Readout systems

M. Urban, R. Moller, and W. Fritzsche, A paralleled readout system for an electrical DNA-hybridization assay based on a microstructured electrode array. Rev. Sci. Instrum. 74, 1077-1081 (2003). 

The small, compact printer can be utilized where the larger Datagram Readout Unit is not needed or convenient, i.e., for quick readout in field locations, or where a graphic display is not necessary. The choice of two readout systems allows maximum versatility and economy for both the large, multiplant, multiproblem user, as well as the small, single substance installation. 

Refractometer. An instrument for determining the refractive index of solutes. Most of these instruments use photometric readout systems. 

The principles underlying the operation of the chromatograph and its use in a commercial separation process are discussed in Volume 2, Chapter 19. In this section emphasis is placed on its function as an on-line process analyser in which form it consists of three major subdivisions (apart from any electronic readout system), viz. the sampling assembly, the chromatograph column and the detector. All three are generally contained within the same temperature-controlled environment (Fig. 6.50). 

Optical gene chips dense arrays of oligonucleotides have been successfully applied to detect transcriptional profiling and SNP discovery, where massively parallel analysis is required. However, the fluorescence-based readout of these chips involves not only highly precise and expensive instrumentation but also sophisticated numerical algorithms to interpret the data, and therefore these methods have been commonly limited to use in research laboratories. In this way, thin-film arrays of 14, 20, 25, 48 and 64 electrodes have already been fabricated [12,15,39,40,44,48], using lithographic techniques. Readout systems for these arrays based on electrical detection have also been developed. 

The speed of the TOF-MS requires fast readout systems that can be expensive, data-intensive, and elaborate. Additionally, one of the most valuable techniques within trace analysis, ion counting, is of less utility when utilized with TOF-MS. These are unavoidable effects of the pulsed nature of the TOF-MS, and of the wealth of information that the TOF-MS is capable of producing. 

Hydrogenated amorphous silicon FET structures are very important candidates for ACSs especially in the field of ISFETs. The long experience with c-Si FETs in the past years (involving membranes, electrode theory, and integrated readout systems) can be advantageously used. 

The radiant energy from the source must be converted into an electrical signal for amplification and measurement by the readout system. This conversion is undertaken almost universally by a photomultiplier tube. 

May be in the future, the industry will develop some kind of large CCD devices, with faster readout systems. This really would bring an innovation. In the meantime it is worth while considering that gas filled detectors already serve their purpose very well at present. 

The most immediate solution (2 years away) is the GFS upgrade to the RAPID readout system. The idea behind this system is that by segmenting the active area of the detector it is able to perform many more operations significantly faster. The predicted performance is a count rate in excess of 10 s , which is certainly sufficient for many experiments. In the longer term truly pixelated detectors, based on readout electronics on a silicon chip, will be necessary to cope with the increased X-ray fluxes. 

Figure 16.10 shows readout images of written bits in 26 consecutive layers. The bit and layer intervals were 2 fim and 5 /xm, respectively. The data were read out with a reflection confocal microscope (RCM). The details of the readout system are discussed in the Section 4. With the RCM, the written data are clearly read without crosstalk. 

Figure 16.15 shows the readout result of the four-layered optical memory. The readout system was a reflection-type confocal microscope. For reading, a He-Ne laser was used as a light source, because the urethane-urea copolymer has little absorption for red light. The scattered light at the recorded bit data... 

The reflection confocal microscope (RCM) is an attractive configuration as a readout system of multilayered optical memories because it has extremely high axial resolution and its configuration is substantially easier than that of transmission confocal microscopes, A typical RCM system is shown in Figure... 

The readout result with RCM optics is shown in Figure 16.15. The four recording layers are clearly detected. As a result, it has been determined that the reflection type confocal microscope configuration can be used as a readout system of multilayered optical memory by using the recording medium in which the photosensitive thin films and transparent films are piled up alternately. 

As described in Section 16.4.5, the detection of refractive-index change between two isomers in a photochromic material is the most promising technique for nondestructive readout.It is necessary to develop a readout system that is sensitive to refractive-index distribution. For this purpose, several methods, such as phase-contrast microscope, differential phase-contrast microscope, and reflection confocal microscope configurations have been proposed. 

An alternative readout system is a scanning differential phase-contrast microscope with a split detector as shown in Figure 16.5. The optical configuration is compact and easy to align. The memory medium, in which the data bits have been recorded, is located at the focus of an objective lens. The band limit of the optical transfer function (OTF) is the same as that of a conventional microscope with incoherent illumination. The resolution, especially the axial resolution of the phase-contrast microscope, is similar to that obtained by Zemike s phase-contrast microscope. The contrast of the image is much improved compared to that of Zernike s phase-contrast microscope, however, because the nondiffracted components are completely eliminated by the subtraction of signals between two detectors. The readout system is therefore sensitive to small phase changes. 

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