PMT—See Photomultiplier tube

The main detectors used in AES today are photomultiplier tubes (PMTs), photodiode arrays (PDAs), charge-coupled devices (CCDs), and vidicons, image dissectors, and charge-injection detectors (CIDs). An innovative CCD detector for AES has been described [147]. New developments are the array detector AES. With modem multichannel echelle spectral analysers it is possible to analyse any luminous event (flash, spark, laser-induced plasma, discharge) instantly. Considering the complexity of emission spectra, the importance of spectral resolution cannot be overemphasised. Table 8.25 shows some typical spectral emission lines of some common elements. Atomic plasma emission sources can act as chromatographic detectors, e.g. GC-AED (see Chapter 4). 

One photomultiplier tube measured the total (broad-band, spectrally) bioluminescence, and it was used as reference to compare the signals through the various filters. All signal counting was preceded by the dark-current counts of the PMT, averaged for the subsequent signal count time, and subtracted. The net signal count when filters were used was also corrected for the total transmittance of each filter and for the quantum efficiency of the phototube see Appendix). 

CCD charge-coupled device, CRP C-reactive protein, FITC Huorescem-5-isothiocyanate, TTO indium tin oxide, LED light-emitting diode, LOD limit of detection, PMT photomultiplier tubes, SEE Staphylococcal enterotoxin B, SIN signal-to-noise ratio, SSPM solid-state photomultiplier, TFT thin film transistor... 

Figure 13.19 An arrangement using an annulus and a plug detector PMT, photomultiplier tube BGO is optional (see text for further details)...

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