Determination of the Fluorine Content of Fluorochemical-Treated Fabrics by Neutron Activation Using the 19F(n,2n)18F Reaction

摘要

An analytical procedure has been developed for determining the fluorine content of fluorochemical-treated fabrics by activation with fast neutrons, using Teflon film as the reference standard. The ultimate success of the technique depends on effective retention of the active recoil F18 nuclei produced in the F19(n,2n) F18 reaction, which is accomplished by sealing all samples individually in Mylar film. It is demonstrated that recoil protons produced in the fabric substrate by the incident neutrons create a measurable amount of F18 in the basic unfinished fabric through the O18(p,n) F18 reaction. The production of such excess F18 tends to compensate for systematic deficiencies encountered in the measurement of the total F18-activity of the finished fabric. It is shown that non-uniform activation of the irradiated samples due to the fall-off in neutron flux near the target could be overcome by use of a rotating and reciprocating sample holder. (Author)