  We present a new survey strategy to discover and study high redshift Type Ia
supernovae (SNe Ia) using the Hubble Space Telescope (HST). By targeting
massive galaxy clusters at 0.9<z<1.5, we obtain a twofold improvement in the
efficiency of finding SNe compared to an HST field survey and a factor of three
improvement in the total yield of SN detections in relatively dust-free
red-sequence galaxies. In total, sixteen SNe were discovered at z>0.95, nine of
which were in galaxy clusters. This strategy provides a SN sample that can be
used to decouple the effects of host galaxy extinction and intrinsic color in
high redshift SNe, thereby reducing one of the largest systematic uncertainties
in SN cosmology.
