  We investigated the noise of interferometric gravitational wave detectors due
to heat energy deposited by cosmic-ray particles. We derived a general formula
that describes the response of a mirror against a cosmic-ray passage. We found
that there are differences in the comic-ray responses (the dependence of
temperature and cosmic-ray track position) in cases of interferometric and
resonant gravitational wave detectors. The power spectral density of vibrations
caused by low-energy secondary muons is 100-times smaller than the goal
sensitivity of future second-generation interferometer projects, such as LCGT
and Advanced LIGO. The arrival frequency of high-energy cosmic-ray muons that
generate enough large showers inside mirrors of LCGT and Advanced LIGO is one
per a millennium. We also discuss the probability of exotic-particle detection
with interferometers.
