Neutrons!

Current images of fusor efforts, components, etc. Try to continuously update from your name, a current photo using edit function. Title post with your name once only. Change image and text as needed. See first posting for details.
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Garrett Young
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Neutrons!

Post by Garrett Young » Tue Feb 21, 2017 5:46 am

Overall Setup:
IMG_1455.png
Cathode potential: -25,550 (Supply: -29,634 with 393 kohm series resistor)
Cathode current: 10.4 mA

Pressure: 33 mTorr (working to lower this and improve mean free path)

BD-PND (24 bub/mrem):
5 bubbles in 5 min
9.5 cm from cathode
Temp indicator showed 24-28 degC

Placement
IMG_1459.png
Bubbles
IMG_1467.png
(Note: After the 5 min run and the plasma extinguished, the bubble dosimeter was monitored for an additional 10 min and no further bubbles formed)

The BF3 tube/moderator and NIM setup (discussed here: viewtopic.php?f=18&t=11312) averaged 15 cpm above background.

I have many improvements planned over the next few days, but I wanted to share my starting point.
- Garrett

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Richard Hull
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Re: Neutrons!

Post by Richard Hull » Tue Feb 21, 2017 8:43 am

Garrett, I am glad you look at this as a starting point. You are to be added to the Neutron club. Good work! Too many people look at this success as their last posting.
Keep all of you run data in a log book so that you can sum all the doses for averaging once you get your electronic system going along side the BTI dosimeter and calibrate your
electronics to arrive at a multiplier for future use to indicate a link to neutrons per second.

To all looking at this post. Take a good look at what the bubbles in a good BTI detecting neutrons looks like. Small, obvious, perfect spheres.

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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Dennis P Brown
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Re: Neutrons!

Post by Dennis P Brown » Tue Feb 21, 2017 1:55 pm

Congratulations! An excellent setup and experiment.

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Garrett Young
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Re: Neutrons!

Post by Garrett Young » Fri Feb 24, 2017 5:11 am

After gaining some operator experience, I achieved 3x the neutrons in the same time period (and same detector location) compared with my previous post.

Running at an average of 27kV@20mA (29kV source with 100kohm series resistor) and 34 mTorr, my bubble detector registered 15 bubbles (only 14 are clearly visible in the picture bellow) in 5 minutes.
IMG_1480.png
- Garrett

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Richard Hull
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Re: Neutrons!

Post by Richard Hull » Fri Feb 24, 2017 10:08 pm

Fabulous work and proof that once you get to fusing, operational skill with your system starts to go through the roof!!! I have harped on this for years and here is another instance that proves it. It is not about the construction all the time or the gear. In the end, it is about operational artistry. We are working at a bleeding edge of this technology operating between a pretty, yet useless glow and a dangerous and destructive arc condition. Wedged in a tiny zone between these two easily achieved extremes, is Fusion!! Only a careful hand can do fusion here and only an experienced hand can do it better.

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.

Titanium007
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Re: Neutrons!

Post by Titanium007 » Sat Mar 04, 2017 10:24 am

Where is this neutron bubble detector purchased? Please give me a link, thank you

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Garrett Young
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Re: Neutrons!

Post by Garrett Young » Sat Mar 04, 2017 5:07 pm

http://bubbletech.ca/product/bd-pnd/

Make sure you check out the FAQs ... lots of good information
- Garrett

John Futter
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Re: Neutrons!

Post by John Futter » Sun Mar 05, 2017 12:53 am

Titanium007
You seem to be short of a few smarts or have a comprehension problem
and have missed the rule of: Only your real name to be used "no handles allowed"
also the rule that stated your first post has to be in the "Please introduce yourself forum"
Please amend these short comings

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Garrett Young
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Re: Neutrons!

Post by Garrett Young » Sat Mar 11, 2017 5:36 am

I activated a 2x7 cm piece of 30 gauge pure silver foil tonight during a record 4 minute run of 150k+ n/sec. The neutron oven is a plastic bucket (30cm diameter / 30cm height) filled with water and a sealed tube in the center for housing the activation material. The sample material is 20cm from the cathode.

I used a Fluke Biomedical Geiger Counter and an Eberline Beta Sensitive Scintillation Detector (discriminated to count 1MeV+ betas)

1 min count (within 5 seconds of removal from neutron oven): Fluke 89 / Eberline 17

Foil removed from detectors for background count:
1 min: Fluke 33 / Eberline 3
2 min: Fluke 28 / Eberline 6
3 min: Fluke 32 / Eberline 4
4 min: Fluke 25 / Eberline 4
5 min: Fluke 40 / Eberline 2

Useful calculator: http://www.wise-uranium.org/rnac.html
- Garrett

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Richard Hull
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Re: Neutrons!

Post by Richard Hull » Sat Mar 11, 2017 4:21 pm

Very nice work! Your rather big moderator took advantage of a large intercept cross section. My neutron oven has only 1/4 your cross section I would require about three times the n/s rate to equal your ratio of background to activation level! Again, thanks for sharing. I use water moderation for my 3He tube, but HDPE for my oven.

Richard Hull
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neutron oven.JPG
The neutron oven with the 3He water moderator behind it
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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