Search found 1059 matches

by Rich Feldman
Fri Apr 16, 2021 5:41 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: How much power is lost to the cathde
Replies: 8
Views: 949

Re: How much power is lost to the cathde

Thank you; beautiful picture & tells the story well. I guess there's a wee risk of indicated temperature being increased by plasma luminance, but that would apply to any optical pyrometer (even one with an imaging sensor). Sometimes I put too much effort into hands-free holding of camera, in place w...
by Rich Feldman
Wed Apr 14, 2021 3:37 am
Forum: Vacuum Technology (& FAQs)
Topic: info about TPH-050
Replies: 7
Views: 721

Re: info about TPH-050

Please let us know your results from using non-super vacuum pump oil to lubricate a turbopump. Familiar parameters are viscosity at various temperatures, vapor pressure, and chemical compatibilities. But can oil be progressively degraded by fluid shearing, which might happen at uncommonly high rates...
by Rich Feldman
Wed Apr 14, 2021 12:31 am
Forum: Fusor Construction & Operation (& FAQs)
Topic: How much power is lost to the cathde
Replies: 8
Views: 949

Re: How much power is lost to the cathde

Applause for the analog optical pyrometer! Can you get a picture of view through the eyepiece? Hard to see how a more modern instrument could be much more accurate than manually matching the brightness of reference lamp filament and luminous target, when one partly eclipses the other in field of view.
by Rich Feldman
Mon Apr 12, 2021 3:41 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Is a PMT a PMT ?
Replies: 8
Views: 401

Re: Is a PMT a PMT ?

Yay for Hamamatsu guide to PMT's.
Years ago I decided to scrounge no more PMT's before actually biasing at least one from my collection.

One difference between PMT's, aside from window size & orientation, and photocathode material,
is sensitivity to magnetic fields.
by Rich Feldman
Tue Mar 16, 2021 6:16 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Some unexpected breakdown voltage measurements
Replies: 10
Views: 1214

Re: Some unexpected breakdown voltage measurements

Applause for using a paper chart recorder, and hand-drawn graphs! My high school physics teacher taught that when "manually" reading instruments in the lab, it's a good idea to chart the point immediately, instead of just write a number in a notebook. That way, transcription blunders are caught righ...
by Rich Feldman
Mon Mar 15, 2021 10:25 pm
Forum: Advanced Technical Discussion Area
Topic: Built a giant electromagnet for magnetized fusion and plasma research
Replies: 2
Views: 1331

Re: Built a giant electromagnet for magnetized fusion and plasma research

Nice work there. What's your field modeling program? The familiar conductor-procurement issues have also been explored in my old DIY electromagnet thread, in which a steel yoke concentrates the field in an air gap much shorter than pole diameters: * For a given DC magnetic field, electric power requ...
by Rich Feldman
Sun Mar 14, 2021 2:41 am
Forum: Announcements and Site Administration Topics
Topic: Two new forums added
Replies: 3
Views: 429

Re: Two new forums added

Frank, has there been any discussion of a forum for deuterium sourcing, generating, drying, and flow control? The closest traditional forum is Vacuum Technology, since both involve plumbing, but it's been an awkward fit. Fusor Construction is an even broader bin in which to put things D2, which are ...
by Rich Feldman
Wed Mar 10, 2021 5:17 am
Forum: Items wanted
Topic: High voltage capacitors
Replies: 2
Views: 741

Re: High voltage capacitors

About how much capacitance? 0.001 uF? 50 uF? Your interest in ESL suggests a pulse discharge application, but ESL might be an important parameter in some exotic Tesla coil, or for DC power smoothing in the presence of large high frequency ripple current. Do the makers you named offer low ESL capacit...
by Rich Feldman
Sun Mar 07, 2021 2:13 am
Forum: Images du Jour
Topic: BGO gemstone
Replies: 2
Views: 457

Re: BGO gemstone

Very cool, Andrew. Thanks for sharing. Picture of real thing is worth 100 simulated renderings. Speaking of faceted gems, at some point I was visiting someone's office & got to handle a big crystal of some kind of magneto-optical garnet. It had a strong yellow or orange color, IIRC. It was amazingly...
by Rich Feldman
Thu Feb 25, 2021 1:47 am
Forum: Announcements and Site Administration Topics
Topic: Fry's Closing Down
Replies: 2
Views: 358

Re: Fry's Closing Down

Yeah, just heard about it in today's newspaper. End of an era. Not as big a cultural sea change as the end of Radio Shack, though. Another small dent in American greatness. A much more unusual institution than the late Orchard Supply Hardware chain. I first encountered Fry's in about 1980, at their ...