ion gun parts

For the design and construction details of ion guns, necessary for more advanced designs and lower vacuums.
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dudleyhd
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ion gun parts

Post by dudleyhd » Wed Apr 09, 2008 11:48 pm

where would be a good place find information and to buy parts to build a farnsworth type ion gun thank you james

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Richard Hull
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Re: ion gun parts

Post by Richard Hull » Thu Apr 10, 2008 2:38 pm

Ion guns are expensive and ready made parts for them are outrageously expensive.

Crude, but effective, ion guns can be easily assembled by adroit hands that are skilled in the use of machine tools.

I would suggest you look at a laboratory handbook of physics harware construction like
viewtopic.php?f=21&t=8046#p57462

Ions guns are a specialized world and making and using a good one can be a year long experience in itself.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

dudleyhd
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Re: ion gun parts

Post by dudleyhd » Thu Apr 10, 2008 2:56 pm

my freind has a cnc and will make me the assembly in trade i just need to find the configuration i want i am leaning towards this for simplicity i am not going to be using it on a fusor im using as an accelerator for different project where it wont be as crutial

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Carl Willis
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Re: ion gun parts

Post by Carl Willis » Thu Apr 10, 2008 10:08 pm

James,

What kind of ion and what current is needed? This will determine the options for an ion source.

Some of the most efficient H+ sources are made almost entirely from glass, which does not catalyze recombination to form molecular ions like metals. A magnetically-enhanced RF electrodeless discharge in a glass tube is an effective and well-documented source of protons that can be extracted at up to a few mA. Some such designs can be read about in great detail in old Rev. Sci. Instruments publications.

At the lab where I work, we use proton sources delivering up to 30 mA from an ECR-enhanced 2.54 GHz discharge. The plasma chamber is a portion of waveguide surfaced in critical places with alumina and boron nitride.

-Carl
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dudleyhd
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Re: ion gun parts

Post by dudleyhd » Thu Apr 10, 2008 11:12 pm

Mr Willis i dont really know what ion source i need cause i dont really know what im doing in the physics department. I want to take hho- an h20 gas load it with protons put it throu the ion source and come out with the most molecularly unstable gas combination i can get . I do know how ever what im trying to copy was around 600 volts has an electron extraction circuit built in it. Im no physics person so i dont 100% know what i need . Do you have an ideas or suggestions. I will go with an educated guess on the ion type


Mr Hull took your advice and am bidding on the procedures in experimental physics on ebay hopefully will win it i bid high so i think i will also looking for the building scientific apparatus one

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Mark Rowley
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Re: ion gun parts

Post by Mark Rowley » Fri Apr 11, 2008 2:10 am

Those books are for immediate sale on Amazon.

Just as a confirmatory side note, Richard was right when he said "Ya' can't really say you have a lab or library without these two books." My constant referencing of them has caused the newer of the two to become quite soiled.

If you want "Building Scientific Apparatus", make sure you get a hardcover edition. The paperback is of a rather odd shape.

Mark Rowley

dudleyhd
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Re: ion gun parts

Post by dudleyhd » Fri Apr 11, 2008 3:05 am

Mr Rowley thank you for your advice also i order the one book from amazon and i already bid on the ebay one so will see what happens in a day or two with that thank you everyone for your help it is most appreciated

DaveC
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Re: ion gun parts

Post by DaveC » Fri Apr 11, 2008 7:15 am

James -

An ion source ("ion gun") is actually very easy to build.... a length of small diameter tungsten or tantalum wire, (nichrome will also work nicely, too)....set in the center, along the axis of a similar length piece of vacuum piping, a few cm to few inches in diameter.... and that's it. Energize the wire with a positive potential of a few hundred volts, ( more or less depending on the pressure) and pump the piece of piping to a pressure below 10-2 Torr and you will have all the ions you want.

It is not difficult with such a configuration to achieve ion currents of 1A/m or more.

Details include the use of some vacuum grade feedtroughs, either home-built or BNC bulkhead connectors, some simple valves and a gas inlet port for whatever gas (He, H, Ar or ??).

You do need to be careful with flammable gase, since the vacuum system will collect them and exhaust them at atmospheric pressure...they can well be in explosive concentrations at the pump outlet.

Systems utilizing this arrangement typically have a port in one side of the tube allowing ions to exit into some other apparatus. The port can have a metallic screen of reasonably open design, if desired.

Power supplies for an ion gun need to be ballasted in some way for stability. The fluorescent lamp ballast with a diode rectifier can be made to work - it's cheap and. reliable... Ballasts for dual 40W lamps typically handle 450 mA at up to 650-700 volts RMS, and can do it continuously. .

So ions aren't hard to generate... What you intend to do after that, will determine how much more apparatus you will need and the basic complexity. It pays to spend a lot of time thinking about what the experiment(s) are going to show. before and during the hardware collection phase.


Dave Cooper

dudleyhd
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Re: ion gun parts

Post by dudleyhd » Fri Apr 11, 2008 5:59 pm

i now have both books you guy suggested coming will be here in a few day

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Re: ion gun parts

Post by dudleyhd » Sat Apr 12, 2008 7:56 pm

mr willis i have researched what i need further i have to make an electrostatic accelerator more than 40kv negative ion dc voltage

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