IV. 6. On the Use of a Thick Carbon Target in the 90º Compton Spectroscopy for the Measurement of Diagnostic X-rays

Radio-diagnostic technologies are widely used in medical fields. In order to perform quality assurance and quality control of the X-ray radiographic systems, we studied the Compton spectroscopy using scatteres with various shape and size to find optimum condition of scattere in terms of efficiency and energy broadening1, 2). For the purpose, simulation was made for Compton scattered photons at 90º after the secondary collimator in the experimental setup (Fig. 1, without the detector) using the MCNP4C code. The flux of 90º scattered photons was calculated for different shapes of carbon scatterers including a cylinder with height and diameter of 2 cm, and five cylinders with the same diameter of 2 cm but cut at 15º, 30º, 45º, 60º and 75º respectively. Figure 2 shows simulation photon spectrum at 90º for 100 keV monoenergetic photons at x-ray focal spot from a cylinder and the scatterers with cutting angle of 15º and 30º. The energy broadening is shown in Fig. 3 for primary photon energy of 100 keV. From Fig. 2 and Fig. 3, it is clear that smaller cutting angle leads to lower values of energy broadening and multiple scattering. However, from the viewpoint of fabrication and practical use, this cutting angle is not convenient. Fortunately, the energy broadening an