Kyle Ryan, R. Weiss Running the ionizer on purge gas air solves the problem of unequal positive and negative ion currents in the gas being used to discharge the test masses. The oxygen which has known negative ion states provides the bulk of the negative ions. The ionizer was run for 2 hours with sampled + and - ion currents of 1.5e-9 Amps ( a factor of 100 more in the ion stream). Optical HR coating test samples and some VITON pieces were placed in the ion stream to determine if the chemically reactive oxygen ions and ozone formed in the ionizer do damage. The optical samples will be sent to Caltech for absorption tests. The purge air system was turned off at 7:10PM last night.