Variable Magnification With Kirkpatrick-Baez Optics for Synchrotron X-Ray Microscopy.
We describe the distinction between the operation of a short focal length x-ray microscope forming a real image with a laboratory source (convergent illumination) and with a highly collimated intense beam from a synchrotron light source (Köhler illumination). We demonstrate the distinction with a Kirkpatrick-Baez microscope consisting of short focal length multilayer mirrors operating at an energy of 8 keV. In addition to realizing improvements in the resolution of the optics, the synchrotron radiation microscope is not limited to the usual single magnification at a fixed image plane. Higher magnification images are produced by projection in the limit of geometrical optics with a collimated beam. However, in distinction to the common method of placing the sample behind the optical source of a diverging beam, we describe the situation in which the sample is located in the collimated beam before the optical element. The ultimate limits of this magnification result from diffraction by the specimen and are determined by the sample position relative to the focal point of the optic. We present criteria by which the diffraction is minimized.
National Institute of Standards and Technology, Gaithersburg, MD 20899.
Terrence
T
Jach
Department of Physics, Purdue University, West Lafayette, IN 47907.
Alex S
AS
Bakulin
Department of Physics, Purdue University, West Lafayette, IN 47907.
Stephen M
SM
Durbin
J. Pedulla Associates, Silver Spring, MD 20906.
Joseph
J
Pedulla
Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439.
Albert
A
Macrander
Kirkpatrick-Baez; diffraction limit; microscopy; multilayer mirror; x-ray optics