Cherenkov Telescope Array a (partly) user-open VHE gamma ray observatory

1. M. Ostrowski Jagiellonian University Cherenkov Telescope Array a (partly) user-open VHE gamma ray observatory with two sites - at southern and northern hemispheres • Main goals: • - to extend observational range to high (~100 TeV) • and low (~10 GeV) energies • to increase sensitivity ~10 times above the H.E.S.S./MAGIC levels • to increase a number of observed sources to several hundreds Based on the Werner Hofmann presentation at the Berlin meeting in May 2006.

2. Unifying European efforts MAGIC VERITAS CTA involves scientists from Czech Republic Germany France Italy Ireland UK Poland Spain Switzerland Armenia South Africa Namibia from several communities astronomy & astrophysics particle physics nuclear physics about 250-300 scientists working currently in the field will be directly involved, user community significantly larger H.E.S.S.

3. Polish institutions in the CTA project Copernicus Astronomical Center, PAS, Warsaw & Torun Institute of Experimental Physics, Lodz University, Lodz Astronomical Observatory Institute of Physics Niewodniczanski Institute of Nuclear Physics, PAS, Cracow Space Research Centre, PAS, Warsaw Astronomical Centre, Nicolaus Copernicus University, Torun (?) (as presented in arbitrary order) } of the Jagiellonian University, Cracow

4. In May 2006, at the Berlin meeting of H.E.S.S. and MAGIC collaborations: • (non-formal) formation of the CTA collaboration • formation of a few working groups preparing the CTA project: • physics (with me and W. Bednarek), • technical issues (frame, optics, electronics) SRC • numerical modelling • site evaluation • Werner Hofmann and Masahiro Teshima managing the project • The groups started to work, to prepare extended LoI till the end of 2006.

5. Proven: MAGIC rapid-slewing 17 m dish Cost / Dish Area Camera cost dominates Dish cost dominates 0 10 m 20 m 30 m Construction started: H.E.S.S. II 28 m dish Dish size Telescope structure Proven: H.E.S.S. 12 m dish

6. Option: Mix of telescope types Not to scale !

7. Option: Single dish type Requires further development of trigger system for central cluster, allowing to combine pixel signals from multiple telescopes Not to scale !

8. Conventional PMTs with improved cathodes, coatings GaAs photo cathodes Semiconductor single-photon detectors: photon counting with small pixels Photon detector technology Improved photon detectors under development allow further improvements in sensitivity and threshold 3 x 3 mm2 silicon PMT (MPP & MEPhI) 5 x 5 mm2 silicon PMT (MPP & MEPhI) 2007: Back-illuminated pixel MPI-HLL, e ~ 70%

9. Readout technology • Several proven solutions • Optimise further, decide on basis of cost, power consumption, performance ADC GHz sampling analog memory ~ 200 ns memory depth H.E.S.S. SAM ASIC Trigger MAGIC FADC/MUX SYSTEM GHz FADC Digital memory ms … ms memory depth Trigger

10. 2 mrad 0.12o 1 mrad 0.06o Camera field of view: Optics J. Buckley • Optics for wide fov • very large f/d • mechanically non-trivial • Dual-mirror optics with (large) secondary • cost, alignment, large effective focal length? • Frensnel corrector plate in front of camera • cost, transmission

11. 1 TeV H.E.S.S. (0.15 degr.) Limiting angular resolution with lots of light

12. Design criteria • CTA will be a user facility (~50% open time) • It will consist of a significant number of telescopes  • Cost-effective design but even more important • Efficient installation and commissioning • High reliability, minimal maintenance • Ease of operation and calibration

13. Sites

14. Ultimately aim for two sites covering the full sky South: Khomas Highland, Namibia, 23o S, 1800 m North: Canary Islands, IAC sites 28o N, 2000+ m Option: South-American High-altitude sites, 3500+ m Multiple sites would be designed, constructed and operated by a single consortium

15. Schedule

16. (Very optimistic) Schedule – Work is going on FP 7 Design Study GLAST