High Energy Physics Group, National Taiwan University

1. Status of NuTel - a Neutrino Telescope for Observing PeV  from AGN Yee Bob Hsiung National Taiwan University for NuTel group UHE  workshop April 23-26, 2006 IHEP, Beijing Introduction Feasibility Study Detector Status Conclusion High Energy Physics Group, National Taiwan University

2. CR + X  e2e ~ 1.2 x 103 /PeV/year/km2/sr Not Well Understood ~ 0.1 /EeV/year/km2/sr UHECR + CMB N +  GZK  Cosmic Rays and Neutrinos - Back to 2002 Cosmic Ray Spectrum AGN ? GZK  Firm!

3. Protons? AGN Jets, CRs and  ?

4. UHECR Detector Conventional Detector ? Window of Opportunity

5. Earth Skimming Earth Skimming + Mountain Penetrating Cherenkov vs. fluorescence Cross Section ~ E1.4 Telescope    t appearanceexperiment! Sensitive to nt ne: electron energy mostly absorbed in mountain nm: no extensive air shower 

6. 1 2 3 Three simulation stages 1. Mountain simulation:  +N cross-section • inelasticity • energy loss of tau 2. Air shower simulation:  Cerenkov photons •  decay mode • CORSIKA detailed air shower simulation vs. fast simulation 3. Detector performance simulation • light propagation + Q.E. • pixelization for triggers • reconstruction 2002-2004

7.  inside mountain • SM CC +N cross-section • Inelasticity & energy loss are calculated by G.L. Lin, J.J. Tseng, T.W. Yeh, F.F. Lee of NCTU • Range (distance when survival prob = e-1) are calculated by M.A. Huang

8. Tau flux No dE/dx dE/dx • Tau flux: • Fast simulation: single interaction inside target • Full-scale transport eq.: Consider multiple interactions   ... • Conversion efficiency: • optimal thickness ~ several times of  • Energy loss decreases conversion efficiency

9. Lateral profile of Cerenkov photons for horizontal shower (CORSIKA ) 1018 eV 1016 eV 1014 eV • Similar profile for showers produced by e– and  • Cerenkov ring distance ~ (L-Rmax)tan c • Outside ring, photon density ~ exponential decay • Detector can trigger far away from Cerenkov ring

10. Photons numbers vs opening angle Photon density 1 PeV shower Shower core to detector plane 30 km away Serious drop with attenuation No atten. Atten.=15km Opening angle (radian)

11. Optics assumptions (back in 2003) • ASHRA-type Mirror + a simple correction lens • Multi-Anode Photomultiplier with 0.5o x 0.5o pixel span • Light collection : 1 m2 aperture, 8o x 16o field of view, over all 10% efficiency for γ→ p.e.

12. The Signal and Background Pattern Cherenkov: ns pulse, angular span ~ 1.5 degrees Night Sky Background (mean) Measured at Lulin observatory: 2.0 x103 ph/ns/m2/sr A magnitude 0 star gives 7.6 ph/m2/ns in (290,390) nm Cosmic Ray background very small Cluster-based trigger algorithm Random Background with NSB flux 1 km away from a 1 PeV e- shower

13. H H L H n1 n2 n3 n8 H n4 n7 n6 n5 Trigger Configuration • Single Pixel Trigger: One pixel pass energy threshold H • Duo Trigger: Two neighbouring pixels pass threshold H • H-L Trigger: Two neighbouring pixels with one passes high threshold H and the other one passes low threshold L • Sum Trigger: 1. (3x3) trigger cell 2. Central pixel pass high threshold H Neighbour Npe Sum pass threshold A=n1+n2+…+n8 Night Sky Background: H • Npe Follows Poisson distribution: Prob(n;μ) = e-μμn/n!, μ = <Npe> Φ tg A FOV εAεq , Φ= 200/ns/m2/sr A=1m2 FOV=0.5ox0.5oεA =0.5 εq =0.2 μ =0.039 tg=25ns ; m=0.076 tg=50ns Range<0.5km: Majority of photon arrives within 25 ns Most of photons arrives within 50 ns

14. NSB Trigger Rate N=107MC, (32x32)Pixels For 10 Hz order NSB trigger rate, the Trigger Configurations are: 25ns Single Pixel Trigger: H=5 H-L Trigger : (H,L)=(5,1) Duo Trigger : H=3 Sum Trigger1: (H,A)=(1,7) Sum Trigger2: (H,A)=(2,6) 8 Npe 50ns Single Pixel Trigger: H=6 H-L Trigger : (H,L)=(6,1) Duo Trigger : H=4 Sum Trigger1: (H,A)=(1,9) Sum Trigger2: (H,A)=(2,8) 10 Npe

