Fusion Message Board

In this space, visitors are invited to post any comments, questions, or skeptical observations about Philo T. Farnsworth's contributions to the field of Nuclear Fusion research.

Subject: Re: Scintillator Crystals
Date: Nov 12, 2:50 pm
Poster: Richard Hester

On Nov 12, 2:50 pm, Richard Hester wrote:

>>Does anyone know of a surplus source of NaI scintillator crystals besides OE Technologies? I have just acquired a pair of beautiful 3" PMTs that would work very well for scintillator applications. The new price for a 3" NaI crystal from Bicron is about $600, which makes the Scots half of me writhe with anguish....
>> Richard Hester

Richard Hull said...
>Try Ebay.........search on "scintillation" and you will often snag a few scintillation counters for cheap. I have! I will give you a money back if any of them work!!! Nothing ever works out-of-box off E-bay.
>However, the PMT's and Thallium activated NaI crystals are always good. >
>Frankly, I have not noted a lot of difference between the NaI and BC-100 plastic scintillators.
>Don at OE Tech has a yard full of the BC-100 or its equivalent for cheap. I buy his junk unpolished disks and polish one side only with Novus plastic polish. They do demand a bi-alakali PMT though. (blue sensitive)

The point about E-Bay is well taken. I've been doing a lot of trolling htere lately, and have comr up with some good deals, including: YAG laser rods, a thermocouple vacuum gauge, a gas bottle + regulator, a multichannel analyzer, etc.

I had briefly considered plastic scintillators, but I probably want to use NaI or even one of the heavier scintillators, as I want to be looking for energetic X and gamma rays, and will need the stopping power of a higher-Z material. I think I will also need the multichannel analyzer to sort out the energies to be able to tell legitimate reactions from the background trash generated by electron impact on the fusor walls. Perhaps one of the reasons you haven't seen any gamma activity in your experiments might be that the protons from the D-D reaction are not efficient X/Gamma generators due to the small charge to mass ratio, and any radiation they do generate is probably sopped up by the walls. I might need to have a detector sticking into the chamber, but anticipate problems due to electron bombardment.