Sagital focusing of synchrotron radiation

We describe a simple device that has successfully been used to sagittally focus about 2.5 mrad of synchrotron radiation with an energy resolution equivalent to that of a double crystal channel cut monochromator. Deep narrow slots are cut into a 6 mm thick silicon crystal wafer cut into a triangular shape. The slots leave a connecting link of 0.25 mm thickness. The triangular shape allows a simple means of providing a cylindrical surface approximated polygonally by the thick crystal segments between the narrow slots. The device was tested with 10 and 15 keV synchrotron radiation on one of the CHESS white beam lines at a magnification of 1/3 as suggested by Sparks et al. At both energies the diffracted beam power in the bent crystal was equivalent to that in the unbent state to within a few percent. (orig.)