Charge-injection devices Array detectors

The classical silicon photodiode linear array manufactured by Reticon was the first detector marketed successfully. Similar solid state linear array detectors based on charge coupled devices, or charge.injection devices may also be of interest. Typical of the families of detectors, the Reticon detectors are built in a number of elements/array sizes. Commercially available units have anywhere from 128 to 1024 elements/array. Each individual element in the array is 1 x 1 mil to 1 x 100 mil in area, and are spaced on approximately 1 mil centers. The spectrometer system discussed in this article was built using Reticon-type devices. 

Charge coupled device (CCD) A solid-state two-dimensional detector array used for spectroscopy and imaging. Charge-injection device (CID) A solid-state photodetector array used in spectroscopy. 

In recent years, a new class of television camera detector based on integrated circuit technology has become available. These Include the charge Injection device (CID) (4, 5), the charge coupled device (CCD), and the photodiode array. Of these new detectors, the CID has many features which qualify it as a unique detector for emission spectrometry. These include ... 

A wide variety of solid-state detectors consisting of multiple elements (multiple channels) have been developed over the past 20 years (140). Devices that fall into this category include silicon photodiode (SPD) arrays, charge injection devices (CID), charge coupled devices (CCD), microchannel plate (MCP) image inten-... 

There are a number of different types of photon detectors, including the photomultiplier tube, the silicon photodiode, the photovoltaic cell, and a class of multichannel detectors called charge transfer devices. Charge transfer detectors include photodiode arrays, charge-coupled devices (CCDs), and charge-injection devices (ClDs). These detectors are used in the UV/VIS and IR regions for both atomic and molecular spectroscopy. 

The detectors in common use for these systems are the PMT or solid-state detectors such as CCDs and charge injection devices (CIDs). PMTs and photodiode arrays (PDAs) are discussed in Chapter 5. More detailed discussion of solid-state detectors is covered in Section 7.2. 

More recently, charge-transfer devices, such as charge-coupled devices (CCDs) and charge-injection devices (ClDs), have been employed in Raman spectrometers. Figure 18-11 shows a fiber-optic Raman spectrometer that uses a CCD as a multichannel detector. Here, high-quality bandpass and band-rejection (notch) filters provide good stray light rejection. The CCD array can be a two-dimensional array or in some cases a linear array. 

FIGURE 4 Examples of single-channel (photomultiplier) and two-dimensional array (charge injection device) detectors for spectroscopic applications. 

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). 

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