Résumé: Chemical and optical modifications induced by 22.5 MeV protons slowed down into a 4.4 mm polyallyl diglycol carbonate (CR-39) stack, which was composed of 16 detectors of different thicknesses, are studied. Irradiation was performed perpendicular to the stack surface, in a vacuum chamber, with proton fluences ranging from 1011 to 1014 particles/cm2. These transformations are analyzed using fourier transform infrared (FTIR) absorption spectroscopy in the total attenuation reflection mode and UV-visible spectroscopy by following C=O, C=C and O-H bands evolution and by following the shift in the absorption edge towards the higher wavelengths. The chemical changes occurring in the CR-39 absorption spectra (both FTIR and UV) are analyzed versus the ion beam fluence, the beam penetration depth into the stack and the average deposited energy density. The results show that degradation of CR-39 presents a maximum in the depths ranging between 3500 and 4000 [mu]m.

Langue: Anglais
Thème Chimie

Mots clés:
CR-39
Proton irradiation
Chain scission
Cross-linking