Design and Experimental Investigation of a Nondestructive Hydrogen‑Detection Device Based on Backscattering Detector Layout via Neutron Incoherent Scattering

Hydrogen plays a crucial role in the evolution of material properties; however, its precise, non-destructive quantitative detection in materials remains a challenge in the field of materials science. Utilizing the characteristic of hydrogen having an extremely high neutron incoherent scattering cross-section, a dedicated device for non-destructive hydrogen detection was developed in this study. The device employs a backscattering detector layout to prevent interference from strong forward stray signals of the incident neutron beam, utilizes an ultra-short sample-to-detector distance to significantly enhance testing efficiency, and adopts a long-wavelength neutron testing mode to eliminate the influence of intrinsic material variations. Experimental tests on polypropylene (PP) thin-film standard samples with known hydrogen content demonstrate an excellent linear relationship between the measured neutron count rate and the hydrogen content. The application of this method to hydrogen measurement in zirconium alloys shows that it can sensitively determine the hydrogen content in materials, with a theoretical limit of detection of approximately 3.3 ppm for zirconium alloy samples. This study provides a novel, non-destructive, and sensitive testing approach for hydrogen measurement.