Search found 17 matches

by Joe Jarski
Fri Aug 17, 2012 4:54 am
Forum: Images du Jour
Topic: Archived - From the Wayback Machine - Farnsworth dynode grid
Replies: 5
Views: 3658

Re: From the Wayback Machine

Nice photo! Probably the most detailed I've seen. It'll be helpful in my project.
by Joe Jarski
Mon Feb 27, 2012 4:11 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Alpha-particle spark detector
Replies: 25
Views: 12781

Re: Alpha-particle spark detector

Yes, the circuit on the right is an input regulator. It does a good job of regulating the output voltage for detector tubes where the voltage isn't real critical. I have a 12V PS that I use to run the HV boards on several detectors in the lab so I don't have to tie up my other HV supplies.
by Joe Jarski
Sun Feb 26, 2012 7:01 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Alpha-particle spark detector
Replies: 25
Views: 12781

Re: Alpha-particle spark detector

<t>Carl, My HV supply is built on some generic boards that I had made. They use a CCFL inverter for the HV and can be stuffed for a one or two stage multiplier and either polarity. I keep several on hand and built them up as needed for GM tubes and neutron detectors. The 5kV is about the limit for t...
by Joe Jarski
Sun Feb 26, 2012 4:43 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Alpha-particle spark detector
Replies: 25
Views: 12781

Re: Alpha-particle spark detector

<t>Hi Carl,<br/> Thanks for the compliment! It seems to work well. The sensitivity appears to be about the same as yours, as best as I can judge from your video. I'm using a 50M resistor that's similar to Caddock's. The sparks may be somewhat on the weak side - they're a little difficult to see in a...
by Joe Jarski
Sun Feb 26, 2012 2:18 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Alpha-particle spark detector
Replies: 25
Views: 12781

Re: Alpha-particle spark detector

<t>I thought this was a cool piece for demonstrations when Carl originally posted it and finally got around to building my own.<br/> <br/> Wire size and spacing is the same as what Carl used. I have 8 wires on mine and the HV supply (~5kV) is mounted in the box to the bottom of the FR4 and I use a w...
by Joe Jarski
Tue Oct 25, 2011 3:50 pm
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Standard activation chamber
Replies: 12
Views: 4734

Re: Standard activation chamber

<t>Richard Hull wrote:<br/> > My general understanding as the original thrust on this was for those few hopefuls out there who would improve an already proficient fusor in a manner that they feel is genuinely significant and to know they had done it, definitively.> <br/> My thoughts on this were as ...
by Joe Jarski
Mon Sep 12, 2011 4:29 pm
Forum: Fusor Construction & Operation (& FAQs)
Topic: Home Power needs for TIG welding a fusor
Replies: 5
Views: 2196

Re: Home Power needs for TIG welding a fusor

I run a 300A inverter TIG on a 240V/50A/1PH circuit without any problems. The efficiency of the inverter helps out in that respect. So, it depends on the particular type of welder that you plan to use.
by Joe Jarski
Wed Jan 19, 2011 2:11 am
Forum: Vacuum Technology (& FAQs)
Topic: MDP Controller?
Replies: 7
Views: 2989

Re: MDP Controller?

Thanks for the link Chris. I was going to have to get my drag pumps running soon, so that'll help a lot with the rest of the wiring and running voltages.
by Joe Jarski
Sun Jan 16, 2011 5:42 pm
Forum: Vacuum Technology (& FAQs)
Topic: MDP Controller?
Replies: 7
Views: 2989

Re: MDP Controller?

<t>I haven't gotten around to making a controller, but this is what I've gathered from the internal wiring on my MDP 5011.<br/> <br/> Pin A (Red) Motor Winding<br/> Pin B (Black) Motor Winding<br/> Pin C (Green) Hall Sensor<br/> Pin D (Gray) Thermistor<br/> Pin E (White) Thermistor & Hall Sensor...
by Joe Jarski
Wed Oct 13, 2010 5:27 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: Help... Ortec 449 NIM
Replies: 7
Views: 3147

Re: Help... Ortec 449 NIM

<t>Thanks for the quick replies. I've read quite a bit on this site about the teardrop cap failures, so I'll have to go in search of the culprit or probably just replace them all. If I can get some schematics from Ortec, all the better. I haven't searched any further than the source of the burnt ele...