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Roadmaps

~ 2000. ~2004. ESFRI European large research infrastruct. Subdivisions concerned with astroparticles. Subcommittee for Astronomy and Astroparticles. ApPEC Astroparticle Physics European Coordination Steering committee Peer review committee. ESFRI Roadmap. ApPEC Roadmap.

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Roadmaps

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  1. ~ 2000 ~2004 ESFRI European large research infrastruct. Subdivisions concerned with astroparticles Subcommittee for Astronomy and Astroparticles ApPEC Astroparticle Physics European Coordination Steering committee Peer review committee ESFRI Roadmap ApPEC Roadmap formal relation not defined! Roadmaps European government science funding agencies

  2. Roadmaps • ApPEC (Astroparticle Physics European Coordination) Roadmap • Draft circulated • Three projects proposed for ESFRI roadmap • KM3NET neutrino telescope • CTA gamma ray telescope • Gravitational wave observatory • ESFRI (European Large Research Infrastructures) Roadmap • Hearings by subcommittees • Filtering by ESFRI committee (Funding agencies) • First roadmap in fall 2006 • Updated in regular intervals • Will (very likely) include things such as KM3NET, FAIR, XFEL, …

  3. Exploring the non-thermal universe the Cherenkov Telescope Array as a facility for gamma ray astronomy in the next decade

  4. The Cherenkov Telescope Array facility • aims to explore the sky in the 10 GeV to 100 TeV energy range • builds on demonstrated technologies • combines guaranteed science with significant discovery potential • is a cornerstone towards a multi-messenger exploration of the nonthermal universe

  5. Unifying European efforts … and maintaining European lead 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.

  6. CTA as a user facility • Significant fraction of open time (~50%) • Guaranteed time for CTA consortium (~50%) • Probably local staff for basic operation, plus experts when needed • Facilities to make data available to outside users • Data public after certain time (~1 y) • Significant fraction of operating funds / user support / data center support needs to come from external (EC?) sources

  7. The Science Case

  8. Science topics Pulsars and PWN SNRs AGNs Dunkle Materie Space-time & relativity GRBs Dark matter Origin of cosmic rays Cosmology

  9. The Milky Way at very high energies

  10. Science potential • Current instruments have passed the critical sensitivity threshold and reveal a rich panorama, but this is clearly only the tip of the iceberg • Broad and diverse program ahead, combining guaranteed astrophysics with significant discovery potential Horan & Weekes 2003 Microquasars Molecular clouds Clusters of galaxies Distance Pulsed emission

  11. Science potential

  12. Physics working groups • Where should we look ? • What can we expect to see ? • Why should we look i.e. what do we learn from the 100…1000 new sources ? • How should the instrument be optimized ?

  13. Possible CTA sensitivity GLAST Crab E.F(>E) [TeV/cm2s] 10% Crab MAGIC looks a bit optimistic looks a bit optimistic 20 wide-angle 10 m telescopes de la Calle Perez, Biller, astro-ph 0602284 30 m stereo telescopes Konopelko Astropart.Phys. 24 (2005) 191 H.E.S.S. Current Simulations 1% Crab

  14. -10 10 2 E F(E) Vela X -11 10 MSH 15-52 -12 10 RXJ 1713-3946 (x 0.1) -13 10 0,01 0,1 1 10 100 Energy [TeV] Extending the energy coverage CTA Cutoff region - crucial to understand acceleration mechanisms Transition region to GLAST Regime of pulsars, AGN,… hadron model Sensitive to acceleration mechanism electron model

  15. GLAST sky Important for schedule: GLAST mission (2007 - 2012+) Provides all-sky monitor Simultaneous spectral coverage from ~2.107 eV to few 1014 eV CTA and GLAST EGRET sky

  16. Possible CTA sensitivity • Low energy region • expect many new sources • new physics regimes (pulsars,…) • but still “modest” sensitivity • technically challenging, poor angular, energy resolution GLAST Crab • High energy region • will generate important physics • but few new sources • and few breath-taking discoveries E.F(>E) [TeV/cm2s] 10% Crab MAGIC H.E.S.S. Current Simulations • Medium energy region • highest sensitivity • predictable performance • “bread and butter” 1% Crab

  17. Possible CTA sensitivity Performance not perfectly predictable MC should be reliable, if detailed enough; input physics and parameters are well known … GLAST Crab E.F(>E) [TeV/cm2s] 10% Crab MAGIC H.E.S.S. Problem in my view (Gamma) signal to (CR) noise is much worse than in TeV range (1:few 10 – 1:few 100 vs 10:1 - 1:10) Not clear if background systematics can be reduced enough – currently stuck at few% level Current Simulations 1% Crab

  18. Possible CTA sensitivity • Need to achieve factor ~10 gain in sensitivity • Aim for full energy range • Cover entire energy range within a facility to maximize temporal overlap and minimize systematics GLAST Crab E.F(>E) [TeV/cm2s] 10% Crab MAGIC H.E.S.S. Current Simulations 1% Crab

  19. Camera field of view • A full-sky survey with an instrument like H.E.S.S. is not very interesting • H.E.S.S. did not find a single serendipidous source in extragalactic exposures (~35% of total H.E.S.S. time) • For the Galaxy, survey mode is most efficient at H.E.S.S. sensitivity and beyond • Is a full sky survey interesting @ 20 GeV and few % Crab sensitivity ? Don’t know (guess not) • Is a full sky survey interesting @ 1 TeV and milli-Crab sensitivity? Don’t know (guess not) • What can one realistically realize? • milli-Crab over modest (few degr.) field

