Charge injection detector

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). 

Figure 21-20 Data from charge injection detector illustrating baseline correction in plasma emission spectrometry. The mean value of pixels on either side of a peak is subtracted from the mean value of pixels under the peak. [Courtesy M. d. Seltzer, Michelson Laboratory, CNna Lake, CA.J...

Charge injection device (CID) and charge-coupled device (CCD) detectors can be used to monitor large portions of the spectrum in multiple orders by taking an electronic photograph. They are analogous to photographic plates which were used in the earliest spectrometers. A typical... 

Color Plate 24 Polychromator for Inductively Coupled Plasma Atomic Emission Spectrometer with One Detector for All Elements (Section 21-4) Light emitted by a sample in the plasma enters the polychromator at the upper right and is dispersed vertically by a prism and then horizontally by a grating. The resulting two-dimensional pattern of wavelengths from 165 to 1 000 nm is detected by a charge injection device detector with 262 000 pixels. All elements are detected simultaneously. [Courtesy TJA Solutions, Franklin, MA.J... 

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. 

The RC-method, or rise-time method, is shown in Fig. 10. Charges injected into the wire by an avalanche at a location x cause a current to flow through the anode wire in both directions, until the initial charge is spread out over the entire length. The position of the avalanche is estimated by measuring and comparing the two currents at both ends of the detector. 

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. 

Multielement Emission Spectrometry Using a Charge-Injection Device Detector... 

A Charge Injection Device (CID) camera system has been designed and constructed for use as a detector for atomic emission spectrometry. 

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 ... 

These Initial Investigations of the charge Injection device have Indicated that the device promises to be a successful detector for simultaneous multielement analysis In atomic emission spectrometry. The unique non-destructive readout, coupled with selective knockdown and pseudo-random addressing give the CID system capabilities unparalleled in any other detector available today. The device has been shown to have at least an adequate sensitivity, can be operated in a manner which reduces pixel cross talk, and the dynamic range of the system can be extended to virtually any desired level. 

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-... 

The measurements were performed using a Thermo Elemental IRIS Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES). A 2 kW crystal-controlled radio frequency (RF) generator operating at 27.12 MHz powers the plasma source. An Echelle optical system with a 381-mm focal length diffracts the light from the plasma source before it is focused onto the Charge Injected Device (CID) camera detector [4]. 

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. 

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