320 likes | 501 Vues
EUSO meeting. The MAGIC Telescope Project. Razmick Mirzoyan. Max-Planck-Institute for Physics Munich, Germany. MAGIC-I: inaugurated recently, on October 10. Location: Canary island La Palma. We hope to take the 1 st gamma ray data from the Crab Nebula in the coming 2 months.
E N D
EUSO meeting The MAGIC Telescope Project Razmick Mirzoyan Max-Planck-Institute for Physics Munich, Germany EUSO meeting: R. Mirzoyan
MAGIC-I: inaugurated recently, on October 10 Location: Canary island La Palma EUSO meeting: R. Mirzoyan
We hope to take the 1st gamma ray data from the Crab Nebula in the coming 2 months EUSO meeting: R. Mirzoyan
Dense fog (or a cloud) helps to visualize the Active Mirror Control laser pointer beams Photo by R. Wagner EUSO meeting: R. Mirzoyan
Outline • The MAGIC Collaboration • Aiming for low threshold • Physics goals • The Telescope • Design overview • MAGIC Key elements for low threshold • Status of commissioning of the telescope elements • Plans & Conclusions EUSO meeting: R. Mirzoyan
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 • Inauguration October 10th EUSO meeting: R. Mirzoyan
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 operating a17 m Cherenkov Telescopefor observation ofHE cosmic –rays. • Main aim: to detect –ray sources in the unexplored energy range: 30 (10)-> 250 GeV • MAGIC is a challenging design to decrease theenergy threshold, by 1)increasing the mirror size 2) using improved optics, light sensors and electronics 3) using advanced trigger • MAGIC shall provide the lowest threshold ever obtained with a Cherenkov telescope !!! EUSO meeting: R. Mirzoyan
The MAGIC PHYSICS Goals • Cosmological g ray horizon • AGNs Origin of Cosmic Rays • Pulsars • GRBs • Tests on Quantum Gravity effects • Cold Dark Matter • SNRs EUSO meeting: R. Mirzoyan
Key elements of the MAGIC telescope • 17 m diameter reflecting surface (240 m2 ) • Light weight carbon fibre frame • Active mirror control • 577 pixels enhanced QE, ~4° deg • FOV camera + advanced • calibration system • Analog optical signal transport via 162m long fibres • 3-level advanced trigger system EUSO meeting: R. Mirzoyan
Absorption of extragalactic - rays Any that crosses cosmological distances through the universe interacts with the EBL Attenuated flux function of g-energy and redshift z. For the energy range of IACTs (10 GeV-10 TeV), the interaction takes place with the infrared (0.01 eV-3 eV, 100 m-0.4 m). Star formation, Radiation of stars, Absorption and reemission by ISM EBL By measuring the cutoffs in the spectra of AGNs, MAGIC can help in determining the IR background MAGIC EUSO meeting: R. Mirzoyan
MAGIC phase I MAGIC phase II 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. Gamma Ray Horizon (GRH) This produces a reduction factor e- in the ray flux. The GRH is defined as the “z” for the observed energy “E” that fulfils: i.e. a reduction 1/e of the flux of the extragalactic source. EUSO meeting: R. Mirzoyan
MAGIC Expected sources MAGIC is just starting to operate, therefore it is still a mystery how many extragalactic sources we would detect.One can use the EGRET catalogue to pickthe probable source candidates. By using50 hours of observation time for each of these candidates, because of high sensitivity we expect to be able to measure the GRH at different redshifts with MAGIC. EUSO meeting: R. Mirzoyan
4-fold nn-logic Pulsars • 7-ray pulsars seen by EGRET. Only upper limits from present IACTs (spectral cut-off) • Where do g-rays come from? Outer gap or polar cap? • Many of the ~170 EGRET unidentified sources may be pulsars. EUSO meeting: R. Mirzoyan
Gamma Ray Bursts • Mechanism not yet fully resolved. • MAGIC can take advantage of: • Huge collection area • Fast repositioning. • Low energy threshold Under the assumption that it is possible to extrapolate the GRB energy spectrum in the GeV region, MAGIC can observe2-3 GRB/year MAGIC is designed to observe the prompt emission of a GRB! EUSO meeting: R. Mirzoyan
