Ultra-low birefringence dodecagonal vacuum glass cell

We eport on an ultra-low birefringence dodecagonal glass cell for ultra-high vacuum applications. The epoxy-bonded trapezoidal windows of the cell are made of SF57 glass, which exhibits a very low stress-induced birefringence. We characterize the birefringence $\Delta n$ of each window with the cell under vacuum conditions, obtaining values around $\num{e-8}$. After baking the cell at $\SI{150}{\degreeCelsius}$, we reach a pressure below $\SI{e-10}{\milli \bar}$. In addition, each window is antireflection coated on both sides, which is highly desirable for quantum optics experiments and precision measurements.