15. Trigger Efficiency for Electron Shower Sum Trigger gives The largest range 1.1km for etrig=90% Sum trigger are similar Other Three triggers are similar Conservative estimation is 200 γneeded 90%

16. E, x, y, ,  N1, T1, x1 , y1,1, 1 N2, T2, x2 , y2,2, 2 2 1 Preliminary Reconstruction • Reconstruction: Minimize 2 for x,y,,, and E • Two Detectors Separated by ~ 100m

17. Possibility for Reconstruction • Possible to Reconstruct Events • Angular Error within 1° • Energy Error ~ 40% • Reconstruction Efficiency > 90% if triggered

18. Acceptance Determination Integration of efficiencies in phase space Three independent methods for cross-checking Results are consistent with each other! All three got consistent results

19. Best FOV Note that FOV is 8o x 32 o ♤ FOV centered on Kea ♥ FOV centered on Hualalai

20. MIME • Pick τenergy • Put detector on top of Loa • Pick τposition randomly on a 20 km by 20 km vertical plane located 25 km north of Loa • Emit τrandomly in 60o cone • Trace the track to find the exit point of τ • Find τdecay point • Assume e/π took away ½ of τenergy and find the shower core position (air density 10-3 g/cm3) • Make sure shower core is above 1.5 km cloud level Big Island contour plot Loa

21. MIME Make sure the pathway is clear between τexit point and shower core Find the angle and distance between shower core and detector Determine the number of photons in the solid angle covered by detector and apply attenuation effect (18 km attenuation length) Set the threshold at 200 γ’s and check the shower core in the FOV (vertical -8o-0o and horizontal -4o- 12o) Event rate = 7.5 x 400 xπx 0.1(duty) x 0.8(BF) x eff The obtained rate for Loa is0.46 per year

22. Acceptance • Mauna Loa watching Mauna Kea • Higher energy shower Þ Larger trigger area, but longer t decay length (50 km @ 1 EeV)

23. Sensitivity Defined as reachable upper limit of flux Assume F(En) = F0 En-2 Assume no signal in 2 years of observation Feldman-Cousin method for upper limits: 2.44 signal events Theo1: ~ 0.5 events/year 4.7 ×102

24. Signal-sharing plate 32 – channels Data Collection Module in cPCI Hamamatsu 8x8 MPMT 16-channels preamplifier 10 bit x 40 MHz ADC cycle RAM buffer RAM 2 m cable HV power supply Preamp. FADC Trigger daisy chain PMT Trigger Front-end electronics Inside cPCI (PXI) chassis DAQ Multi-anode PMT (MAPMT) “H7546” of 8x8 pixels is used as photon-sensitive device Schematics of electronics

25. Signal-sharing plate 32 – channels Data Collection Module in cPCI Hamamatsu 8x8 MPMT 16-channels preamplifier 10 bit x 40 MHz ADC cycle RAM buffer RAM 2 m cable HV power supply Preamp. FADC Trigger daisy chain PMT Trigger Front-end electronics Inside cPCI (PXI) chassis DAQ Computer-controlled HV power supply “VHQ-202M” in VME is used for MAPMT, 2 channels/module, 1 channel supplies 4 MAPMT (256 pixels) “SBS” PCIVME adapter Schematics of electronics

26. Signal-sharing plate 32 – channels Data Collection Module in cPCI Hamamatsu 8x8 MPMT 16-channels preamplifier 10 bit x 40 MHz ADC cycle RAM buffer RAM 2 m cable HV power supply Preamp. FADC Trigger daisy chain PMT Trigger Front-end electronics Inside cPCI (PXI) chassis DAQ “SBS” PCIVME adapter Signal-sharing plate is used for increasing dynamic range of the system in factor of about 10-20 times Schematics of electronics

27. Signal-sharing plate 32 – channels Data Collection Module in cPCI Hamamatsu 8x8 MPMT 16-channels preamplifier 10 bit x 40 MHz ADC cycle RAM buffer RAM 2 m cable HV power supply Preamp. FADC Trigger daisy chain PMT Trigger Front-end electronics Inside cPCI (PXI) chassis DAQ 16-channels charge sensitive preamplifier transforms charge into voltage for digitising by pipelined ADC Schematics of electronics

