Neutron detection moderator embedded activation!

This area is for discussions involving any fusion related radiation metrology issues. Neutrons are the key signature of fusion, but other radiations are of interest to the amateur fusioneer as well.
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Dennis P Brown
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Re: Neutron detection moderator embedded activation!

Post by Dennis P Brown » Tue Dec 08, 2020 11:01 pm

Excellent results - especially using the 'old fashion' method of hand recording data; something I still do. Just nice to see it still is done! Intergrating electrontics for work is one thing, in my home lab, not something I would waste energy on if I can avoid it.

Still, I guess at some point I really need to finish my new fusor and try my hand at Ag activation - especially since I have a new lab building and that I too will use the old tried and true method of recording counts using pencil and paper. ;)

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Richard Hull
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Re: Neutron detection moderator embedded activation!

Post by Richard Hull » Wed Dec 09, 2020 12:34 am

It is difficult to avoid the hand done data. (neutron one minute counts) as I have to adjust after each little run to improve things and this can take a few seconds to nearly another minute before I zero the counter to count the next minute's run. Yes, it could be done at the press of a button but when does the CPU grab and record the instrumented data??? I might start a one minute run at 11 microns, 36kv applied and 9 ma. Then at 21 seconds the instruments might read 11.2 microns 34.6kv and 8ma. I will, in mid stroke, make a correction to add a bit of gas to 11.6 microns, pump it up to 37kv at 11ma. and the last 25 seconds run at this new setting before the one minute count stops and the new count is recorded. My job is to mentally average it all out in the notes. I might write down 11.4 microns, 35kv and 11.2 ma and record the total one minute count shown on the digital display.

The upshot is that most fusor operators of some experience recognize this dance on the part of a good operator. Tough to put this into a simple programming, data collection effort.... Too much meat engine averaging among shifting sands during the one minute count. Like I say, a lot of artifice in among the science.

A complex system could grab all instrument readings each second and at the end of the minute use the averaging based on time integrated operation at somewhat stable points during the minute, then store its best guessed average of all the readings for a recorded and stored pressure voltage and current related to the finished one minute count. I am not ready to do that as long as I have pencil and paper. Actually, in the time it takes to write the data, the fusor is still running and as I look up, I get to start afresh looking at what's going on with the instruments and make intelligent decisions on what to adjust to make the next one minute run more successful than the last.

Folks who have been to HEAS and observed me during a run know what it is all about.

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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