Search found 141 matches

by Liam David
Wed Jul 31, 2019 11:09 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Joe Gayo's lab tour
Replies: 69
Views: 23330

Re: Joe Gayo's lab tour

Having my enthusiasm for detecting tritium crushed in the post (http://www.fusor.net/board/viewtopic.php?f=50&t=12900) Robert mentioned, I think I can safely say that strange light-atom combinations are producing the false positives. About a week ago I measured the partial pressure of m/z = 6 to be ...
by Liam David
Wed Jul 24, 2019 7:21 pm
Forum: Advanced Technical Discussion Area
Topic: Tritium from Deuterium Lecture Bottle? (Edit: Misattribution of D3+ Factor)
Replies: 4
Views: 152

Re: Tritium from Deuterium Lecture Bottle? (Edit: Misattribution of D3+ Factor)

My RGA, which is the Spectra Vacscan Plus (late 90's to early 2000's) with a 100amu range, does have a multiplier, though the maximum operating pressure for it is 2e-6. For all purposes but measuring the base pressure of my system (9e-8torr) I use the Faraday cup. I managed to score the RGA and all ...
by Liam David
Wed Jul 24, 2019 4:10 am
Forum: Advanced Technical Discussion Area
Topic: Tritium from Deuterium Lecture Bottle? (Edit: Misattribution of D3+ Factor)
Replies: 4
Views: 152

Re: Tritium from Deuterium Lecture Bottle?

Ah, as per usual the explanation is more nuanced. I am still surprised that 50% of the deuterium pressure (only in the RGA, of course) was D3+. According to one paper (http://www.forensic-isotopes.org/assets/IRMS%20Guide%20Finalv3.1_Web.pdf), "The H3+ factor should not exceed 10ppm/nA [...]" which i...
by Liam David
Tue Jul 23, 2019 11:49 pm
Forum: Advanced Technical Discussion Area
Topic: Tritium from Deuterium Lecture Bottle? (Edit: Misattribution of D3+ Factor)
Replies: 4
Views: 152

Tritium from Deuterium Lecture Bottle? (Edit: Misattribution of D3+ Factor)

This morning, while I was evacuating my fusor chamber and differentially pumping the RGA for high-pressure measurement, I cracked the needle valve on the still-pressurized deuterium gas line and immediately noticed a large peak at m/z = 6. The pressure in the main chamber was around 10mtorr and that...
by Liam David
Mon Jul 22, 2019 11:25 pm
Forum: Images du Jour
Topic: I'm back, and fusing
Replies: 5
Views: 3412

Re: I'm back, and fusing

FBM printing leaves too many irregularities and any hope of preventing breakdown would require 100% fill. That would really take some time to print. I suspect that SLA would work better, but I don't know about the dielectric strength of the resin. ABS is pretty bad at ~500V/mil, but that's likely mu...
by Liam David
Thu Jul 18, 2019 1:53 am
Forum: Images du Jour
Topic: I'm back, and fusing
Replies: 5
Views: 3412

Re: I'm back, and fusing

Funny you should ask that. I 3D printed a connector out of ABS a couple years ago but once I pushed ~35kV there were arcing issues. It finally bit the dust just a couple days ago and left a carbonized trace. The socket cannot be run to any appreciable voltage unless there's a proper connector instal...
by Liam David
Mon Jul 15, 2019 10:49 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Transparent Ceramic Viewports
Replies: 8
Views: 3328

Re: Transparent Ceramic Viewports

This is not to shoot down your idea to use exotic (and likely expensive) materials, but regarding ion beam viewport damage there are simpler solutions. First, just don't orient the grid such that gaps are inline with glass or ceramic. It's localized heating and large spacial and temporal thermal gra...
by Liam David
Mon Jul 15, 2019 2:37 pm
Forum: Images du Jour
Topic: Ion Beams Destroying Viewports
Replies: 5
Views: 2600

Re: Ion Beams Destroying Viewports

The turbo's fine as it was at 66% speed and the inrush was only to ~10 torr. I isolated it immediately after noticing the problem and didn't know whether the viewport would still implode. The viewport has since been replaced with a blank and I have again done fusion, but I added some magnets on the ...
by Liam David
Sat Jul 13, 2019 11:59 pm
Forum: Images du Jour
Topic: Ion Beams Destroying Viewports
Replies: 5
Views: 2600

Ion Beams Destroying Viewports

This is yet another demonstration of why fusor chambers should not be made of glass or other brittle materials. It may also serve as a warning for those building small chambers based on 2.75" conflat systems. I have a 2.75" conflat 6-way chamber with two viewports, one on axis with a graphite and tu...
by Liam David
Sat Jul 06, 2019 4:33 pm
Forum: Images du Jour
Topic: I'm back, and fusing
Replies: 5
Views: 3412

I'm back, and fusing

It's been a few years since I posted in these forums, though recent progress on my fusor and a free summer have demanded I return. I have likely been grouped with the scores of youngsters who arrive here excited but fade away having failed to achieve fusion or lost interest. I want to remove myself ...