  20. Camera field of view: (a) Sky coverage Effective field of view for given camera diameter 3o 5o 8o

  21. Cost per (Galactic) Source 24 C = 50 C = 25 22 20 18 16 14 2 4 6 8 10 12 Diameter [Degr.] Camera field of view: (a) Sky coverage C = Dish cost in units of cost of camera per square degree for one-dimensional band of sources

  22. Camera field of view: (b) Energy coverage • Current instruments: 3o-5o fov • Larger fov desirable for high energy part of array Image centroids 100 m2 telescope astro-ph/0602284 Efficiency 10 m2 telescope J. Phys. G 26 (2000) 183

  23. Technology and Maturity

  24. Array layout: 2-3 Zones High-energy section ~0.05% area coverage Medium-energy section ~1% area coverage Low-energy section ~10% area coverage FoV increasing to 8-10 degr. in outer sections 70 m 250 m few 1000 m Eth ~ 10-20 GeV Eth ~ 50-100 GeV Eth ~ 1-2 TeV

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

  26. Option: Single dish type Modes of operation • Deep wide-band mode: all telescopes track the same source • Survey mode: staggered fields of view survey sky • Search & monitoring mode: subclusters track different sources • Narrow-band mode: halo telescopes accumulate high-energy data, core telescopes hunt pulsars • … Requires further development of trigger system for central cluster, allowing to combine pixel signals from multiple telescopes Not to scale !

  27. 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

  28. Camera 1 Camera 2 Mirror Structure Total 1 Total 2 1000 Cost (KEuro) 100 3 4 5 6 7 8 9 10 20 Diameter Telescope costs versus diameter … unless new camera technology is available … gated image intensifiers??

  29. 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%

  30. 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

  31. Saclay SAM ASIC • 2 GHz sampling freq. • 256 memory cells • Hi/low gain channel • 11.5 bit dynamic range (single channel) Future versions: • parallel DACs • on-board FPGA • on-board trigger comparator

  32. 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

  33. Low-energy region • Dish options • 30 m dish with conventional PMTs • can be built now; cost? • 21 ± 4 m dish with semiconductor PMTs • under R&D: when available? cost? • 13 ± 3 m dish with FADC and digital intertelescope trigger • R&D: trigger non-trivial • small 3-5 m dish and digital intertelescope trigger (STAR) • I don’t see how this could be cost-effective • Other considerations • Field of view: “small” (4-5 degr.) • Pixel size: “small” (<0.1 degr.) to provide high angular resolution at higher energies

  34. 1 TeV H.E.S.S. (0.15 degr.) Limiting angular resolution with lots of light

  35. One option (?) • High energy • ~20 10-12 m dishes with 8-12 degr. fov, spread out • 1.5 – 2 M€ each -> 30-40 M€ • Medium energy • ~15 15-18 m dishes with 7-10 degr. fov, loose cluster • ~ 3 - 4 M€ each -> 45-60 M€ • Low energy • few 25-30 m dishes with 4-6 degr. fov, clustered • ~ 10 M€ each -> 40 M€ Well beyond unitarity limit … combine functions ?

  36. 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

  37. Design criteria • Cost • seems unrealistic to assume that one will have more than 40-50 M€ for a first stage (before 2015, say) • need to find design which optimizes physics output and represents a significant step beyond HESS II / MAGIC II • Construction mode • very likely, HEP-like model (splitting work over institute shops) is better (=cheaper) than ALMA like models (order system from industry) • modest number of different components – sharing of work is nontrivial to organize • but see examples: AUGER, LHC Silicon trackers, …

  38. Sites

  39. 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

  40. Search Results – Near West from Stephen Fegan(UCLA) Elevation Key >2500m>3000m>3500m >4000m >4500m >5000m Colombia Ecuador • Search SRTM preliminary data set for • Contiguous circular region • With radius 720m (9×80m / 1.6km2) • At elevation >2500m • Flat to 100m • Ignoring voids in data Peru Bolivia Chile Argentina

  41. Clear (“photometric”?) nights from satellite survey (Erasmus)

  42. Sites - south • New site might offer • slightly better performance at low energy • larger fraction of clear nights • easier cooperation with US + Japanese groups, if desired • New site might involve • longer lead times • higher infrastructure costs • more difficult access • Need to better understand options and balance

  43. Schedule

  44. (Very optimistic) Schedule FP 7 Design Study GLAST “Letter of Intent” (100 pages, physics + conceptual design) Technical proposal

  45. Next steps • Project will receive high priority in upcoming APPEC roadmap • Strong support by MPG, CNRS,… • Plan to apply for FP7 design study • In parallel, continue • site exploration • simulations & design optimization • technical developments • tests with existing instruments • funding discussion • Next goals: conceptual & technical design

  46. Organisation • Facility with mix (~50/50) of open and guaranteed time • Public data (after grace period) Scientific and techn. advisory committee Steering committee Core groups Program committee Project management General assembly Associated scientists Users Operation Technical tasks Science tasks To be defined: organisational form / host organisation

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