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If I am asked to design a simple experiment to detect neutrons, how can I do that?

The problem is, neutron is a neutral particle. So, application of electric and magnetic fields won't help. Can I detect them by photographic plate? And even if I am able to detect, how can I design an experiment with it?

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  • $\begingroup$ A little research on your own might help. en.wikipedia.org/wiki/Neutron_detection $\endgroup$
    – Dan
    Commented Nov 28, 2021 at 8:16
  • $\begingroup$ I have seen this article and many research papers too. But I was asked to design a very simple experiment that we can construct at a university lab to detect neutrons. That is why I asked the question. $\endgroup$
    – Neutralino
    Commented Nov 28, 2021 at 8:29

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Generally neutron detectors are built around detection of nuclear reactions that occur in the presence of neutron radiation. For a simple example, if helium-3 is exposed to thermal neutrons, it tends to interact like:

$$ \rm ^3He + n\to {^3H}+{^1H} $$

producing a proton and a tritium nucleus, both of which are created with a fair amount of energy and thus tend to be ionized. At this point the detection of the resulting ionized gas is similar to a more conventional particle detector you may already be familiar with.

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  • $\begingroup$ Can we detect the neutrons by photographic plate? $\endgroup$
    – Neutralino
    Commented Nov 28, 2021 at 8:19
  • $\begingroup$ @SAGARMODAK I have used plastic scintillator doped with lithium-6 and attached to a photomultiplier tube. If your photo plate had to be made with some neutron-absorbing isotope, that could get prohibitively expensive very fast. $\endgroup$
    – rob
    Commented Nov 29, 2021 at 11:45
  • $\begingroup$ Somewhere I've heard, also neutrons let some trace in bubble chamber (maybe on photo plate), but it is much weaker than of the charged particles. $\endgroup$
    – peterh
    Commented Nov 29, 2021 at 14:07
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You could purchase a commercial scintillator cell, even good, large, new ones go for under 4000$. There, typically a photomultiplier is coupled to a liquid scintillator, or to a solid state crystal. Read out the signal with an oscilloscope or other digitizer. Find some pulse shape algorithm of your liking and let it run over each recorded pulse. At low energies, you will see two populations, one from electronic recoils, caused by gamma and beta backgrounds, and one from nuclear recoils, caused by neutrons. If you are on a shoestring budget, you can reduce the volume of the scintillator, and use SiPMs instead, but then your rate of neutrons will get so low that you'll have a hard time doing anything with it.

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