A Grid-Type Scintillating Device for Radiation Imaging

Abstract

High-resolution radiation imaging is desired in a variety of fields, including material science and medical diagnostics. The authors propose a new radiation imaging system with a gridded scintillating device. The scintillator resin was polymerized in a metal grid. Scintillation photons can transmit in two directions along the grid channels which serve as waveguides. They are then collected by clear optical fibers placed at the ends. To evaluate the imaging capability, measurements with a 90Sr/90Y beta source were carried out. The pitch of the scintillator was set to 1.0 mm and the width of the wall was 0.2 mm. A 10 mm-thick aluminum plate with a 1 mm-diameter hole collimated the beta rays. It was demonstrated that this structure can measure two-dimensional radiation distributions. The FWHM of the measured distribution was about 1.2 mm in both directions. Also experiments with fast neutron beam were carried out. For fast neutron beam with a diameter of 10 mm, the distribution could be measured with the FWHM of 16 mm, where the scintillator channel pitch and wall thickness were set 3.55 mm and 1.45 mm. The current system is for evaluating the fundamental possibility of this gridded scintillator as a two dimensional waveguide. From the result, it can be said that the system can be applied to fusion neutron distribution measurements. By adapting some neutron to charged particle converter, it may be applied to thermal and cold neutron distribution measurements.