28. Signal-sharing plate 32 – channels Data Collection Module in cPCI Hamamatsu 8x8 MPMT 16-channels preamplifier 10 bit x 40 MHz ADC cycle RAM buffer RAM 2 m cable HV power supply Preamp. FADC Trigger daisy chain PMT Trigger Front-end electronics Inside cPCI (PXI) chassis DAQ Holes for mechanical purposes in future 4 preamplifier boards and signal- sharing plate are connected to one MAPMT Schematics of electronics

29. Signal-sharing plate 32 – channels Data Collection Module in cPCI Hamamatsu 8x8 MPMT 16-channels preamplifier 10 bit x 40 MHz ADC cycle RAM buffer RAM 2 m cable HV power supply Preamp. FADC Trigger daisy chain PMT Trigger Front-end electronics Inside cPCI (PXI) chassis DAQ 32-channels Data Collection module in cPCI (PXI) processes signals from 32 channels, has Trigger logic on the module and memory of 256 ADC clocks. If one event is 8 clocks (200 ns), memory could keep up to 32 events. Schematics of electronics

30. Signal-sharing plate 32 – channels Data Collection Module in cPCI Hamamatsu 8x8 MPMT 16-channels preamplifier 10 bit x 40 MHz ADC buffer RAM cycle RAM 2 m cable HV power supply Preamp. FADC Trigger daisy chain PMT Trigger Front-end electronics Inside cPCI (PXI) chassis DAQ System (CPU) card There will be 16 DCM boards (512 channels) inside one PXI chassis DCM Active cPCI extender for debugging Schematics of electronics

31. Signal-sharing plate 32 – channels Data Collection Module in cPCI Hamamatsu 8x8 MPMT 16-channels preamplifier 10 bit x 40 MHz ADC cycle RAM buffer RAM 2 m cable HV power supply Preamp. FADC Trigger daisy chain PMT Trigger Front-end electronics Inside cPCI (PXI) chassis DAQ DAQ – in Linux, inside cPCI (PXI) CPU card Schematics of electronics

32. buffer RAM cycle RAM Preamp. FADC DAQ Some tests 32 – channels Data Collection Module in cPCI 10 bit x 40 MHz ADC C 16-channels preamplifier A From generator B Trigger C C D Cable ~20m Double pulse (~100 ns difference) C B A D

33. Telescope parameters Aperture: 1m2 Image size at FP: 24cm(H) X 12cm(V) Light guide: reduces image 3:1.8 Photo sensor: 8X8 MAPMTs w. 512 pixelsX2 for 2 telescopes FOV: 16o horizontally 8o vertically

34. Three-fresnel surface telescope ---: 8o ---: 4o ---: 0o Front side: fresnel 1.1 m f Both sides: fresnel A fresnel-edge loss: 17%

35. Spot image of 3-fresnel telescope

36. Telescope w. two-identical fresnel lens Tow fresnel lens are identical ---: 8o ---: 4o ---: 0o Aspheric lens 0.4 m f Front side: fresnel 1.1 m f Back side: fresnel A fresel-edge loss: 11%

37. Spot image of two-identical fresnel telescope

38. Light guide simulation

39. Light guide

40. Conclusion • NuTel is an experiment dedicated to Earth skimming / mountaing watching • The PeV cosmic nt rate is ~ 1 event/year • The cost is low: O(1) million US dollars to build it • Very good project for training students • However, lack of funding support in last two years • Ceased collaboration with ASHRA last year • Look for new funding support from university this spring, if succeed will start the optics this summer • Schedule: prototype deployment in ~2007-2008 for initial observation

41. NTUHEP/CosPA2 PIs: W.S. Hou & Y.B. Hsiung Hardware Team: K. Ueno (Optics) Y.K. Chi (Electronics) Y.S. Velikzhanin (Electronics) J.G.Shiu(DAQ) M.W.C. Lin (Technician) Master students Simulation Team: M.Z. Wang(Faculty) P. Yeh (Faculty) C.C. Hsu (Ph.D. student) master students NUU M.A. Huang + students (Faculty) From 2002-2005 People who worked on NuTel before • Italy: IASF, CNR, Palermo • N. La Barbera, O. Catalano,G. Cusumano, T. Mineo,B. Sacco • France: Paris, FranceF. Vannucci, S. Bouaissi • USA: HawaiiJ.G. Learned • Japan: ICRRM. Sasaki • Taiwan: • NCTS/CosPA3 • G.L. Lin, H. Athar (Faculty)