1. 1 Tibet Air Shower Array plus Muon Detector Array for the 100 TeV Gamma-Ray Wide Sky Survey K. Kawata For the Tibet AS  Collaboration ICRR, University of Tokyo Locating PeV Cosmic-Ray Accelerators: Future Detectors in Multi-TeV Gamma-Ray Astronomy Adelaide 6 - 8 December 2006

2. 2 M.Amenomori, 1 S.Ayabe, 2 X.J.Bi, 3 D.Chen, 4 S.W.Cui, 5 Danzengluobu, 6 L.K.Ding, 3 X.H.Ding, 6 C.F.Feng, 7 Zhaoyang Feng, 3 Z.Y.Feng, 8 X.Y.Gao, 9 Q.X.Geng, 9 H.W.Guo, 6 H.H.He, 3 M.He, 7 K.Hibino, 10 N.Hotta, 11 HaibingHu, 6 H.B.Hu, 3 J.Huang, 12 Q.Huang, 8 H.Y.Jia, 8 F.Kajino, 13 K.Kasahara, 14 Y.Katayose, 4 C.Kato, 15 K.Kawata, 12 Labaciren, 6 G.M.Le, 16 A.F. Li, 7 J.Y.Li, 7 Y.-Q. Lou, 17 H.Lu, 3 S.L.Lu, 3 X.R.Meng, 6 K.Mizutani, 2,18 J.Mu, 9 K.Munakata, 15 A.Nagai, 19 H.Nanjo, 1 M.Nishizawa, 20 M.Ohnishi, 12 I.Ohta, 21 H.Onuma, 2 T.Ouchi, 10 S.Ozawa, 12 J.R.Ren, 3 T.Saito, 22 T.Y.Saito, 23 M.Sakata, 13 T.K.Sako, 12 T.Sasaki, 10 M.Shibata, 4 A.Shiomi, 12 T.Shirai, 10 H.Sugimoto, 24 M.Takita, 12 Y.H.Tan, 3 N.Tateyama, 10 S.Torii, 18 H.Tsuchiya, 25 S.Udo, 12 B. Wang, 9 H.Wang, 3 X.Wang, 12 Y.G.Wang, 7 H.R.Wu, 3 L.Xue, 7 Y.Yamamoto, 13 C.T.Yan, 12 X.C.Yang, 9 S.Yasue, 26 Z.H.Ye, 16 G.C.Yu, 8 A.F.Yuan, 6 T.Yuda, 10 H.M.Zhang, 3 J.L.Zhang, 3 N.J.Zhang, 7 X.Y.Zhang, 7 Y.Zhang, 3 Yi Zhang, 3 Zhaxisangzhu, 6 and X.X.Zhou 8 (1) Dep. of Phys., Hirosaki Univ., Hirosaki, Japan (2) Dep. of Phys., Saitama Univ., Saitama, Japan (3) Key Lab. of Particle Astrophys., IHEP, CAS, Beijing, China (4) Fac. of Eng., Yokohama National Univ., Yokohama, Japan (5) Dep. of Phys., Hebei Normal Univ., Shijiazhuang, China (6) Dep. of Math. and Phys., Tibet Univ., Lhasa, China (7) Dep. of Phys., Shandong Univ., Jinan, China (8) Inst. of Modern Phys., South West Jiaotong Univ., Chengdu, China (9) Dep. of Phys., Yunnan Univ., Kunming, China (10) Fac. of Eng., Kanagawa Univ, Yokohama, Japan (11) Fac. f of Educ., Utsunomiya Univ., Utsunomiya, Japan (12) ICRR., Univ. of Tokyo, Kashiwa, Japan (13) Dep of Phys., Konan Univ., Kobe, Japan (14) Fac. of Systems Eng., Shibaura Inst. of Tech., Saitama, Japan (15) Dep. of Phys., Shinshu Univ., Matsumoto, Japan (16) Center of Space Sci. and Application Research, CAS, Beijing, China (17) Phys. Dep. and Tsinghua Center for Astrophys., Tsinghua Univ., Beijing, China (18) Advanced Research Inst. for Sci. and Engin., Waseda Univ., Tokyo, Japan (19) Advanced Media Network Center, Utsunomiya University, Utsunomiya, Japan (20) National Inst. of Info., Tokyo, Japan (21) Tochigi Study Center, Univ. of the Air, Utsunomiya, Japan (22) Tokyo Metropolitan College of Industrial Tech., Tokyo, Japan (23) Max-Planck-Institut fuer Physik, Muenchen, Germany (24) Shonan Inst. of Tech., Fujisawa, Japan (25) RIKEN, Wako, Japan (26) School of General Educ.,Shinshu Univ., Matsumoto, Japan The Tibet AS  Collaboration

3. 3 Contents 1.Introduction 2.Tibet Air Shower Array Tibet Muon Detector Array 3.Sensitivity Simulation 4.Outlook 5.Costs 6.Summary

