1 The overview of the ALPACA experiment Munehiro OHNISHI for The ALPACA Collaboration GA099, 35th ICRC, 17 July 2017, Busan, Korea
The ALPACA Experiment Andes Large area PArticle detector for Cosmic ray physics and Astronomy 2
The ALPACA experiment ★ A New Project in Southern Hemisphere (Bolivia) Bolivia side 5 members UMSA (Universidad Mayor de San Andrés) Japan side 29 members Some members of (BASJE + GRAPES-3 + Tibet AS γ ) ★ Targets 10 - 1000 TeV gamma-ray astronomy (Southern sky) Cosmic-ray anisotropy Sun shadow Chemical composition at Knee region ★ Site and Detectors Halfway up Mt. Chacaltaya, Bolivia 4,740 m a.s.l. Surface air shower array ~83,000 m 2 Underground muon detector array ~5,400 m 2 3
The ALPACA Collaboration IIF, UMSA, Bolivia Faculty of Engineering, Kanagawa Univ., Japan Martin SUBIETA, Rolando TICONA, Hugo RIVERA, Kinya HIBINO, Shigeharu UDO Mirko RALJEVICH, Pedro MIRANDA Faculty of Engineering, Yokohama National Univ., Japan Faculty of Education, Utsunomiya Univ., Japan Yusaku KATAYOSE, Takanori ASABA, Mikihiro KATAOKA, Naoki HOTTA Takuro SASAKI, Masaru SUZUKI, Miho WAKAMATSU Japan Atomic Energy Agency, Japan College of Engineering, Chubu Univ., Japan Harufumi TSUCHIYA Akitoshi OSHIMA, Shoichi SHIBATA Dept. of Physics, Shinshu Univ., Japan Faculty of Engineering, Aichi Inst. of Tech., Japan Kazuoki MUNAKATA, Chihiro KATO, Yoshiaki NAKAMURA Hiroshi KOJIMA ICRR, Univ. of Tokyo, Japan Graduate School of Science, Osaka City Univ., Japan Masato TAKITA, Munehiro OHNISHI, Kazumasa KAWATA Shoichi OGIO, Yoshiki TSUNESADA, Rosa MAYTA College of Industrial Technology, Nihon Univ., Japan Faculty of Engineering, Osaka Electro-Communication Univ., Japan Atsushi SHIOMI Yuichiro TAMEDA Tokyo Metropolitan College of Industrial Tech., Japan Graduate School of Information Sciences, Hiroshima City Toshiharu SAITO Univ., Japan National Inst. of Informatics, Japan Koichi TANAKA Masaki NISHIZAWA Escuela de Ciencias Físicas y Nanotechnología, Yachay Tech, RIKEN, Japan Ecuador Norio TAJIMA Takashi K. SAKO 4
ALPACA Site Mt. Chacaltaya, Bolivia 5 5
UMSA CR Observatory 5200 m a.s.l. 4 8 0 0 m 4 6 0 0 m ALPACA site 4740 m a.s.l. 4 4 0 0 m 4 2 0 0 m 4 0 0 0 m La Paz 6 6
28 April 2016 Observation Cite: Chacaltaya Hill 500 m × 500 m flat within ± 1° 4,740 m above sea level (16°23’S, 68°08’W) 7
Why in Bolivia • Flat land at high altitude: (> 4,500 m a.s.l.) Cosmic rays absorbed in atmosphere before reaching sea level • Galactic Center: Observable in the southern hemisphere (not in the northern hemisphere) Promising candidate of the origin of cosmic rays • Long-term collaboration between Bolivia and Japan (Good infrastructure: electricity, water, road,…) Since 1962 in the field of cosmic rays, for example, BASJE
Schematic view of ALPACA AS Image of 1 m 2 plastic scintillation detector MD Image of unit (56 m 2 ) underground water Cherenkov muon detector 9
p/ γ discrimination by counting # of muons TeV-PeV gamma ray TeV-PeV proton, helium… Atmosphere Air shower # of muon within <100m from core ~50 µ for 100 TeV proton ~1 µ for 100 TeV gamma ray Muon detector 10
Performance of ALPACA Location: 4,740 m above sea level (16˚23’ S, 68˚08’ W) # of scintillation detectors 1.0 m 2 × 401 detectors Effective area of ~83,000 m 2 Modal energy ~5 TeV Angular resolution ~0.2 ˚ @ 100 TeV Energy resolution ~20 % @ 100 TeV gamma Field of view ~2 sr CR rejection power > 99.9 % @ 100 TeV ( γ ray efficiency ~90%) 11
Sensitivity to the Point Source * * *Based on MC simulation CTA Review by Kubo (JPS 2015) for the Tibet AS+MD M. Daniel, Proc. of 28 th Texas Sympo. (2015) 12
ALPACA Galactic Center as PeVatron!? ✓ Detection of diffuse component ✓ sub-PeV γ -ray expected ALPACA x10 ✓ Promising candidate for PeVatron D i f f u s e x 1 0 ALPACA HESS J1745-290 Abramowski, et al, Nature (2016) δ ~ − 29° 13
Young SNRs SNRs Observed by Fermi & IACTs ALPACA (4 σ 2yrs) Reproduced from slides presented by S. Funk (TeVPA 2011) 14
ALPAQUITA ALPACA Project ALPACA Collaboration � � � A Prototype AS Array : Performance & Science ALPAQUITA: prototype AS array # of scintillation detectors 1.0 m 2 × 45 detectors Effective area of ~8,000 m 2 Start data taking end of 2017 or beginning of 2018 ← Detector deployment ↓ 1m 2 Detector 2 1m 15m Detector cf. PoS (ICRC2017) 437 - Poster #1247, 18-19 July 15 � � � � � � �
Summary ★ new project ALPACA in southern hemisphere Halfway up Mt. Chacaltaya, Bolivia 4,740 m a.s.l. Surface air shower array ~83,000 m 2 Underground muon detector array ~5,400 m 2 ★ Targets 10 - 1000 TeV gamma-ray astronomy (Southern sky) Cosmic-ray anisotropy Sun shadow Chemical composition at Knee region ★ ALPAQUITA: prototype AS array 45 x 1.0 m 2 scintillation detectors (~8,000 m 2 ) cf. PoS (ICRC2017) 437 - Poster #1247, 18-19 July 16
Thank you for your attention! 17
Recommend
More recommend
