This page presents the results of a study that looks at the triggering
differences that can be expected for single 10 m telescope when the
mirror is either isochronic or anisochronic. The study of the effects
of timing aberrations that result from the present anisochronous mirror
shape can be seen at
Timing Aberrations for the 10m Mirror
. The effect that this time spread has on the pulses from the pmts
can belooked at at
Effect on pulse shape due to the
anisochronous 10m Mirror
. The expected effect of this spread on expected Cherenkov light
pulses from gamma ray showers can be seen at
PMT Pulses from Gamma Ray Shower
Cherenkov light pulses . One thing to notice from this last set of
plots is that due to the additional time spread of the individual
photons for the anisochronic mirror the resultant PMT pulse heights for
that type of mirror will generally be lower then for the isochronic
mirror. The night sky background level will be the same for both types
of mirrors. This means that in general the isochronic mirror will have
a lower energy threshold then the anisochronicmirror when the same
discriminator threshold is used. We present below the results of this
effect on energy threshold and gamma ray trigger rate for various
discriminator threshold levels for both the isochronic and anisochronic
mirrors for a 331 1/4 deg. pixel camera with a multiplicity of 2
requirement. All 331 pixels are included in the trigger. The Crab
spectrum at zenith was used as the incident spectrum.
Multiplicity = 2. Discriminator threshold = 15 pe's
Multiplicity = 2. Discriminator threshold = 20 pe's
Multiplicity = 2. Discriminator threshold = 30 pe's
Multiplicity = 2. Discriminator threshold = 40 pe's
Multiplicity = 2. Discriminator threshold = 50 pe's
Multiplicity = 2. Discriminator threshold = 55 pe's
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Last modified 24-Oct-2005
