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: Neutron rate meters.
Date: Jan 26, 12:19 pm
Poster: Richard Hull

On Jan 26, 12:19 pm, Richard Hull wrote:

>We have an old Eberline He3 counter. NIST said they don't calibrate neutron counters any more, and also said Eberline's calibration is flaky.
>We sent it to Eberline anyway. The resulting data took considerable handwaving to interpret, and I have never trusted it. Just a warning to anyone with this brand of meter. They calibrate for mRem, and can't understand why anyone would actually want neutron flux instead.


Thanks for the heads up on the Eberline He3 counter, I remember it from my visit to the EMC squared labs. It might yet be turned to a good purpose.

In th' biz of neutron counting there are only two really broadly accepted methods. Proton recoil and Boron counters (B10 and BF3 tubes). The boron method is very old and well understood, in Neut counting circles. Most folks have real fluxes to count, we don't. We have to count indivdual neutrons slowly. This is very tough. Efficiency of counting is very low and this mandates very long counts and detailed background count data for light to moderate neutron production levels. For very rare and extremely sparse neutron events the process sinks into the "nosie" and one becomes easily lost in the quagmire of extended handwaving and magical statistical incantations. I call it reading the noise scientifically......."they" used to call it "casting th' bones".

Richard Hull