This study presents the characterization of a compact NaI(Tl)-SiPM detector system for wide-energy gamma-ray spectroscopy from 0.511 to 20.28 MeV. The system utilizes a dual-channel architecture with high-gain and low-gain channels to address dynamic range limitations. Performance was calibrated using standard radioactive sources and quasi-monoenergetic gamma rays produced via inverse Compton scattering at the Shanghai Laser Electron Gamma Source (SLEGS) beamline of the Shanghai Synchrotron Radiation Facility (SSRF). A simulation-based analysis revealed a fundamental challenge for spectroscopy with this compact instrument at high energies. While the total detection efficiency remains high at approximately 30%, the corresponding full-energy peak (FEP) efficiency was found to drop to a negligible 0.01% at 20.28 MeV. This low FEP efficiency, a direct consequence of incomplete energy deposition in the detector's limited volume, precludes the use of traditional photopeak-based calibration in the high-energy domain. A calibration was performed across the full energy range using methodologies appropriate for each domain. In the low-energy range, where photopeaks are well-defined, a standard calibration achieved an energy resolution of 6.64% at 0.662 MeV and a linear response with a coefficient of determination R ² of 0.99993. To address the challenge in the high-energy range, a non-photopeak methodology using a simulation-corrected characteristic inflection point was validated. This approach yielded a non-linear calibration described by a second-order polynomial with an R ² of 0.99973. This work thus provides a comprehensive characterization and a viable methodology for utilizing compact detectors in wide energy-range applications, indicating their potential as sensors for advanced systems employing spectrum unfolding.

An integrated airfoil alkali metal high-temperature heat pipe structure is proposed for the air rudder. The heat transfer properties of lithium and sodium are analyzed, and the equal-thickness test pieces are designed and prepared. The sonic limit, condensation limit, viscosity limit, entrainment limit, capillary limit and boiling limit are calculated theoretically, and the corresponding feasible working areas are drawn according to each limit curve. It is found that the optimal working temperature range of the test piece is 800∼1500 K. The effects of heating power and placement angle on the start-up time, isothermal performance, and heat transfer performance of the test piece are studied by experiments. The increase in heating power is helpful to shorten the start-up time and improve the isothermal performance and heat transfer performance of the test piece. The placement angle has little effect on the start-up time, but it has an effect on the isothermal performance and heat transfer performance.

The detection of radiation in intense fields frequently necessitates high count-rate capabilities. The discernment of neutron signatures from heterogeneous radiation fields characterized by multiple coexisting particle species presents a considerable challenge. Although plastic scintillators endowed with Pulse Shape Discrimination (PSD) capabilities offer a primary modality for neutron-gamma discrimination, the mitigation of charged-particle-induced interference requires coincidence screening methodologies, wherein the anti-coincidence technique is of significant utility. Conventional AC approaches, often reliant upon rudimentary energy thresholding from veto detectors, typically exhibit deficiencies in precise temporal coincidence and event-type characterization. Conversely, acquisition systems based on Full Waveform Digitization, when subjected to high count rates, encounter data transmission bottlenecks attributable to voluminous datasets. To surmount these impediments, this investigation introduces and substantiates a novel hardware-instantiated Anti-Coincidence (AC) system. This system integrates high-speed operational amplifiers, voltage comparators, and radio-frequency analog switches to form an analog signal selection unit, thereby facilitating real-time, analog-domain filtration of signals pertinent to target particles with lower power consumption. Experimental evaluations, conducted with a Silicon Photomultiplier (SiPM) array coupled to a plastic scintillator possessing fast-neutron detection capabilities and exposed to mixed ²⁵² Cf and ⁹⁰ Sr sources, demonstrate that the hardware AC system reduced the total event count by 89.34 ± 0.03%. More importantly, by efficiently suppressing the electron background, the AC system significantly enhances the reliability of the subsequent PSD analysis. This is evidenced by an increase in the calculated Figure of Merit (FOM) for neutron-gamma discrimination from 1.34 ± 0.02 to 1.41 ± 0.02, This improvement can be explained by the reduction of the electron background in the region of PSD values used for neutron selection.