Neutron detection with plastic scintillator

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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Dan Knapp
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Real name: Dan Knapp

Neutron detection with plastic scintillator

Post by Dan Knapp » Sat Sep 28, 2019 9:23 am

Shumlak’s group at the University of Washington have been using an array of plastic scintillation detectors to detect neutrons in their sheared z-pinch experiment. A paper on the detector has just been posted online (https://authors.elsevier.com/c/1ZnJdcPqbanWj) in Nuclear Instruments and Methods A. They used EJ-204 plastic scintillator and logged data using a high speed (2 Gs/s) digital scope. Peaks were detected with a peakfinding program available online. They report no interference from gamma/x-rays and had only an aluminum cover on the scintillator. Their data collection approach is probably beyond the budget of the amateur, but it should be possible to use NIM modules for analog peak detection. For fusor use, one could put a lead shield over the scintillator to block x-rays.I have a large plastic scintillation detector with the equivalent plastic that I picked up on eBay and plan to give this approach a try. I’ll post results when I finally get around to this (among the umpteen other projects on my agenda).

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Richard Hull
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Re: Neutron detection with plastic scintillator

Post by Richard Hull » Sat Sep 28, 2019 9:09 pm

This is great, of course and always has been, but as you and the paper suggests, a good set up, peak detection, and a lead encasement of the scintillator plastic is a must. Most folks arriving here lack the skills, gear and understanding to make this sort of system up. The proper scintillator, BC720, is unfortunately only about .5% efficient and is far better for very high neutron rate fusors. Such fusors are almost never found in the first pass efforts.

I have always recognized the difficulty of the first pass people in obtaining verifiable neutron detection. Of late, the Russian Corona tubes in "good hands" have worked great in that they can show proof via the moderator/no moderator test.

In the type scintillator shown in the paper, a thick lead shield versus no lead shield might tell the story. I would look forward to someone perfecting this hand assembled electronic effort. It would take a clever and talented person to pull it off and not the common newbie we normally see show up.

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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