Setting up for Activation.

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Bob Reite
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Setting up for Activation.

Post by Bob Reite »

Richard inspired me at the last HEAS meeting to try and make a go of activation after he showed it was possible with 500,000 n/s isotropic. Mine is going to be a bit old school, no Arduino board, just a CDV-700 geiger counter. The "hot dog" tube is wrapped in silver foil and inserted into a one inch hole drilled in a three inch diameter piece of HPDE plastic. The beta window on the CDV-700 tube is open, but facing away from the chamber. This way, I can actually have the CDV-700 running while the HV is on and not have it respond to X-rays from the chamber. The plan is to take pictures of the CDV-700 meter every minute, using a "speaking clock" to tell me when to snap the next photo. The first photo will be taken right when the HV is turned off. I have tested with and without the silver foil installed, and the meter only counts background with no foil. With the silver foil in place I got a 3/4 scale reading on the X1 range, at the same time the REM ball was detecting neutrons during todays best run.

Not quite ready for prime time however, only the short lived 110Ag isotope is detectable above background, the longer life but less active 108Ag is buried below the noise floor. The fusor has been at atmosphere for about a month, so it needs to be "broken in" again.
activation_setup.jpg
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.
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Richard Hull
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Re: Setting up for Activation.

Post by Richard Hull »

Great work Bob! Neutron activation is the ultimate proof of superior operation in a fusor. I have slowly improved the fusor operation to where I can actually see the Ag108 curve on the slope after 10, 10 second counts when the Ag110 is officially dead. The best run on 10-3 during the HEAS shows a good 108 slope virtually to its extinction at 10 minutes of counting. This made me very happy as I have slowly pulled the Ag110 out of the noise. I think that the Arduino, precision, 10 second count periods was an inspired idea that allows for excel graphing. I am glad I poured on the midnight oil designing, programing and making that little activation tracking box.

I am glad I inspired you to do some activation work. You used what was at hand and made a good effort of it. Like I say, get enough neutrons and you don't need a neutron counter for proof of fusion beyond its usefulness in calibration of your actual production. Once you activate to no matter how low a level, a GM counter is all you need to prove you are doing D-D fusion. It is the ultimate experiment in amateur fusion's quest to get neutrons. They do cool stuff.

Richard
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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Bob Reite
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Real name: Bob Reite
Location: Wilkes Barre/Scranton area

Re: Setting up for Activation.

Post by Bob Reite »

Still do not have satisfying results. The fusor has started acting up. I can't get to 40 KV without arcing and general "carrying on". Note that if under a hard vacuum, I can go to 60 KV with no issues, it's only when there is a plasma drawing current, that I seem to have the internal chamber arcing issues. I suspect I have some kind of stalk insulator contamination issue, which I will investigate once the work that pays the bills slows down for the Winter.
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.
User avatar
Richard Hull
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Posts: 14991
Joined: Fri Jun 15, 2001 9:44 am
Real name: Richard Hull

Re: Setting up for Activation.

Post by Richard Hull »

All the best in solving your issues in the attempt to improve activation. It will be worth the effort.

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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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