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: Helium & tritium measurement
Date: Mar 02, 07:24 am
Poster: Eugene R. Kopf

On Mar 02, 07:24 am, Eugene R. Kopf wrote:

>This is in response to Eugene Kopf's posting.
>I fully realize that no geiger counter can count tritium due to the weak 5-16KV beta emission. Even a mica windowed gieger tube won't see it! BUT....... A scintillation counter won't see it either Eugene!
>I was able to easily detect Tritium, As I noted in my posting by CONVERTING the valved off, freshly run fusor into a geiger counter THAT WAS READING ITS OWN GUTS OR CONTAINED GAS! That gas should contain Tritium if fusion was going on. 10KV electrons flying around inside a geiger tube WILL BE detected!
>Most geiger counters and PMT counters are light and gas tight. The problem with tritium is getting it to the detector's sensitive volume. In a geiger counter, it is internal gas load and with a PMT it is a scintillation crystal. The weak radiation from Tritium will not penetrate the housing of either instrument in their standard configuration. Vacuum system electron multipliers can be used to detect the tritium Beta electrons, but again it would have to be buried in the gas to be measured.

I realize your arrangement is ideal for measuring internally, and actually applaud it's design (taking advantage of the existing electrodes). I was just giving an advanced "heads up" if you decided to measure externally as to what the nuclear industry uses for tritium measurement. I was doing this because I didn't know what you had in mind for the future, due to the "plateau" you were encountering.

Pardon me for not being clear. I didn't mean to doubt your abilities or knowledge.

>Regarding the spectrometer, my good friend Tom Ligon has a nice little Ocean optics spectral photometer/spectrograph.
> (see my earlier post on doppler broadening of the Hb line.)
> Unfortunately, he and the spectrometer are in California for a number of months. I am making do with what I have at hand to verify fusion. The neutron counter and the rad test following a run was a good cross check.

Indeed it was. In your next design though, you may want to hook up a prism or diffraction grating. A homebrew spectrometer isn't too tough of a project as long as you are after relative ratings just to get "ballpark" reading as to the He content. It only becomes a tough issue if you wish to calibrate it to known readings, although that may be easier with access to the spectrometer your friend has.

Best of luck, and happy fusing!

>Richard Hull