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This paper describes a procedure for experimental determination of metastable and resonant populations along a surface wave argon plasma column at atmospheric pressure. As modeling work progresses extensively, an experimental database is necessary to confirm these models. Obtained results, within the range of values reported in literature, indicate that densities of metastable and resonant levels grow along the plasma column for positions near the energy coupler device, where the energy of the surface wave which creates discharge is the highest. This behavior is also found for electron density and temperature; however, it is not the same for gradient. Therefore, at atmospheric pressure, populations of 4s levels are not only controlled by collision with electrons from ground state, but the dissociative recombination mechanism is also important, in agreement with results found by other authors using collisional-radiative models. Index Terms--Argon, atmospheric pressure, metastable atoms, optical spectroscopy, plasmas, self-absorption.

A two-step technique for modeling the radiation from circuit boards with attached cables is developed and applied to various board--cable structures. The technique divides a complex source geometry into two components. One component consists of differential-mode sources and the pieces of the structure that contribute to the differential-mode radiation. The other component consists of common-mode sources at cable attachment points and the parts of the structure that play a role in the radiation due to common-mode cable currents. The two component geometries are much easier to model than the complete structure. This modeling approach also provides the modeler with insight regarding the design parameters that most influence one type of radiation or the other. Index Terms--Balance, common-mode current, power bus noise, radiated emissions.

We have developed a computational model of energy transfer processes in scintillators using the kinetic Monte Carlo (KMC) approach. In this publication, we focus on the alkali halide compound CsI both pure and doped with a range of thallium concentrations. The KMC model makes use of an explicit atomistic representation of the crystal lattice, activator sites, defect sites, and individual electron-hole pairs. The probability of individual diffusion, recombination, and scintillation events is calculated from rate equations parameterized with data published in the literature. Scintillation decay curves, relative intensities of emission peaks, and light yields are computed and found to be in good agreement with experimental data for a range of temperatures and thallium concentrations. This demonstrates that the KMC scintillation model is capable of reproducing both the kinetics and the efficiency of the scintillation process in CsI. In addition, novel predictions emerge from our simulations such as the diffusion distance distributions of serf-trapped holes and excitous. Finally, the KMC scintillation model provides a framework for probing possible physical processes responsible for the nonlinear relationship between scintillation light yield and incident gamma-ray energy. Index Terms--Alkali halides, cesium iodide, emission spectra, gamma-ray radiation, kinetic Monte Carlo, light yield, nonlinearity, scintillation decay curves, scintillation mechanisms, thallium.

We identify a discrepancy between experimental data and model predictions by a widely used radiation transport code, SRIM. We describe a method for determining the implant and damage profiles of energetic heavy ions that better agrees with experimental data than SRIM Monte Carlo predictions. Results of our method are given and compared to experimental data for a range of ion types and energies. Finally, the reason for discrepancy is discussed. Index Terms--Computer simulation of radiation transport, heavy ion damage in silicon, ion implantation in silicon, range and straggle of ions in silicon.

We have identified atomic scale processes involved in the so called 'interface trap transformation' process. These changes involve the generation of a silicon 'dangling bond' defect called [P.sub.b1]. This defect is somewhat different in electronic density of states and slightly different in physical structure than the dominating radiation induced Si/Si[O.sub.2] interface trap defect, the [P.sub.b0] center. Index Terms--Defect transformation, electron spin resistance, interface traps, MOSFET, Pb centers, Si[O.sub.2].

An evaluation programme of Thomson CSF-TCS GaAs low noise and power MMIC technologies to 1 MeV equivalent neutron fluence levels, up to 1x[10.sup.15] n/[cm.sup.2], ionizing 1.17-1.33 MeV C[O.sup.60] dose levels in excess of 200 Mrad(GaAs) and dose rate levels reaching 1.89x[10.sup.11] rad(GaAs)/s is presented in terms of proper components and parameter choices, DC/RF electrical measurements and test methods under irradiation. Experimental results are explained together with drift analyses of electrical parameters that have determined threshold limits of component degradations. Modelling the effects of radiation on GaAs components relies on degradation analysis of active layer which appears to be the most sensitive factor. MMICs degradation under neutron fluence was simulated from irradiated FET data. Finally, based on sensitivity of technological parameters, rad-hard design including material, technology and MMIC design enhancement is discussed.

Results from an investigation into methods of modeling the radiation patterns of phased arrays that include the effects of radiative mutual coupling are presented. The approaches are based either on the principle of pattern multiplication or the use of active element patterns. Theoretical derivations of the various active element pattern methods are also presented. In addition, a new method, the hybrid active element pattern method, is introduced which accurately predicts the patterns of small and medium-sized arrays of equally spaced elements. Example arrays of center-fed dipoles are analyzed to verify and illustrate the representations. The results are general, however, and can be applied to arrays of any type of element. The array patterns computed using both the classical pattern multiplication approach and the methods based on active element patterns are compared to those computed using accurate numerical codes based on the method of moments.

The level of spurious radiation from microstrip interconnects, which are modeled here as either single or asymmetric parallel microstrip lines terminated by arbitrary complex load impedances, is investigated in this paper. The calculation of the spurious radiation requires a knowledge of the current distributions on the microstrip lines, and the first step is to compute these distributions efficiently. This is carried out here by using the method of moments in conjunction with closed-form spatial domain Green's functions that circumvent the need for time-consuming evaluation of Sommerfeld integrals. Once the current distributions on the etches have been obtained, the level of spurious radiation, which is defined as the radiated power crossing the plane parallel to the plane of interconnects, is calculated. The dependence of the spurious radiation on the lengths of the lines and on the termination impedances of the etches is also studied.

Grating coupled twin-waveguide structures with a semitransparent metal-low-index waveguide over a corrugated high-index laser waveguide are investigated. An extensive Floquet analysis of TE modes is conducted for trapezoid shaped gratings, and a relation to simple coupled-mode equations is established. Results show that grating coupled radiation plays a significant role in the waveguide structures under study, especially with respect to narrow-band resonant suppression of radiation loss with linewidths in the subnanometer environment.

Terahertz waveforms are measured using photoconductive and free-space electrooptic sampling techniques. An analysis of the terahertz waveform measurements shows that a short dipole antenna used in a PC receiver generates a flat frequency response when used in the absence of a substrate lens and a jw response when used in the presence of a substrate lens. Near-field effects in the PC-sampling measurements of broadband terahertz waveforms are also observed.