  We report on trapping and cooling Li-6 atoms in a monolithic ring bowtie
cavity. To make the cavity insensitive to magnetic fields used to tune atomic
interactions, we constructed it entirely from fused silica and Zerodur. The
components were assembled using hydroxide bonding, which we show can be
compatible with ultra-high vacuum. Backscattering in high-finesse ring cavities
readily causes trap intensity fluctuations and heating, but with
phase-controlled bi-directional pumping the trap lifetime can be made long
enough for quantum gas experiments in both the crossed-beam trap
(unidirectional pump) and 2D lattice trap (bidirectional pump) configurations.