4. 4 1. Introduction Cosmic rayAccelerationOrigin New 14 HESS sources Hard spectral indices Faint in other wavelengths Theoretical possibility  0 decay IC* … Old SNR Asymmetric PWN … Key observation100 TeV regionWide sky survey Aharonian et al, ApJ, 636, 777 (2006) * >100TeV IC is difficult due to sync. cooling & KN effect 200GeV-10TeV New 14 HESS sources Suzaku HESS J1616-508 Matsumoto et al, PASJ, in press astro-ph/0608475 Yamazaki et al, MNRA, 371, 1975 (2006) Blondin et al, ApJ, 563, 806 (2001)

5. 5 2. Tibet Air Shower (AS) Array Tibet China (90.522 o E, 30.102 o N) 4300 m a.s.l.  Number of Scinti. Det.0.5 m 2 x 789  Effective Area for AS~37,000 m 2 ~50,000 m 2  Energy region~TeV - 100 PeV  Angular Resolution~0.4 @10 TeV (Gamma) ~0.2 @100 TeV  Energy Resolution~70% @10 TeV (Gamma)~40% @100TeV  F.O.V.~2 sr Tibet Muon Detectors (Image)

6. 6 Tibet Muon Detector (MD) Array 7.2m x 7.2m x 1.5m depth Water pool 20”  PMT x 2 (HAMAMATSU R3600) Underground 2.5m ( ~515g/cm 2 ~19X 0 ) Material:  Concrete pool  White epoxy resin paint 184 detctors Total 9540 m 2 Counting the number of muons accompanying an air shower Present AS ArrayFuture AS+MD Array (Type 1)Future AS+MD Array (Type 2) Gamma/Hadron separation

7. 7 MilagroSK (Anti)Tibet MD PMT 8”  PMT 20”  PMT Detector Area 80m ｘ 60m Depth8m (Upper4800m 2 /Lower2000m 2 ) All Surface ~7400m 2 Thickness ~2.5m 9540m 2 Depth1.5m Unit1PMT@2.8m×2.8m2PMTs@6m 2 2PMTs@52m 2 Photo- Coverage 0.4 ％ 0.52 ％ 0.75 ％ Number of PMTs Upper: Depth 1.4m, 450 Lower: Depth 6.0m, 273 1885368  Already established technique  High cost performance  Easy to design long path length detector  Cherenkov threshold (electron 750keV in the water) Water Cherenkov Technique High rejection power for low energy e +/- &  Good technique for muon detection

8. 8 Future AS+MD Array (Type 2)  Air Shower Generation - Corsika Ver.6.204 CR: 0.3TeV-10PeV, Crab Orbit Chemical components Interaction model: QGSJET01c Gamma: 0.3TeV-10PeV, Crab Orbit E -2.6 Core position: Throw randomly within 300 ｍ radius  Scintillation det. (Tibet AS) - Epics UV8.00 Estimate energy, direction, core position, …  Soil + Cherenkov det. (Tibet MD) - GEANT4 8.0 Reflectance at walls 70% Att. length ~40m@400nm (Dependant on wave length) Quantum Eff. ~20%@400nm (Dependant on wave length)  Accidental muons 300 Hz/m 2 x 9540m 2 x 200 ns = ~0.57 muons/an air shower (Poisson noise distribution) AS MD MD (Type2) AS 3. Sensitivity Simulation

9. 9 Air Shower Reconstruction by AS Array Energy - Sum of particle density by all scintillation detectors (we do not use the lateral function in this talk.) Direction - Relative timings at each detectors ~10 TeV Air Shower (Simulation)

10. 10 Energy & Angular Resolution (Simulation) 10 TeV ~+70%-40% 100 TeV ~+40%-30% (Gamma rays) 10 TeV ~0.4 degrees 100 TeV ~0.2 degrees (Gamma rays) Energy Resolution Angular Resolution two typical air-shower size bins ~10 TeV ~100 TeV 10TeV100TeV1000TeV

11. 11  N PE ~100TeV  N PE ~10TeV Muon Number vs. Shower Size (Type2 Simulation)  ( Shower Size)  N PE  ( Muon Number)  10TeV100TeV1000TeV 20% 50% 80%  : Sum of particle density by all scintillation det. Shower Size  N PE :Sum of photoelectrons by all muon det. Muon number GCR G 0 0 10TeV: Cut value  N PE =~40 Background: ~99% Rejection Gamma rays: ~60% Survival Sensitivity: ~6 times Improved 100TeV: Cut value  N PE =~600 Background: >99.8% Rejection Gamma rays: ~100% Survival Sensitivity: >20 times Improved (gamma)

12. 12 Survival Efficiency (Type2 Simulation) CR Gamma 10TeV100TeV1000TeV E:E: 10 TeV: Cut value  N PE =~40 Background: ~99% Rejection Gamma rays: ~60% Survival Sensitivity: ~6 times Improved 100 TeV: Cut value  N PE =~600 Background: >99.8% Rejection Gamma rays: ~100% Survival Sensitivity: >20 times Improved Almost background free! 1000 TeV: Cut value  N PE =~8000 Background: >>99.8% Rejection Gamma rays: ~100% Survival Sensitivity: Background free!

