Neutron radiation distribution sensor using flexible plastic scintillating fiber combined with the time-of-flight technique

As a promising neutron radiation distribution sensor, a long fiber system has been made using two silica fibers connected to both ends of the plastic scintillating fiber (PSF). Its basic properties were investigated to detect the position of neutron incidence with the time-of-flight (TOF) method. From the experimental results for the fission neutron source, the two linear relations were confirmed (1) between the incident position of the neutrons and the time difference and (2) between the neutron flux level and the counting rate. The spatial resolution and the counting efficiency of this system were about 60 cm (FWHM) and about 1.0×10^-4 [counts/incident neutron] respectively using 1 mm diameter fiber of 100 m length. A neutron dose distribution measured by this system was compared with the mapping result using a conventional neutron Sievert(Sv) counter. After some correction for the spatial resolution by an unfolding method, both results showed good agreement