Image echelle spectrometer

Simultaneous Multielement Determinations by Atomic Absorption and Atomic Emission with a Computerized Echelle Spectrometer/Imaging Detector System... 

In the work reported here, the two-dimensional spectrum from the echelle spectrometer is displayed onto the active surface of a two-dimensional imaging detector that can monitor the different lines independently so that emission or absorption lines for multiple elements can be monitored simultaneously. 

It should also be noted at this point that a multichannel detector can have multiple detector elements along two axes, one parallel to the direction of wavelength dispersion, and one perpendicular. The latter is parallel to the entrance slit in most dispersive instruments. For example, a CCD may have 1024 pixels along the wavelength axis and 256 along the vertical axis, for a total of 262,144 independent elements. This second dimension of the detector may be used in a variety of applications involving Raman imaging, multiple detection tracks, or echelle spectrometers. 

Image dissector tubes (Fig. 26) make use of an entrance aperture behind the photocathode, by which the photoelectrons stemming from different locations of the photocathode can be scanned and measured after amplification in the dynode train, as in a conventional photomultiplier. Although used in combination with an echelle spectrometer with crossed dispersion for flexible rapid sequential analyses [59], these systems have not had any commercial breakthrough. This might be due to the limited cathode dimensions but also to stability problems. 

Fig. 4.11. Optical diagram of the echelle spectrometer using a custom designed off axis Schmidt image reduction configuration to provide an optical focal plane suitable for use with a CID array detector.

Image Devices. Although he never assembled an actual TV-spectrometer, Margoshes was the first to recognize the potential of TV-type detectors in analytical atomic spectroscopy. In a series of reports (50,51,52) he speculated on the advantages of using an SEC tube [vide infra] to detect radiation dispersed by an echelle spectrograph. These reports and the recent availability of various solid-state array detectors have prompted numerous... 

Switch-Board Optics. The preceding discussion has summarized the various approaches which have been taken to achieve a practical spectrometer for SMA. The direct reader, the vidicon detector, and the development of image device/echelle systems... 

Felkel, H. L., Jr., "Evaluation of imaging detector coupled to an echelle grating spectrometer for atomic spectroscopy", Ph.D. Thesis, Purdue University, 1978. 

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