Four larger apertures were installed yesterday. This morning we fired up the modified source. It lit immediately. Plenty of beam. Development at 28kV, then scaled to 15kV. Beam intensities and ratios did not scale. Thesis: Space charge effects are too much for 15kV. Also, I3 accel-decel lens p/s needs work. We added a ballast to it today; p/s in tomorrow, then retest.