Throughput detector

the detector is not a limitation on detector throughput at the count rates we are considering. However, as I noted in Chapter 4, conventional wisdom suggests that the shaping time of the amplifier should be set somewhat greater than the notional charge collection time and that will, as we shall see, significantly limit our count rates. 

The mechanisms of the resistive feedback (RF) preamplifiers and transistor reset preamplifiers (TRPs) were discussed in Chapter 4, Section 4.3. Some of their properties are compared in Table 14.2, and some of the differences between them are explored in the following sections. 

For emergency monitoring systems, such behaviour is clearly not acceptable. It is when there is an emergency that count rates are expected to be high. A detector system that shuts down as soon as it is required to do some real work will not do. Throughput can be improved by reducing the value of the feedback resistor 

Pole zero collection essential (not easy at high rates) 

Saturates due to energy rate limit, typically 2 X 10 MeVs . When saturated, no output 

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Since only a small fraction of the interfering material reaches the second column and Subsequently the detector, the next analysis can start after the analyte has been transferred to column 2. This provides a high throughput (about 7 samples per hour). 

Before the slit. Motion of the image delivered by the telescope with respect to the slit causes both a loss of throughput and an error in the barycentre of the spectral lines recorded on the detector, unless the object uniformly fills the slit (which implies low throughput). This can cause errors in measurement of radial velocities. For MOS, there is the particular problem of variations in the image scale or rotations of the mask. These can cause errors which depend on position in the field resulting in spurious radial trends in the data. Fibre systems are almost immune to this problem because the fibres scramble posifional information. 

Assessing the resources available for method development should also be done before beginning a project. The resources available include not only HPLCs, detectors, and columns, but also tools for sample preparation, data capture and analysis software, trained analysts, and especially samples representative of the ultimate analyte matrix. Also, it should be considered whether a fast, secondary method of analysis can be used to optimize sample preparation steps. Often, a simple colorimetric or fluorimetric assay, without separation, can be used for this purpose. A preliminary estimate of the required assay throughput will help to guide selection of methods. 

ICP-MS presents various shortcomings as compared to the requirements of an ideal PS-MS technique (Tables 8.62 and 8.56). Simultaneous detectors, as in ToF-MS or array-detector atomic mass spectra (ADAMS), offer several advantages in terms of sensitivity, precision, LOD (50ppq), resolving power and sample throughput. PS-ToFMS and ICP-ADAMS are still in their infancy. 

Both TCSPC and TG benefit from operation in SPC mode. SPC results in little or no noise and a high photon-economy [10]. Therefore, TCSPC and TG are ideal for high spatial and lifetime resolution imaging [24], Both techniques offer high image contrast also on dim samples. However, the dead-time of the detectors and the point scanning character limit the throughput of these systems. 

The acquisition throughput of a microscope is often determined by photon statistics, but depends also on many parameters including instrumental limitations, for example, the read-out and dead-time of the detector and electronics [40],... 

The above limitations are implementation dependent and no intrinsic limitations. The throughput of TCSPC can for instance be improved by the use of multiple detectors, and multiple TCSPC boards [42]. The photon-economy of TGSPC could be optimized somewhat by increasing the number of gates. 

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