Reply To: Space Fountain

[Henning]

There are already some more suggestions from the Polywellers.
For the removal of copper residuals there are two suggestions:

As far as removal of the Copper from the chamber walls, a simple DC glow discharge with Ar or O2 should do the job. The glow discharge would be simple capacitive DC with the bias plate at 500 or 1000 V bias. The Ar or O2 gas flow should be at around 1-10 torr with a base pressure of 0.1 torr (need only a roughing pump).

Change to sapphire windows and scratching during cleaning becomes less of a problem. ‘Course the sapphire windows may be out-of-budget.

Alternatively, treat the glass windows as replaceable items and don’t bother cleaning them.

Sapphire windows shouldn’t be too expensive, though: http://www.sapphirewindows.com/
There are other suppliers, but this one quotes the price directly on the front page.