F. Goebel, MPI München, 4 May 2006, Berlin

Florian GoebelFlorian GoebelMax-Planck-Institut für Max-Planck-Institut für

PhysikPhysik(Werner-Heisenberg-Institut)(Werner-Heisenberg-Institut)

MünchenMünchenfor the for the

MAGICMAGIC collaboration collaboration

MAGIC-I current designMAGIC-I current design CameraCamera ReadoutReadout TriggerTrigger

Upgrades: (MAGIC I&II)Upgrades: (MAGIC I&II) Gsample/s FADC readoutGsample/s FADC readout MAGIC-II camera designMAGIC-II camera design

MAGIC - Camera and MAGIC - Camera and ReadoutReadout

present & futurepresent & future

F. Goebel, MPI München, 4 May 2006, Berlin

Key technological elements for Key technological elements for MAGICMAGIC

17 m diameter parabolic reflecting surface (240 m17 m diameter parabolic reflecting surface (240 m2 2 ))

Analog signal transport Analog signal transport via optical fibers via optical fibers

IPEIPEIPECENET

2-level trigger system2-level trigger system& 300 MHz FADC system& 300 MHz FADC system being upgraded to 2GS/sbeing upgraded to 2GS/s

Active mirror controlActive mirror control

(PSF: 90% of light in (PSF: 90% of light in 0.1 0.1oo inner pixel) inner pixel)

high reflective diamond milled high reflective diamond milled aluminum mirrorsaluminum mirrorsLight weight

Carbon fiber structure for

fast repositioning

- 3.5- 3.5oo FOV camera FOV camera - 576 - 576 high QE PMTshigh QE PMTs (QE (QEmaxmax= 30%)= 30%)

F. Goebel, MPI München, 4 May 2006, Berlin

Light Sensors: QE extended PMTs Light Sensors: QE extended PMTs

6 stage PMTs (6 stage PMTs (ET 9116A (1”) , ET 9117A ET 9116A (1”) , ET 9117A (1,5”))(1,5”))

characteristics:

- low gain - low gain => operation under partial moon

- rise time: 0.6 nsec- FWHM: 1.0- 1.2 nsec

QE increased up to 30 % with diffuse scattering coating

extended UV sensitivity using wavelength shifter coating

stabilize: HVPhK-D1

=> stable Single PhE response

stabilize: HVD5-D6 & HVD6-A

=> dynamic range: 5000

F. Goebel, MPI München, 4 May 2006, Berlin

Winston ConesWinston 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

CameraCamera

• Matrix of 577 PMTs• Field of View: 3.5o

optimized for sources in center of camera

Inner camera• 397 pixels: 0.1o

Outer Camera

• 180 pixels: 0.2o

F. Goebel, MPI München, 4 May 2006, Berlin

Camera CharacteristicsCamera 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: 3o

• 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 TransmissionOptical Transmission Analog signalsAnalog signals transmitted over transmitted over

162 m162 m long long optical fiberoptical fiber

- noise immune - noise immune - no signal dispersion- no signal dispersion - light weight- light weight

160 m optical fiberFWHM = 3.1 ns

156 m RG58G coax cableFWHM = 15.4 ns

Vertical Cavity Surface Emitting Vertical Cavity Surface Emitting Laser (VCSEL)Laser (VCSEL)

= 850 nm= 850 nm– multimode fibermultimode fiber– E2000 connectors E2000 connectors

(eye safe, allows many (eye safe, allows many connections)connections)

F. Goebel, MPI München, 4 May 2006, Berlin

Signal ProcessingSignal Processing

• Stretch pulse to 6 nsecStretch pulse to 6 nsec

• Split to high (*10) & low gainSplit to high (*10) & low gain((dynamic range > 1000dynamic range > 1000) )

300 MSamples/s300 MSamples/s 8 bit FADCs8 bit FADCs • commercial FADC chips• 1 FADC per readout channel

(expensive, power & space consuming)

Ring Buffer Ring Buffer -> FIFO-> single linux PC-> RAID system (~100GB/night)

