1. Department of Physics and Electronic，Hunan University of Arts and Science，Changde 415000，China 2. College of Automation, Chongqing University, Chongqing 400030, China 3. College of Science, Chongqing University, Chongqing 400030, China
Abstract：In the case of a polychromatic source in X-ray TICT, the variation of attenuation coefficient with energy leads to low energy radiation being absorbed preferentially. In other words, the higher the energy, the lower the attenuation coefficient. With the transmission thickness augmenting, it is easier for X-ray to transmit the matter. The phenomenon is energy spectrum hardening. Thus, hardening correction has to be done. In the present paper, not only is energy spectrum hardening analyzed by theory and the relation stated between attenuation coefficient and transmission thickness in testing composites workpiece, but also the precise accurate theory model for hardening correction of energy spectrum and theory method are reasoned out in testing composites workpiece, which results from Beer′s law and the characteristics of X-ray interaction with composites. Then, the attenuation coefficient that has been corrected is used for product back-projection reconstruction. Thus, the effect caused by X-ray beam hardening is wipped out effectively in testing composites workpiece.
[1] Krohn Barbara R，Silver Michael D. Materials Evaluation，1990, 49(10)：1296. [2] Rogerio Ferreira de Paiva, John Lynch, Elisabeth Rosenberg，et al. Non-destructive Testing & International, 1998, 31(1): 17. [3] Hanke R，Bobel F. Non-destructive Testing & E International, 1992, 25(2): 87. [4] PENG Guang-han，YANG Xue-heng，HAN Zhong，et al(彭光含，杨学恒，韩 忠，等). Spectroscopy and Spectral Analysis(光谱学与光谱分析), 2005，25(11): 1880. [5] PENG Guang-han, YANG Xue-heng(彭光含，杨学恒). Non-destructive Testing(无损检测), 2005, 27(11): 565. [6] Guy M J, Castellano-Smith I A, Flower M A, IEEE Trans. on Nuclear Science, 1998, 45(3): 1261.
