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Status of the H.E.S.S. Experiment and First Results. Paula Chadwick University of Durham, U.K. for the H.E.S.S. Collaboration. Ground-based -r ay Telescopes. Detect gamma rays via the Cherenkov light produced by secondary showers – most usually in the atmosphere.
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Status of the H.E.S.S. Experiment and First Results Paula Chadwick University of Durham, U.K. for the H.E.S.S. Collaboration
Ground-based -ray Telescopes Detect gamma rays via the Cherenkov light produced by secondary showers – most usually in the atmosphere. • Imaging atmospheric Cherenkov telescopes have: • Large effective area • Excellent background rejection • Good source location
The H.E.S.S. Collaboration MPIK, Heidelberg Humboldt Universität, Berlin Ruhr- Universität, Bochum Universität Hamburg Landessternwarte Heidelberg Universität Kiel Ecole Polytechnique, Palaiseau LPHNE, Universités Paris VI-VII PCC Collège de France, Paris Université de Grenoble CERS Toulouse CEA Saclay Observatoire de Paris-Meudon University of Durham Dublin Institute for Advanced Studies Charles University, Prague Yerevan Physics Institute University of Namibia University of Potchefstroom
H.E.S.S. Location H.E.S.S
Vital Statistics • 4 telescopes in Phase 1 • Arranged on a square of side 120m • Diameter 12m, area 108 m2 • 382 mirrors • Focal length 15m • 960-pixel camera • Total telescope weight around 60 tonnes
Mirrors Quartz-coated aluminized glass, reflectivity > 80% Measured spot width 0.02º for angles between 0 and 45º.
The Cameras 960 photon detector elements, each subtending 0.16o angle, using 29 mm, Photonis 8-stage PMTs with borosilicate windows, equipped with Winston cones to improve light collection.
The final result weighs about 800 kg, is 1.6 m in diameter and 1.5 m in length. Close to 5kW of heat is dissipated by 80 computer-controlled fans.
Telescope monitoring Telescope pointing is monitored by CCDs LEDs in the camera lid simulate events A laser/LED system flat-fields the camera
Information from the CCD cameras allows the pointing to be corrected to give a resolution of 2.5 arcsec. Calculations courtesy of Stefan Gillessen
Atmospheric Monitoring Comprehensive monitoring with IR detectors on each telescope, scanning IR detector, LIDAR and of course a weather station on site.
The ROTSE 3C First light June 18 2003. Designed for GRB location; some time available to H.E.S.S.
First Results: The Crab Nebula 4.65 hours of on-source observations, z.a. range 45-50º, one telescope only. 20.1σ, 3.6 gammas/min See Masterson’s paper at the ICRC
First Results: PKS2155-304 July 2002: 2.2 hours, 9.9σ, 3.1 gammas/min Oct 2002: 4.7 hours, 6.6σ, 1.2 gammas/min See Djannati-Ataï’s paper at the ICRC.
To Conclude…. • The first two H.E.S.S. telescopes are fully operational • The third telescope has mirrors fitted and aligned • Phase 1 completion early 2004 • The Crab Nebula and PKS2155-304 have been detected with the 1st telescope alone • Routine observations are under way