We present a viewport for use in ultrahigh vacuum (UHV) based upon the preflattened solder seal design presented in earlier work [ Cox et al., Rev. Sci. Instrum. 74, 3185 (2003) ]. The design features significant modifications to improve long term performance. The windows have been leak tested to less than 10−10 atm cm3/s. From atom number measurements in an optical dipole trap loaded from a vapor cell magneto-optical trap inside a vacuum chamber accommodating these viewports, we measure a trap lifetime of 9.5 s suggesting a pressure of around 10−10 Torr limited by background rubidium vapor pressure. We also present a simplified design where the UHV seal is made directly to a vacuum pipe.
Weatherill, K., Pritchard, J., Griffin, P., Dammalapati, U., Adams, C., & Riis, E. (2009). A versatile and reliably re-usable ultra-high vacuum viewport. Review of Scientific Instruments, 80(2), https://doi.org/10.1063/1.3075547