In order to monitor the neutron energy spectrum in designated regions inside the reactor blankets while minimizing perturbations to the medium, a miniature liquid scintillation detector was designed and tested in this study. The detector features an ultra small sensitive volume of 0.785 cc with a cylindrical structure of 10 mm in diameter and 10 mm in length, which is 3 to 10 times smaller than other reported miniature liquid scintillation detectors. Comprehensive experiments were meticulously designed to characterize the detector’s performance, including energy resolution, linearity, angular dependence, and neutron-gamma (n-γ) discrimination capability. Experimental results show that the response shift of the detector is less than 4% under different orientation angles and with the internal gas bubbles at different positions, far superior to the reported 40% shift of a 12.7-cm-diameter detector, demonstrating excellent response consistency. This miniature liquid scintillation detector also exhibits robust gamma suppression performance, achieving a discrimination Figure of Merit (FOM) of 1.45 in a 252 Cf neutron-gamma mixed field. • A miniature liquid scintillation detector with an ultra-small sensitive volume of 0.785 cc (10 mm × 10 mm cylindrical structure) is designed, which is 3–10 times smaller than other reported miniature liquid scintillation detectors. • The detector exhibits excellent response consistency, with a maximum response shift of less than 4% under different orientation angles and internal gas bubble positions, far outperforming the 40% shift of a 12.7-cm-diameter liquid scintillation detector reported previously. • Good gamma-ray suppression and high neutron-gamma (n-γ) discrimination performance are achieved, with a Figure of Merit (FOM) of up to 1.45 in the 252 Cf n-γ mixed field and a gamma breakthrough ratio of PSD lower than 3.2%. • The detector shows favorable gamma-ray response performance, including a good linearity (R 2 =0.99723) in the energy range of 0.0135–1.062 MeVee and a reasonable energy resolution of 24% at 0.340 MeVee, which is only slightly degraded compared with larger miniature liquid scintillation detectors. • The detector has a fast pulse response (average rise time of 5.1 ns, most probable fall time of 35.5 ns) and low angular dependence on gamma-ray incidence, making it suitable for accurate neutron spectrum measurement.
朱 et al. (Fri,) studied this question.