1. Jamie Holder University of Leeds August 2005 Status and Performance of the First VERITAS Telescope

2. VERITAS Telescope I 12m diameter reflector –Davies-Cotton F/1.0 –110m 2 499 PMT Camera Steel OSS Installed at Mt. Hopkins Basecamp (1275m) in January 2005

3. Mechanical Performance Alt-Az mount Slew speed –0.3  /sec –1.0  /sec modified Tracking accuracy –Still evaluating –Encoders give <0.005  –Source location good

4. Optical Performance 350 mirror facets –glass –aluminium coated on- site reflectivity >90% at 320nm PSF –0.09  FWHM initially –0.06  now PSF plot (with PMT size)

5. Camera 499 PMTs –Photonis XP2970 –0.15  spacing –3.5  FOV PMT Gain = 2  10 5 NSB ~100 - 200 MHz No light cones yet Single photoelectron peak (5 times operating voltage)

6. Trigger Each channel has programmable CFDs CFD output sent to pattern selection trigger –any 3 adjacent PMTs Trigger rate ~ 150Hz

7. Data Acquisition PMT signals digitized with 500MHz sampling FADCs Data rates –24 samples/channel –13.5 kb/event –10% deadtime @ 150 Hz –4% with zero supression

8. Timing Define optimum integration gate (10ns) Poster: “Exploiting VERITAS Timing Information” Holder et al.

9. Results Crab Nebula observations –3.9 hours ON/OFF –19.4 s –10 s /hour Note –Engineering data –Preliminary analysis –No light cones –cf Whipple 10m (7 s /hour) Mkn 421 and Mkn 501 also detected (Poster: Cogan et al)

10. Results Local Muon background –~150 GeV trigger threshold –~400 GeV analysis threshold Need Stereo! Local Muons

11. Kitt Peak Site Horseshoe Canyon –1800m –KPNO Completed –Site Clearance –Power –Telescope Pads Temporary access problems

12. Temporary Site 2 Telescopes at Mt. Hopkins Basecamp –88m baseline First light October 2005 Test –array trigger –array analysis 4 telescopes on Kitt Peak October 2006