Electrode design update

Posted by Admin on Jan 14, 2004 at 04:12 PM
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Doug Olsen’s studies of the electrode design (see Electrode Design)  indicate that the original design of very thin anodes, 0.25 cm radius, is not practical because of the mechanical stress caused by both heating and pinching.

In addition calculations indicate that, for the range of x-ray intensity that would exist for a reactor, a layer of copper would be vaporized from the anode for each shot. So we have concluded that for the operational reactor, and probably for high current experiments with pB11, we will need beryllium (Be) anodes. Here the x-rays will mostly pass through the Be and the small number that are absorbed will be harmlessly dissipated in a large volume, due to beryllium’s transparency to x-rays. In addition, to reduce the thermal stress we are looking at a tapered electrode, perhaps as large as 2 cm in radius at the base, tapering to 1 cm at the tip. This would require a larger cathode as well, 5 cm in radius and a larger current, 3MA rather than 1.5 MA. But these are preliminary guesses and analysis is not yet complete.