2um x 8 mm Ni windows leaked tested on TUDA gas cell. With window placed on the outside of the cell, cell was evacuated and pressure monitored with time, i.e. 1atm differential air pressure. Comparison to leak rate with blank flange also do.

Tests were performed in order: Ni, 30 minuets pumping, Ni again, blank, Ni third time.

Plots are the same data, different scales.