Search found 275 matches

by Dan Knapp
Thu Apr 30, 2020 7:23 pm
Forum: Books & References
Topic: Penning trap
Replies: 3
Views: 1487

Re: Penning trap

My two pennings worth: It doesn't look like the classic hyperbolic electrode Penning trap is a viable approach to a fusion reactor. The required potentials are too high to avoid breakdown between the closely spaced electrodes. This is another example of something that looks very promising in a compu...
by Dan Knapp
Wed Apr 29, 2020 12:02 pm
Forum: Books & References
Topic: Penning trap
Replies: 3
Views: 1487

Penning trap

If anyone is interested in details of our Penning trap efforts, a paper on it is now posted on arXiv:
arXiv:2004.13103 (Go to arXiv.org and type in identifier. I couldn’t get the pasted link to work on this page).
by Dan Knapp
Fri Apr 17, 2020 12:08 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Solderless Grid Design with Shaft Coupler
Replies: 8
Views: 1957

Re: Solderless Grid Design with Shaft Coupler

If you drill a depression in the feedthrough stalk where the setscrew tightens, it will stay on even if temperature cycling losses the setscrew.
by Dan Knapp
Fri Apr 17, 2020 2:33 am
Forum: Fusor Construction & Operation (& FAQs)
Topic: Solderless Grid Design with Shaft Coupler
Replies: 8
Views: 1957

Re: Solderless Grid Design with Shaft Coupler

I have used a similar design with a set screw sleeve having six holes (parallel to the bore). Using tungsten wire loops, the originally springy loops after heating to incandescence became stiff and brittle.
by Dan Knapp
Wed Apr 15, 2020 11:11 am
Forum: Vacuum Technology (& FAQs)
Topic: First ever Turbo experience
Replies: 38
Views: 10681

Re: First ever Turbo experience

I suspect that the SEM application would be considered “heavy use” with frequent cycling. I have run these turbos on mass spectrometers under constant vacuum for years before bearing changes were needed. Fusor use might be considered “medium” or “heavy” depending upon how much cycling of pressure on...
by Dan Knapp
Mon Apr 13, 2020 3:44 pm
Forum: Vacuum Technology (& FAQs)
Topic: First ever Turbo experience
Replies: 38
Views: 10681

Re: First ever Turbo experience

I run a Varian TV-301 (300 l/s) turbo full time without a fan. I regularly monitor its temperature with an infrared thermometer, and it usually runs 52 degrees C. They offer an optional fan for this pump "for heavy duty use" whatever that means. My guess is that I would get longer bearing life runni...
by Dan Knapp
Sat Apr 11, 2020 11:44 am
Forum: Vacuum Technology (& FAQs)
Topic: First ever Turbo experience
Replies: 38
Views: 10681

Re: First ever Turbo experience

Turbo controllers often include signal lines for rotational speed readout (commonly 0-10 VDC) as well as a switchable line for reduced speed or “soft start.” I find it useful to be able to switch to reduced speed and read out the rotational speed (yet another use for the red HF freebie meters).
by Dan Knapp
Sun Apr 05, 2020 7:54 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Fusor V construction - the process long running
Replies: 48
Views: 17817

Re: Fusor V construction - the process long running

If you need a way to make really sharp tungsten tips, I suggest using the electrochemical etching method used to make scanning tunneling microscopy probes. I used this approach when I tried to make a sharp focus cold cathode electron source. I wasn't able to get the electron current I was seeking, b...
by Dan Knapp
Wed Mar 25, 2020 2:20 am
Forum: Ion Gun Design and Construction (& FAQs)
Topic: EGPS-1012b with EGF-7 Electron Gun Kimball Physics
Replies: 1
Views: 2950

Re: EGPS-1012b with EGF-7 Electron Gun Kimball Physics

I may have that information; I’ll check my files. While I’m doing that, you should read the rules about joining and the
proper name requirement, and do as it states.
by Dan Knapp
Tue Mar 24, 2020 2:19 am
Forum: Vacuum Technology (& FAQs)
Topic: March issue of the bell jar - HV supply article
Replies: 5
Views: 1467

Re: March issue of the bell jar - HV supply article

It works for me just clicking on the link.