Neutron Detection Methods and Instruments

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JoeBallantyne
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Neutron Detection Methods and Instruments

Post by JoeBallantyne » Mon Nov 30, 2020 2:32 am

Found this article online and thought it was relevant.
NeutronDetectionMethodsAndInstruments.pdf
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Richard Hull
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Re: Neutron Detection Methods and Instruments

Post by Richard Hull » Mon Nov 30, 2020 5:22 pm

Good catch Joe. I note in the preface that I have 3 of the 4 books referenced there in my radiation library here. I have the full set of volumes produced in Fast Neutron Physics series and the later follow on volume.

By 1965, neutron measurement was pretty well locked down. Helium3 was in abundance, (the ultimate neutron detector), and the stock pile of suitable neutron detectors from gas filled to modern plastic neutron scintillators, fission tubes, etc., were all in place. Almost nothing in the way of major advances in neutron detection occurred until the semi-conductor work offered its early, yet poor, detectors to the list in the 80's and 90's. I still await the first semi-conductor detector that can easily handle very low neutron flux levels. So very much in neutron detection demands either reasonably large flux levels or large detection volumes and or large surface areas in weak neutron fields. The semi-detectors just don't have the area needed to detect low levels of neutrons and are currently expensive.

For really weak fields and low to virtually non-extant flux levels, Large gas detectors like BF3 and 3He are needed in large moderators to thermalize what few fast neutrons there are in a weak field. The physics of the fact that neutrons are neutral coupled with their failure to be captured in so many things of low capture cross section needed to release the demanded "charged particle" used in detection, really cripples accurate counting and even detection at ultra low fast neutron emitting events.

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
Retired now...Doing only what I want and not what I should...every day is a saturday.

Cai Arcos
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Re: Neutron Detection Methods and Instruments

Post by Cai Arcos » Mon Nov 30, 2020 6:04 pm

Richard:

I got lucky and found the three volumes of Fast Neutron Physics for 20 dollars in great condition! I'm currently digesting all the info. The chapters on long counters and activation are specially great.

Joe:

Thanks for posting the article! I'm going to print it and bind it, as it is a very good summary of all the existing techniques. Defintiely worth the wear and tear on a printer.

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Richard Hull
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Re: Neutron Detection Methods and Instruments

Post by Richard Hull » Mon Nov 30, 2020 7:22 pm

That was a fabulous buy!!! (you stole them!) I think I had to pay about $70 or so for my set back in 1999. You almost never find a set, but have to buy them piecemeal. Volume 1 is the rarest of them all as it contains 95% of all the data useful to the amateur or casual neutron metrologist. (gobbled up by all and sundry)
The other volumes are fluff to the specialist and for someone who makes their daily bread off of the fast neutron measurement world.
It was the failure of the electrochemists in the 1989-90 time frame to read volume 1 or obtain the services of an expert neutron metrologist that boosted the cold fusion biz back then as they initially claimed they were getting neutrons and then on to detecting tritium in there cells. I wonder how many reading this were even on planet earth during that time? It was an exciting time then and a wild ride.

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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