Development and characterization of the integrated fiber-optic sensor for remote detection of alpha radiation

In this study, we developed and characterized an integrated fiber-optic sensor for the remote detection of alpha radiation emitted from radioactive contamination in areas relatively inaccessible by radiation workers. The fiber-optic sensor consisted of an epoxy-resin supporter and a sensing probe attached to it. The epoxy-resin supporter to hold the optical fiber tightly was fabricated by using epoxy-resin and a small amount of hardener. The sensing probe was fabricated by mixing epoxy-resin with inorganic scintillator ZnS(Ag) powder and solidifying the mixture. Then, the sensing probe was attached to the epoxy-resin supporter. As a light guide, an optical fiber, which was also compatible with the epoxy-resin, was used. The optical fiber was submerged in the epoxyresin supporter before solidification to make it in an integral form to minimize the loss of scintillation light due to incomplete connections between them. The four assembled fiber-optic sensors with sensing probes whose density thicknesses of ZnS(Ag) were 10, 15, 20 and 25 mg/cm2, respectively, were evaluated in terms of the total counts of alpha radiation to determine the optimum density thickness of ZnS(Ag). From the evaluation, a density thickness of 15 mg/cm2 was found to be the best for detecting alpha radiation.