Search found 122 matches

by Bruce Meagher
Sat Nov 23, 2019 12:38 am
Forum: Vacuum Technology (& FAQs)
Topic: Oil options for rough pumps
Replies: 13
Views: 437

Re: Oil options for rough pumps

Mark, I respectively disagree with your statement about HVAC oil, and I believe it’s poor advice to provide others on the forum. I was the one that had my son run the test with HVAC oil so he could learn about vapor pressure. Here’s the thread < https://fusor.net/board/viewtopic.php?f=10&t=12189&sta...
by Bruce Meagher
Sat May 18, 2019 5:06 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Ludlum 42-31
Replies: 10
Views: 5682

Re: Ludlum 42-31

One way to determine if you have a BF3 or He3 tube is to look at the output pulse height spectrum. The two spectrums are significantly different. Knoll’s book covers this in detail, but there are many practical examples in past fusor posts. One He3 pulse height spectrum I captured is described in th...
by Bruce Meagher
Sat May 11, 2019 6:31 pm
Forum: Vacuum Technology (& FAQs)
Topic: Poor performance of old diff pump.
Replies: 13
Views: 7688

Re: Poor performance of old diff pump.

Wow that’s an impressive pump! Thanks for sharing and updating your post. I look forward to hearing how your system performs with your new pump. Many of the combo gauges have replaceable Pirani sensor. I’m not sure about your particular gauge (or if it’s really worth your time), but something to con...
by Bruce Meagher
Tue Apr 30, 2019 2:29 pm
Forum: Images du Jour
Topic: More Upgrades
Replies: 14
Views: 7804

Re: More Upgrades

I misinterpreted your previous post. I thought you were implying the D-D fusion cross section decreased above 150 keV. My Bad. Even though there is only a small increase in cross section between say 100 and 200 keV the neutron production rate more than doubles over this interval. However, as your ri...
by Bruce Meagher
Sat Apr 27, 2019 6:51 am
Forum: Images du Jour
Topic: More Upgrades
Replies: 14
Views: 7804

Re: More Upgrades

Richard, I believe you are quoting the D-T cross-section curve (not the D-D cross-section) in your comment above. The D-D fusion cross-section doesn't fall off until a few MeV. Below is a graph of the different fusion reaction cross-sections vs energy taken from: http://www.kayelaby.npl.co.uk/atomic...
by Bruce Meagher
Tue Apr 23, 2019 5:59 pm
Forum: Images du Jour
Topic: Starting fusor build
Replies: 2
Views: 2362

Re: Starting fusor build

Luke, Here are a few comments on your nice setup... Have you considered the expected temperature your grid will reach during operation? At fusion producing power levels will your silver brazed connections hold? Jon R. had a nice post about his grid design and how he mechanically attached the grid to...
by Bruce Meagher
Thu Mar 28, 2019 4:01 pm
Forum: Images du Jour
Topic: We've got plasma!
Replies: 7
Views: 3696

Re: We've got plasma!

Your team has a very nice looking setup. I would suggest you be careful reporting your pressure results with such precision. I would be surprised if your pressure gauge has the precision or accuracy to report to the tenth of a millitorr. With the proliferation of digital gauges it's easy to forget t...
by Bruce Meagher
Mon Mar 18, 2019 6:37 pm
Forum: Announcements and Site Administration Topics
Topic: Commentary on Doing Fusion
Replies: 17
Views: 7362

Re: Commentary on Doing Fusion

Here’s my take… If you look back to the first “youngest” fusonieer, Taylor, we see his fusor was hardly a solo effort. Taylor's first working fusor was built in a lab at the University of Nevada, with many, if not most, of the parts and detection gear coming from the university. In several of Taylor...
by Bruce Meagher
Thu Mar 14, 2019 10:13 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Vaccum Leak Testing / Technique and Power Supply Question
Replies: 18
Views: 8409

Re: Vaccum Leak Testing / Technique and Power Supply Question

Ian, I think you’re giving incorrect advice on vacuum pump oil. Look at the experiment Tyler ran to see why typical A/C vacuum oil is a poor choice http://www.fusor.net/board/viewtopic.php?f=10&t=12189&p=80054&hilit=Tyler#p80054 I'd recommend ballasting the pump for a couple hours with the inlet bla...
by Bruce Meagher
Thu Feb 14, 2019 6:09 pm
Forum: Vacuum Technology (& FAQs)
Topic: Cleaning/Repairing Edwards E2M5
Replies: 24
Views: 10061

Re: Cleaning/Repairing Edwards E2M5

Before you disassemble your pump are your sure you don't have a leak around the BSP threads on the intake flange? I know I steered you to the inexpensive intake flange, and as I mentioned this cheap version does not have a proper o-ring seal. The BSP threads are straight making it a little more diff...