The influence of radiation damage on electrons and ion scattering measurements from PVC films

• Published in: Radiation physics and chemistry (Oxford, England : 1993) England : 1993), 2021-02, Vol.179, p.109173, Article 109173
• Main Authors: Tee, B.P.E., Vos, M., Trombini, H., Selau, F.F., Grande, P.L., Thomaz, R.
• Format: Article
• Language: English
• Subjects: Atomic properties; Backscattering; Charged particles; Electron beams; Electron radiation; Energy; Energy dissipation; Energy distribution; Energy gap; Energy spectra; Excitation; Fluence; Ion scattering; Polyvinyl chloride; Protons; Radiation damage; reflection electron energy loss spectroscopy
• ISSN: 0969-806X; 1879-0895
• DOI: 10.1016/j.radphyschem.2020.109173

Polyvinyl chloride (PVC) is a material that decomposes rapidly when irradiated by charged particles. Here we use energy spectra of electrons reflected from the PVC films during electron radiation to monitor this process. This is accomplished by measuring the energy distribution of elastically scattered electrons which depends on the mass of the scattering atoms. Incoming electrons with energy between 5 and 40 keV are used. Information is obtained about both the relative amount of Cl, C and H present in the sample. Especially the Cl concentration decreases quickly during irradiation. At larger energy losses the signature of the band gap is visible in the energy loss spectrum. The number of excitations within the band gap increases rapidly when the composition of the film changes. The H intensity is somewhat less affected by the electron beam than the Cl intensity but accurate determination of the H content is complicated due to the changing background. Medium-energy ion scattering measurements (using 200 keV protons) and Rutherford backscattering measurements (using 2 MeV He ions) showed a strong decrease in the measured Cl intensity with ion fluence used. The Cl concentration as a function of fluence for electrons, protons and He ions can be described in a uniform way by considering the density of electronic excitations produced under the different irradiation conditions. •PVC films are irradiated with electrons, protons and alpha particles.•The composition of the films is monitored by measuring spectra of backscattered particles.•Strong depletion of chloride with fluence is observed, and a slower depletion of hydrogen.•The rate of decrease scales with the energy density deposited in the films by the impinging radiation .