Detector characteristics dynamic range

There are several important characteristics of a good detector sensitivity, dynamic range, stability, and for specific ones selectivity. Sensitivity should be in fact characterized by two parameters the ratio of the detector response to the amount of sample (sensitivity slope) and the minimum detectable level of a given compound (commonly measured for a signal to noise ratio of 3). The dynamic range is the range... 

Another important characteristic of a detector is the linear dynamic range a range of analyte concentrations that produce a calibration line best described with a linear equation. Non-linear calibrations with subtle curvatures may be also used in the linear dynamic range of the detector. 

The device functions in the same way as the conventional electron-capture detector with a radioactive source. The column eluent enters just below the third electrode, any electron-capturing substance present removes some of the free electrons, and the current collected by the fourth electrode falls. The sensitivity claimed for the detector is 0.2-1.0 ng, but this is not very informative as its significance depends on the characteristics of the column used and on the k of the solute peak on which the measurements were made. The sensitivity should be given as that solute concentration that produces a signal equivalent to twice the noise. Such data allow a rational comparison between detectors. The sensitivity or minimum detectable concentration of this detector is probably similar to the conventional pulsed ECD (viz. 1 X 10 g/mL). The linear dynamic range appears to be at least three orders of magnitude for a response index of r, where 0.97 [Pg.607]

The first two-dimensional detector in X-ray diffraction was conventional film. It remained for decades the detector of choice for both single crystal as well as powder diffraction experiments. In the field of two-dimensional detection it was surpassed initially by image plates and later by CCD cameras (Figure 14.1). Today virtually no film is in use, with perhaps the exception of Polaroid used for single-crystal images. To be able to compare various detectors with one another, and to select the most appropriate detector for a specific experiment, certain key technical qualities are important. These are in general the detective quantum efficiency, the spatial response characteristics, the size, speed and dynamic range. ... 

Primary performance characteristic benchmarks of UV/Vis detectors are sensitivity, linear dynamic range, and band dispersion. These are primarily controlled by the design of the optics and the flow cell. 

Due to low, dark current and rapid readout characteristics, their large dynamic range (>18 bit for the CCD) and the two-dimensional array feature, the CCD and LCI-CCD are more versatile detectors. These detectors and the MCP-SPD array detector are particularly useful for picosecond, time-resolved emission, absorption, and Raman spectroscopy, and for imaging applications where signal averaging is required. 

The characteristic curve of a typical digital mammography detector is shown in Fig. 1.4b. The detector inherently produces a signal that is linearly proportional to the intensity of X-rays transmitted by the breast. It has a very large dynamic range, so that it is possible to produce a faithful representation of X-ray transmission for all parts of the breast Furthermore, unlike film, the shape of the chararteristic curve for these detectors is much less dependent on the level of radiation exposing the detector. Maintaining an adequate value of is still important however, both the... 

McNair and Miller have characterized the FID based on the following criteria (63). The FID is selective for all carbon-containing compounds. The FID has a minimal detectable amount of 10 " g. A linear dynamic range of 10 enables, for a 1-pL injection volume, a detector response that is linear from 1 g of hydrocarbon all the way down to 1 pg of hydrocarbon. The next criterion is that of good baseline stability over time and this translates into minimal baseline drift. Also, the effect of a change in flow rate or temperature on baseline stability is an important characteristic of FIDs. Finally, it is... 

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