Vacuum chamber

For posts specifically relating to fusor design, construction, and operation.
Post Reply
Eldarion
Posts: 51
Joined: Wed Nov 19, 2008 3:31 am
Real name:
Contact:

Vacuum chamber

Post by Eldarion » Sun Nov 23, 2008 1:30 am

How thick must the walls of your vacuum chamber be if you wish to do fusion within it. How thick do the need to be to be safe when operating at energies of 10-20Kv? 20-50Kv?
Thanks for the help

User avatar
Doug Coulter
Posts: 1312
Joined: Sun May 27, 2007 7:18 pm
Real name: Doug Coulter
Location: Floyd, VA, USA
Contact:

Re: Vacuum chamber

Post by Doug Coulter » Sun Nov 23, 2008 2:43 am

Thick enough to withstand the outside air pressure without deforming. This is very dependent on shape and size. If you're worried about radiation coming out, you would add some other shield to the outside of the tank. This won't stop neutrons, or many of them (neutrons are very hard to stop), but relatively thin (say 1/4") lead sheeting will stop most of the X-rays, and it can easily be removed for working on the tank proper.
Why guess when you can know? Measure!

Eldarion
Posts: 51
Joined: Wed Nov 19, 2008 3:31 am
Real name:
Contact:

Re: Vacuum chamber

Post by Eldarion » Sun Nov 23, 2008 3:11 am

Thank you for your quick reply, so what do you do about the neutron radiation? just use the rule of square and stand further back from the fusor, or use shielding of an element that absorbs neutrons? I heard somewhere that water mixed with borox will do the trick, is this accurate?

User avatar
Mike Beauford
Posts: 419
Joined: Wed Apr 25, 2007 6:24 pm
Real name:
Location: Morton Grove, IL

Re: Vacuum chamber

Post by Mike Beauford » Sun Nov 23, 2008 4:08 am

Yes, water mixed with borox would do the trick, but it's usually way way overkill. Unless you're a 'luck donkey' as Richard Hull is used to saying and your system puts out a large amount of neutrons, the only thing you really need to do is keep some physical distance between you and your machine. Power supply voltages around 30~50kv are usually stopped by various thickness of stainless steel. but in the end distance is the cheapest/best solution.

Mike
Mike Beauford

User avatar
Richard Hull
Moderator
Posts: 12295
Joined: Fri Jun 15, 2001 1:44 pm
Real name: Richard Hull

Re: Vacuum chamber

Post by Richard Hull » Mon Nov 24, 2008 6:01 pm

Most standard stainless sphere are .060 thick and at about 35kv these go transparent to the x-rays at this level and above. As doug noted a 1/4" of lead in the form of a shadow cone shield is all that is needed up to 60 or 70 kv.

See the FAQ on shielding.

viewtopic.php?f=13&t=5783&hilit=FAQ#p34227

Forget neutron shielding use distance as noted up to about 50kv, then consider a light borax and paraffin shadow cone shield.

I am currently concidering a nice ceiling mounted, track run, movable shadow cone shield for fusor V.

SIDE NOTE:.... Such a shield is seen in great detail on the classic, must see, sci-fi movie "This Island Earth". It hangs via massive chains from a track in the ceiling of the lab of the lead scientist. It is used in an attempt to keep the aliens from spying on the scientsts while using their "interocitor" which was a combination remote viewer-blaster device. Interestingly, the shield did not work, but the scientists were ultimately warned of its failure when the lab's pet cat "neutron" leaps up on the thick shield and scowls and hisses. The impression given is that the cat's elevated senses detected the intruding wavefront from the interocitor.

Such a shield will definitely work with a fusor and need not be large at all.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

Post Reply