The dual-axis duo-lateral position-sensitive silicon detector was developed to detect charged particles with high quality position and energy resolution. When these detectors were used with conventional signal processing electronics, an empirically determined correction was used to improve energy resolution. In this work, the waveforms from the detector after preamplification are studied in detail to investigate position information contained in the waveforms. A 7.22 MeV/nucleon alpha particle beam was impinged directly on a masked dual-axis duo-lateral detector. Data obtained using a 228Th alpha particle source was also used. By studying the waveform characteristics that give rise to the position-dependent distortions, a new summed trigger analysis method has been developed to significantly improve linearity in position reconstruction without sacrificing energy resolution.

Experiments have been performed to study the bremsstrahlung from 5 keV electrons incident on BeO and NaCl targets. The main objectives of the study were to compare the experimental results to those produced using pyPENELOPE (which is based on the main program of the Monte Carlo code, PENELOPE) in order to examine the accuracy of the code's implementation of the additivity approximation and its predictions for experiments involving insulating targets. Comparisons of experimental results to results produced using pyPENELOPE were made both for situations where surface-charging effects were significant and for situations where the insulating targets' surfaces were continuously neutralized. The results suggest that the PENELOPE code's main program, PENEPMA, does not simulate charging effects. Instead, it accurately simulates bremsstrahlung produced by low-energy electrons incident on insulating targets for situations where surface-charging is not significant. The results also support the validity of the additivity approximation, as incorporated into PENELOPE.

Graphene oxide (GO) is a nanofilm composed of graphene with various oxygen functional groups attached. GO is of interest due to its unique mechanical-enhancement properties, its tunable electronic properties, and its potential use in the wide-scale production of graphene. Scanning electron microscopes (SEMs) are frequently used to characterize and study GO films. The purpose of this project was to study the effects of SEM-imaging on GO films. Using an SEM, we irradiated GO samples at electron beam-energies of 10, 20, and 30 keV (at a constant emission current of ~40 micro-amps) for times ranging from 15 minutes to one hour. Raman D- and G-band intensities were used to examine structural modifications/damage to GO samples as a function of beam energy and exposure time. The results suggest that imaging with a 30 keV electron beam for 30 minutes may lead to the formation of amorphous carbon, while imaging with 10 keV or 20 keV beams for 30 minutes does not have a significant effect on GO samples.

We have studied the visible and infrared radiation emitted by multiwalled carbon nanotubes (MWCNTs) of different diameters when exposed to 2.45-GHz microwaves. A comparison of the spectra suggests that MWCNTs with larger diameters emit radiation of greater intensity than those with smaller diameters. Furthermore, the MWCNTs continue to emit visible and infrared radiation over the course of several microwave-irradiation cycles, with no degradation in the intensity of the emitted radiation. A comparison of Raman D- to G-band peak-intensity ratios reveals that microwave-irradiation did not significantly impact the MWCNTs' defect densities. The results of our experiments suggest that MWCNTs may have the potential for use in lighting technologies and that ohmic heating caused by the polarization of the MWCNTs in the microwave field is likely responsible for the observed emissions of visible and infrared radiation. (C) 2018 Society of Photo-Optical Instrumentation Engineers (SPIE)