Wait, what? Tiny fusors? Not for me!

[Jim Kovalchick]

So, it seems that the 2.75" tee fusor is the flavor of the day such that evem Richard is advocating them. Recently I had a chance to get a plus ultra grande chamber, and in spite of tiny fusors being in style, I am going it. I offer for your viewing pleasure the start of my next model fusor chamber complete with two 8" ports, four 6" ports, and four 2.75" ports. This ahows my progress so far. I'll post updates as I reach major milestones. Cheers, Jim K

[John Futter]

Jim
That seems to be entirely adequate

[Richard Hull]

A fine catch on the surplus scene.

I'm not ditching my 6" spherical fusor IV either. The smaller systems might let the new guys save some money by purchasing smaller, less expensive crosses and Tee's. They still have to prove they have done fusion to the same standard as everyone else, of course.

For Spheres, a 6-8 inch system looks very impressive and will not waste a lot of gas as would a giant 12" sphere or giant cylinder.

Richard Hull

[Dennis P Brown]

Small fusors appear to offer higher neutron rates for a given voltage and power; whether that is valid will, with more experiments posted, be proven one way or the other.

In any case, your chamber has a lot of gadgets attached - what are they?

[Jim Kovalchick]

Dennis,
The Eye-Sys is a low pressure gage. It likely won't stay and will be replaced by a standard glass vacuum gage because it is of dubious heritage and may not work. The blue box is a mini convectron that I'm using only because it has a switch that I can use to trigger the Eye-Sys off when pressure gets into millitorr range. I'm keeping my fingers crossed for the Eye-Sys because I don't care to have glass hanging from my chamber.

My primary instrument will be an old, reliable baratron not seen in the picture.

The 2.75 port on upper left is a secondary view port. It will be looking down toward the poisser and will give better views of star mode than the primary view port that will be installed on the 8" port in the rear after a sacrificial pyrex disc is applied. The spacious vista of a 5 inch window will help me see a good bit of the chamber interior which will be useful for seeing any issues such as arcing and for just really nice video. It's x-rays will face the back wall, and the secondary view port will get a lead cap.

The feedthrough is still under construction and will attach to the left.

I haven't settled on a grid design yet. I've been begging my son to design me one...

This chamber is large, but it's only slightly larger than my son's original mixing bowl fusor that he got pretty good numbers from. My goal is to do some activation experiments. If this version doesnt meet my needs, I have a 6-sided 2.75 conflat I can try.

Jim K

[Jim Kovalchick]

Some comments on the big vs small debate... I am skeptical of neutron numbers derived fron bubble detectors parked close to small chambers. You dont get accurate activity numbers from a detector parked right up next to radiation and then treat it like a point source. The geometry of the source and detector sizes just don't make sense to me. My nuke professors back in school would have given me no mercy if I did that.

I get that big chambers may waste deuterium, but that would seem to be something fixed by both design and operational considerations. Fixing a leak or outgassing issue by flushing more d with bigger in and out flow is not a size issue. Also, wasting current by using it for plasma production vs using an ion source is not a size issue.

[Dennis P Brown]

Jim, I agree that more data is required - especially (and hopefully soon), Ag activation. If the flux is over a million neutrons/sec, activation will be strong and provable. That, I would think, will be the 'Au' standard for proof, maybe (lol.)

Don't know the voltage you are planing on using but a thick glass plate (or stack of thinner plates) can also shield for x-rays very well.

[Jim Kovalchick]

Some status updates

I've added the view port you see in the front. I will turn the fusor to face the wall during operation. I added a 5 inch sacrificial pyrex plate to protect me and the view port. The plate is held in place with wedged aluminum foil.

I've also added the high volt feed through. It's fabricated from a 6" CF flange and a dual post insulator. The stalk is #6 all-thread.

Upon sealing his chamber my son always left a coin or two inside much like the coin ceremony during the building of old masted ships. In keeping with the tradition but with my own personal twist, I put a uranium marble in mine. I doubt it brings the chamber good luck, but maybe it will tell me something about the UV light output of the plasma.

[Dennis P Brown]

Looks really good; also, might want to place a glass blank inside the chamber view port to shield your main window so as to keep it clean.

[Jim Kovalchick]

Dennis, I put the pyrex plate inside the chamber. It will keep the view port clean, act as a sacrificial heat shield, and block a view x-rays. This is a technique I used on my last fusor, and it worked pretty well.