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Easily Tunable Monochromator for 5eV Approx. Less Than Wavelength Approx. Less Than 1000eV Synchrotron Radiation

IP.com Disclosure Number: IPCOM000088171D
Original Publication Date: 1977-Apr-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 14K

Publishing Venue

IBM

Related People

Eastman, DE: AUTHOR [+2]

Abstract

Wavelength tuning is provided which involves one simple rotation for the entire range for fixed incoming and outgoing beams. An exceptionally large frequency range for a single monochromator is obtained.

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Easily Tunable Monochromator for 5eV Approx. Less Than Wavelength Approx. Less Than 1000eV Synchrotron Radiation

Wavelength tuning is provided which involves one simple rotation for the entire range for fixed incoming and outgoing beams. An exceptionally large frequency range for a single monochromator is obtained.

Holographically produced transmission gratings have recently been tested in the soft X-ray region and found to be exceedingly promising. Such gratings permit the design of a new type of monochromator which is specifically designed to match and exploit the characteristics of synchrotron radiation.

A monochromator design is presented herein utilizing such a grating, as described above, to cover photon energies from 5 eV to 1000 eV. A parabolic mirror M(1) whose focus is the synchrotron radiation source, is used to make the light plane parallel. A plane mirror M(2) is then used to deflect the light to the grating G. The light that leaves the grating parallel to the axis of a second parabolic mirror M(3) will then be focused onto the exit slit S . The angular resolution (and therefore wavelength resolution) of such an instrument is limited by the ratio of the image size to the distance between the source, the grating, and the exit slit. The highly directional nature of synchrotron radiation permits the use of relatively small mirrors (for lower cost) while maintaining large distances between the source, the grating, and the exit slit (for higher resolution) while maintaining very high overall efficiency. The theoretical efficiency of the design shown is given in the table below, assuming gold-coated mirrors and an existing 1000 groove/mm transmission grating. Also shown in the table is the input and output flux to be expected in coupling this monochromator to a proposed new electron storage ring source of synchrotron radiation (within a bandpass DeltaE/E = 0.001).

(Image Omitted)

In this table: R(1), R(2), R(3) are the relevant reflectance coefficients (at the proper angles) for the Au-coated mirrors M(1), M(2) and M(3)3; epsilon(m) is the product (epsilon(m) = R(1) x R(2) x R(3)). Epsilon(g) is the theoretical grating efficiency; E(s) is the slit injection factor telling how much of the spot size can be used for the quoted bandpass; N is the ratio of the output flux of the...