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| Titel: |
The Use of Ensemble Averaging to Increase the Sensitivity of Measurements with Flame Photometers†|
| Auteur: |
Fisher, D. J. Stelzner, R. W. Jones, H. C. |
| Verschenen in: |
Instrumentation science & technology |
| Paginering: | Jaargang 2 (1969) nr. 1 pagina's 51-64 |
| Jaar: |
1969 |
| Inhoud: |
A number of steps that optimize the signal-to-noise ratio, S/N, were provided in the flame spectrophotometer design, including beam chopping followed by narrow-band-tuned amplification. It has been shown that the relative effectiveness of three methods of optimizing or enhancing S/N to increase the sensitivity and decrease the lower limit of detection of flame photometric measurements increases in this order: linear detection followed by RC filter averaging; linear detection followed by RC filter averaging followed by active integration averaging; ensemble averaging of output of tuned amplifiers. Correlation in both the frequency and time domains is provided, respectively, by tuned amplification and by ensemble averaging. Other advantages of the use of ensemble averagers in flame photometry are pointed out, including correction for background, calibration in the sample matrix, data transformations, faster wavelength scanning without S distortion, testing of design steps to optimize S/N, digital data acquisition, and the attainment of a greater advantage from the dependence of multiplier phototube gain upon the spectral sensitivity of the photocathode and upon the voltage applied to the tube. To obtain measurements of highest sensitivity, all portions of the measurement system must be designed to optimize S/N wherever economically and technically feasible in order to obtain a system output that has the highest S/N. The enhancement of the optimized S/N by ensemble averaging can provide a further increase in the sensitivity of measurement, or, in a practical problem, enhancement of S/N by ensemble averaging may be attractive because of the achievement of sufficiently high sensitivity (and low detection limits) with the use of relatively simple procedural steps. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
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