Ebert-Fastie

Coderg PHO 0.25 10-11 Ebert-Fastie double gratings 0.6 1200 lines/mm, blazed at... 

The two most popular monochromator designs are the Littrow and the Ebert-Fastie, shown schematically in Figure 23. The merits of the two systems have been compared for many years for atomic absorption purposes, there seems to be little to choose between them. 

FIGURE 4-5. Schematic diagram of an Ebert-Fastie plane grating spectrometer. 

FIGURE 4-6. Photograph of a 3.4-m Ebert-Fastie spectrograph. [Courtesy Jarrell-Ash Division, Fisher Scientific Co.]... 

The whole subject of optical mounting design occupies many volumes. The discussion herein will be limited to an overview of modern grating instm-ments. Of these, four designs dominate the plane grating applications namely, Littrow, Ebert-Fastie, Czemy-Tumer, and Monk-Gillieson. 

Ebert-Fastie 1 mirror 3 reflections Coma compensation Requires large mirror Needs curved slits to minimize effects of astigmatism High energy losses... 

The Ebert-Fastie configuration uses two separate sections of a common mirror for collimating and focusing. The entrance and exit slits can be placed on opposite sides, or above and below the grating. The primary advantage of the Ebert-Fastie... 

Figure 11.2. Portions of typical spectra taken on a JACO 3.4-w Fastie-Ebert spectrograph employing a 15,000 line finch grating giving a dispersion of 5 Afmm at the focal plane. From top down, materials are iron, aluminum, magnesium, lead, steel, nickel, and beryllium ore. Courtesy of Jarrell Ash Division, Fisher Scientific Co.

FIGURE 3 Schematic representation of the most frequently used grating-based monochromators (A, B, C) and polychromators (D, E, F). A and D are known as Czerny-Turner design. Fastie-Ebert (B) and Littrow (C) have similar designs in that both use a single reflective mirror. A Rowland circle polychromator is depicted in E, and F represents an Echelle spectrograph. 

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