Search found 211 matches

by Jeroen Vriesman
Wed Sep 16, 2015 11:18 am
Forum: Ion Gun Design and Construction (& FAQs)
Topic: Tungsten Emitter
Replies: 20
Views: 15278

Re: Tungsten Emitter

Your emission will be much better if you can use thoriated tungsten. (So you need less heating for the same amount of electrons, and your wire lives longer). You do need to activate it, which simply means running the wire very hot for a short time, a very thin layer of thorium will form on the surfa...
by Jeroen Vriesman
Thu Sep 03, 2015 7:53 am
Forum: Vacuum Technology (& FAQs)
Topic: Capacitive manometers
Replies: 28
Views: 9705

Re: Capacitive manometers

Hi Doug, correction, it's 5 torr at 10V, but what you say is exactly what I've done. It's just that I don't have any reference, so besides the fact that the baratron says "10V means 5 torr" (which I translated to Pa with the resistor divider) I don't know how precise that value is. Is there a way to...
by Jeroen Vriesman
Wed Sep 02, 2015 8:21 am
Forum: Vacuum Technology (& FAQs)
Topic: Capacitive manometers
Replies: 28
Views: 9705

Re: Capacitive manometers

We use a "baratron" (capacitive sensor) for our bell jar chamber. Very simple, a 20VAC output transformer making a symmetrical DC voltage over two caps with two diodes, then 7815 and 7915 to make symmetrical +/- 15V for the baratron. Our baratron is 1 Torr @ 10V, we connected a standard DVM module w...
by Jeroen Vriesman
Fri Aug 21, 2015 7:40 am
Forum: Images du Jour
Topic: Magnetic grid
Replies: 7
Views: 3339

Re: Magnetic grid

Roberto,

hydrogenation is a NdFeB problem, CoSm doesn't have this problem.
I use nickel plated CoSm.

http://www.mceproducts.com/Knowledge_Ba ... marium.htm
by Jeroen Vriesman
Wed Aug 19, 2015 10:23 am
Forum: Images du Jour
Topic: Magnetic grid
Replies: 7
Views: 3339

Re: Magnetic grid

Richard, indeed I chose CoSm for the high curie point. And I also would be amazed if it works as expected. (and even if the current is lower at the same voltage/pressure I still wouldn't know if my ideas have any relation with reality :) ) Because of the thermal effects I can only use a low current,...
by Jeroen Vriesman
Tue Aug 18, 2015 9:28 pm
Forum: Images du Jour
Topic: Magnetic grid
Replies: 7
Views: 3339

Magnetic grid

This grid is made of 24 CoSm magnets, each side of the cube is a magnetic quadrupole. Still working on pressure control, no star mode yet. The idea is that a particle beam going in and out the cube (star mode) travels in both directions through the quadrupole, which might have an effect similar to "...
by Jeroen Vriesman
Mon Jul 13, 2015 1:15 pm
Forum: Fusion --- Past, Present, and Future
Topic: Major Milestone for Fusion Stellarator W 7-X
Replies: 5
Views: 3303

Re: Major Milestone for Fusion Stellarator W 7-X

Thanks for the link, really great, seems much more promising than tokamaks.

But the 10MW is not energy production, it's ECRH "electron cyclotron resonance heating".
In other words: it's not producing 10MW, the plasma is consuming 10MW.
by Jeroen Vriesman
Tue Jun 23, 2015 10:51 am
Forum: High Voltage - Fusor Input Power (& FAQs)
Topic: Rectifier with X-Ray Transformer
Replies: 4
Views: 2899

Re: Rectifier with X-Ray Transformer

The neon transformer usually has a center tap connected to ground (case of the transformer). To use both sides for the secondary winding two diodes are needed. Any non-superconducting transformer is always AC, so the output from your X-ray transformer is AC, not negative. You can rectify is with one...