Gadolinium Loaded Scintiilaors for Neutron Detection

[Richard Hull]

Thanks for the reponse Richard. It may not have renamed the post as your e-mail may be different now or it may be only the old forum that it updated and not the old intranet forum which was active following the songs demise. That intranet forum was only in use a bit over 1 year maybe two, at most. I have taken the liberty of updating the first post in this chain to credit you with original posting.

As for the neutron scintillating material, who knows what happened to it. There are many things that pop up in technology as "this new and wonderful thing", only to fall by the wayside as a no-go. In some cases, ten or more years pass from announcement to the item entering the market and another 5 or 6 years before any real individual person can afford it. Like you say, sounded great at the time. At that time, as I remember, we were all on a search for the least expensive, yet good, neutron detection scheme.

Currently, the number one on down for sensitivity are 3He, BF3, Boron lined tubes and the corrugated, large area, silver activation in liquid scintillator. Each has its own expenses, difficulties, and setup issues. All of them are a bit tangled for the first pass, entry level, amateur with almost no experience in electronics. Only the BTI bubble detectors are true no brainers and easy to operate, provided you have the cash on hand and don't mind it becoming a worthless curio in 6 months or so.

The beat goes on.......

Richard Hull

[Richard Hester]

There's been a fair number of nibbles for neutron detectors in the intervening years, mostly in the realm of scintillators. Boron Nitride and Boron Carbide both might be useful as thermal neutron scintillators. Polyethylene Naphthalate (PEN) is useful as a basic plastic requiring no wavelength shifting additives to make a gamma scintillator, and it would probably make a lovely fast neutron scintillator as well.
The Gd-loaded silicone scintillators are patented by ORNL, and it would take someone sniffing profit to step up and pay the licensing fee to make them.
Another interesting development is the solution-based growth of large stilbene crystals for use as fast neutron scintillators These respond well to pulse shape analysis to sort out gamma-derived pulses from those generated by neutrons.
I did not previously know this until fairly recently, but this generally works well only for liquid scintillators and not the plastic easily available to thee and me.....

Most of these newish things will take a long time to trickle down (if ever) to bottom feeders like us. The technology we commonly have available to us was hammered out 50-60 years ago.

P.S. As a nudge, I've seen mention now of two Gd additives for loading plastic scintillators - one is Gadilinium Isopropoxide, and the other is Gadolinium Phenylproprionate