Search found 1056 matches

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: 211

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: 1177

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: 1213

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: 423

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: 703

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: 452

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: 354

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 ...
by Rich Feldman
Mon Feb 22, 2021 5:40 am
Forum: Items For Sale
Topic: Random Transformer for sale
Replies: 1
Views: 416

Re: Random Transformer for sale

Looks like it could be a HV-isolated filament transformer.
What's the resistance between the two brass terminals on top? Does the red insulated part have any other terminals?
by Rich Feldman
Thu Feb 11, 2021 12:00 am
Forum: Fusor Construction & Operation (& FAQs)
Topic: Mass flow controller question
Replies: 20
Views: 2090

Re: Mass flow controller question

I've been happy with several purchases from Svcstore, generally picking them up in person since they are not far away. I think that's where I got my NIM bin and detector-bias power supply. Here's a post by Joe Gayo about MFC's, with a followup by me about what's inside one I was given by Greg Courvi...
by Rich Feldman
Mon Feb 08, 2021 6:38 pm
Forum: Items For Sale
Topic: Rich Feldman's store. Today's feature: beryllium sheet
Replies: 17
Views: 5051

Re: Rich Feldman's store. Today's feature: beryllium sheet

Just measured both kinds of vacuum hose, which are still available for cost of shipping. I think both are intended to go on 1/2" OD spigots, or similar hose-barb fittings. hosen.jpg The clear stuff is 0.50" inside, 0.77" outside. In my experience, ordinary worm-gear hose clamps can secure and seal t...