Spectral resolution instruments

Spectral resolution instruments of different kinds are used for resolving the different wavelength components of light. Important factors of merit for such devices are resolving power and light transmission. The resolving power is defined by 

We will describe four types of instruments prism and grating instruments, the Fabry-Perot interferometer and the Fourier transform spectrometer. A large number of varieties of these different types are used in spectroscopic research and various applications. Spectroscopic instruments have been discussed in [6.6,7,66]. 

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Flip angle Pulse width No. of scans Rep. time Weighting Line broad. Spectral resolution Instrument ... 

Spectral Resolution Instruments 121 6.2.3 The Fabry—P6rot Interferometer... 

FT instruments of higher magnetic field strengths, providing greater spectral resolution and sensitivity... 

Sensitivity of chemical shift analysis is determined by the spectral resolution of the XPS system. The resolution of a typical XPS system without a monochromator is 1.0 eV. This corresponds to the intrinsic line width of Al Ka or Mg Ka radiation. The analysing system contributes only little to the overall resolution. This resolution is sufficient to determine the binding energies of most core levels within 0.1 eV. Considerable improvement of the resolution down to 0.3 eV can be achieved by use of a monochromator. The higher resolution has to be paid for by a loss in intensity which, however, is no problem in modern instruments. 

Instrumentally, spectral FLIM generates a spectrally resolved set of lifetimes by either introducing filters to provide spectral resolution or a spectrograph between the sample and image intensifier. The first such system was created for looking at the long lifetimes of lanthanide dyes [37]. Later, a spectral FLIM system was described for measuring from a two-dimensional (2D) area of a microscope field... 

The selected extragalactic carbon stars have been observed with the VLT/UVES instrument in service mode. The spectral resolution was around 40000 over the domains 420-500 nm and 670-900 nm. We used carbon-rich MARCS model atmospheres and specific linelists in order to derive the abundances of metals,... 

Diode resolution is an important consideration in a PDAD detector. It is calculated by dividing the wavelength range by the number of diodes in the array. This, in combination with the optical resolution, will affect the spectral resolution of the instrument (i.e., the wavelength in nm, between data points in an acquired spectrum). (Operation and Maintenance of the ZQ with MassLynx, Waters Corporation.)... 

Important ongoing developments in HRTEM that are expected to be valuable in catalysis research include the correction of spherical aberrations in electron microscope lenses and monochromatization of the electron beam for improvement of the spatial and spectral resolution. Recently, scanning-TEM (STEM) of atomically dispersed lanthanum atoms on alumina (63) has provided e.x situ aberration-corrected images, but it is noteworthy that there is no technical limitation in applying the correction devices to instruments used for making measurements of samples in reactive environments. 

The availability of solid-state detectors (such as the charge-coupled detector, CCD) makes it possible to acquire simultaneously significant portions of the spectra or even the entire rich spectra obtained by ICP-OES in the UV-Vis region, thus providing a large amount of data. The commercial availability of ICP-OES instruments with these multichannel detectors has significantly renewed interest in this technique. However, some limitations, such as the degradation of the spectral resolution compared with photomultiplier-based dispersive systems, still remain. 

Required precision. This will lead you to the instrument you need. Quadru-pole ICP-MS is easy to use, robust and relatively inexpensive. In general, these instruments permit good precision of isotopes ratio measurements ranging from 0.1 to 0.5%. Applying high-resolution ICP-MS precision in isotope ratio measurements can generally be improved by a factor of 5-10 (mainly because of the flat-topped peak shapes and fewer spectral overlaps obtained with these high-resolution instruments). Multicollector ICP-MS systems increase precision due to the collection of all isotopes of interest simultaneously in a multicollector array and so they provide an opportunity to measure the isotopic composition of many elements more accurately than other ICP-MS instruments. 

Because they can precisely measure wavelengths, FTIR spectrometers permit spectra and file storage using an instrument form at and certain rules so that spectra can be treated by instruments from other manufacturers. Each data point in the spectrum can be stored as an ACSII file. However, the software normalises the raw data and lowers the spectral resolution to obtain fewer calculated values (one point every 8 or 4 cm-1 - giving less than 1 Koctet/spectrum). The inverse operation can be used to give a proper corrected image of the spectrum. 

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