George W.S. Hou & M.A. Huang Center for Cosmology and Particle Astrophysics

1. Expected Performance of a Neutrino Telescope for Seeing AGN/GC Behind a Mountain Abstract We study the expected performance of building a neutrino telescope, which targets at energy greater than 10^14 eV utilizing a mountain to interact with neutrinos. The telescope's efficiency in converting neutrinos into leptons is first examined. Then using a potential site on the Big Island of Hawaii, we estimate the acceptance of the proposed detector. The neutrino flux limit at event rate 0.3/year/half decade of energy is estimated to be comparable to that of AMANDA neutrino flux limit at above 10^16 eV. astro-ph/0204145 George W.S. Hou & M.A. Huang Center for Cosmology and Particle Astrophysics Department of Physics, National Taiwan University, 1, Sec. 4, Roosevelt Rd.,Taipei, 106,TAIWAN http://www.hep1.phys.ntu.edu.tw hou@phys.ntu.edu.tw & huangmh@phys.ntu.edu.tw Window of new techniques for observing Neutrinos VHE Neutrino Telescope Workshop Mar. 21-23, 2002, Taipei, Taiwan, http://hep1.phys.ntu.edu.tw/VHENTW Conventional  detectors such as SK have difficulty to expand target volume, maximum energy ~ 1015 eV. UHECR detector such as Auger array also detect , energy threshold is high ~ 1018 eV. • Detection mechanism similar to -ray imaging Chrenkov telescope. • Cherenkov light image on a 8x8 MAPMT • EUSO type compact detector (Fresnel lens + MAPMT) • Tentative international collaboration: • NTU, Taiwan • U. Paris, French • U. Palermo, Italy • U. Hawaii, USA • RIKEN, Japan ? Euso prototype 40cm diameter Fresnel lens, assembled in RIKEN, Japan (Kawasaki et al., 2001, 27th ICRC, 893) • Potential site: Hawaii Big Island • Good weather & Less artificial light • Mt. Hualalai provide a good view of Mt. Loa and situated in the dryer west side of island. • Mt. Loa provide long base line, ~ 90 km wide and 4 km high. • Alternative approach • Use mountain as target and shield. • Use atmosphere as calorimeter, measured air shower initiated by the decay of .  appearance Only  can be seen, observation such event prove  to  oscillation seen by SK. Field of view of telescope Azimuth angle: from south to east. Zenith angle: from 86.9º to 91.5º Slice along this line • Acceptance • Select field of view, count mountain-passing events only! • Effective solid angle is Cerenkov light cone, c ~ 5 º. • Effective area: area where tau decay and initiate shower. • Consider conversion efficiency  : Conversion efficiency • Sky coverage • From field of view and operation from 12/2003 to 12/2007; 20% duty time • Optical detector operate in moonless and cloudless night, typical duty cycle 10%. Galactic center is visible! Blue : No dE/dXRed: dE/dX Over 1 km2 sr! • Conclusions: • Hualalai site provide acceptance > 1km2 sr and good weather condition. • Chance to explore MPR limits and set similar upper limit as AMANDA-B10 at higher energy. • Nearby point source could be detected, AGN and galactic center could be good candidate for such point source. • Earth skimming and Near Horizon shower are being studied. Acceptance will be updated. Assuming sensitivity is the flux which produce0.3 events/year* per half decade of energy. * Calendar year, consider 10% duty cycle.