Design Optimization and Characterization of Cold Neutron Imaging Detector Based on Novel Gadolinium Scintillation Glass Fiber Arrays and Infinity Corrected Optics

The use of scintillation glass fiber array in the reported cold neutron imaging detector can suppress lateral spreading of the scintillation light effectively and achieve a high spatial resolution while maintaining high detection efficiency. Theoretical analysis and experiments were combined to investigate influencing factors on the spatial resolution, the imaging contrast, the signal-to-noise ratio (SNR), and the detection efficiency with a cold neutron imaging detector made of new gadolinium scintillation glass fiber array and an infinity corrected optical readout system. The experiments were carried out on the Cold Neutron Radiography Facility at China Academy of Engineering Physics (CAEP). The cold neutron imaging detector made of 0.3-mm-thick Tb3+/Ce3+ co-doped Gd2O3 scintillation glass fiber array with a fiber diameter of 6 mm achieved a spatial resolution of 28.8 lp/mm (17.4
$\mu \text{m}$
), an SNR of 28.6:1, and a cold neutron detection efficiency of 31.6%, i.e., a cold neutron absorption efficiency of 81.0%.