The MAGIC Telescope

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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 TelescopeEGEE Generic Applications Advisory PanelCERN, 14. June 2004Florian GoebelMax-Planck-Institut für Physik(Werner-Heisenberg-Institut)Münchenfor the MAGIC collaborationF. Goebel, MPI München, 14. June 2004, EGAAP, CERNOutline
  • 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, CERNBarcelona 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 ZürichThe MAGIC CollaborationMajor Atmospheric Gamma-Ray Imaging Cherenkov Telescope
  • International collaboration of
  • > 100 physicists
  • 16 institutes
  • 11 countries
  • F. Goebel, MPI München, 14. June 2004, EGAAP, CERNThe 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, CERNGammarayParticleshower~ 10 km~ 1oCherenkov light~ 120 mImaging Air Cherenkov TelescopesCherenkov light Image of particle shower in telescope cameraF. Goebel, MPI München, 14. June 2004, EGAAP, CERNgamma showerhadron shower (background)Standard Analysis Shower reconstructionand background rejectionbased on image shapeanalysisHillas parameters:Length, width, distance,alpharaw imagecleaned imageF. Goebel, MPI München, 14. June 2004, EGAAP, CERNSource positionAlpha distribution1200 excess events800 background eventsFirst source observationsMkn 421 (AGN)February 2004(in flaring state)preliminary100 minutes observation=> Significance: 23 sigmaF. Goebel, MPI München, 14. June 2004, EGAAP, CERNMAGIC IFuture 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 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, CERN17 m diameter reflecting surface (240 m2 )
  • Diamond milled aluminum mirrors
  • Active mirror control
  • IPELight weightCarbon fiberStructurefor fast repositioningIPEIPE
  • 4o FOV camera 577 high QE PMTs
  • NETCE
  • Analog signal transport via optical fibers
  • 2-level trigger system& 300 MHz FADC system
  • Key Elements of the MAGIC TelescopeF. Goebel, MPI München, 14. June 2004, EGAAP, CERN 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, CERNDiscriminatorsL0Software adjustable threshold for minimum number of photoelectrons per pixelFast (2-5 nsec)coincidence deviceperforming simple n-next-neighbor logicLevel 1L1Slower (50-150 nsec) butadvanced topological pattern recognitionLevel 2L2
  • 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 FADCTwo Level TriggerF. Goebel, MPI München, 14. June 2004, EGAAP, CERNIPEIPEIPEIPEIPEIPENETNETCECEData 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/yearF. Goebel, MPI München, 14. June 2004, EGAAP, CERNFileserverLTO2 Tapes (x 2)DAQLa Palma:Tape transferFileserverData Center:Wuerzburg(+ Barcelona)raw dataTape archivePreprocessing &Data reduction(c++, root)MERPPRegionalData CenterspreprocesseddataPhysics analysisData Flux SchemeF. Goebel, MPI München, 14. June 2004, EGAAP, CERNStandard Data ProcessingOn 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, CERNStandard 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 neededF. Goebel, MPI München, 14. June 2004, EGAAP, CERNLow 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, CERNModel 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, CERNMC generationShower 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, CERNMC 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, CERNMC storage requirementsGammas Hadrons
  • Corsika output: 28kB/event 10.8kB/event
  • Reflector output: 7.6kB/event 1.3kB/event
  • Keep only Reflector outputGammas: 45 M events => 320 GBHadrons: 11 G events => 13 TBF. Goebel, MPI München, 14. June 2004, EGAAP, CERNMAGIC: 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, CERNMAGIC:is a new generation gamma ray Cherenkov telescope has large discovery potential both in astrophysics and fundamental physicsjust started data takinghas large computing requirements > 100 CPU> 50 TB / yearis 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)ConclusionsF. Goebel, MPI München, 14. June 2004, EGAAP, CERN
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