Search found 134 matches

by Maciek Szymanski
Wed Feb 03, 2021 8:52 pm
Forum: Vacuum Technology (& FAQs)
Topic: Bell and whistles diffusion pump based vacuum system.
Replies: 32
Views: 4693

Re: Bell and whistles diffusion pump based vacuum system.

I’ve finally replaced the faulty switches with the 5A old stock Russian ones. And today I’ve started the diffusion pump for the first time. It worked seamlessly pumping the chamber (the gate valve body blanked with a 100mm flange and a viewport) down below 1 micron in less than minute. But I was sur...
by Maciek Szymanski
Mon Feb 01, 2021 9:22 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Extremally cheap HV feed through (if you have a lathe in hand)
Replies: 18
Views: 2058

Re: Extremally cheap HV feed through (if you have a lathe in hand)

I’m not sure what kind of glass it was, but probably borosilicate. And regarding the resistor - I suppose that this HF switching Glassman PSU is much more “jumpy” than that this big, high inductance iron core you are using Richard. I had chance to buy a 125kV 3 phase X-ray transformer for much less ...
by Maciek Szymanski
Mon Feb 01, 2021 6:35 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Extremally cheap HV feed through (if you have a lathe in hand)
Replies: 18
Views: 2058

Re: Extremally cheap HV feed through (if you have a lathe in hand)

Today I’ve installed the 40kΩ 150W ballast resistor. It has improved the power supply operation - I was able to stabilize the discharge at 18kV 30mA at pressure 4 to 6e-3 mbar. Still it required lot of fiddling with controls, and before I’ve mastered the technique the electron beam heating has cause...
by Maciek Szymanski
Mon Feb 01, 2021 7:38 am
Forum: Vacuum Technology (& FAQs)
Topic: DIY Penning gauge controller?
Replies: 6
Views: 844

Re: DIY Penning gauge controller?

Here you are the schematic of the Unima PWN100 vacuum gauge. It is combined gauge with two TC low vacuum sensors (G1 and G2) and cold cathode ionization sensor (GJ). There is also automatic range switching comparator for the low vacuum range, making the circuit a bit more complicated. But the basic ...
by Maciek Szymanski
Sun Jan 31, 2021 4:16 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Extremally cheap HV feed through (if you have a lathe in hand)
Replies: 18
Views: 2058

Re: Extremally cheap HV feed through (if you have a lathe in hand)

I’m using Edwards’ product, but probably it’s very similar to the Apiezon Wax. I have quite good results with it, albeit it takes some time to master the technique and getting an ugly mess on first trying is rather mandatory. An important trick is that is doesn’t stick to the wet fingers. The Apiezo...
by Maciek Szymanski
Wed Jan 27, 2021 7:30 pm
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Extremally cheap HV feed through (if you have a lathe in hand)
Replies: 18
Views: 2058

Re: Extremally cheap HV feed through (if you have a lathe in hand)

Today I’ve finally wired the Glassman LK power supply (I’ve to swap the HV module for the negative polarity) and tested the feed through. I’ve successfully brought it to 30kV. With the chamber pumped to some 1e-5 mbar the leak current was in 0.1-0.3 mA range. There were some spots of electron emissi...
by Maciek Szymanski
Thu Jan 21, 2021 4:58 pm
Forum: Fusion --- Past, Present, and Future
Topic: The planet of the humans equivalent. A no fusion future
Replies: 2
Views: 2357

Re: The planet of the humans equivalent. A no fusion future

I’m a born skeptic so looking back into fusion research leads me to many doubts. But I don’t agree with economic arguments against fusion. Magnetic fields, plasma confinement and radiation are real things that can be researched and tamed. Economy and money are only in human heads. They work, because...
by Maciek Szymanski
Thu Jan 21, 2021 10:35 am
Forum: Neutrons, Radiation, and Detection (& FAQs)
Topic: DIY gas filled proportional tubes
Replies: 8
Views: 1038

Re: DIY gas filled proportional tubes

There is a grat chapter on practical building GM and proportional tubes (1939 state of art) in "Procedures In Experimental Physics" by Roger Hayward

https://archive.org/details/in.ernet.dli.2015.212054/
by Maciek Szymanski
Mon Jan 18, 2021 7:31 am
Forum: Items For Sale
Topic: PMT-4M thermocouple vacuum gauges
Replies: 3
Views: 1446

Re: PMT-4M thermocouple vacuum gauges

Yes, the tubes are still available. I don't have sockets, but they are standard octal type tube sockets. Regarding the pickup - yes it is possible, check your PM.