F. Goebel, MPI München, 14. June 2004, EGAAP, CERN Florian Goebel Max-Planck-Institut für Physik...

F. Goebel, MPI München, 14. June 2004, EGAAP, CERN

Florian GoebelFlorian GoebelMax-Planck-Institut für PhysikMax-Planck-Institut für Physik(Werner-Heisenberg-Institut)(Werner-Heisenberg-Institut)

MünchenMünchen

for the for the

MAGIC collaborationMAGIC collaboration

EGEE Generic Applications Advisory Panel

CERN, 14. June 2004

The The MAGICMAGIC Telescope Telescope


OutlineOutline

What is MAGIC?What is MAGIC?

The collaborationThe collaboration The TelescopeThe Telescope

Commissioning StatusCommissioning Status

The physics caseThe physics case

Computing RequirementsComputing Requirements

Data AcquisitionData Acquisition

Data analysisData analysis

MC productionMC production

First steps to the GRIDFirst steps to the GRID ConclusionsConclusions


The The MAGICMAGIC Collaboration Collaboration

Barcelona IFAE, Barcelona UAB, Crimean Observatory, U.C. Davis, U. Lodz, Barcelona IFAE, Barcelona UAB, Crimean Observatory, U.C. Davis, U. Lodz, UCM Madrid, INR Moscow, MPI München, INFN/ U. Padua, INFN/ U. Siena, UCM Madrid, INR Moscow, MPI München, INFN/ U. Padua, INFN/ U. Siena, U. Siegen / U. Berlin, Tuorla Observatory, Yerevan Phys. Institute, INFN/ U. U. Siegen / U. Berlin, Tuorla Observatory, Yerevan Phys. Institute, INFN/ U. Udine, U. Würzburg, ETH ZürichUdine, U. Würzburg, ETH Zürich

MMajor ajor AAtmospheric tmospheric GGamma-Ray amma-Ray IImaging maging CCherenkov herenkov TelescopeTelescope

International collaborationInternational collaboration ofof

> 100 physicists > 100 physicists

16 institutes 16 institutes

11 countries11 countries


The The MAGICMAGIC telescope telescope

Largest Imaging Air Largest Imaging Air Cherenkov TelescopeCherenkov Telescope (17 m mirror dish)(17 m mirror dish)

Located on Canary Island Located on Canary Island La PalmaLa Palma (@ 2200 m asl) (@ 2200 m asl)

LowestLowest energy threshold energy threshold ever obtained with a ever obtained with a Cherenkov telescopeCherenkov telescope

Aim: detect Aim: detect –ray sources–ray sources in the unexplored energy in the unexplored energy range: range: 30 30 (10)-> (10)-> 300 GeV300 GeV


IImaging maging AAir ir CCherenkov herenkov TTelescopeselescopes

~ 10 kmParticleshower

~ 1o

Ch

eren

kov

ligh

t

~ 120 m

Gammaray Cherenkov light Image

of particle shower in telescope camera


Standard Analysis Standard Analysis

hadron shower (background)

gamma shower

raw image cleaned image

Shower reconstructionand background rejectionbased on image shapeanalysis

Hillas parameters:Length, width, distance,alpha


First source observationsFirst source observations

Mkn 421 (AGN)February 2004(in flaring state)

Alpha distribution

1200 excess events

800 background events

Source position

100 minutes observation=> Significance: 23 sigma


Future of MAGIC observatoryFuture of MAGIC observatory

Second telescope MAGIC Second telescope MAGIC type telescope under type telescope under constructionconstruction(more observation time, (more observation time, background rejection & background rejection & better event reconstruction better event reconstruction in coincidence mode)in coincidence mode)

Plans for 30 m telescope Plans for 30 m telescope for gamma astronomy for gamma astronomy down to down to E = 5 GeVE = 5 GeV

MAGIC I


AGNsAGNs

SNRsSNRs Cold Dark MatterCold Dark Matter

PulsarsPulsars

GRBsGRBs

Tests of Tests of Quantum Quantum Gravity effectsGravity effects

Cosmological Cosmological

-Ray -Ray HorizonHorizon

The The MAGICMAGIC Physics Program Physics Program

Origin of Origin of Cosmic Cosmic RaysRays


Key Elements of the Key Elements of the MAGICMAGIC TelescopeTelescope

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

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

2-level trigger system2-level trigger system& 300 MHz FADC system& 300 MHz FADC system IPE

