely readiness and cost!

31. The Optics - revised Current direction: ASHRA-type Mirror + correction lens Photon Sensor: Multi-Anode Photomultiplier Don’t need arc-min resolution: optics is basically ready NOW Sasaki’s talk

32. The Electronics Dynamic Range x4

33. Schematics of the Electronics PMT Preamp. UV filter Hamamatsu 8x8 MPMT 16-channels preamplifier DAQ PMT Preamp. UV filter Trigger Detector pair Start readout 32 – channels DCM (Data Collection Module) in cPCI 10 bit x 40 MHz Pipelined ADC 16 RAM x 256 x 16 per 8 channels Mirror Trigger FPGA FADC buffer RAM ADC control FPGA (x4) To/from Another DCM Trigger cycle RAM Start readout 10 bit x 40 MHz Pipelined ADC FADC buffer RAM DAQ cycle RAM To/from Another DCM Signal-sharing plate Front-end electronics box 8x8 pixels (1 MPMT, 1 SSP, 4 preamplifiers)

34. Calibration: Pointing Crab Nebula as the standard candle Can 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 /km 2 /s Random background > 10 times higher in “stary stary nights” Use neutral density filter + tighter trigger

35. Acceptance to the Crab Acceptance ~ around O(0.1) km 2 sr Rate ~ 6 events/hr Exposure of several nights would be useful Photon density (1/m 2 ) 1 TeV gamma Distance (m) log E (TeV) Trigger Range (m)

36. Site Primary Site: Mt. Hualalai looking at Mauna Loa –Good weather condition, less background, GC in FOV –No electricity, no water, no communication Prototype Site: Mauna Loa looking at Mauna Kea –Infrastructure ready, on-site help from CosPA1! –No GC observation Mt. Hualalai Mauna KeaMauna Loa Still looking for possible sites!

37. Schedule Detector Design Construct 1024 Ch. Prototype 200320042005 Prototype Operation Construct Full-size Telescope Site Survey / Preparation Installation & Calibration Full Telescope Operation Crab’s itinerary dictates October - December

38. Conclusion NuTel is the first experiment dedicated to Earth skimming / mountaing watching The PeV cosmic  rate is a few events/year The cost is low: O(1) million US dollars to build it The time is short: prototype deployment in 2004 The window of opportunity is good, both in energy and time (Hmm… the uncertainty principle?) Ashra is a natural continuation for NuTel –Site coincides –Physics complimentary –Schedule looks promising