Direct neutron detection based on semiconductor crystals holds promise to transform current neutron detector technologies and further boosts their widespread applications. It is, however, long impeded by the dearth of suitable materials in the form of sizeable bulk crystals. Here, high‐quality centimeter‐sized LiInP2Se6 single crystals are developed using the Bridgman method and their structure and property characteristics are systematically investigated. The prototype detectors fabricated from the crystals demonstrate an energy resolution of 53.7% in response to α‐particles generated from an 241Am source and robust, well‐defined response spectra to thermal neutrons that exhibit no polarization or degradation effects under prolonged neutron/γ‐ray irradiation. The primary mechanisms of Se‐vacancy and InLi antisite defects in the carrier trapping process are also identified. Such insights are critical for further enhancing the energy resolution of LiInP2Se6 bulk crystals toward the intrinsic level (≈8.6% as indicated by the chemical vapor transport‐grown thin crystals). These results pave the way for practically adopting LiInP2Se6 single crystals in new‐generation solid‐state neutron detectors.

Low energy accelerator driven neutron sources are promising candidates to obtain a neutron yield as high as 1014 n/s, which is required for a variety of applications, such as boron neutron capture therapy, neutron imaging, and neutron scattering. The methods to generate neutrons can be divided into two categories: hadron-based and photon-based methods. In order to better understand which kind of source would be the better choice for delivering a brilliant neutron beam robustly, in this paper, the underlying principles of neutron production, as well as the simulation results of neutron yield, target heat dissipation, thermal stress, and reaction byproducts concentration of these two types of neutron sources, will be elaborated on. A preliminary photoneutron target station design based on a 50 MeV/50 kW electron linear accelerator, including the optimized neutron yield, thermal hydraulic analysis, and shielding calculation, is presented as well to demonstrate the method to deliver brilliant thermal neutron beam of 1.03 × 1010 cm−2 s−1 sr−1.