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Calibrating a Neutron Detector With Background Neutrons

Posted: Sun Jan 27, 2019 9:01 pm
by Kai Kaletsch
The thermal neutron fluence rate at the earth's surface is well known and we should be able to use that as a way to get an approximate calibration for neutron detectors. This video proposes a method: https://www.youtube.com/watch?v=OahvY0g ... e=youtu.be

The thermal neutron fluence at the reference location is supposed to be ~ 4 n/cm2/hr ( https://ieeexplore.ieee.org/document/1263842 ). At Saskatoon’s latitude and altitude, the n flux is 1.6 times reference ( http://www.seutest.com/cgi-bin/FluxCalculator.cgi ), or around 6.4 n/cm2/hr.

Borax absorbs thermal neutrons. So, by comparing the count rate of a detector surrounded by borax to the same detector bare, we can determine how much of the bare count rate is due to background thermal neutrons. Cadmium would be a better neutron absorber than borax but it isn't as readily available.

We found that our detector has a sensitivity of ~ 8.4 cps/nv.

Re: Calibrating a Neutron Detector With Background Neutrons

Posted: Thu Sep 05, 2019 1:53 am
by Trent Carter
Thank you for sharing this. I have spent the better part of 3 years researching, scouring, and purchasing neutron detection hardware.

A. Somehow I had missed the CT007-T neutron detector, likely because it has not yet been released. They dont disclose the technology. My guess is LiI(Eu) or CLYC.
B. I liked the scientific process in the video with Background No Mod / BGND+Mod / BGND+MoreMod / BGND+Boron. I think I might add a Boron test to my Neutron calibrations in early 2020.
C. I have always wondered why one could not calibrate a baseline with background Neutrons.
D. I had not considered background calibration using thermalized Vs fast and boron no-boron.