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Re: Beam on Pd-D-Li Target Fusor

Posted: Thu Dec 27, 2018 6:08 am
by ian_krase
Personally, I would avoid messing around with a cathode ray tube and just build up an ion source from normal lab-bench vacuum components.

Also worth noting is that electron beams are not really efficient for bulk ionization of gas, and they have drawbacks. The coating on the cathode may not survive exposure to air even when cold and is easily poisoned by various materials.

I would use a kanal or magnetron style of ion source.

Re: Beam on Pd-D-Li Target Fusor

Posted: Thu Dec 27, 2018 2:05 pm
by Dennis P Brown
There are many posts and designs for true deuterium ion guns here in this forum to search out. Also, focusing of the beam, while not really needed for short systems, is extremely easy using a simple electro-magnet (wound copper wire coil) or even a simple ring magnet mounted onto a glass tube (the glass tube being your vacuum accelerating path - gun at one end, target at the other.)

These designs require high vacuum to work (10^-6 torr) - so a diffusion pump with a trap or turbo is essential - ions do not travel far otherwise.

Another issue is the accelerating voltage. Most people use a positive 50 - 100 kV power supply to repeal/drive the ions (and a 5-15 kV negative supply to ionize the gas.) As for voltage the higher the better to get good rates of fusion; also, power supply current matters since that will ultimately determine your ion current.

These designs can be fierce x-ray sources so one needs to shield these devices carefully and take precautions.

As someone who built such a unit they are not too difficult to build in theory but in practice, can get complex fast. I abandoned mine at its test stage for a fusor after building a complete unit - my van de graaf failed and the 75 kV supply I built was far too dangerous to operate in the open - hind site. But it was fun building that monster.

A titanium target is just as good as a Pd one since both can be used to hold deuterium.

The amount of any tritium created in any fusor reaction by any system someone can build is so trivial and irrelevant that it will have essentially zero probability of reacting in any manner. As for health dangers from tritium even from a high end fusor - that is zero.

That all said, building a simple ion gun (low voltage ionizer system) isn't difficult and can be useful as an exercise in vacuum work and learning about moderate voltage power supplies (1 - 5 kV.) But don't expect any fusion at all relative to a target if you use any such low voltage system.