Assumption ofF−centre creation in lif bombarded with high-energy particles

Optical measurements have been made of the concentration of F centres produced in LiF by 2 MeV proton, 28 MeV lithium, 28 MeV deuteron and 56 MeV alpha particles. An assumption is proposed to explain the growth of F centres with the irradiation. The creation of defects by one particle is supposed to be localized in a volume surrounding the particle trajectory, named the tube, associated with the particle. In a first approximation, the tube is compared to a cylinder and taking into account the high energy loss of the energetic ions, the lateral distribution of defects in a tube is supposed to be homogeneous. The experimental result of F centre creation are fitted by the hypothesis. The mean radii for the tube are respectively: 12, 63, 70 and 165 A for the particles 2H (2 MeV), 7Li (28 MeV) and 4He (56 MeV). The temperature of the irradiation has an influence on the mean radius.