Study of track formation mechanism in CR-39 plastics by heavy ion irradiation

Gas chromatography mass spectrometry (GC-MS) and matrix assisted laser desorption ionization mass spectrometry (MALDI-MS) have been applied for the analysis of etched products from CR-39 plastics containing in etchants of sodium hydroxide solution (NaOH) by oxygen ion beam irradiation at Heavy Ion Medical Accelerator in Chiba (HIMAC) accelerator. The GC-MS analysis of etchants of irradiated and unirradiated CR-39 plastics detected the diethylene glycol and ethylene glycol. It was found that the concentration of diethylene glycol was decreased while ethylene glycol was increased after the heavy ion irradiation. The mass distribution of poly allylalcohol in the etchants was confirmed between 800 and 3500 of m/z by MALDI-MS analysis. These analyses confirmed the expected etched products of diethylene glycol and poly allylalchol from CR-39 plastics by hydrolysis with NaOH solution. The mass spectrometry analysis using GC-MS and MALDI-MS will be powerful tool to confirm the radiation-induced polymeric fragments of bonds for resolving the heavy ion track formation mechanism in CR-39 plastics (author)