Image-providing detectors

Imagers having detector elements and read-out means provided in the same semiconductor body are presented in this part. 

Several embodiments of the invention are disclosed. For example, an imager having an array of lenses corresponding to the array of detector elements and an imager provided with a cold-shield are shown. One embodiment is shown in chapter 2.5. 

The imager provides a technique for achieving a small scale pre-multiplexing of the detector array while retaining a photovoltaic structure. By cycling the potentials on the control lines to selectively create field induced junctions, the effective collection area for incoming radiation will cycle about the unit cell. Consequently, the number of resolution elements on the focal plane is multiplied. 

The images of diffracted crystal lattices can be observed with specialized precession photographic equipment, although the modern day image plate detectors used in most laboratories produce a diffraction image that can be analyzed by computer to provide the indices of the lattice diffraction spots (Fig. ll.l,a-c). 

Over the past decade, there has been considerable development in imaging type detectors for the measurement of ultraviolet (UV) and visible light. These new detectors have attracted the interest of a number of analytical spectroscopists. For absorption spectroscopy, analytical chemists have traditionally used such instruments as the photometer, which uses a narrow-band light source (for example the 254 nm emission line from a low pressure Hg lamp or a continuous source with a filter), a sample cell and a photomultiplier tube (FMT) as the detector. While useful for many specific applications, the single-wavelength photometer cannot determine multiple sample components simultaneously or provide a general absorbance characterization of the system. When information at multiple wavelengths is desired,... 

Complete MCP s can be stacked to provide even higher gains. For response in the vacuum ultra-violet spectral region (50-200 nm) a SSANACON, self-scanned anode array with microchannel plate electron multiplier, has been used (36). This involves photoelectron multiplication through two MOP S, collection of the electrons directly on aluminum anodes and readout with standard diode array circuitry. In cases where analyte concentrations are well above conventional detection limits, multi-element analysis with multi-channel detectors by atomic emission has been demonstrated to be quite feasible (37). Spectral source profiling has also been done with photodiode arrays (27.29.31). In molecular spectrometry, imaging type detectors have been used in spectrophotometry, spectrofluometry and chemiluminescence (23.24.26.33). These detectors are often employed to monitor the output from an HPLC or GC (13.38.39.40). 

Figure 9.9 Schematic diagram of an FIA system with an injection valve, peristaltic pump, two reaction coils (RC1 and RC2) and a UV-Vis detector there are two reagents (reagent 1 and reagent 2) and a carrier buffer (Image provided by kind permission of FIAlab Instruments).

Fig. 2.26 NCD Beamline at ALBA, (a) Image of the WAXS detector Blue box in the top centre of image) (Picture taken by Sergio Ruiz) and (b) Image of part of the SAXS beamline (Picture taken by Juan Carlos Martinez). Images provided courtesy of Alba Synchrotron...

Modem IRFPA thermal imagers provide quantitative temperature measuring capability and high resolution image quality. Detector cooling is sometimes required and this is most often accomplished by means of a thermoelectric, or Peltier effect, cooler or an electric-powered Stirling-cycle nitrogen or helium cooler. 

The software US-SCAN 3.0 (IBT GmbH, Ober-Ramstadt, Germany) provides all functions of a portable flaw detector and a powerful ultrasonic imaging in A-, B-, C- and D-scans. Not only motor driven scanners can he used, but also manual scanning systems with encoders. Further documentation and test reports can be carried out with Windows software. 

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