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The MAGIC Telescope

The MAGIC Telescope. EGEE Generic Applications Advisory Panel CERN, 14. June 2004. Florian Goebel Max-Planck-Institut für Physik (Werner-Heisenberg-Institut) München for the MAGIC collaboration. Outline. What is MAGIC? The collaboration The Telescope Commissioning Status

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The MAGIC Telescope

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  1. The MAGIC Telescope EGEE Generic Applications Advisory Panel CERN, 14. June 2004 Florian Goebel Max-Planck-Institut für Physik(Werner-Heisenberg-Institut) München for the MAGIC collaboration F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

  2. Outline • What is MAGIC? • The collaboration • The Telescope • Commissioning Status • The physics case • Computing Requirements • Data Acquisition • Data analysis • MC production • First steps to the GRID • Conclusions F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

  3. Barcelona IFAE, Barcelona UAB, Crimean Observatory, U.C. Davis, U. Lodz, UCM Madrid, INR Moscow, MPI München, INFN/ U. Padua, INFN/ U. Siena, U. Siegen / U. Berlin, Tuorla Observatory, Yerevan Phys. Institute, INFN/ U. Udine, U. Würzburg, ETH Zürich The MAGIC Collaboration Major Atmospheric Gamma-Ray Imaging Cherenkov Telescope • International collaboration of • > 100 physicists • 16 institutes • 11 countries F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

  4. The MAGIC telescope • Largest Imaging Air Cherenkov Telescope(17 m mirror dish) • Located on Canary Island La Palma (@ 2200 m asl) • Lowest energy threshold ever obtained with a Cherenkov telescope • Aim: detect –ray sources in the unexplored energy range: 30 (10)-> 300 GeV F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

  5. Gamma ray Particle shower ~ 10 km ~ 1o Cherenkov light ~ 120 m Imaging Air Cherenkov Telescopes Cherenkov light Image of particle shower in telescope camera F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

  6. gamma shower hadron shower (background) Standard Analysis Shower reconstruction and background rejection based on image shape analysis Hillas parameters: Length, width, distance, alpha raw image cleaned image F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

  7. Source position Alpha distribution 1200 excess events 800 background events First source observations Mkn 421 (AGN) February 2004 (in flaring state) preliminary 100 minutes observation => Significance: 23 sigma F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

  8. MAGIC I Future of MAGIC observatory • Second telescope MAGIC type telescope under construction(more observation time, background rejection & better event reconstruction in coincidence mode) • Plans for 30 m telescope for gamma astronomy down to E = 5 GeV F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

  9. The MAGIC Physics Program • Cosmological g-Ray Horizon • AGNs • Pulsars • Origin of Cosmic Rays • Tests of Quantum Gravity effects • SNRs • Cold Dark Matter • GRBs F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

  10. 17 m diameter reflecting surface (240 m2 ) • Diamond milled aluminum mirrors • Active mirror control IPE Light weight Carbon fiber Structure for fast repositioning IPE IPE • 4o FOV camera 577 high QE PMTs NET CE • Analog signal transport via optical fibers • 2-level trigger system& 300 MHz FADC system Key Elements of the MAGIC Telescope F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

  11. Camera: 577 PMTs (up to 30% QE) ~ 2 nsec short pulses • in Counting House: • Stretch pulse to 6 nsec • Split to high & low gain • Digitize with 300 MSamples/s8 bit FlashADCs(in future 2GS/s) The Signal Processing • DAQ: • Linux PC with multithreaded C++ DAQ program • FPGA based PCI readout card • 15 high + 15 low gain slices/channel • Typical dead time < 1 % F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

  12. Discriminators L0 Software adjustable threshold for minimum number of photoelectrons per pixel Fast (2-5 nsec)coincidence device performing simple n-next-neighbor logic Level 1 L1 Slower (50-150 nsec) but advanced topological pattern recognition Level 2 L2 • Total trigger rate: • so far ~ 200 Hz (@ 60 - 80 GeV threshold) • reduce threshold to 30 GeV => 500 Hz expected rate • rate dominated by hadronic background To FADC Two Level Trigger F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

