Preliminary testing of the anode layer ion source (ALIS) from RTFtechnologies. I am waiting for MHV feedthroughs from Lesker and once they come I will be able to mount the ion source on a proper flange rather than having it rest on a KF adapter in the center of my chamber.
Tests were run at 50millitorr and between 800-1000v. Air plasma can been seen as low as 300v. Typical current at 1kv is 4ma. When the source is current limited, you can see a de-focusing effect as seen in the 2nd picture. This is because the ion source is not operating through the closed drift mechanism but is rather operating closer to a modified glow discharge under the influence of a local magnetic field.
Above pictures taken at much lower pressure and higher voltage (5e-4 torr and 4kv+)
ALIS mounted on 2.75″ CF flange via 10-32 standoff and electrical connection via MHV connector. As suggested and fabricated by J.D Guerard machining Co., a ditch was formed around the hole drilled for MHV feedthrough on the interior side of the flange which created a wall matching in thickness to the MHV connector feedthrough to facilitate with fusing. This can be seen in the first picture. When welded, the two surfaces of identical thickness are fused together easier, with lower current (this weld was done at only 20amps), and with consequently with no warping of the entire flange because of the localized heat.
Using the anode layer ion source as a crude ion pump (far from ideal conditions, stainless steel chamber walls do not have high getter/sputter capacity)
Ion source power up sweep 400v – 4000v