High-resolution phosphors as X-ray detectors for synchrotron radiation experiments

In this paper, the comparative performance of high-resolution phosphors using CCD(Charge Coupled Device) and CMOS(Complementary Metal Oxide Semiconductor) sensors for synchrotron radiation imaging is reported. Various phosphor films (ZnS [Cu, Al], ZnS [Ag, Al], Y₂O₂S [Tb], BiTiO₃) are deposited on glass substrates using printing techniques. The phosphor plates used were 5 μm, 10 μm, 15 μm, and 20 μm thick, respectively. To investigate the luminescent properties of phosphor plates, the excitation and photoluminescence spectra were measured. The 20 line-pair test pattern images were obtained and evaluated by calculating the modulation transfer function (MTF). From the experimental results, it was concluded that the thicker the phosphor plates, the better the luminescent efficiency of X-ray-induced light photons. The phosphor thickness, however, decreases the MTF due to light blurring. ZnS (Cu, Al) phosphor of 15 μm thickness had a maximum value of 0.8 at 5 lp/mm.