Basic Duoplasmatron Ion Gun
Posted: Wed Jul 29, 2015 4:13 pm
Hi,
I've been planning a deuterium ion source that's fairly simple and just wanted some feedback on it. A diagram is posted below of the ion gun but I'll describe it too. Basically it uses a filament emitting electrons through thermionic emission. The filament will be negatively charged DC which should enhance the emission due to the schottchky effect. A plate with a strong negative bias placed behind the filament will push the electrons away as well. A small pipe will be charged with a negative bias and concentrate the electrons. This will change into a smaller pipe which concentrates the electrons into a more dense e beam. An inductor will be placed throughout this area and direct the electrons motion using magnetic field lines. The concentrated e beam will be shot into the second stage of the ion gun where deuterium gas leaks into the chamber. The gas, initially not ionized, will be bombarded with electrons from the e beam. The electrons will "knock off" valence electrons from their orbit of the deuterium gas, ionizing it. The deuterons will reach a pipe with a magnetic field created from an inductor and be organized into a specific direction. The ions will be concentrated using a smaller positive bias rod which will also terminate remaining electrons from the plasma. They will then reach my main vacuum chamber where the fusion happens!
It's not too hard of a design; however, I need to figure out the correct voltages for my filament (which will have a DC neg. bias) and for both pipes with negative and positive biases. If someone could suggest a range of voltages and currents for these it'd be great! I don't want to do anything with radio frequency yet because it's my first time building an ion gun and I've read about how complicated it can get- just out of curiosity though is the RF pulsed through an inductor creating a magnetic field?
As far as materials go for this design I'm probably going to use some parts from McMaster Carr. I want to use a thicker filament so it doesn't risk burning out like a regular tungsten lightbulb filament might. Also more surface area should increase emissions which is good. It's hard to find a thicker filament, any suggestions on what to do for this? It should probably be coated too because that will help emission rate. I was wondering if class 150 black steel flanges will create a strong enough seal for a low pressure (http://www.zoro.com/value-brand-slip-on ... /G1657162/)?
- Jeremy
I've been planning a deuterium ion source that's fairly simple and just wanted some feedback on it. A diagram is posted below of the ion gun but I'll describe it too. Basically it uses a filament emitting electrons through thermionic emission. The filament will be negatively charged DC which should enhance the emission due to the schottchky effect. A plate with a strong negative bias placed behind the filament will push the electrons away as well. A small pipe will be charged with a negative bias and concentrate the electrons. This will change into a smaller pipe which concentrates the electrons into a more dense e beam. An inductor will be placed throughout this area and direct the electrons motion using magnetic field lines. The concentrated e beam will be shot into the second stage of the ion gun where deuterium gas leaks into the chamber. The gas, initially not ionized, will be bombarded with electrons from the e beam. The electrons will "knock off" valence electrons from their orbit of the deuterium gas, ionizing it. The deuterons will reach a pipe with a magnetic field created from an inductor and be organized into a specific direction. The ions will be concentrated using a smaller positive bias rod which will also terminate remaining electrons from the plasma. They will then reach my main vacuum chamber where the fusion happens!
It's not too hard of a design; however, I need to figure out the correct voltages for my filament (which will have a DC neg. bias) and for both pipes with negative and positive biases. If someone could suggest a range of voltages and currents for these it'd be great! I don't want to do anything with radio frequency yet because it's my first time building an ion gun and I've read about how complicated it can get- just out of curiosity though is the RF pulsed through an inductor creating a magnetic field?
As far as materials go for this design I'm probably going to use some parts from McMaster Carr. I want to use a thicker filament so it doesn't risk burning out like a regular tungsten lightbulb filament might. Also more surface area should increase emissions which is good. It's hard to find a thicker filament, any suggestions on what to do for this? It should probably be coated too because that will help emission rate. I was wondering if class 150 black steel flanges will create a strong enough seal for a low pressure (http://www.zoro.com/value-brand-slip-on ... /G1657162/)?
- Jeremy