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Florian Goebel Max-Planck-Institut für Physik (Werner-Heisenberg-Institut) München for the

MAGIC-I current design Camera Readout Trigger Upgrades: (MAGIC I&II) Gsample/s FADC readout MAGIC-II camera design. MAGIC - Camera and Readout present & future. Florian Goebel Max-Planck-Institut für Physik (Werner-Heisenberg-Institut) München for the MAGIC collaboration.

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Florian Goebel Max-Planck-Institut für Physik (Werner-Heisenberg-Institut) München for the

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  1. MAGIC-I current design • Camera • Readout • Trigger Upgrades: (MAGIC I&II) • Gsample/s FADC readout • MAGIC-II camera design MAGIC - Camera and Readoutpresent & future Florian Goebel Max-Planck-Institut für Physik(Werner-Heisenberg-Institut) München for the MAGIC collaboration F. Goebel, MPI München, 4 May 2006, Berlin

  2. 17 m diameter parabolic reflecting surface (240 m2 ) Light weight Carbon fiber structure for fast repositioning high reflective diamond milled aluminum mirrors IPE - 3.5o FOV camera - 576 high QE PMTs (QEmax= 30%) IPE IPE NET CE Analog signal transport via optical fibers 2-level trigger system& 300 MHz FADC system being upgraded to 2GS/s Key technological elements for MAGIC Active mirror control(PSF: 90% of light in 0.1o inner pixel) F. Goebel, MPI München, 4 May 2006, Berlin

  3. QE increased up to 30 % with diffuse scattering coating extended UV sensitivity usingwavelength shiftercoating Light Sensors: QE extended PMTs 6 stage PMTs (ET 9116A (1”) , ET 9117A (1,5”)) characteristics: - low gain => operation under partial moon - rise time: 0.6 nsec - FWHM: 1.0- 1.2 nsec stabilize: HVPhK-D1=> stable Single PhE response stabilize: HVD5-D6 & HVD6-A => dynamic range: 5000 F. Goebel, MPI München, 4 May 2006, Berlin

  4. Winston Cones • avoid dead areas • limit angular acceptance to light coming from reflector surface • aluminized Mylar foil (92% reflectivity) • increase double crossing probability => increase effective QE F. Goebel, MPI München, 4 May 2006, Berlin

  5. Matrix of 577 PMTs Field of View: 3.5o Camera Inner camera • 397 pixels: 0.1o Outer Camera • 180 pixels: 0.2o optimized for sources in center of camera F. Goebel, MPI München, 4 May 2006, Berlin

  6. Camera Characteristics • special features: • movable in z to adjust focal distance (1km - ∞) • Spectralon plate integrated in camera lids for focusing & reflectivity measurements • external HV power supply • individual, remote adjustable HV regulators • HV & anode current monitoring (3 Hz) • total power consumption: ~600 W (~ 1 W / channel) • water cooling • => temperature stabilization:  3o • total weight: 600 kg F. Goebel, MPI München, 4 May 2006, Berlin

  7. 156 m RG58G coax cable FWHM = 15.4 ns 160 m optical fiber FWHM = 3.1 ns Optical Transmission • Analog signals transmitted over 162 m long optical fiber - noise immune - no signal dispersion - light weight • Vertical Cavity Surface Emitting Laser (VCSEL) •  = 850 nm • multimode fiber • E2000 connectors (eye safe, allows many connections) F. Goebel, MPI München, 4 May 2006, Berlin

  8. 300 MSamples/s8 bit FADCs • commercial FADC chips • 1 FADC per readout channel (expensive, power & space consuming) LTO tapes Internet transfer Signal Processing • Split to high (*10) & low gain(dynamic range > 1000) • Stretch pulse to 6 nsec -> FIFO -> single linux PC -> RAID system (~100GB/night) Ring Buffer dead time < 1% @ 300 Hz trigger rate F. Goebel, MPI München, 4 May 2006, Berlin

  9. Discriminators L0 Software adjustable thresholds • - Fast (2-5 nsec)coincidence • simple n-next-neighbor logic • decision time: 50 nsec Level 1 L1 • Topological pattern recognition • rough image reconstruction (e.g. “pseudosize”) • decision time: 500 nsec Level 2 L2 PsSize=11 PsSize= 8 To FADC Two Level Trigger F. Goebel, MPI München, 4 May 2006, Berlin

  10. Calibration System LED light pulses • uniform illumination of camera • 3 colors • pulse shape like cosmics • different intensitiesdynamic range: 200 Absolute calibration • determine light intensity based on photon statistics (“F-factor method”) • crosscheck with • PIN diode • blinded pixel (single PhE peak) F. Goebel, MPI München, 4 May 2006, Berlin

  11. Upgrades • for MAGIC-II: • same concept (e.g. optical transmission) • improvement for physics: • higher QE (PMTs, HPDs, SiPMs, see J. Ninkovic) • faster sampling • higher granularity (not for MAGIC-II) F. Goebel, MPI München, 4 May 2006, Berlin

  12. High resolution timing measurement • Cherenkov pulses are 1-2 nsec wide • Photosensors are fast enough => digitize with  2 GSamples/s better background suppression • reduce integration time16 nsec => 6 - 8 nsec(MAGIC: 0.1-0.2 pe/nsec) • use time profile for muon rejection (under investigation) F. Goebel, MPI München, 4 May 2006, Berlin

  13. Multiplexing 2 Gsample/s FADC • Idea: use commercially available but expensive 2 Gsample/s FADC to digitize several channels • possible due to low duty cycle (trigger: 1kHz, Signal: ~20 nsec) F. Goebel, MPI München, 4 May 2006, Berlin

  14. Multiplex electrical signal of 16 channels • use fast CMOS switches Optical Splitter & Signal Multiplex circuit • use optical fibers to delay signal • low attenuation (3 dB/km) • small dispersion • Split optical signal into readout and trigger signal • use 2 Gsample/s, 10 bit FADCs from Acqiris • upgrade MAGIC I started • currently running in test mode F. Goebel, MPI München, 4 May 2006, Berlin

  15. MAGIC-II: Ring Sampler FADC • freely propagating rotating sampling signal ( 2 GHz) • analog sampling in a series of 1024 capacitors • slow (40 MHz) readout and external digitization Design: Stefan Ritt Paul Scherrer Institute (Villigen,CH) • Advantages: • low cost • low power consumption • very flexible F. Goebel, MPI München, 4 May 2006, Berlin

  16. MAGIC-II camera Cluster design: • 7 pixel cluster contains: • HV generator (DC-DC converter) • slow control & monitoring • signal chain up to optical transmitter • easier maintenance • flexibility to exchange PMT with HPDs FOV like MAGIC-I … but: • increase area with small pixels(add signal in outer pixels to save readout channels?) • increase trigger area F. Goebel, MPI München, 4 May 2006, Berlin

  17. DT new in MAGIC-II:Level 3 (Two Telescope coincidence) Triggers (Level 2) Programmable Delays Delay Register Coincidence Unit L3 trigger Trigger Flag VME L3 Pattern F. Goebel, MPI München, 4 May 2006, Berlin

  18. Conclusions • MAGIC successfully employed several new technologies • Upgrades MAGIC-I&II are under way • Promising for future Cherenkov Telescopes F. Goebel, MPI München, 4 May 2006, Berlin

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