Search found 254 matches

by JohnCuthbert
Sun Sep 04, 2016 12:17 pm
Forum: Other Forms of Fusion - Theory, Construction, Discussion, URLs
Topic: Shining UV-C on a Tungsten wire to increase emittance?
Replies: 5
Views: 2910

Re: Shining UV-C on a Tungsten wire to increase emittance?

At anything like a decent vacuum, the alpha particles will be emitted from the source, fly across the empty space and hit the wall opposite the source where they will mainly warm it up slightly. The range of alphas in air is a few cm before they hit something. At a tenth of an atmosphere the range w...
by JohnCuthbert
Tue Aug 30, 2016 8:33 pm
Forum: Other Forms of Fusion - Theory, Construction, Discussion, URLs
Topic: Want to ionize D2 or H2 gas with UV light!
Replies: 4
Views: 2267

Re: Want to ionize D2 or H2 gas with UV light!

Realistically, you are not going to get radiation that will ionise hydrogen from one place to another. Air will absorb it strongly and so would any window. You would be looking at this sort of thing http://www.spring8.or.jp/pdf/en/res_fro/09/172-173.pdf A heated filament acting as an electron source...
by JohnCuthbert
Sat Jul 23, 2016 1:55 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Water as Neutron Shield
Replies: 17
Views: 9255

Re: Water as Neutron Shield

Water does not play nicely with high voltages.
It's a pity- because water is cheap and effective.
by JohnCuthbert
Sun Sep 20, 2015 5:52 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: X-ray shielding and the argument for ZnSe viewports
Replies: 1
Views: 2066

Re: X-ray shielding and the argument for ZnSe viewports

According to this http://www.edmundoptics.co.uk/optics/windows-diffusers/ultraviolet-uv-infrared-ir-windows/zinc-selenide-znse-windows/2721/ the list price for a 40mm dia 4mm thick ZnSe window is £359.20 I can buy a lot of lead glass for that (or, being a chemistry nerd I can use a clear plastic cel...
by JohnCuthbert
Sun Mar 01, 2015 6:00 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Van De Graaff Belt Source
Replies: 5
Views: 2907

Re: Van De Graaff Belt Source

A friend of mine is a lab tech in a high school and she sent me this by email a while back It seem s you need to register with the site before you can read the item ,but the information is here anyway. Hope it helps "We recently discovered that you can make a replacement Van De Graaff belt out of vi...
by JohnCuthbert
Mon Sep 08, 2014 7:57 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Deuterium purity check
Replies: 8
Views: 3247

Re: Deuterium purity check

Measuring the density is probably good enough to tell you if it's hydrogen, deuterium or air.
Of course, it won't help much with mixtures.
by JohnCuthbert
Mon Sep 01, 2014 7:37 pm
Forum: Vacuum Technology (& FAQs)
Topic: Cleaning the Chamber
Replies: 11
Views: 4036

Re: Cleaning the Chamber

Jerry,
Water is a very polar solvent- it doesn't do a very good job of dissolving oil.
by JohnCuthbert
Thu Aug 28, 2014 8:52 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Measuring grid temp
Replies: 9
Views: 3640

Re: Measuring grid temp

Those IR thermometers measure the average temperature in their field of view. Only a tiny part of that would be the grid so you would, as David says in the OP, be measuring the temperature of the back wall of the fusor (unless the window is opaque, in which case you will measure its temperature.) Th...
by JohnCuthbert
Sun May 25, 2014 3:06 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Galvanized Steel?
Replies: 5
Views: 2150

Re: Galvanized Steel?

It's an interesting idea, but wouldn't answer the question. There's no doubt that galvanised steel would be a poor choice. The point I raised was that it's not clear if it's poor because zinc is volatile (and, at low temperatures, it's not) or if the issue is the fact that, on exposure to air, the z...