BP 28 Neutron counter Teardown

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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John Futter
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BP 28 Neutron counter Teardown

Post by John Futter »

So we have been cleaning up at work and stuff not used for more than 5 years had to go
I saw this neutron counter outside so I took it apart to see what actually was inside
So we have an absolutely massive BF3 tube 1.9 meters long (6' 5") and 150mm in diameter (6")
The BF3 tube is surrounded by an aluminium protective sleeve and this in turn is inside an inch and a quarter (32mm) wall thickness polyethylene sleeve.
We used to use these to measure neutrons from space at ground level
DSC00282.JPG
DSC00283.JPG
And you have guessed it, it is now in the skip
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Richard Hull
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Re: BP 28 Neutron counter Teardown

Post by Richard Hull »

Wow! Due to its sheer size, if it is functional, It will be hypersensitive and expect a relatively high background count once properly discriminated against Gamma false counts.
BF3 is the second best detector on earth and with this volume It will far exceed even a 24" 3He detector. Background will be a factor on this beast.

If it works, good luck in tuning it up to spec, though it looks like it is relatively complete. Please keep us informed if you have a go at it.

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: BP 28 Neutron counter Teardown

Post by Dennis P Brown »

From the pic, I guess it is heading for the dump? If so, sad but I understand. Hopefully, it gets to continue its good work!
David Kunkle
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Re: BP 28 Neutron counter Teardown

Post by David Kunkle »

I interpreted "skip" to be some kind of canuck slang for the dumpster sitting beside it.

You said you used it to measure neutrons from space. I thought free neutrons had a very short 1/2 life of about 10 minutes? What neutrons are coming from space? Or are you talking about cosmic rays generating neutrons in the atmosphere?
If your experiment needs statistics, you ought to have done a better experiment.

Ernest Rutherford
JoeBallantyne
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Re: BP 28 Neutron counter Teardown

Post by JoeBallantyne »

skip: (Canada, US) Translations . An open-topped rubbish bin.

That seems like a real shame.

Where are you located? Can you rescue it from the trash bin? I'd gladly pay the shipping to get it. I'm sure I am not alone.
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Richard Hull
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Re: BP 28 Neutron counter Teardown

Post by Richard Hull »

There are typically zero cosmic neutrons for the reason you stated. Virtually all of the neutrons counted on earth, regardless of altitude above sea level, are cosmic ray "star" events in earth's atmosphere. This neutron production zone peaks at about 10 to 20 miles up where the atmosphere is thick enough to tangle with cosmic ray nuclei, creating earth based neutrons. Moisture in the air below the neutron peak region stops or scatters neutrons so that very few energetic neutrons make it to sea level.

Major nasty solar events, giant flares and CMEs can increase the neutron counts at ground level for short periods.

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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