Cadmium-Lined Outer-Core Irradiation Tube (CLOCIT)

Description

Just like the ICIT, the Cadmium-Lined Outer-Core Irradiation Tube (CLOCIT) is an internally dry tube designed to irradiate samples in the reactor core at the highest neutron flux region.  The CLOCIT is a 1.25 inch aluminum tube that runs from the reactor to the F20 core position, near the periphery of the core.  The CLOCIT differs from the ICIT in that it has a 0.0200 inch layer of cadmium within the tube wall over the vertical length of the core.  An offset bend, designed to limit radiation streaming, limits the sample size to a length of 4 inches.The CLOCIT is primarily used for ⁴⁰Ar/³⁹Ar age dating, as the necessary reaction of ³⁹K(n,p)³⁹Ar is a threshold reaction that takes place in the fast neutron energy spectrum. Irradiating samples in the CLOCIT removes most of the “noise” from thermal neutron reactions. One hour in the CLICIT is roughly equivalent to 1.8 hours in the CLOCIT, due to decreased neutron flux.