LTO tapes

Internet transferdead time < 1% @ 300 Hz trigger rate

F. Goebel, MPI München, 4 May 2006, Berlin

Two Level TriggerTwo Level Trigger

To FADC

Level 1L1

Level 1L1

- Fast (2-5 nsec) coincidence- simple n-next-neighbor logic - decision time: 50 nsec

TWO FOLD KINDS (86) THREE FOLD KINDS (51)

FOUR FOLD KINDS (67) FIVE FOLD KINDS (106)

DiscriminatorsL0

DiscriminatorsL0

Software adjustable thresholds

Level 2L2

Level 2L2

Topological pattern recognition- rough image reconstruction (e.g. “pseudosize”) - decision time: 500 nsec

PsSize= 8PsSize=11

F. Goebel, MPI München, 4 May 2006, Berlin

Calibration SystemCalibration System

LED light pulses - uniform illumination of camera- 3 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

UpgradesUpgrades

• 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 High resolution timing measurementmeasurement

Cherenkov pulses are 1-2 nsec wideCherenkov pulses are 1-2 nsec wide Photosensors are fast enoughPhotosensors are fast enough

=> => digitize with digitize with 2 GSamples/s 2 GSamples/s

better background suppressionbetter background suppression reduce integration timereduce integration time

16 nsec => 6 - 8 nsec16 nsec => 6 - 8 nsec(MAGIC: 0.1-0.2 pe/nsec)(MAGIC: 0.1-0.2 pe/nsec)

use use time profiletime profile for muon for muon rejection (under rejection (under investigation)investigation)

F. Goebel, MPI München, 4 May 2006, Berlin

Multiplexing 2 Gsample/s FADCMultiplexing 2 Gsample/s FADC Idea: use commercially available but expensive 2 Gsample/s FADC Idea: use commercially available but expensive 2 Gsample/s FADC

to digitize several channelsto 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 circuitOptical Splitter & Signal Multiplex circuit

use use optical fibersoptical fibers to delay signal to delay signal low attenuation (3 dB/km)low attenuation (3 dB/km) small dispersionsmall dispersion

Split optical signalSplit optical signal into readout into readout and trigger signaland trigger signal

Multiplex electrical signal of 16 Multiplex electrical signal of 16 channelschannels use use fast CMOS switchesfast CMOS switches

use use 2 Gsample/s2 Gsample/s, , 10 bit10 bit FADCs FADCs from Acqiris 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 FADCMAGIC-II: Ring Sampler FADC freely propagating rotating sampling signal freely propagating rotating sampling signal

(( 2 GHz) 2 GHz) analog samplinganalog sampling in a series of 1024 capacitors in a series of 1024 capacitors slow (40 MHz) readoutslow (40 MHz) readout and external digitization and external digitization

Design: Stefan Ritt Paul Scherrer Institute (Villigen,CH)

Advantages:Advantages: low costlow cost low power consumptionlow power consumption very flexiblevery flexible

F. Goebel, MPI München, 4 May 2006, Berlin

MAGIC-II cameraMAGIC-II camera

Cluster designCluster design::

– 7 pixel cluster contains:7 pixel cluster contains:– HV generator (DC-DC HV generator (DC-DC

converter) converter) – slow control & monitoring slow control & monitoring – signal chain up to optical signal chain up to optical

transmittertransmitter– easier maintenanceeasier maintenance– flexibility to exchange PMT with flexibility to exchange PMT with

HPDsHPDs

- 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)

ProgrammableDelays Delay

Register

CoincidenceUnit

Trigger FlagL3 Pattern VME

L3 trigger

T

new in MAGIC-II:new in MAGIC-II:Level 3 (Two Telescope Level 3 (Two Telescope

coincidence)coincidence)

F. Goebel, MPI München, 4 May 2006, Berlin

ConclusionsConclusions

• MAGIC successfully employed several MAGIC successfully employed several new technologiesnew technologies

• Upgrades MAGIC-I&II are under wayUpgrades MAGIC-I&II are under way• Promising for future Cherenkov Promising for future Cherenkov

TelescopesTelescopes