Search found 213 matches

by Dan Knapp
Fri Nov 30, 2018 12:25 pm
Forum: Ion Gun Design and Construction (& FAQs)
Topic: Electron Impact Ion Source pictures wanted
Replies: 3
Views: 467

Re: Electron Impact Ion Source pictures wanted

The ion sources I’ve worked with were typically about a 15 x 15 x 10 mm “box” with the ion exit hole centered on a 15 x 15 side. The holes were on the order of about 2 mm diameter. For RGA’s, the “box is more open to sample the vacuum environment. For externally introduced samples, an insulating tub...
by Dan Knapp
Mon Nov 26, 2018 1:06 pm
Forum: Ion Gun Design and Construction (& FAQs)
Topic: Electron Impact Ion Source pictures wanted
Replies: 3
Views: 467

Re: Electron Impact Ion Source pictures wanted

Mass spectrometer electron impact ions sources tend to be of relatively simple construction. I’ve worked on dozens of different ones in my forty plus years in that business. They are essentially a box (“ion volume”) with an ion exit hole usually orthogonal to the electron beam, which is provided typ...
by Dan Knapp
Thu Nov 22, 2018 1:53 pm
Forum: Advanced Technical Discussion Area
Topic: Harbor Freight freebie meters
Replies: 12
Views: 949

Re: Harbor Freight freebie meters

It looks like I should have been aware of the 1 Meg input resistance if I had remembered some previous posts on these meters, but at my age I’m doing well to remember my name. At any rate, my post precipitated some interesting discussion. I have an unrelated question that relates to my present task ...
by Dan Knapp
Tue Nov 20, 2018 1:09 pm
Forum: Advanced Technical Discussion Area
Topic: Harbor Freight freebie meters
Replies: 12
Views: 949

Harbor Freight freebie meters

This is not exactly advanced technical discussion, but I didn’t find a more appropriate section. The Harbor Freight red digital multimeters have been mentioned multiple times. I just discovered yesterday that these have only a 1 megohm input impedance. Nowhere in the manual or online specifications ...
by Dan Knapp
Mon Nov 12, 2018 3:21 am
Forum: New User Chat Area
Topic: Crystal synthesis inside a vacuum?
Replies: 3
Views: 307

Re: Crystal synthesis inside a vacuum?

That’s how they make synthetic diamonds (as well as other crystals), but they don’t start with powders; they use gaseous precursors. It is a very slow process and requires extremely well controlled conditions.
by Dan Knapp
Thu Nov 01, 2018 2:15 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Neutron Detector and Moderator Test
Replies: 9
Views: 1136

Re: Neutron Detector and Moderator Test

Kai I can’t offer any input on your numbers, but the fact that the moderator increases your counts suggests you are indeed counting neutrons. You haven’t demonstrated selectivity for neutrons over gammas (the Troxler gauge also contains a cesium-137 gamma source), so some of your counts could be fro...
by Dan Knapp
Tue Oct 30, 2018 3:17 pm
Forum: Fusor and/or General Fusion Theory (& FAQs)
Topic: Titanium walls
Replies: 10
Views: 2277

Re: Titanium walls

Check the presentations from the recent fusion neutron sources meeting at: http://www.fusor.net/board/viewtopic.php?f=47&t=12463 The Kyoto group saw a fourfold increase in neutron production going from a stainless steel chamber to a titanium chamber. This group is one of the top IEC labs in the worl...
by Dan Knapp
Thu Oct 18, 2018 9:34 pm
Forum: Announcements and Site Administration Topics
Topic: Abstracts posted for 20th US-Japan IECF Workshop
Replies: 6
Views: 1485

Re: Abstracts posted for 20th US-Japan IECF Workshop

The meeting was held on Tuesday this week. It was a full day of very interesting presentations. Of possible interest to this group in particular, the Kansai University group reported results from fusors using cubic anodes and cathodes. The cubic shapes are easier to construct than spherical grids. T...
by Dan Knapp
Mon Oct 08, 2018 2:54 pm
Forum: Announcements and Site Administration Topics
Topic: Abstracts posted for 20th US-Japan IECF Workshop
Replies: 6
Views: 1485

Abstracts posted for 20th US-Japan IECF Workshop

The 20th US-Japan Workshop on Fusion Neutron Sources for Nuclear Assay and Alternate Applications (formerly called workshop on IECF) will be held next week at the University of Maryland. The abstracts for the meeting are now posted at: https://blog.umd.edu/iecf/posterspresentations/ Of particular in...