Search found 29 matches

by Paul W Fontana
Tue Feb 20, 2018 6:05 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Saving another PNC-1
Replies: 6
Views: 3435

Re: Saving another PNC-1

Does anyone have a schematic for the PNC-1, and/or some troubleshooting tips? We found four of these in the back of a cupboard dating back at least to the 1970's, but none of them are in working order. Some students are trying to see if they can refurbish at least one.

-- pwf
by Paul W Fontana
Thu Apr 27, 2017 11:22 pm
Forum: Other Forms of Fusion - Theory, Construction, Discussion, URLs
Topic: Laser-driven Spherically Convergent Plasma Fusion
Replies: 8
Views: 4821

Re: Laser-driven Spherically Convergent Plasma Fusion

Of course, the stated purpose of the device is not to produce energy, but to generate neutrons. To that end, it appears to me to do a pretty good job. Each pulse produces as many neutrons as about 15 min. of operation of a good fusor. What's not clear to me is whether the hohlraum needs to be replac...
by Paul W Fontana
Wed Apr 26, 2017 6:34 pm
Forum: Other Forms of Fusion - Theory, Construction, Discussion, URLs
Topic: Laser-driven Spherically Convergent Plasma Fusion
Replies: 8
Views: 4821

Laser-driven Spherically Convergent Plasma Fusion

A "new" method for producing fusion neutrons has been demonstrated - looks like it's basically a tabletop ICF device: https://physics.aps.org/synopsis-for/10 ... 118.165001.

-- pwf
by Paul W Fontana
Thu Mar 09, 2017 10:17 pm
Forum: Fusion --- Past, Present, and Future
Topic: Shine - a real use for fusion, now!
Replies: 23
Views: 14952

Re: Shine - a real use for fusion, now!

Update: The students got the neutron detector tuned up (a small 3He tube device), but were only able to detect about 1 cpm (over a background of about 0.2 cpm) from the Po-Be source after counting with and without moderator for 45 min each. We estimate that source is generating about 6000 n/s isotro...
by Paul W Fontana
Mon Feb 20, 2017 5:09 pm
Forum: Fusion --- Past, Present, and Future
Topic: Shine - a real use for fusion, now!
Replies: 23
Views: 14952

Re: Shine - a real use for fusion, now!

Thanks, Jon! Nice work. Gamma spec we got. Nuclespot Po-Be source we got. Time for long activation runs we got. Moly we don't have yet - I'm guessing a run-of-the-mill coin will do the trick? Is there an ideal thickness? I'm looking for some interesting and challenging things for the students in the...
by Paul W Fontana
Fri Feb 17, 2017 12:44 am
Forum: Fusion --- Past, Present, and Future
Topic: Shine - a real use for fusion, now!
Replies: 23
Views: 14952

Re: Shine - a real use for fusion, now!

Has anyone here tried to generate Mo99 by neutron bombardment of Mo98? Would it be feasible (just to observe the transmutation to Tc99, not for commercial purposes) with a Po-Be neutron source, if not a fusor? I saw a thread ( http://www.fusor.net/board/viewtopic.php?f=13&t=6266 ) where @RobertTubbs...
by Paul W Fontana
Sun Sep 25, 2016 5:12 am
Forum: Images du Jour
Topic: Images of 100 kV Voltage Multiplier
Replies: 7
Views: 3199

Re: Images of 100 kV Voltage Multiplier

Looks really nice! Is that a five-stage Cockroft-Walton?

Let us know what happens when you put a load on it.

-- pwf
by Paul W Fontana
Tue Feb 16, 2016 10:38 pm
Forum: Vacuum Technology (& FAQs)
Topic: Best gas for plasma cleaning?
Replies: 7
Views: 2712

Re: Best gas for plasma cleaning?

Back when I worked in toroidal magnetic confinement (not-quite-tokamak), we would make hydrogen plasmas during the day and use helium discharges for daily overnight conditioning. I'm not sure why, except that it was less prone to loading the walls than hydrogen and tended to produce a consistent sta...
by Paul W Fontana
Fri Feb 05, 2016 9:47 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Need HV connector for Spellman XLF
Replies: 10
Views: 6030

Re: Need HV connector for Spellman XLF

Here's what I came up with. 1/4" o.d. copper tubing for the tip, soldered to conductor of 50kV-insulated wire, inserted through 5/8" o.d. x 1/2" i.d. Delrin tube long enough to stick out of the socket about 3-1/2", tip epoxied to the end with (2) 1/4 sae washers for centering and mechanical support....
by Paul W Fontana
Fri Jan 29, 2016 6:22 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Dummy load for HV supply
Replies: 23
Views: 12269

Re: Dummy load for HV supply

@John Thanks for the photos! Where do you get those nice corona rings? I was thinking I would make one out of copper tubing, but if I wanted to get a commercial one I have no idea where I would look. Speaking of, with all the HV experience here someone will be able to tell me - am I likely to need m...