Download PPT-Version - EPS 2003, Aachen

The MAGIC Telescope
EPS (July 17th-23rd 2003)
Aachen, Germany
Razmick Mirzoyan
Max-Planck-Institute for Physics
Munich, Germany
Outline


The MAGIC Collaboration
 Aiming for low threshold
 Physiscs goals
The Telescope


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Design overview
MAGIC Key elements for
low threshold
Status of commissioning of
the telescope elements
Plans & Conclusions
17.7.03, R.Mirzoyan,
MPI Munich
The MAGIC project

First presentation in 95 at the ICRC,
Rome, (Bradbury et al)

Approval of funding only late 2000

Start of construction in 2001

Now commissioning

Innauguration October 10th
17.7.03, R.Mirzoyan,
MPI Munich
The MAGIC Collaboration
Major Atmospheric Gamma-Ray Imaging Cherenkov Telescope
Barcelona IFAE, Barcelona UAB, Crimean Observatory, U.C. Davis, U. Lodz, UCM Madrid, INR
Moscow, MPI Munich, INFN/ U. Padua, INFN/ U. Siena U. Siegen, Tuorla Observatory,
Yerevan Phys. Institute, INFN/U. Udine , U. Wuerzburg, ETH Zurich

MAGIC is an international collaboration building
a 17 m Cherenkov Telescope for the
observation of HE cosmic –rays.

Main aim: to detect –ray sources in the
unexplored energy range: 30 (10)-> 250 GeV

MAGIC was a challenging design to decrease
the energy threshold, by pushing the
technology in terms of mirror size, trigger,
camera sensors and electronics.
�
MAGIC shall provide the lowest threshold
ever obtained with a Cherenkov telescope!!!
17.7.03, R.Mirzoyan,
MPI Munich
The unexplored spectrum gap

Satellites give a nice
crowded picture of
energies up to 10 GeV.
Effective area << 1 m2

Ground-based
experiments show very
few sources with
energies > ~300 GeV.
Effective area > 104 m2
17.7.03, R.Mirzoyan,
MPI Munich
The MAGIC PHYSICS Goals
AGNs
Cosmological
ray horizon

Pulsars
GRBs
Tests
SNRs
17.7.03, R.Mirzoyan,
MPI Munich
Cold
Dark
Matter
on
Quantum
Gravity
effects
Absorption of extragalactic  - rays
Any  that crosses cosmological distances through the universe interacts with the EBL
 HE  EBL  e e


E1 cos    2me c

2 2
Attenuated flux function of -energy and redshift z.
 (10
For the energy range of IACTs
GeV-10 TeV), the interaction takes
place with the infrared (0.01 eV-3
eV, 100 m-0.4 m).
EBL
Star formation, Radiation of stars, Absorption and reemission by ISM
By measuring the cutoffs in the
spectra of AGNs, MAGIC can help in
determining the IR background
17.7.03, R.Mirzoyan,
MPI Munich
MAGIC
Optical Depth & GRH
Optical Depth
The probability of being absorbed for HE gamma crossing the
universe is the integration of the cross-section over the incident angle
and along the path from its origin to the observation.
z
 E,z 
0
dt 2
x
dzc
dx

dz 0
2


d  n, z 2xE1 z
2m 2 c 4
Ex1 z 
Gamma Ray Horizon (GRH)


