Spectroscopy detectors

Additional detectors currently available use other technologies such as electrochemical detectors for blister, nerve, blood, and choking agents, and infrared spectroscopy detectors or photo ionization detectors for the detection of blister and nerve... 

The morphology and size of the palladium particles on the alumina washcoat were studied using a transmission electron microscope (TEM - JEOL 2000 FX) operated at 200 kV. The microscope was equipped with an EDS (energy dispersive x-ray spectroscopy) detector (LINK AN 10000). The samples were prepared by applying a few droplets of a dispersion of a finely ground catalyst in ethanol onto a hollow carbon film supported by a copper grid. 

In 1953, Stockmayer and Fixman observed that the ratio, h, of hydrodynamic or Stokes radii (/ h) of the branched and linear macromolecules could also be used as a measure of branching. The relatively recent introduction of online quasielastic light scattering (QELS, also known as dynamic light scattering and as photon correlation spectroscopy) detectors for SEC permits direct determination of h by... 

Another method included in this chapter is ICP-MS, which, although not based on atomic spectroscopy in a true sense, utilizes the same instrumental approach as ICP-AES for sample introduction. The difference is that analyte quantification takes place using a mass spectroscopy detector. 

The fact that a high Z material surrounds the HPGe spectroscopy detector is useful in that it will provide extra shielding for it - both passive and active. An external gamma-ray will have to pass through the guard detector to reach the HPGe. If it interacts with both detectors, the event will be rejected. As a side effect, escape peaks will... 

The concentration-response relationship, unlike ion mobility spectroscopy detectors, is usually linear. For phosphorus, this relationship remains linear over a large concentration range. However, since sulfur exists in the flame as S2, the concentration-response relationship is a second-order one. Response linearity is related to the square root of sulfur concentration. The overall dynamic range for both sulfur and phosphorous are over 10 or even 10 ... 

In conventional spectroscopy, detectors measure radiation intensity. This method is inappropriate for detecting pulsed radiation. Because THz electromagnetic fields affect electronic devices by inducing electronic transitions, it is the time evolution of the THz electric field that is measured instead. Hence, alternative... 

PINS Portable Isotopic Neutron Spectroscopy (detector)... 

Mass and MS spectrum TGA-MS In TGA-MS, the TG is connected online with a mass spectroscopy detector to determine the nature and amount of volatile product emitted by the sample during a thermogravimetric experiment... 

Time-of-flight mass spectrometers have been used as detectors in a wider variety of experiments tlian any other mass spectrometer. This is especially true of spectroscopic applications, many of which are discussed in this encyclopedia. Unlike the other instruments described in this chapter, the TOP mass spectrometer is usually used for one purpose, to acquire the mass spectrum of a compound. They caimot generally be used for the kinds of ion-molecule chemistry discussed in this chapter, or structural characterization experiments such as collision-induced dissociation. Plowever, they are easily used as detectors for spectroscopic applications such as multi-photoionization (for the spectroscopy of molecular excited states) [38], zero kinetic energy electron spectroscopy [39] (ZEKE, for the precise measurement of ionization energies) and comcidence measurements (such as photoelectron-photoion coincidence spectroscopy [40] for the measurement of ion fragmentation breakdown diagrams). 

The low MW power levels conuuonly employed in TREPR spectroscopy do not require any precautions to avoid detector overload and, therefore, the fiill time development of the transient magnetization is obtained undiminished by any MW detection deadtime. (3) Standard CW EPR equipment can be used for TREPR requiring only moderate efforts to adapt the MW detection part of the spectrometer for the observation of the transient response to a pulsed light excitation with high time resolution. (4) TREPR spectroscopy proved to be a suitable teclmique for observing a variety of spin coherence phenomena, such as transient nutations [16], quantum beats [17] and nuclear modulations [18], that have been usefi.il to interpret EPR data on light-mduced spm-correlated radical pairs. 

A MBER spectrometer is shown schematically in figure C1.3.1. The teclmique relies on using two inhomogeneous electric fields, the A and B fields, to focus the beam. Since the Stark effect is different for different rotational states, the A and B fields can be set up so that a particular rotational state (with a positive Stark effect) is focused onto the detector. In MBER spectroscopy, the molecular beam is irradiated with microwave or radiofrequency radiation in the... 

In contrast to IR and NMR spectroscopy, the principle of mass spectrometry (MS) is based on decomposition and reactions of organic molecules on theii way from the ion source to the detector. Consequently, structure-MS correlation is basically a matter of relating reactions to the signals in a mass spectrum. The chemical structure information contained in mass spectra is difficult to extract because of the complicated relationships between MS data and chemical structures. The aim of spectra evaluation can be either the identification of a compound or the interpretation of spectral data in order to elucidate the chemical structure [78-80],... 

The first detector for optical spectroscopy was the human eye, which, of course, is limited both by its accuracy and its limited sensitivity to electromagnetic radiation. Modern detectors use a sensitive transducer to convert a signal consisting of photons into an easily measured electrical signal. Ideally the detector s signal, S, should be a linear function of the electromagnetic radiation s power, P,... 

Molecular Fluorescence A typical instrumental block diagram for molecular fluorescence is shown in Figure 10.45. In contrast to instruments for absorption spectroscopy, the optical paths for the source and detector are usually positioned at an angle of 90°. 

Spectroscopy Partl, AnaZ. Chem. 1985, 57, 1057A-1073A. Jones, D. G. Photodiode Array Detectors in UV-Vis... 

Detector Detection in FIA may be accomplished using many of the electrochemical and optical detectors used in ITPLC. These detectors were discussed in Chapter 12 and are not considered further in this section. In addition, FIA detectors also have been designed around the use of ion-selective electrodes and atomic absorption spectroscopy. 

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