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The CANGAROO Experiment

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Collaboration of Australia and Nippon for a Gamma-Ray ... alignment: flood light (5km distance) point size: 0.2o (FWHM) H.E.S.S.. 13m Davies-Cotton design ... – PowerPoint PPT presentation

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Title: The CANGAROO Experiment


1
The CANGAROO Experiment
  • What, Where, Who?
  • Air Cherenkov Astronomy
  • History
  • Telescope Design (in comparison with H.E.S.S.)
  • Preliminary Results
  • Summary

2
What
  • Collaboration of Australia and Nippon for a
    Gamma-Ray Observatory in the Outback
  • 2nd generation imaging air cherenkov telescopes

superimposed image
3
Where, Who
  • Cherenkov telescope array in Woomera, South
    Australia
  • 160m ASL
  • 17 institutes from Japan and Australia

4
Air Cherenkov Astronomy
  • air shower induced by cosmic gamma
  • Cherenkov emission
  • optical telescopes for observation
  • stereoscopic reconstruction of shower axis

5
CANGAROO I
  • 3.8m telescope
  • 256 pixels
  • in operation since 1992

6
CANGAROO II
  • 7m telescope
  • since May 1999
  • various observations (Crab, Vela, ...)
  • focal length 8m
  • 512 PMTs
  • mirror 30 m2

7
CANGAROO III array
  • 4 telescopes
  • distance 71m (100m)
  • using upgraded C II telescope (in operation)
  • 2 telescopes will start in April 2002
  • all telescopes 2004

10m (2002)
8
CANGAROO III
  • 10m telescopes
  • focal length 8m
  • 552 PMTs
  • mirror 57 m2
  • 1st telescope in operation

9
Reflector
  • CANGAROO
  • 10m parabola
  • 57m2
  • 114 mirrors 80cm ?
  • alignment flood light (5km distance)
  • point size 0.2o (FWHM)
  • H.E.S.S.
  • 13m Davies-Cotton design
  • 108m2
  • 382 mirrors 60cm ?
  • Alignment star light
  • point size 0.04o (FWHM)

10
Parabola vs. Davies-Cotton
  • ideal mirror parabola ? focal point
  • spherical mirror ? focal spot
  • Davies-Cotton
  • spherical frame
  • spherical mirror tiles (same focal length)
  • mirror tiles individually aligned
  • Parabola made from tiles
  • spherical tiles
  • different focal length

11
Camera
  • CANGAROO
  • 552 PMTs
  • 0.17o angle
  • FoV 4o
  • hexagonal shape
  • H.E.S.S.
  • 960 PMTs
  • 0.16o angle
  • FoV 5o
  • hexagonal shape

12
Trigger
  • CANGAROO
  • 3 adjacent pixels
  • telescope coincidence
  • H.E.S.S.
  • 3-5 pixels in one sector (lt64 pixel)
  • gt 2ns
  • 1 sector out of 38 overlapping sectors
  • telescope coincidence

13
Data Acquisition
  • CANGAROO
  • Linux PCs
  • camera event 1.5kB
  • dead time efficiency 20 _at_ 400Hz
  • H.E.S.S.
  • Linux PCs
  • camera event 1.2 kB
  • dead time efficiency 20 _at_ 400Hz

14
CANGAROO and H.E.S.S.
15
Preliminary Results Mkn 421
  • strong flare 2001
  • large zenith angle 70o
  • threshold 10 TeV
  • eff. area 8x105 m2
  • 80 events/14h gt20TeV

16
Sensitivity
CANGAROO
H.E.S.S.
17
Summary
  • Introduction to the CANGAROO experiment
  • comparison with H.E.S.S.
  • presentation of recent CANGAROO results
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