IPEIPE

CENET

Active mirror controlActive mirror control

Diamond milled aluminum mirrorsDiamond milled aluminum mirrors

Light weightCarbon fiberStructurefor fast repositioning 44oo FOV camera FOV camera

577 high QE PMTs577 high QE PMTs


The Signal ProcessingThe Signal Processing Camera:

577 PMTs (up to 30% QE) ~ 2 nsec short pulses

in Counting House:in Counting House: Stretch pulse to 6 nsecStretch pulse to 6 nsec Split to high & low gain Split to high & low gain Digitize with Digitize with 300 MSamples/s300 MSamples/s

8 bit FlashADCs8 bit FlashADCs (in future 2GS/s)

DAQDAQ:: Linux PC with multithreaded C+Linux PC with multithreaded C+

+ DAQ program+ DAQ program FPGA based PCI readout cardFPGA based PCI readout card 15 high + 15 low gain 15 high + 15 low gain

slices/channelslices/channel Typical dead time < 1 %Typical dead time < 1 %


Two Level TriggerTwo Level Trigger

DiscriminatorsL0

DiscriminatorsL0

Software adjustable threshold for minimum number of photoelectrons per pixel

Level 2L2

Level 2L2

Slower (50-150 nsec) butadvanced topological pattern recognition

Level 1L1

Level 1L1

Fast (2-5 nsec) coincidence deviceperforming simple n-next-neighbor logic

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

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

To FADC

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


Data Acquisition Rate & Data Acquisition Rate & Storage Storage

Event Size:Event Size: 577 PM x 1 Byte x 30 samples 577 PM x 1 Byte x 30 samples

~ 20 kByte/event~ 20 kByte/event

IPEIPEIPE

CENET

IPEIPEIPE

CENET

Data Acquisition Rate:Data Acquisition Rate: 500 Hz typical trigger rate500 Hz typical trigger rate

~ 10 MByte/sec~ 10 MByte/sec

Data Storage Requirements:Data Storage Requirements: ~ 1000 h / year ~ 1000 h / year

useful moonless observation time useful moonless observation time

~ ~ 36 TByte/year36 TByte/year


Data Flux SchemeData Flux Scheme

La Palma:

Fileserver LTO2 Tapes (x 2)

DAQ

MERPP

Data Center:Wuerzburg(+ Barcelona)

Fileserver

Tape archive

Tape transfer

Preprocessing &Data reduction(c++, root)

raw data

RegionalData Centers

Physics analysis

preprocesseddata


Standard Data ProcessingStandard Data Processing

data processing rate data processing rate data size data size (events/sec)(events/sec) (% of raw (% of raw

data)data) RootificationRootification 400 400 ~ 53 %~ 53 %

(event building & compression)(event building & compression) Pedestal subtraction,Pedestal subtraction,

signal extraction,signal extraction, 200200 ~ 32 % ~ 32 % calibrationcalibration

Image cleaning,Image cleaning, 400 400 ~ 0.5 %~ 0.5 %Hillas parameter calculationHillas parameter calculation

Total:Total: 100100

@ 500 Hz data acquisition rate @ 500 Hz data acquisition rate => need ~ 5 Xeon 3GHz type processors=> need ~ 5 Xeon 3GHz type processors

On 3 GHz Xeon Processor


Standard Physics Analysis Standard Physics Analysis MethodsMethods

Main challenge: Main challenge: Reject Reject backgroundbackground from from cosmic ray cosmic ray hadronshadrons Background rate: ~ 500 Hz Background rate: ~ 500 Hz

compared to ≤< 1 Hz signal ratecompared to ≤< 1 Hz signal rate dynamical cutdynamical cut methods methods Neural network, random forestNeural network, random forest

=> Significant additional computing => Significant additional computing neededneeded


Low energy analysis methodsLow energy analysis methods Hillas analysis fails sinceHillas analysis fails since

shower shape not well reconstructedshower shape not well reconstructed Strong dependence on suppression of night sky background Strong dependence on suppression of night sky background

(“image cleaning”)(“image cleaning”) Model analysisModel analysis

fit mean shower shape to complete camera datafit mean shower shape to complete camera data precise statistical testsprecise statistical tests better shower reconstruction using shower tail informationbetter shower reconstruction using shower tail information very promising results obtained from CAT & HESS telescopesvery promising results obtained from CAT & HESS telescopes


