LAUSR

Abstract The “fission electron-collection” neutron detector (FECND) is a fission-based neutron detector which has simple structure and could be used as a passive detector. In this work, a FECND prototype is fabricated and studied with thermal neutrons from a reactor. Due to the low sensitivity of FECND, the fission coat with an diameter of 93 mm and a235U mass thickness of 1 mg/cm2 was electroplated on the coated electrode of the prototype to obtain a robust signal. The experimental results indicate that the sensitivity of the prototype to thermal neutrons is 2.8 × 10−18C·cm2 and 1.3 × 10−18C·cm2 without a high voltage when the electrodes gap is 30 mm and 15 mm respectively. The sensitivities for various applied voltages are also provided for the two gaps. The data show that the both sensitivities were increased to about 1.0 × 10−17C·cm2 after a high voltage of one hundred volts was applied, and a higher voltage up to 4 kV would not increase the sensitivity distinctly. The impacts of different electrode gaps and various applied voltages are discussed.