  Bubble Chambers provided the dominant particle detection technology in
accelerator experiments for several decades, eventually falling into disuse
with the advent of other techniques. We report here on the first period of
operation of an ultra-clean, room-temperature bubble chamber containing 1.5 kg
of superheated CF$_{3}$I, a target maximally sensitive to spin-dependent and
-independent Weakly Interacting Massive Particle (WIMP) couplings. An exposure
in excess of 250 kg-days is obtained, with a live-time fraction reaching 80%.
This illustrates the ability to employ bubble chambers in a new realm, the
search for dark matter particles. Improved limits on the spin-dependent
WIMP-proton scattering cross section are extracted from this first period. An
extreme intrinsic insensitivity to the backgrounds commonly limiting these
experiments (a rejection factor for photon-induced electrons of $\sim10^{-10}$)
has been measured in operating conditions leading to the detection of
low-energy nuclear recoils such as those expected from WIMPs.
