Magnetron Ion Gun

For the design and construction details of ion guns, necessary for more advanced designs and lower vacuums.
User avatar
Steven Sesselmann
Posts: 2127
Joined: Wed Aug 10, 2005 9:50 pm
Real name: Steven Sesselmann
Location: Sydney - Australia
Contact:

Re: Magnetron Ion Gun

Post by Steven Sesselmann »

Chris,

Not sure which diagram you are referring to, but to clarify the Starfire ion source merely uses the filament and power supply "from" a commercial magnetron, as it happens to be the perfect shape and very robust. So not a magnetron per se.

Steven
http://www.gammaspectacular.com - Gamma Spectrometry Systems
https://www.researchgate.net/profile/Steven_Sesselmann - Various papers and patents on RG
User avatar
Chris Bradley
Posts: 2930
Joined: Fri May 02, 2008 7:05 am
Real name:

Re: Magnetron Ion Gun

Post by Chris Bradley »

It was a post under (and in respect of) Ethan's, with "magnetron" printed on his image.
User avatar
Carl Willis
Posts: 2841
Joined: Thu Jul 26, 2001 7:33 pm
Real name: Carl Willis
Location: Albuquerque, New Mexico, USA
Contact:

Re: Magnetron Ion Gun

Post by Carl Willis »

Chris:

"Figure 2A" represents the standard circuit of a household microwave oven.

The magnetron tube is depicted as a high-vacuum diode, of which it is a variant.

-Carl
Carl Willis
http://carlwillis.wordpress.com/
TEL: +1-505-412-3277
EthanH719
Posts: 10
Joined: Sun Jun 21, 2009 12:56 pm
Real name:

Re: Magnetron Ion Gun

Post by EthanH719 »

Doug, you say that the ideal voltage is 70-150v? Doesn't a magnetron filament transformer only produce 3-6v (with the 2kv bias)? Yes, I do have a variac to limit current, might also be a good idea to stick a light bulb in there. I found some barium carbonate laying around, so I'll probably just use that for the coating. Also, will the fact that my vacuum chamber is charged to 15kv during operation effect the ion gun? I had to do this so I could get 30kv total across the chamber and inner grid without using a ton of current.
User avatar
Doug Coulter
Posts: 1312
Joined: Sun May 27, 2007 3:18 pm
Real name: Doug Coulter
Location: Floyd, VA, USA
Contact:

Re: Magnetron Ion Gun

Post by Doug Coulter »

That 70-100v number is for the electron velocity, not the filament heating voltage. You can try more or less, Steven seems to be saying he's using the full couple kV for this.

You'd have to ask Steven about that other question, or fill me in with a bunch more detail for me to answer. If I understand right, Steven's design uses the tank itself as the anode for the electrons, so this would make some problems perhaps....

I'm avoiding chambers that are off ground for now, but I do plan to do some interesting things in quartz tubing (pumped by the same system) with split supplies so I can use less voltage from ground on either end (which what I think you meant by "current" -- very much not the same thing, think of voltage as pressure and current as flow in a plumbing analogy and you're close).
Why guess when you can know? Measure!
Starfire
Posts: 1482
Joined: Wed Oct 24, 2001 2:14 pm
Real name:

Re: Magnetron Ion Gun

Post by Starfire »

The Starfure uses a Tungsten ring as the anode - it is swetted to the body. It is shown in photo 2

viewtopic.php?f=12&t=5013#p32321
Post Reply

Return to “Ion Gun Design and Construction (& FAQs)”