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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.
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Unifying European efforts
MAGIC
VERITAS
CTA involves scientists from Czech
Republic Germany France Italy Ireland UK Poland Sp
ain 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.
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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
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• 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.

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Telescope structure
Proven H.E.S.S. 12 m dish
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Option Mix of telescope types
Not to scale !
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Option Single dish type
Requires further development of trigger system
for central cluster, allowing to combine pixel
signals from multiple telescopes
Not to scale !
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Photon detector technology
Improved photon detectors under development allow
further improvements in sensitivity and threshold
3 x 3 mm2 silicon PMT (MPP MEPhI)

• Conventional PMTs with improved cathodes,
  coatings
• GaAs photo cathodes
• Semiconductor single-photon detectors photon
  counting with small pixels

5 x 5 mm2 silicon PMT (MPP MEPhI)
2007 Back-illuminated pixel MPI-HLL, e 70
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Readout technology
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

• Several proven solutions
• Optimise further, decide on basis of cost, power
  consumption, performance

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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

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Limiting angular resolution with lots of light
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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

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Sites
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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
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Schedule
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(Very optimistic) Schedule Work is going on
FP 7 Design Study
06 07 08 09 10 11 12 13
Site exploration
Array design
Component prototypes
Telescope prototypes
Array construction
Partial operation
Full operation
GLAST