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 Detection
Date: Oct 07, 7:51 pm
Poster: Richard Hull

On Oct 07, 7:51 pm, Richard Hull wrote:

A lot of info on neut counting is in the past posts on this board.

The absolute best book in existence for such things is Knoll's "Radiation Detection and Measurement", 1979, Wiley&Sons.

Neutrons are not detectable directly, at least in a quantitative manner. All detectors rely on secondary reactions. All the secondary reactions produce simple ionizing radiation which is then detected by normal means. (all in above ref.)

The real bitch is that there is no counter that will count every neutron! As a matter of fact, all such counters are graded in terms of efficiency. For most all neutron counters that efficiency is abysmal, at best. An efficiency of 0.6% is considered great. Thus, you need a hail of the suckers before you get a single count! The bigger the neutron hailstorm, the more statistically meaningful are the time averaged results.

I have said it before and I'll say it again, Neutron measurements, especially in the noise floor, is an art form! Self deception is easy and rampant among newcomers to the art. One doesn't just fetch a counter, place it next to a suspected neutron source, get a reading and believe it! A lot of background counting, diurnal effects, etc have to be factored in.

I have posted rather extensively on my neutron counter which is about the best and cheapest the amateur will be able to get his or her hands on.

Good luck on your quest.

Richard Hull