Developments in atomic analysis and imaging utilizing scientific charge-transfer devices: Axial viewing of the inductively coupled plasma, advanced hollow cathode designs, and latent fingerprint imaging

Abstract

This document describes the development of spectroscopic techniques which benefit from the use of charge-transfer devices. Both charge-coupled devices (CCD's) and charge-injection devices (CID's) are used in the techniques presented here such as atomic emission spectroscopy and latent fingerprint imaging. The use of a CID echelle system for axial viewing of the inductively coupled plasma (ICP) demonstrates the enhancement in sensitivity that can be obtained over tangential viewing. More importantly though, are the advantages afforded by simultaneous multi-element detection. Axial viewing of the ICP has shown to not only improve upon the detection limits of several metals by, in some cases, a half order of magnitude, but also to increase the amount of light collected and thus reduce the time of analysis. Along with this, the effect of interferences upon the detection of various metals is, at worst, equivalent to that of an ICP with tangential viewing. Further enhancement of sensitivity in atomic analysis can be achieved by atomic fluorescence with an ICP. Although in the past, hollow cathode lamps have proven to be insufficient, advanced designs of hollow cathode lamps presented here have demonstrated an increase in the intensity of lines of copper best suited for use in ICP atomic fluorescence. Lastly, a latent fingerprint has been imaged with the use of a scientific CCD and a flashlight where in the past such a technique was accomplished with high power lasers. By using a CCD, the immediate digitization of information combined with the sensitivity and image processing capabilities offer a portable means by which to image latent fingerprints on poor surfaces.