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

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

F. Goebel, MPI München, 4 May 2006, Berlin Light Sensors: QE extended PMTs 6 stage PMTs ( ET 9116A (1”), ET 9117A (1,5”)) characteristics: - low gain - low gain => operation under partial moon - rise time: 0.6 nsec - FWHM: nsec QE increased up to 30 % with diffuse scattering coating extended UV sensitivity using wavelength shifter coating stabilize: HV PhK-D1 => stable Single PhE response stabilize: HV D5-D6 & HV D6-A => dynamic range: 5000

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

F. Goebel, MPI München, 4 May 2006, Berlin Camera Characteristics 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:  3 o total weight: 600 kg special features: movable in z to adjust focal distance (1km - ∞) Spectralon plate integrated in camera lids for focusing & reflectivity measurements

F. Goebel, MPI München, 4 May 2006, Berlin Optical Transmission Analog signals transmitted over 162 m long optical fiber Analog signals transmitted over 162 m long optical fiber - noise immune - noise immune - no signal dispersion - no signal dispersion - light weight - light weight 160 m optical fiber FWHM = 3.1 ns 156 m RG58G coax cable FWHM = 15.4 ns Vertical Cavity Surface Emitting Laser (VCSEL) 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 Signal Processing Stretch pulse to 6 nsec Stretch pulse to 6 nsec Split to high (*10) & low gain (dynamic range > 1000) Split to high (*10) & low gain (dynamic range > 1000) 300 MSamples/s 8 bit FADCs commercial FADC chips 1 FADC per readout channel (expensive, power & space consuming) Ring Buffer -> FIFO-> single linux PC-> RAID system (~100GB/night) LTO tapes Internet transfer dead time < 300 Hz trigger rate

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

F. Goebel, MPI München, 4 May 2006, Berlin Calibration System LED light pulses - - uniform illumination of camera colors - - pulse shape like cosmics - - different intensities dynamic 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 Upgrades for MAGIC-II: for MAGIC-II: same concept (e.g. optical transmission) same concept (e.g. optical transmission) improvement for physics: improvement for physics: higher QE (PMTs, HPDs, SiPMs, see J. Ninkovic) higher QE (PMTs, HPDs, SiPMs, see J. Ninkovic) faster sampling higher granularity (not for MAGIC-II) higher granularity (not for MAGIC-II)

F. Goebel, MPI München, 4 May 2006, Berlin High resolution timing measurement Cherenkov pulses are 1-2 nsec wide Cherenkov pulses are 1-2 nsec wide Photosensors are fast enough Photosensors are fast enough => digitize with  2 GSamples/s better background suppression reduce integration time 16 nsec => nsec (MAGIC: pe/nsec) reduce integration time 16 nsec => nsec (MAGIC: pe/nsec) use time profile for muon rejection (under investigation) use time profile for muon rejection (under investigation)

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

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

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

F. Goebel, MPI München, 4 May 2006, Berlin 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 -increase area with small pixels (add signal in outer pixels to save readout channels?) FOV like MAGIC-I… but: -increase trigger area

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

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