ICP D2 gas feed

For the design and construction details of ion guns, necessary for more advanced designs and lower vacuums.
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steve_rb
Posts: 133
Joined: Sun Oct 18, 2009 8:18 am
Real name: Steve Robinson
Location: Tehran University

ICP D2 gas feed

Post by steve_rb » Mon Jan 25, 2010 6:01 am

In a steel cylindrical ICP chamber (20 cm long and 10 cm diameter) with antenna inside what is the best way of feeding D2 gas? I am planning to feed the gas right at the center of ICP chamber via a steel tube goes coaxial with RF antena until the center of the antenna/chamber . This way gas will ionize imidiatley after exiting from steel tube holes and will have no chance to scape through ICP apertures without ionization. will this may disturb RF effect?

Linda Haile
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Re: ICP D2 gas feed

Post by Linda Haile » Mon Jan 25, 2010 2:16 pm

I'm no expert but I imagine the steel gas feed tube will get hot due to induction heating. This may also use a lot of the available power and may result in cooling problems. I'm also interested in ICP ion sources but as I said I'm no expert, I'm just guessing. Why don't you feed the D in from one end and extract ions from the other end? Why use a metal cylinder instead of quartz?I'm interested in your reasons as I'm planning to construct my own ICP source.

steve_rb
Posts: 133
Joined: Sun Oct 18, 2009 8:18 am
Real name: Steve Robinson
Location: Tehran University

Re: ICP D2 gas feed

Post by steve_rb » Tue Jan 26, 2010 4:33 am

yes you are right I might use quartz feeding tube with some holes at the end instead of steel tube. I mentioned the reason. I want to minimize gas molecules scape chance before ionization. injecting at the center of the antenna will cause all molecules to be ionized. feeding from one end will cause density to increase and molecules to start diffusing in different directions and they may go towards exit holes and scape. If you put a radiator in the middle of a room in the winter you can get uniform heat in every direction (although this is not good for a living place) but if you put it in one corner of your room you will get one corner too hot and oposite corner too cold.

I have to use steel cylinder since need to connect cylinder wall to positive voltage and the target to negative voltage. I am thingking about building Ka-ngo leung type fusor.

What type of ICP are you planning to build?

Linda Haile
Posts: 230
Joined: Mon Jan 04, 2010 9:28 pm
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Re: ICP D2 gas feed

Post by Linda Haile » Tue Jan 26, 2010 6:12 pm

I mean't quartz instead of the steel cylinder, but I now follow what you are trying yo do. As I understand it putting the coil inside could result in some reaction between the coil and plasma but this may be acceptable, I don't know.It does sounde like a worthwhile experiment but it may be interesting to see what others think, as I said I'm no expert. My ICP will be conventional quartz tube with coil on the outside but I will experiment with different frequencies/power circuits etc

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