A modified diffusion-based model for radiolytically evolved gases during ion implantation in polymers

Pathak, Ramji; Menon, V. J.; Chaturvedi, U. K.; Nigam, A.K.

doi:10.1016/0168-583x(89)90057-8

Cited by 2 publications

(2 citation statements)

References 7 publications

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“…More robust multidimensional models have been used to analyze gas evolution in ion beam irradiated polymers. 35 It is beyond the scope of the present work to examine the diffusion processes in great detail, but such an effort will be performed at a future time.…”

Section: Resultsmentioning

confidence: 99%

“…Diffusion of hydrogen in the polymer along the plane perpendicular to the axis of the ion beam would spread a part of the hydrogen molecules out of the irradiation zone. More robust multidimensional models have been used to analyze gas evolution in ion beam irradiated polymers . It is beyond the scope of the present work to examine the diffusion processes in great detail, but such an effort will be performed at a future time.…”

Section: Resultsmentioning

confidence: 99%

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Molecular Hydrogen Production in the Radiolysis of High-Density Polyethylene

and

LaVerne

1999

J. Phys. Chem. B

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The production of molecular hydrogen in the radiolysis of high-density polyethylene by γ rays and heavy ion beams has been investigated. Only the slightest increase in the radiation chemical yield of 3.1 molecules/100 eV was found from γ rays to protons of 5-15 MeV. A gradual increase in yield was observed on further increasing the linear energy transfer of the incident particles. This increase amounted to almost a doubling in the hydrogen yield from 10 eV/nm protons to about 800 eV/nm carbon ions. The exact reason for the increase in molecular hydrogen yield is uncertain, but it may involve reactions of excited states or enhanced combination reactions of carbon-centered radicals, thereby allowing more hydrogen to escape the particle tracks. Diffusion from the bulk material was found to have a dominant role on the observed dynamic profiles of hydrogen gas. A simple one-dimensional diffusion model was used to estimate the diffusion constant of hydrogen in polyethylene to be 2.2 × 10 -6 cm 2 /s.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Molecular Hydrogen Production in the Radiolysis of High-Density Polyethylene

and

LaVerne

1999

J. Phys. Chem. B

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Dynamic evolution of gases in the γ‐ and helium‐ion radiolyses of solid polymers

Chang

LaVerne

2001

J Polym Sci B Polym Phys

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The dynamic evolution of gaseous hydrogen, methane, and carbon dioxide in the ␥and 4 He-ion radiolyses of solid polymers was investigated. The polymers used include low-density and high-density polyethylene, polypropylene, polystyrene, poly-(methyl methacrylate), Nylon 11, Nylon 6, and poly(dimer acid-co-alkyl polyamine). An inline quadrupole mass spectrometer was utilized to monitor the dynamic profiles of the gases produced in the radiolysis. One-and two-dimensional numerical diffusion models were developed to simulate and extract optimum diffusion coefficients and gas yields from the experimental dynamic gas profiles. It was found that the dynamic evolution of molecular hydrogen from the bulk polymer is controlled by its diffusion in most cases, such as CO 2 in poly(methyl methacrylate). In the ␥ radiolysis of some polymers such as low-density polyethylene and polypropylene, the dynamic evolution of methane is only partially controlled by the diffusion process, and some other postirradiation process is a factor. It is concluded that the simulation method developed in this article is helpful in understanding and predicting the mechanisms of gas evolution in the radiolysis of solid polymers.

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A modified diffusion-based model for radiolytically evolved gases during ion implantation in polymers

Cited by 2 publications

References 7 publications

Molecular Hydrogen Production in the Radiolysis of High-Density Polyethylene

Molecular Hydrogen Production in the Radiolysis of High-Density Polyethylene

Dynamic evolution of gases in the γ‐ and helium‐ion radiolyses of solid polymers

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