³He is a splendid neutron detection material due to its high neutron reaction cross section, gaseous state, and nonelectronegative and nonpoisonous nature. With the worldwide problem of the “³He supply crisis” arising, boron-lined gaseous neutron detectors are being widely used in neutron detection to replace ³He neutron detectors. In this work, to reduce the scattering neutron background coming from the substrate of a boron-lined neutron detector in the application of neutron scattering, a new design of the boron-lined gaseous neutron detector composed of a boron-lined multichip converter and a multiwire proportional chamber was proposed. The electron drift efficiency matrix simulated by Garfield++ (Version 2023.4) and the values and positions of electron energy deposition simulated by Geant4 were obtained. The α, ⁷Li, and total charged particle energy deposition spectra were acquired via coupling calculations of the electron drift efficiency matrix and the values and positions of electron energy deposition, and the width of the slit was selected as 3 mm. The boron-lined multilayer converter neutron detector (BMCND) was tested using a ²⁴¹Am–²³⁹Pu mixture α source, and the total count rate of α charged particles was measured as 599.5 s⁻¹, which is 89% of the theoretical α particle emission rate of 672.9 s⁻¹. The drift voltage experiments showed that 1200 V is enough to acquire a relatively ideal count, and a 2500 V drift voltage was confirmed, considering the higher count and instrument safety. We also performed the neutron detection experiments using a photo-neutron source, and a characteristic spectrum shape of “two stairs” was measured. When borated polyethylene was used to shield the BMCND, the detected total count decreased while keeping the characteristic spectrum shape, demonstrating that the BMCND was equipped with the ability to detect neurons, indicating that BMCNDs have the potential to be an outstanding ³He alternative neutron detector.

Investigation of the cross-section for the 78Kr(n,2n)77Kr reaction is essential for studies of nuclear reaction mechanisms and fusion plasma diagnostics. Currently, experimental data are limited and exhibit significant discrepancies. This study provides new measurements within this energy range and a comprehensive evaluation up to 20 MeV. Enriched 78Kr, prepared as a high-density solid, served as the target material. Quasi-monoenergetic deuterium–tritium (D–T) neutrons were employed for neutron activation analysis, followed by offline high-resolution gamma-ray spectrometry. The measured cross-sections are 159.7 ± 5.9 mb at 13.89 ± 0.15 MeV and 268.2 ± 10.1 mb at 14.57 ± 0.15 MeV, with total uncertainties below 3.76%. All six available experimental data sets were systematically examined and recalibrated using the most recent nuclear parameters. The recommended excitation function, spanning from the reaction threshold to 15 MeV, was determined by combining a third-order polynomial and an SPCC spline fit. Additionally, a correlation covariance matrix for this reaction in the 14 MeV region was constructed for the first time. Comparisons with TALYS-2.2 and EMPIRE-3.2.3 calculations provide valuable constraints for model optimization and further development of nuclear data libraries.

This study evaluates the neutron measurement and discrimination capabilities of a Eu:LiCaAlF₆ scintillator before and after coupling it to an optical fiber, and introduces a miniature Eu:LiCaAlF₆ fiber-coupled detector for reactor neutron measurement. Comprehensive Geant4 simulations were performed, and the results show that thinner scintillators effectively suppress high-energy gamma responses, thus improving the high n/γ discrimination capability. Experimental measurements were performed using a 0.8-mm-thick scintillator, both before and after its coupling to a 30-cm-long plastic optical fiber, in response to a ²⁵²Cf neutron source and gamma sources. The detector exhibited a distinct peak response to thermal neutrons in both configurations, with an equivalent 1456 keV electron energy response. A miniature fiber-optic neutron detector was designed for monitoring the neutron flux in a zero-power research reactor. It featured a 0.6 mm × 0.6 mm × 0.6 mm Eu:LiCaAlF₆ scintillator coupled to a 1 m long quartz optical fiber with a 600 μm core diameter. The relative variation in neutron flux within the zero-power reactor was measured online during control rod movement. This measurement system was deemed to be adaptable for the measurement of thermal neutron flux up to 10⁸ n/cm²/s. Future research should focus on employing in-core extended optical fibers and detector arrays for internal, multi-point monitoring, with the aim of evaluating the system's long-term stability and reliability during continuous reactor operation to enable practical deployment.