Coherent scatter X-ray imaging of plastic–titanium targets

Abstract

Coherently scattered photons provide information about the molecular structure of target materials and the circularly symmetric scatter patterns of amorphous materials that exhibit the characteristics of the material. This study was designed to investigate the impact of varying positions of the multiple materials that comprise an X-ray target on its coherent scatter pattern. The projection of the scatter imaging technique for different combinations of three types of materials (i.e., polymethyl methacrylate (PMMA); high-density polyethylene (HDPE); and titanium (Ti)) was investigated. A polychromatic molybdenum anode X-ray tube was used as a radiation source, and a computed radiographic plate was used as a detector. The scatter patterns resulting from the interaction of a 1-mm primary beam with three single materials (i.e., 9-mm-thick PMMA, 6-mm-thick HDPE, and 1-mm-thick Ti) were recorded and analyzed. Then, to investigate the effects of material position in a multiple-material target, a 16-mm-thick composite target, made of four arrangement combinations, was assembled. The order of the composite target's materials with respect to the source and detector was changed in each combination. The scatter patterns of the four arrangement combinations were analyzed. The scatter patterns of the three materials—PMMA, HDPE, and Ti—had different ring sizes. The radial intensity profiles of the materials peaked at different angles. The angle-dependent projected scatter images, made using the diffraction patterns of the target with changes in the position of the materials in the target, showed changes according to the angle. These changes depended on the position of the materials in the target. The results indicate that the coherent scatter imaging technique can help determine the position of the materials in composite targets.