Model AnalysisModel Analysis computing computing requirementsrequirements

CPU requirementsCPU requirements Fit very CPU intensiveFit very CPU intensive

Event reconstruction rate only several 10’s of HzEvent reconstruction rate only several 10’s of Hz Computation of mean shower shapeComputation of mean shower shape

Use MC or semi-analytical approachUse MC or semi-analytical approach Shape depends on: energy, impact parameter, zenith angleShape depends on: energy, impact parameter, zenith angle Integrate over: shower depth, energy, angular, lateral Integrate over: shower depth, energy, angular, lateral

distributiondistribution 4 x 104 x 101111 steps ≈ steps ≈ 500 days x CPUs500 days x CPUs

Data storage requirementsData storage requirements Need to keep calibrated data Need to keep calibrated data no zero suppression (image cleaning) possibleno zero suppression (image cleaning) possible


MC generationMC generation

Events needed:Events needed: Signal (gamma) events: Signal (gamma) events: > 1 x data > 1 x data => ~ 3 M events=> ~ 3 M events Background events:Background events: > 1/100 x data > 1/100 x data => ~ 16 M => ~ 16 M

eventsevents

Shower development in atmosphere CORSIKA (f77)

Atmospheric absorption &Reflection on mirror Reflector (c)

Detector response Camera (c++)


MC CPU requirementsMC CPU requirements Gammas (Signal)Gammas (Signal)

Trigger efficiency:Trigger efficiency: 7%7% 3 M events 3 M events => generate: => generate: 43 M events43 M events

Hadrons (background):Hadrons (background): Trigger efficiency:Trigger efficiency: 0.15 %0.15 % 16 M events16 M events => generate: => generate: 10 G 10 G

eventsevents Production rate (Xeon 3GHz):Production rate (Xeon 3GHz):

Shower simulation:Shower simulation: 900 900 events/h/CPUevents/h/CPU

(x ~100) reuse event (x ~100) reuse event for various impact parametersfor various impact parameters

Mirror & detector simulation:Mirror & detector simulation: 60 kevents/h/CPU60 kevents/h/CPU CPU power neededCPU power needed::

10 Gevents/year / 60 kevents/h/CPU => 10 Gevents/year / 60 kevents/h/CPU => need 50 need 50 CPUCPU


MC storage requirementsMC storage requirements

Corsika output: Corsika output: 28kB/event28kB/event10.8kB/event10.8kB/event

Reflector output: Reflector output: 7.6kB/event 7.6kB/event 1.3kB/event1.3kB/event

Keep only Reflector output

Gammas Hadrons

Gammas: 45 M events => 320 GBHadrons: 11 G events => 13 TB


MAGIC: steps towards the MAGIC: steps towards the GRIDGRID

Start with MC production in Italy Start with MC production in Italy (CNAF in Bologna)(CNAF in Bologna)

3 years of experience with use of CONDOR3 years of experience with use of CONDOR(mainly INFN, Italy)(mainly INFN, Italy) 90 M events produced using up to 100 CPUs90 M events produced using up to 100 CPUs

Connect main computing centers inside MAGICConnect main computing centers inside MAGICfor MC production & data analysis and storagefor MC production & data analysis and storage Wuerzburg, Barcelona, INFN (Padova, Bologna), Wuerzburg, Barcelona, INFN (Padova, Bologna),

ETH Zuerich, MPI MunichETH Zuerich, MPI Munich


ConclusionsConclusions

MAGIC:MAGIC: is a new generation gamma ray Cherenkov telescope is a new generation gamma ray Cherenkov telescope has has large discoverylarge discovery potential both in potential both in

astrophysicsastrophysics and and fundamental physicsfundamental physics just started data takingjust started data taking has large computing requirements has large computing requirements

> 100 CPU> 100 CPU > 50 TB / year> 50 TB / year

is is well suited to join and test GRIDwell suited to join and test GRID technology with technology with 16 participating institutions over all Europe (and 16 participating institutions over all Europe (and beyond)beyond)some with strong links to mayor GRID sites (Bologna, some with strong links to mayor GRID sites (Bologna, Barcelona)Barcelona)

F. Goebel, MPI München, 14. June 2004, EGAAP, CERN Florian Goebel Max-Planck-Institut für Physik...

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