| 摘要 |
In a double grating monochromator, the scanner comprises a programming device specifying the angular positions of the diffraction gratings, as the radiation spectrum is scanned, so that the angles of radiation incident thereon are related by <IMAGE> where sigma 1, alpha 1, and beta 1 are: constant of one of the diffraction gratings, angle of radiation incident on this grating, and angle of radiation diffracted from this grating, respectively; sigma 2, alpha 2, and beta 2 are: constant of the other diffraction grating, angle of radiation incident on this grating, and angle of radiation diffracted from this grating, respectively; and "K" is spectral order of radiation diffracted from one of the diffraction gratings and extracted by this slit positioned immediately after this grating, the value of "K" being determined by the working portion of the monochromator spectrum. The scanner also comprises two electric motors, each kinematically coupled with one of the diffraction gratings, pickups sensing the angular position of the diffraction gratings, two comparators, the inputs of each being connected to one of the outputs of the programming device and to the respective pickup, and two controllers, the input of each being connected to the output of one of the comparator and the output thereof, to the control input of the respective electric motor. |