2

2
This produces a reduction factor e- in the  ray
flux. The GRH is defined as the “z” for the
observed energy “E” that fulfils:
  E , z  1
i.e. a reduction 1/e of the flux of the
extragalactic source.
MAGIC phase I
MAGIC phase II
EBL absorption
The absorption effect seen at TeV energies on a nearby blazars
H1426+428 (z=0.129)
Mkn 501 (z=0.034)
MAGIC Expected sources
MAGIC is not operating yet, so it is still a mystery how many extragalactic
sources is going to detect but one can use the EGRET catalogue to find
some very provable candidates.
Assuming the foreseen MAGIC
characteristics and 50 hours of
observation time for each of
these candidates, we expect to
be able to measure the GRH at
different redshifts.
Measurements from 20 expected sources
From the extrapolation of the EGRET
catalogue data we expect to be able to
measure the GRH for 20 extragalactic
sources using 50 hours for each.
H 0  66.5  1.5  10.1 km s -1 Mpc -1
 M  0.32  0.08  00..39
16
   0.65  0.07  00..37
18
We can use half of the sample to
improve EBL knowledge; i.e. to
reduce systematics
H 0  65.9  1.3  10.3 km s -1 Mpc -1
 M  0.38  0.04  00..42
19
   0.67  0.05  00..38
17
The Energy cut-off could be due to the
source itself. It could be unfolded if one
gets several sources at the same redshift.
So we selected among these 20 sources
the ones that have several at the same
redshift and we kept 7.
H 0  66.9  1.8km s -1 Mpc -1
M  0.38  0.11
  0.61 0.12
Pulsars
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7 -ray pulsars seen by
EGRET. Only upper
limits from present
IACTs (spectral cut-off)
4-fold nn-logic
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Where do -rays come from?
Outer gap or polar cap?

Many of the ~170 EGRET
unidentified sources may be
pulsars.
Gamma Ray Bursts
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Mechanism not yet fully
resolved.
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MAGIC take advantage:
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Huge collection area
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Fast repositioning.
Low energy threshold
Under the assumption that it is
possible to extrapolate the GRB
energy spectrum in the GeV region,
MAGIC can observe 2-3 GRB/year
MAGIC is designed to
observe the prompt emission
of a GRB!
17.7.03, R.Mirzoyan,
MPI Munich
Other Physics targets for MAGIC

Search for neutralino annihilation gamma-ray line
(galactic center, neighboring galaxies, globular clusters)

Tests of possible Lorentz invariance deformation:
search for delay of HE gamma rays in rapidly
varying phenomena at large distances (AGN
flares, GRBs)
17.7.03, R.Mirzoyan,
MPI Munich
Key elements of the MAGIC telescope

17 m diameter reflecting
surface (240 m2 )
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Light weight carbon fiber frame
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Active mirror control
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577 pixels enhanced QE, 3.9 deg FOV
camera + advanced calibration system
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Analog optical signal transport
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2-level advanced trigger system
17.7.03, R.Mirzoyan,
MPI Munich
The frame

The 17m diameter f/1
telescope frame is a
lightweight carbon fiber
structure (tube and knot
system)
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The foundation started in
September 2001 and the
telescope was completed in
Dec. 2001. The assembly of
the frame took only one
month

17.7.03, R.Mirzoyan,
MPI Munich
The reflector
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The overall reflector shape is
parabolic (f/1), isochronous, to
maintain the time structure of
Cherenkov light flashes in the
camera plane
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Better light of night sky
rejection (less pile-up)
Tessellated surface:
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~950 mirror elements
49.5 x 49.5 cm2 (~240 m2)
All-aluminium, quartz coated,
diamond milled, internal heating
>85% reflectivity in 300-650nm
17.7.03, R.Mirzoyan,
MPI Munich
mirror assembly
Adjustment legs screwed on the mirror
Cabling of the mirror internal heating
2 mirrors mounted on a panel
Optical alignment
Final spot of a panel after
The precise alignment of
the mirrors
4 mirrors spots after the pre-alignment
close to the virtual center of the MAGIC camera
The Active Mirror Control

The panels can be oriented
during the telescope operation
through an Active Mirror Control
system (AMC) to correct for
possible deformation of the
telescope structure
17.7.03, R.Mirzoyan,
MPI Munich
The alignment of the mirrors
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
The alignment of the first 103 mirrors in the telescope structure has
been done by using a 20 W light source at a distance of 920m
The camera plane was moved 29 cm backward to focus the lamp
light
~1 pixel
103 spots before and after the alignment
17.7.03, R.Mirzoyan,
MPI Munich
The alignment of the mirrors
17.7.03, R.Mirzoyan,
MPI Munich
The camera
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includes 577 PMTs
Two sections:
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Inner part: 0.100 PMTs
Outer part: 0.200 PMTs
Plate of Winston cones 
Active camera area  98 %
17.7.03, R.Mirzoyan,
MPI Munich
The camera
Pixels:

