The other night I was in for quite a shock looking at the laser cut extractor apertures for the ILIS1 under the microscope for the first time. If I put them on the thruster as is, there would be no way it would have worked. So, I went through polishing it up by hand!
Here we can see the end flares of the aperture to reduce field strength and emissions at the corners of the glass ridge emitter. The tolerancing is quite lousy and the shape horribly uneven, but it should work for now for this upcoming test.
Nothing that a bit of 3000 grit sandpaper and some buffing can’t do! Left is one of the spare extractors, and right is the selected one that has been polished up. Moving forward, I will want the extractors polished and finished to a very high mirror shine.