title: Density and spatial resolutions of proton radiography using a range modulation technique.
abstract: The image quality of proton radiography using the method of beam energy modulation was studied to look into its practical uses. Two different depth-dose distributions generated by modulation were applied to investigate their effects on the density and spatial resolutions of the radiographic image. A steeper slope was found to provide higher resolution for the matching thickness of a phantom. The image was taken on a scintillation screen, and the distance between the phantom and the screen was a sensitive parameter on the resolution. For a beam with a range of 1.2 cm in Lucite, high-resolution images were attainable in the whole range. The resolution of proton images for different kinds of phantoms was examined in comparison with x-ray images as well as images simulated by a Monte Carlo code MCNPX. For a longer range of 18 cm, images attained by simulations indicated that density resolution is better maintained compared to spatial resolution, which is deteriorated by multiple Coulomb scattering.
authors.affiliation: Department of Nuclear Engineering, Hanyang University, 17 Haengdang, Sungdong, Korea.
authors.forename: Hyungjoon
authors.initials: H
authors.lastname: Ryu
authors.forename: Eunsuk
authors.initials: E
authors.lastname: Song
authors.forename: Jaeki
authors.initials: J
authors.lastname: Lee
authors.forename: Jongwon
authors.initials: J
authors.lastname: Kim