Radiation-induced conductivity in polyethyleneterephthalate and polyimide: Trap distribution effects
We have analyzed the radiation-induced conductivity in polyethyleneterephthalate (PET) and polyimide in terms of the recently developed semi-empirical model whose parameters have been determined numerically by a trial and error method based on our previously published results which have been shown to be correct with respect to such experimental limitations as recombination and current saturation. It has been shown that an application of the Onsager theory in PET meets with serious problems. Numerical and experimental results have been compared with published data.
The radiation-induced conductivity (RIC) of low-density polyethylene (LDPE) under continuous irradiation with fast electrons (50 keV) was experimentally studied. The dose dependence of the concentration of stable paramagnetic centers was determined. The kinetics of RIC in LDPE was calculated on the basis of the Rose–Fowler–Vaisberg (RFV) model taking into account the buildup of radiation-induced traps. Good correlation between the experimental results and calculated data was found.
The results of experimental investigation of the combined action of 500-keV protons and ~20-eV oxygen plasma on thin polyimide films are presented. The samples are irradiated with a proton fluence of 1014–1016 cm–2 and an oxygen plasma fluence of ~1020 cm–2. The transmission and Raman spectra of the films, which are measured at different stages of sample irradiation, are compared. Data on the mass loss of the samples as a result of surface erosion are presented.
This paper presents results of experimental investigation of combined impact of 500 keV protons with fluences of 1015–1016 cm−2 and oxygen plasma with fluences of (0.8–3.5) 1020 cm−2 on polyimide films. Measured UV–vis transmission, Raman and XPS spectra of polyimide specimens before and after combined impact and data on the sample mass losses as a result of erosion due to oxygen plasma exposure are given. On the base of the obtained spectroscopic results, the changes in the polyimide structure caused by the proton and oxygen irradiation are analyzed and discussed.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.