Two-dimensional neutron imaging method using scintillators with wavelength shifting fibers

Abstract

We have developed a two-dimensional neutron imaging method using rectangular scintillators with wavelength shifting (WLS) fibers for neutron scattering experiments using a next-generation high-intense pulsed-neutron source. In the method, rectangular scintillators are arranged at longitudinal direction and transverse direction and WLS fibers are arranged on the four sides of these scintillators. Luminescences generated in the scintillator are absorbed by the four fibers and wavelength-shifted luminescences are detected by multi-anode photomultipliers. The position of incident neutron is decided by coincidence of the four signals. By preliminary experiments using 5 mm×5 mm×2 mm t 6Li glass scintillators and 0.5 mm∅ WLS fibers, it was concluded that detection efficiency for thermal neutron was 13%. By scanning experiment using a 4×4 6Li glass scintillator array neutron detection system, we obtained the clear spot of incident neutron beam that the cross talk was <10%.