FAQ - Really high voltage feed-thru issues

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Richard Hull
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FAQ - Really high voltage feed-thru issues

Post by Richard Hull » Fri Oct 26, 2018 10:17 pm

Thanks to Dan Knapp for posting the recent IEC meeting papers and poster locations. It is highly recommended that you look at the paper related to the "Homer" insulator at the now famous and ever modified U of W IEC lab.

https://cpb-us-e1.wpmucdn.com/blog.umd. ... vhnwzx.pdf

I hope it remains at the URL for a long time.

This is very instructive to newbies and old boys alike. I found the entire paper interesting, but the most valuable page for me was page 19. This very instructive page is historical in nature. You can track the U of W fusor and insulator through the years along with the neutron production.

A synopsis..........(stable operation)

1994-1999...Never exceeded 60 kv applied using a simple common HV rated feed-thru. Best fusion was close to 10e7n/s
1999-2002...Advanced fuels program still worked at no more than 60kv. Same insulator similar fusion levels with other fuels.
2002...New 200 kv supply obtained
2002-2006..New supply allowed the continuation of advanced fuel work using same insulator but it limited input to 140kv D-D to 5X10e7n/s
2006...New 300kv supply obtained and use of advanced HV and stalk design
2006-2014..Diagnostic studies period operation allowed stable operation to 150kv.
2014-2016..A period 2nd HV campaign begins. Advanced 2 stage feed-thru installed in 2016
2106-2018..operation at 170 kv possible for stable operation at reduced pressures. 3.3X10e8 possible at 1 micron 175kv @100ma 17.5kilowatts!
current Homer design implemented mid 2018 allowing full 200kv operation for the first time.
Further improved fusion numbers are expected.

Above data combined from pages 4, 11 and 19

A close look at their current Homer reactor, (page 6), will reveal that it is almost identical in general design the the original Hirsch-Meeks fusor of the mid-1960s, though it is much larger, does not use D-T and is built to a more modern standard, being continuously refined over the 24 year period that Homer has been in use.

The upshot of this FAQ is that 60kv would typically be the limit for a superior amateur effort within a dwelling on a limited budget. With a proper degree of attention and shielding a larger amateur fusor could be pushed to 100kv provided funding and space is available on the part of a very advanced fusioneer.

Newbies who have big dreams and aspirations need to take a look at what is required in a feed-thru at voltage in excess of 100KV and how little resultant D-D fusion is gained beyond 100kv versus costs, x-ray hazards, and power supply voltage and current demands.

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.

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