Telescope Array for Extremely High Energy Cosmic Rays

Telescope Array for Extremely High Energy Cosmic Rays. July 30 th, 2003 Masaki FUKUSHIMA ICRR, Univ. of Tokyo

Galactic Extra‐Galactic Magnetic Confinement 1 ０ Hi. Res: Composition Change from Heavy to Light Ankle Structure 3 ２ ＡＧＡＳＡ： Ａｎｉｓｏｔｒｏｐｙ towards Galactic Center

Galactic to extra-galactic transition We are starting to collect First samples of extra-galactic Matter-Particles

Energy Spectrum of the Highest Energy Cosmic Rays There is a Horizon for Cosmic Rays with Energy exceeding 10 20 e. V Log ( FLUX x E 3) AGASA by GZK mechanism Log（ENERGY［e. V］） Cosmic Rays with Energy above GZK cutoff exists. No obvious astronomical counterpart within ~ 50 Mpc.

Arrival Directions and Clustering “Point” Sources E > 10 19 e. V AGASA E > 10 19. 6 e. V > 10 20. 0 e. V > 10 19. 6 e. V > 10 19. 0 e. V Isotropic Distribution

super-GZK + cluster Hard to explain by standard Astrophysics ・ Particle Physics ・ Cosmology

Possibilities of creating continued spectrum exceeding GZK-cutoff mechanism Decay of super-heavy X １ Particle （ big bang origin） EHEν＋ＣνＢ → reason signature concentration in galactic halo γ+ν gal. center ＣνＢ over-density Ｚ０ in super-cluster ２ EHEν with extra-dimension ３ Violation of Lorentz inv. “Ordinary” galaxies； ４ Excess in super-cluster 5 Experimental Problem? γ＋ν σ～ 100 m. B （shower in atmosph. ） showerprofile No Δ(1232) prod. proton over-density～１０ within 50 Mpc point source Statistics, Systematics Acceleration problem unresolved for 2 -4.

Establish ・ Galactic to Extra-galactic transition Confirm / Refute ・ super-GZK ・ cluster

“AGASA” x 10 Plastic Scintillator Array + 3 -station “Hi. Res” Fluorescence Telescope + Low energy extension

TA Detector Configuration Millard County Utah/USA 20 km Exp AGASA Res. 1. 60 TA SD TA FD ~1. 00 0. 60 TA Hyb. 0. 40 24 x 24 Scintillators (1. 2 km spacing) AGASA x 9 3 x Fluorescence Stations km AGASA 20 x 10 Low Energy Hybrid Extension

Energy Calibration by SD-FD Coincidence Meas. . SD - FD； Two Independent Methods for Energy Determination. ○ E > 1019 e. V ~ 100 ev. / Year ○ E > 1020 e. V ~ 1 ev. / Year Phase-1 Hybrid TA gives ENERGY SCALE by ● SCINTILLATOR ARRAY ● AIR FLUORESCENCE Calibration Comparison e /γ meas. Energy Spectrum by Only-one, Unique Energy （Systematic Energy Uncertainty ＜ １０％ Aimed） Scale

cutting 1. 5 mm deep groove TA Scintillator Development proto: 50 cm x 50 cm, 1 cm thick Wave Length Shifter Fiber readout 50 modules used in L 3 for 2. 5 years. WLS: BCF-91 A （ 1 mm Φ ） Final: 3 m 2 by 2 PMT readout.

Energy Loss in the Air “μ” Density at 1 km for p/Fe EAIR / E 0 ~10% of Total Energy MODEL p / Fe Uncertainty ~90% of Total Energy ｐ AUGER water tank simulation Plastic Scintillator: e＋e－ Ｆｅ Water Tank: μ＋μ－ & soft γ Electron Measurement by Scintillator ● Reasonable resolution ● Small model / composition dependence

Telescope： ３ｍΦ Spherical Mirror TA Telescope Development Electronics： ２００ ns continuous ADC ＋ Signal recognition by software Imaging Camera：１６Ｘ１６ PMT Array Shower Image 1 0 x 1 0 Fo. V/PMT

3 Fold Stereo Measurement ① ３ independent energy meas. for 60% of events at 1020 e. V Estimate of Systematics ・ Atmosph. Clarity ・ Cherenkov Light ② ③

Shoot electron Linac beam into the sky. 20 Me. V 100 m away 40 Me. V 100 m away 20 Me. V / particle x 109 ppp = 2 x 1016 e. V total energy deposit. Absolute End-to-End energy calibration. Feasibility study

Construction Plan of Hybrid TA: 2003 SITE PREPARATION TELESCOPE TEST IN UTAH TELESCOPE PRODUCTION TELESCOPE INSTAL. ARRAY TEST IN UTAH ARRAY PRODUCTION CALIB. with AGASA SD only Start Obs. with SD only Start Hybrid Obs. SD + FD AGASA Hi. Res AUGER construction observation

Telescope Array ; Summary 1. Well-defined purposes; ① Establish galactic to extra-galactic transition. ② Confirm/Refute cluster + super-GZK. 2. Seamless coverage from 1016 to 1020. 5 e. V. 3. Fluorescence + Surface hybrid. 4. Common technology and existing resources based on AGASA + Hi. Res. 5. Start measurement in 2006(SD) / 2007(+FD).