Accelerator Tube Revisited

For the design and construction details of ion guns, necessary for more advanced designs and lower vacuums.
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Peter Schmelcher
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Real name: Peter Schmelcher

Re: Accelerator Tube Revisited

Post by Peter Schmelcher »

George these attachments are on HV insulation design and there worth looking at. I think the work was done for the EU space program.
Attachments
HV vacuum Metis123201.pdf
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HV vacuum Metis123209.pdf
(740.29 KiB) Downloaded 503 times
George Schmermund
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Real name: George Schmermund
Location: Carlsbad, CA

Re: Accelerator Tube Revisited

Post by George Schmermund »

Peter - Thanks for the links. Their experiments are quite detailed and very interesting to read. I'm sure I'll be able to use the info in upcoming projects.
Anything obvious in high vacuum is probably wrong.
George Schmermund
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Joined: Tue Aug 15, 2006 8:51 pm
Real name: George Schmermund
Location: Carlsbad, CA

Re: Accelerator Tube Revisited

Post by George Schmermund »

I've finally gotten around to doing another test for breakdown voltage on the accelerator tube electrodes. I was somewhat skeptical about the hold-off ability of the Delrin insulator, but my intended needs aimed only as high as 10 KV/electrode under vacuum. The gap between electrode surfaces is only .072". It was a pleasant surprise to find that the section was good (so far) to 15KV! The aim is for a 10 section tube, so this arrangement should be good for 150 KV with a length of less than 1 foot. The maximum hold-off voltage will be determined in the next round of tests. These tests are being done using a 40KV Spellman HVPS and it has the floating ground option. This option allows the measurement of current far below the metered current on the front panel. Using a Keithley picoammeter, leakage from corona and field emission can be easily evaluated.

Tests are under way to determine the best way to make an equipotential resistor string for the tube. The original plan was going to use 200 Meg resistors when this project first got started, but it will require something closer to 1G ohm/electrode to keep the current drain reasonable for the VdG voltage source.
Last edited by George Schmermund on Fri Jul 04, 2014 2:13 pm, edited 1 time in total.
Anything obvious in high vacuum is probably wrong.
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Dennis P Brown
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Re: Accelerator Tube Revisited

Post by Dennis P Brown »

Since you are aiming for 150 kV for your tube, how will you achieve that voltage?
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