Theoretical Analysis of the Radiation-Induced Conductivity in Polymers Exposed to Pulsed and Continuous Electron Beams
Abstract: We have performed comparative numerical calculations using a multiple trapping (MT)
formalism with an exponential and an aggregate two-exponential trap distributions for describing
two mostly used experimental setups for studying the radiation-induced conductivity (RIC) and
the time-of-flight (TOF) effects. Computations have been done for pulsed and long-time
electron-beam irradiations in a small-signal regime. Predictions of these two approaches differ
appreciably in both setups. The classical MT approach proved very popular in photoconductive
polymers generally and in molecularly doped polymers in particular, while a newly proposed
complex MT worked well in common polymers. It has been shown that the complex MT
successfully accounts for the presence of inherent deep traps, which may or may not have an
The flexible compound materials of test objects (type test patterns) to adjust the aviation optical equipment for the Earth remote sensing obtained by the method of ink-jet printing on the banner fabric have been studied. The quantitative regularities of changes in the optical and mechanical properties have been determined, which allow predicting the maintenance of the operational characteristics of the type test pattern.
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.
We have compared time-of-flight curves predicted by hopping and multiple trapping models with the Gaussian and exponential site/trap energy distributions, fitting Monte-Carlo predictions of the former with numerical calculations of the latter in a wide time domain using logarithmic coordinates lg j–lg t for the characterization of current shapes and an estimation of transit times. As a prototype hopping theory, we used the Gaussian disorder model while for representing the quasi-band theories we relied on the multiple trapping model, both of these for two types of the site/trap energy distributions. In case of the Gaussian distribution of trap depths, fitting procedure requires adjusting of the two model parameters (an energy distribution parameter σ and a frequency factor ν0). For an exponential distribution, a one-parameter (ν0) fitting suffices. The dipolar glass model, unlike the Gaussian disorder model, is basically different from the multiple trapping formalism, but a recently introduced two-layer multiple trapping model seems capable of reproducing TOF current shapes rather well.
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.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.