Eric Lifshin

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A new Monte Carlo program, Win X-ray, is presented that predicts X-ray spectra measured with an energy dispersive spectrometer (EDS) attached to a scanning electron microscope (SEM) operating between 10 and 40 keV. All the underlying equations of the Monte Carlo simulation model are included. By simulating X-ray spectra, it is possible to establish the(More)
A method is presented for determining the point spread function (PSF) of an electron beam in a scanning electron microscope for the examination of near planar samples. Once measured, PSFs can be used with two or more low-resolution images of a selected area to create a high-resolution reconstructed image of that area. As an example, a 4× improvement in(More)
Scanning electron microscopy (SEM) resolution is limited by many factors that include sample specific properties, microscope stability, noise, the three dimensional nature of the sample and the excitation volume, and the spatial distribution of electrons in the probe known as the point spread function (PSF). If all, but the latter are optimized, the loss of(More)
Quantitative X-ray microanalysis of thick samples is usually performed by measuring the characteristic X-ray intensities of each element in a sample and in corresponding standards. The ratio of the measured intensities from the unknown material to that from the standard is related to the concentration using the ZAF or ϕ(ρz) equations. Under optimal(More)
An image is understood as the point spread function (PSF) of an imaging system convolved with the scene being imaged. An image can be restored to more accurately depict the scene by performing a deconvolution of the PSF and the image. In a scanning electron microscope (SEM), the PSF describes the shape of the electron beam. PSF deconvolution is a promising(More)
These experiments were performed using a Carl Zeiss 1540 crossbeam instrument that permits SEM imaging during ion milling. The FIB beam consists of 30 KV Ga ions with currents ranging from several nanoamperes down to several picoamperes. The Schottky source electron gun was run in the high current mode at 1 and 5 KV to provide an electron beam current of(More)
ACKNOWLEDGEMENTS We sincerely thank our research advisor Dr. Eric Lifshin for his guidance on this project. We also acknowledge our other group members: and Ben Trudell. We express our gratitude to all the developers who contributed to the creation of the two modeling programs used in this work, CASINO and SIMION. ABSTRACT The efficiency of secondary(More)
Particle tracks in Apollo 11 samples are dominantly of cosmic ray and solar origin: primary galactic and solar flare particles, likely spallation recoil tracks, and possible solar-wind heavy particles. The energy spectrum of irongroup nuclei is inferred from track density gradients in surface layers, and a limit of << 10(-7) centimeter per year is deduced(More)
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