Evaluation of saturation dose in spatial distributions of color centers generated by 18 MeV proton beams in lithium fluoride.

• Photoluminescence behavior of color centers in LiF irradiated by 18 MeV protons. • Proton beam imaging by visible photoluminescence of color centers in LiF crystals. • Photoluminescence saturation dose from Bragg curve profiles reconstruction. • Photoluminescence saturation dose from proton beam transversal intensity maps. • Reliable method for proton-beam diagnostics and LiF dose response investigation. The paper concerns the analysis of spatial distributions of visible photoluminescence of optically active F 2 and F 3 + color centers created in lithium fluoride crystals by irradiation with proton beams. Spectrally integrated photoluminescent maps are detected in a fluorescence microscope and numerically elaborated to gather pieces of information regarding both the beam characteristics and the material response. A method based on two independent measurements (Bragg curve and beam transversal map) is developed to evaluate the saturation dose defined as the value above which the photoluminescence intensity begins saturating up to an asymptotic maximum. The paper describes the procedure and demonstrates its application to the experimental case of LiF crystals irradiated by a proton beam of 18 MeV nominal energy. [ABSTRACT FROM AUTHOR]