Venkatesan T., Calcagno L., Elman B. S., Foti G., in: Ion Beam Modification of Insulators, eds. <...> Effect of amorphization cross-section of polymer due to MeV-proton irradiation B. Mallick Institute of Physics, Bhubaneswar, 751005, India E-mail: bmallick_iopb@scientist.com S. Panigrahi Department of Physics, National Institute of Technology, Rourkela, 769008, India Irradiation of semicrystalline polymers with high-energetic heavy ions usually reduced the sample crystallinity up to a complete amorphization. <...> However, proton-like lighter high-energetic ions show a negative value of amorphization cross-section a, which indicates an improvement of crystallinity in the above polymeric samples. <...> This increase in crystallinity though observed earlier could not be defined because of the lack of proper theory (ion-induced crystallinity and microstrain). <...> Charlesby A., in "Atomic Radiation and Polymers" (Pergamon press, Oxford, 1960). 22. <...>