The photocatode QE is
enhanced up to 30 % and
extended to UV by a special
coating of PM surface with
milky wavelength shifter
• Each PM is connected to an
ultrafast low-noise
transimpedance preamp.
• 6-dynode HV system zener
stabilized with an active load
17.7.03, R.Mirzoyan,
MPI Munich
240 m2 -> 312 m2 !!!
The camera status
•The temperature inside is controlled
by a water cooling system with
temperature/humidity sensors.
•The camera was completed in
summer 2002, after extensive tests
and characterization
•installed in November 2002
•commissioned March 2003 after the
winter break.
First starlight using DC current
readout was recorded on March 8th.
17.7.03, R.Mirzoyan,
MPI Munich
The readout
Cherenkov light pulses from air showers are typically ~ a few ns long

Pixel signals transported 162 m
over optical fibres:
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No signal dispersion
Cable weight, optically
decoupled, noise inmune.
Sampling using 300 MHz1GHz FlashADCs:
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/h discrimination through
signal shape
Noise reduction
Event buffering, telescope
system synchronization...
17.7.03, R.Mirzoyan,
MPI Munich
Trigger
Discriminators
L0
Two level trigger system
The level 1 (L1) is a fast
coincidence device (2-5 ns)
with simple patterns
(N-next-neighbour logic) on
single trigger cells.
Level 2 (L2) is slower (50-150
ns), and can perform a global
sophisticated pattern
recognition
17.7.03, R.Mirzoyan,
MPI Munich
Level 1
L1
Level 2
L2
To FADC
Set the minimum number of
photoelectrons per pixel to be
used in the trigger
Make a tight time
coincidence
on simple pattern
of compact images
and enable L2
TWO FOLD KINDS (86)
THREE FOLD KINDS (51)
FOUR FOLD KINDS (67)
FIVE FOLD KINDS (106)
Perform an advanced pattern recognition
to use topological constraint:
• pixel counting in a given region of the
detector
• mask hot spots like bright stars
• rough image reconstruction, etc….
On-line event selection
Trigger
- 44 GeV
Trigger display
L2 pattern recognition
On-line
On-line image
analysis on the
trigger event
Off-line analysis
Off-line
Trigger status
The trigger has
been commissioned
since:
Dec. 2002 (LT1)
March 2003 (LT2)
L1T
L2T
The Data Acquisition System
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Needs:
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577 PMT x 1 Byte x 30 samples x 1 kHz
 ~ 20 MByte/s (x 11 hours )
 ~ 800 GB/night (longest nights in
December)
Cheap PC based solution:
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Multiprocessor threaded
system.
PCI FPGA based readout card
& RAID0 disks system.
IPE
IPE
IPE
NET
CE
17.7.03, R.Mirzoyan,
MPI Munich
IPE
IPE
IPE
NET
CE
MAGIC first light
17.7.03, R.Mirzoyan,
MPI Munich
MAGIC first light
17.7.03, R.Mirzoyan,
MPI Munich
MAGIC first light
17.7.03, R.Mirzoyan,
MPI Munich
GRB alert: early follow-up
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The light weight structure and the low inertia of the structure allows a fast
slewing time in such a way that the telescope will be able to perform an
early follow-up of a Gamma Ray Burst
With the engines at 70% of full power, the telescope was able to move of
180º in both axes in less than 30s
QuickTime™ and a Cinepak decompressor are needed to see this picture.
Future Plans
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August-September -> finishing installation of mirrors and
electronics
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September -> move to new counting house
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October 10th Inaguration
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Winter 2003-2004: start regular observation
17.7.03, R.Mirzoyan,
MPI Munich
Counting house
17.7.03, R.Mirzoyan,
MPI Munich
Conclusions

So far all the new technical and technological novelties implemented
in MAGIC behave as expected

In the next few month we will make extensive tests of the apparatus
with engineering and physics runs

We are considering MAGIC as the first element of an international
observatory to study the deep universe with high energy gamma rays.

Our proposal is to transform the MAGIC site, Roque de los
Muchachos, in the “European Cherenkov Observatory” ECO
17.7.03, R.Mirzoyan,
MPI Munich