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	Applications  NIR Spectrometer Informationen in deutsch Informations en français Информация на русском языке	Invited Paper Monochromator/Detector Design for NIR-Spectroscopy - H.W.Siesler Department of Physical Chemistry University of Essen D 45117 Essen Germany At this stage it would be of extreme importance to both, scientists using NIR-spectroscopy already on a day-to-day routine as well as to prospective users, to learn about the experiences of other colleagues working with different monochromator/detector designs in different fields of research. Therefore, I encourage the start of a discussion forum on the basis of this fast-growing and global medium with contributions ranging from requests for help/advice with reference to specific problems to progress reports on the advantages/disadvantages of new instrumentation and accessories. In continuation of the attached overview on the different vibrational spectroscopies it is of interest to discuss the perspective of NIR instrumentation relative to the other techniques. Of all the vibrational spectroscopic methods NIR offers the largest variability in monochromator/ detector design. The diagram summarizes the different types of instrumentation splitted up in instruments working with a limited number of fixed frequencies (filter instruments, light-emitting diodes (LED´s)) and scanning instruments. Most of the instruments (frequently hand-held) used for the measurement of simple parameters or well-defined materials belong to the first category. Most of the laboratory- or production-based instrumentation used for chemical quality and process control of a broad range of materials are usually scanning-type instruments. These can further be subdivided into instruments with and without mechanically moving parts. The lastmentioned type of instruments (acousto-optic tunable filter (AOTF) and diode-array spectrometers) has certainly made the fastest progress in miniaturization. The highest spectral resolution (< 0.1cm-1) can be obtained with Michelson-interferometer based Fourier-Transform instrumentation. Although this high spectral resolution is certainly not necessary for the majority of NIR-spectroscopic applications, it may be a competitive advantage for the calibration of the wavenumber scale. Speed of data acquisition lies for most of the scanning instruments in the range of a few seconds for good signal-to-noise data. Extremely high scanning rates (> 100 scans per second) can be achieved with AOTF-instrumentation and diode-array spectrometers, however, at the expense of spectral resolution. Additional Literature: Quality-Control and Process-Monitoring by Vibrational Spectroscopy by H. W. Siesler Tell us your opinion