13. 13 Tibet AS Array 50,000m 2 + Tibet MD Array 9,540m 2 Crab orbit Sensitivity to Point-like Gamma-ray Source EGRET GLAST MAGIC VERITAS HESS Tibet AS Tibet AS+MD (Type2) Tibet AS+MD (Type1) Search window size 0.3 degrees >50TeV, while angular resolution <0.3 degrees.

14. 14 4. Outlook Tibet AS+MD ~100 TeV HESS ~200 GeV Location30N-90E23S-16E F.O.V. ~1.5 sr~0.02 sr Duty Cycle ~90%~10% Angular Resol. ~0.2°~0.1° Energy Resol. ~40%~20% Background Rejection >99%~99% Sensitivity (RX J1713 Unit PL Index = –2.19) ~5% RXJ1713 (1 year 5σ) ~1% RXJ1713 (50 hours 5σ) Number of detections ？ >20 Tibet AS+MD ability will be close to HESS. How many sources can we detect in the 100 TeV Northern Sky?

15. 15 Known Galactic Sources in the Northern Sky TeV J2032+4130HESS J1837-069HESS J1834-087 Cas ALS I +01 303 Large Zenith ~ 37 o Large Zenith ~ 39 o Periodic object MAGIC - Peak flux MGRO J2019+37 Diffuse gamma flux is corresponding to (3.0 x 3.0 deg.) Our sensitivity Very preliminary! Type 1 Type 2 VERITAS Extrapolation

16. 16 How Many New Sources? Induces are harder Aharonian et al, ApJ, 636, 777 (2006) (If it is constructed at southern hemisphere) Most of new HESS sources detectable by Tibet AS+MD

17. 17 Green, arXiv:astro-ph/0411083 http://www.mrao.cam.ac.uk/surveys/snrs/index.html Green’s SNR catalog HESS survey region 82 SNRs Tibet F.O.V. region 86 SNRs ~new 14 detected (SNR-like)~new 14 detectable?? (SNR-like) optimistic value? But, could not be 0? Expectation of the number of SNR-like sources in the Northern Sky Aharonian et al, ApJ, 636, 777 (2006)

18. 18 5. Costs ItemsRemarksUnit price (US $) QuantityTotal (US $) PMT 20”  PMT 5,0003681.84M Electronics ADC, TDC, HV, Cable, … 8001840.147M Water pool Construction fee (Waterproof paint, Concrete, … ) 250/m 2 9,540m 2 2.39M Water purification & circulation MF filters, …0.15M Others +  Total (US $) 4.5M +  Total ~5M US$

19. 19  Tibet MD Project 50,000 m 2 Tibet air shower array + 9,540 m 2 Water cherenkov muon detector array ~ 5M US$ - 100 TeV gamma-ray wide sky survey.  Sensitivity simulation Detailed simulation was done (two configurations). F(>100TeV) ~2 x 10 -15 cm -2 s -1 (1 calender year, 5  or 10 events). Improve sensitivity by an order of magnitude. Inner MDs are very important.  Candidates of 100 TeV sources in the northern sky Promising: Crab, TeV J2032+4130, HESS J1837-069, MGRO J2019+37 Interesting: Cas A, HESS J1834-089, LS I +61 303 (Need several years) + several new sources? 6. Summary

20. 20 Tibet AS+MD 200?~ CASA-MIA 1991~1996 Milagro 2000~ KASCADE 1996~ Grapes-III 2001~ Location30.102N 90.522E Tibet 4300m (606g/cm 2 ) 40.2N 112.8W Utah1500m (870g/cm 2 ) 35.9N 106.7W NewMexico 2650m (750g/ cm 2 ) 49.1 N8.4E Karlsruhe 110m (1022 g/cm 2 ) 11.4N 76.7E Ooty 2200m (800 g/cm 2 ) Energy E TH75% 1-10 4.5 TeV 10TeV 50-10 4.5 TeV 60TeV ~0.1TeV-? 10TeV 100-10 4.5 TeV 260TeV 10-10 4 TeV ? Energy Resolution 40% (100TeV)100%(100TeV)??? Angular Resolution 0.4° (>10TeV) 0.2° (>100TeV) 2 °(>~100TeV) 0.5°(>~700TeV) 1°(>~1TeV) 0.55° (>~600TeV) ? AS Eff Area (Particle coverage) 50,000m 2 Scinti. (0.9%) 230,000m 2 Scinti. (0.7%) 4,800m 2 Water (100%) (with Outrigger 34,000m 2 ) 40,000m 2 Scinti.(1.3%) 10,000m 2 Scinti.(1.2%) μ Eff Area9,540m 2 Water 2,500m 2 Scinti. ~2,000m 2 Water 622m 2 Scinti. 560m 2 x4 layers Prop. Counters AbsorberSoil 2m + Concrete 0.5m (515g/cm 2 ) 19X 0 Soil 3m (600g/ cm 2 ) 22X 0 Water 6m (600g/ cm 2 ) 16X 0 Lead 10cm + Iron 4cm (145g/cm 2 ) 20X 0 Concrete 2m (460g/cm 2 ) 17X 0 Muon Eth>1GeV >1.2GeV>0.23GeV>1GeV