探测量子效率
光传递函数
光学
X射线探测器
电场
俘获
载流子
探测器
材料科学
噪音(视频)
噪声功率
物理
光电子学
图像质量
功率(物理)
生物
生态学
图像(数学)
量子力学
人工智能
计算机科学
摘要
The effects of charge carrier trapping on the x-ray sensitivity, resolution, and detective quantum efficiency (DQE) in polycrystalline lead oxide (PbO) x-ray imaging detectors are theoretically analyzed. The theoretical models for calculating carrier trapping-limited x-ray sensitivity and modulation transfer function (MTF), and DQE incorporating polyenergetic x-ray spectrum are described. A cascaded linear system model is developed for calculating the spatial frequency f dependent DQE of PbO detectors by incorporating the effects of bulk charge carrier trapping on the MTF and the x-ray interaction depth dependent charge collection efficiency and noise. The theoretical calculations are compared with the published experimental data and show a very good agreement. From the fittings of the sensitivity and MTF curves, the electron and hole ranges in polycrystalline PbO are found to be 3.5×10−7 and ∼10−8 cm2/V, respectively. The f dependent noise power spectrum NPS(f) and DQE(f) performances are analyzed as a function of applied electric field and carrier lifetimes. The calculation shows that the carrier trapping is responsible for a 21% reduction in the MTF at the applied field of 1.0 V/μm at the Nyquist frequency (fN) and the aliased NPS at fN is reduced to 63% of that at zero spatial frequency. The sensitivity, MTF, NPS(f), and DQE(f) strongly depend on the applied electric field and carrier ranges. It is found that the DQE(f) for fluoroscopic applications can be improved dramatically by simply enhancing the carrier lifetimes through improving material properties of the PbO sample.
科研通智能强力驱动
Strongly Powered by AbleSci AI