This isn't what I've described elsewhere as Fusor-II, just another fusor -- the next step to the big changes I plan. This one is being put together on my smaller turbo system to test some different things. The system was originally built to do beam on target work, and someday, it will again. But I wanted a place to test some things without disturbing the main fusor, which is in a very nice state of tune just now.
So, we make another one to try some new things on. As I write this, it's sealed back up, baking, and coming down in pressure about as quick as I can expect, given that I just touched a bunch of things in there -- fingerprints everywhere, new HV feedthrough, grid, electron emitter, faraday probe, secondary grid to influence the main field, and a new screen to protect the window from charged particle bombardment. That's a lot of new surface area that is only now seeing vaccum for the first time, and after about an hour of pumping and baking, it's down to about 4 e-5 mbar.
Before I opened it this morning, it was hitting low e-7 mbar, and that was with a leak I found with the new mass spec. I think I fixed that, but there's just a heck of a lot of new stuff with a lot of surface area in there now to outgas. It's baking at about 70C and warming the room nicely -- should have done this in winter!
Pictures are fun and not only for eye candy. They save words (even for me!)
Here's the thing as it now sits. HV isn't yet hooked up for real, but I have a ballast resistor standing on end there. I have a 60kv 150w supply I plan to use on this, as soon as I make a cable for it.
Here's what's on the computer screen right now as I'm baking it out:
Yup, water, air, dust, fingerprints. Not unexpected at all. I expect that tomorrow it will look like it did yesterday, or close.
Here are the new screen for the window, and one to lay on the bottom of the tank and act as an electrode to both measure and perturb the E fields we will have.
This is stainless steel screen Bill brought over the other day. The electrode one is tied to the fat wire with nichrome wire, in the manner of sewing. I also sewed a few fish beads to the bottom to insulate it from the tank. A piece of pyrex tubing is the main insulation, and the other end of the wire plugs into an octal tube socket I put on an 8 pin feedthrough. Can't do much kV on that one, but that's not what it's for.
Here's what it looks like before I put in the protective screen and seal it up.
I've already run a glow discharge in (mostly) He with an oil burner ignitor to see that things basically are OK. I expect to run real fusion tonight or tomorrow, depending on when the beer overcomes my shop and fabrication energy - and if it's not too late at night -- we run on batteries after sundown, no point wasting them.
If It works, the other neutron detectors are only about 20 ft away as the crow flies, so I should be able to see them get out of background without moving things. One of the things I plan to "test" here is a couple of BF3 tubes we've had but not lashed into anything...
This will be a severe use-test of the new HV feed through I did the other day.