Warming up fusor IV for HEAS

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Richard Hull
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Warming up fusor IV for HEAS

Post by Richard Hull »

As usual, the long fallow fusor IV is being spun up in the usual manner prior to HEAS.
Over the last two days it got up to 250,000 n/sec and did a little silver activation.
It will be run every day or every other day from now until HEAS to keep it frosty for show and tells.
The numbers, as always, will improve, day by day.

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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Dennis P Brown
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Re: Warming up fusor IV for HEAS

Post by Dennis P Brown »

Sounds really good and I look forward to seeing the fusor exceeding 500,000+; so, when can we sign up for HEAS 2016 and get the map?
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Richard Hull
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Re: Warming up fusor IV for HEAS

Post by Richard Hull »

I had the notice up in the announcement forum here for the past two months and we are now filled up so I erased it as I always do when the door closes on attendance.

However you are a regular and are welcome to come. I will send you the package.

An overflow crowd is expected and with good weather, the outdoor fleamarket of scientific, vacuum, high voltage and other goodies will be huge.

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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Richard Hull
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Re: Warming up fusor IV for HEAS

Post by Richard Hull »

Hit 600,000 n/s in yesterday's 1 hour start to finish run. I have a fellow bringing a 1 oz 999 Rhodium bar for activation at HEAS event.
The cross section for rhodium is vastly better than Silver which is the poor man's activation metal.

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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Richard Hull
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Posts: 14992
Joined: Fri Jun 15, 2001 9:44 am
Real name: Richard Hull

Re: Warming up fusor IV for HEAS

Post by Richard Hull »

Interesting day....Two events.

1.Fusor IV consistently ran over 1million n/s is 4 one minute runs. The best was 1.2mega n/s. Data: 13 microns D2, 41.2kv, 15.4ma, 1, 246,820 n/s (assumed +/- 5%)
2. I activated both silver .9999 and indium .9999. I just manufactured a nice indium insert for the neutron oven, 1.75 inch diameter on a fiberglass ring. My standard silver insert is 2.1 inches in diameter on an aluminum ring. While I have activated indium before, it was never a serious effort. Indium is different from silver in a number of ways.

Silver has two nautral isotopes that can activate, neither of which last very long, ( short half life), in a given flux over any amateur period of exposure. The cross sections for these silver isotopes are very good for thermal neutrons. My typical avtivations over a few minutes yield about 2.2 times background at 700k n/s.

Indium has a number of activation paths from its major isotope 115In. A worthless 116In (2.4sec 1/2t) Xsec= only 4, 116In m1 with a huge cross section of 146 and a 1/2t of 54 min, and 116In m2 with a Xsec of 40 but a super short half life. Thus, the best indium activation is 116In m1. The drawback is that if you expose it in any flux it will only activate half way in 54 min!!
I exposed my Indium for about 1/2 hour to a flux averaging 800,000 n/s plus with excursions from 650K n/s to over 1.2 mega n/s. In the end, it beat silver by about 20% in net counts.
In short, silver activates fast, Indium does not. However, once activated, you have plenty of time to play with your 116In m1. I ran into an interesting anomaly that puzzles me though.

After activation, four, successive 1 minute counts were 288, 277, 268, 274 averaging about 277 cpm. While shutting down the fusor, having left the indium undisturbed, about 6 or 7 minutes elapsed. ( not absolutely sure of the lapse) Just for grins to see how far the count had sunk back I pressed reset on the rate meter for another one minute run on the 2" pancake GM. To my amazement, it recorded 329! I now set about counting every minute or so thereafter. Here are the counts 327, 321,324, 338, 324, 334, 300, 334, 292, 303, 278, 286, 277. I do not think my background moves around that much. My long term background does move about based on how long the lab is shut up, what the radon level is, etc. But this day my 20 minute average background was 131cpm. I have recorded as low as 115cpm and as high as 180 cpm in the past 3 years. All explainable by what kind and how much ore I have in the lab being sorted for sale and how long the lab was closed up and not ventilated by the exhaust fans.

This short term count variance looked as if something was "growing in", but after consulting the original "table of the isotopes" (Perlman, et al.), and other sources, I am at a loss for the boost in counts following those initial counts.....???? Curiouser and curiouser, noted Alice........

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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