  13. IPE IPE IPE IPE IPE IPE NET NET CE CE Data Acquisition Rate & Storage • Event Size: • 577 PM x 1 Byte x 30 samples  ~ 20 kByte/event • Data Acquisition Rate: • 500 Hz typical trigger rate  ~ 10 MByte/sec • Data Storage Requirements: • ~ 1000 h / year useful moonless observation time  ~ 36 TByte/year F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

  14. Fileserver LTO2 Tapes (x 2) DAQ La Palma: Tape transfer Fileserver Data Center: Wuerzburg (+ Barcelona) raw data Tape archive Preprocessing & Data reduction (c++, root) MERPP RegionalData Centers preprocessed data Physics analysis Data Flux Scheme F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

  15. Standard Data Processing On 3 GHz Xeon Processor data processing rate data size (events/sec) (% of raw data) • Rootification 400 ~ 53 %(event building & compression) • Pedestal subtraction,signal extraction, 200 ~ 32 % calibration • Image cleaning, 400 ~ 0.5 %Hillas parameter calculation • Total: 100 • @ 500 Hz data acquisition rate => need ~ 5 Xeon 3GHz type processors F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

  16. Standard Physics Analysis Methods • Main challenge: Reject background from cosmic ray hadrons • Background rate: ~ 500 Hz compared to ≤< 1 Hz signal rate • dynamical cut methods • Neural network, random forest => Significant additional computing needed F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

  17. Low energy analysis methods • Hillas analysis fails since • shower shape not well reconstructed • Strong dependence on suppression of night sky background (“image cleaning”) • Model analysis • fit mean shower shape to complete camera data • precise statistical tests • better shower reconstruction using shower tail information • very promising results obtained from CAT & HESS telescopes F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

  18. Model Analysis computing requirements • CPU requirements • Fit very CPU intensiveEvent reconstruction rate only several 10’s of Hz • Computation of mean shower shape • Use MC or semi-analytical approach • Shape depends on: energy, impact parameter, zenith angle • Integrate over: shower depth, energy, angular, lateral distribution • 4 x 1011 steps ≈ 500 days x CPUs • Data storage requirements • Need to keep calibrated data • no zero suppression (image cleaning) possible F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

  19. MC generation Shower development in atmosphere CORSIKA (f77) • Events needed: • Signal (gamma) events: > 1 x data => ~ 3 M events • Background events: > 1/100 x data => ~ 16 M events Atmospheric absorption & Reflection on mirror Reflector (c) Camera (c++) Detector response F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

  20. MC CPU requirements • Gammas (Signal) • Trigger efficiency: 7% • 3 M events => generate: 43 M events • Hadrons (background): • Trigger efficiency: 0.15 % • 16 M events => generate: 10 G events • Production rate (Xeon 3GHz): • Shower simulation: 900 events/h/CPU • (x ~100) reuse event for various impact parameters • Mirror & detector simulation: 60 kevents/h/CPU • CPU power needed: • 10 Gevents/year / 60 kevents/h/CPU => need 50 CPU F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

  21. MC storage requirements Gammas Hadrons • Corsika output: 28kB/event 10.8kB/event • Reflector output: 7.6kB/event 1.3kB/event Keep only Reflector output Gammas: 45 M events => 320 GB Hadrons: 11 G events => 13 TB F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

  22. MAGIC: steps towards the GRID • Start with MC production in Italy (CNAF in Bologna) • 3 years of experience with use of CONDOR(mainly INFN, Italy) • 90 M events produced using up to 100 CPUs • Connect main computing centers inside MAGICfor MC production & data analysis and storage • Wuerzburg, Barcelona, INFN (Padova, Bologna), ETH Zuerich, MPI Munich F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

  23. MAGIC: is a new generation gamma ray Cherenkov telescope has large discovery potential both in astrophysics and fundamental physics just started data taking has large computing requirements > 100 CPU > 50 TB / year is well suited to join and test GRID technology with 16 participating institutions over all Europe (and beyond)some with strong links to mayor GRID sites (Bologna, Barcelona) Conclusions F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

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