An inductively coupled plasma (ICP)-echelle optical system coupled with a charge-injection device (CID) detector was evaluated for precision and noise. Simultaneous collection of analyte wavelengths and simultaneous background correction have invalidated underlying assumptions in some traditional models. Signal flicker noise, a major limitation in single-channel detection, was eliminated by the time correlation of analyte and internal standard wavelengths. Once flicker noise was eliminated, most fluctuation was found to be caused by slight wavelength shifts along the axis of the detector, rather than by the theoretically predicted signal shot noise. This fluctuation can be corrected by increasing center subarray sizes or by employing well-matched internal standard lines. In either case, precision of 0.3 to 0.18% relative standard deviation (RSD) was achieved over a time span of 7 h. Background flicker noise was also eliminated by simultaneous background correction, demonstrating a multichannel advantage of ICP detection using charge-transfer devices. In this work, theoretical expressions were developed to incorporate major sources of noise based on the specific readout characteristics of an array detector. These expressions match experimental data extremely well for measurement of relative standard deviation in background (RSDB) and detection limits. These data have then been compared to the single-channel case, which describes photomultiplier tube (PMT) detection, as well as the theoretical limit dictated by background shot noise.
Recent developments in technology have suggested a promising ATOMIC EMISSION DETECTORS future for plasma spectroscopy. New optical technologies, suchResearch in spectroscopic detectors continues to improve as volume phase technology and unconventional optical measurements in plasma spectroscopy. Current 'state of the systems, when coupled with new generations of optical art' detection is performed using charge transfer devices detectors promise to provide powerful tools for plasma (CTDs). When run in the scientific mode, these devices achieve diagnostics or spectrochemical analysis. Next generation very low read noise and almost non-existent dark current.1-3 charge injection devices will provide both complete random When CTDs are coupled with e ´chelle spectrometers, a powerful access of individual detector sites and 'collective readout,' a system for measuring atomic emission is created, as illustrated new readout mode. Collective readout will promise faster in Table 1. This system has many desirable properties such as readout and improved signal to noise ratios. A new generation high resolution, high sensitivity and a wide dynamic range. of pre-amp per pixel array detectors with proper addressing Furthermore, CTDs achieve simultaneous multichannel detecarchitecture will allow random pixel readout and extreme tion of signal and background. Improvements in the near resistance to blooming. These technological advances will yield future should occur through the modification of current array new capabilities for not only current and future plasma detector technology and readout and in the development of sources, but also vintage sources such as the microwavenovel detector arrays. induced plasma, the direct current plasma, direct current arc Unfortunately, improvements in conventional CCD technoland the direct current spark. Developments in software data ogy are required to accommodate the wide range of intensities processing techniques including neural networks and other found in atomic spectroscopy. When the full well potential of chemometric techniques will allow present and future a pixel is reached, charge can spill over into nearby pixels in spectroscopists to extract useful diagnostic and chemical a process called blooming. In atomic emission, where strong information from the almost overwhelming abundance of and weak lines occur in close spatial proximity, blooming from analytical data generated by the present and future generations strong analyte or background (Ar) lines will typically cause of array detectors.interference and decrease the sensitivity and dynamic range of the device. While the CCD can be made antiblooming, quanti-Keywords: Spectroscopic instrumentation; plasma fication of the collected charge is not possible for strong lines spectroscopy; volume phase technology; charge injection in which the full well has been surpassed.4,5 Hence, during a devices; array detectors; charge transfer devices multicomponent analysis, multiple measurements can be required at a variety of different integration ti...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.