ABSTRACT
This chapter describes the fabricated a fiber-optic Cerenkov radiation sensor using a gadolinium foil (Gd-foil), a rutile crystal and an optical fiber. Relative fluxes of thermal neutrons in a polyethylene generated by a Cf-252 neutron source were obtained by using the fiber-optic Cerenkov radiation sensor. The results obtained by the fiber-optic Cerenkov radiation sensor were close to calculated thermal neutron fluxes by using the Monte Carlo N-particle transport code simulations. Fiber-optic radiation sensors for detecting neutrons consist of neutron converters, optical fibers and scintillators. In addition, their small radii or thicknesses make it possible to detect neutrons with a high spatial resolution in a narrow space. The chapter discusses a fabricated a fibber-optic Cerenkov radiation sensor using a Gd-foil, a rutile crystal and an optical fiber, and have measured pure thermal neutrons successfully. When the sensor probes are irradiated by the neutrons, the electrons and gamma-rays emitted from the Gd-foil pass through the rutile crystals.