Other Physics targets for MAGIC • Search for neutralino annihilation gamma-rays (galactic center, neighboring galaxies, globular clusters) • Tests of possible Lorentz invariance violation: search for delay of HE gamma rays in rapidly varying phenomena at large distances (AGN flares, GRBs) EUSO meeting: R. Mirzoyan
EQG > 61016 GeV S.D. Biller et al. PhRev Let 83, 2108 (1999) Test of invariance of speed of light Lorenz Invariance Violation 10 s delay • Quantum Gravity models predict energy dispersion of c. • Non trivial dispersion relation where EQG appears! (1016-1019) • Photon delay depending on energy over distance Given the huge sensitivity, MAGIC can observe fast transient phenomena like GRB and/or flare of AGN. EUSO meeting: R. Mirzoyan
The 17m diameter f/1 telescope frame is a lightweight carbon fiber structure (tube and knot system) • The foundation started in September 2001 and the telescope frame was completed in Dec. 2001. The assembly of the frame took ~2 months The frame EUSO meeting: R. Mirzoyan
The reflector • The overall reflector shape is parabolic (f/1), isochronous, to maintain the time structure of Cherenkov light flashes in the camera plane • Better light of night sky rejection (less pile-up) • Tessellated surface: • ~950 mirror elements • 49.5 x 49.5 cm2 (~240 m2) • All-aluminium, quartz coated, diamond milled, internal heating • >85% reflectivity in 300-650nm EUSO meeting: R. Mirzoyan
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 EUSO meeting: R. Mirzoyan
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 EUSO meeting: R. Mirzoyan
The alignment of the mirrors • 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 EUSO meeting: R. Mirzoyan
The camera • includes 577 PMTs • Two sections: • Inner part: 0.100 PMTs • Outer part: 0.200 PMTs Plate of Winston cones Active camera area 95 % EUSO meeting: R. Mirzoyan
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 240 m2 -> 312 m2 !!! EUSO meeting: R. Mirzoyan
The readout Cherenkov light pulses from air showers are typically ~ 2-5 ns long • Pixel signals are modulating the VCSEL lasers @850 nm and thus transported over 162 m multimode optical fibres to the counting house: • Very low dispersion • Low weight, noise inmune. • Sampling using 300 Msample/s FlashADCs: • g/h discrimination through signal shape • LONS pick-up reduction • Event buffering, telescope system synchronization... EUSO meeting: R. Mirzoyan
Discriminators L0 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 Level 1 L1 • 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 Level 2 L2 To FADC Trigger 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 EUSO meeting: R. Mirzoyan
On-line image analysis on the trigger event Off-line analysis Trigger • - 44 GeV L2 pattern recognition Trigger display On-line Off-line EUSO meeting: R. Mirzoyan
IPE IPE IPE IPE IPE IPE NET NET CE CE The Data Acquisition System • Needs: • 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: • Multiprocessor threaded system. • PCI FPGA based readout card & RAID0 disks system. EUSO meeting: R. Mirzoyan
GRB alert from satellites: prompt follow-up • 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 motors running at 70% of full power, the telescope is able to turn 180º in both axes in less than 22s EUSO meeting: R. Mirzoyan
Near Future Plans: MAGIC-I • Winter 2003- spring 2004: • System debugging & • Start regular observations • Step-by-step lowering of the threshold setting towards few 10’s of GeV EUSO meeting: R. Mirzoyan
Near Future Plans: MAGIC-II Just now ordering the frame structure for the MAGIC-II telescope. The frame with understructure shall be ready in La Palma in May 2005, the 2nd Telescope to be completed near the end of 2005. The 2nd telescope will essentially be the clone of the 1st telescope, only a few improvements will be implemented. This will save us time and finances. EUSO meeting: R. Mirzoyan
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. Construction of the 2nd telescope has already been started. • Our proposal is to transform the MAGIC site, Roque de los Muchachos, in the “European Cherenkov Observatory” ECO EUSO meeting: R. Mirzoyan