Development of a Double Crystal Monochromator

A high-precision water-cooled, small offset, double crystal monochromator has been developed for the Advanced Photon Source (APS) UNICAT Sector 34 beamline. The design incorporates the supports and gravity feed water cooling of two diamond or silicon crystals correctly positioned about a common rotation axis so that the incident and diffracted beam do not walk off the edges of the crystals within the energy range 6-15KeV (30 deg. <q<11. 6 deg.). In the 34ID implementation, the first crystal sees unfocussed pink beam from an undulator. The second crystal has a ±5 deg. motorized tilt motion around an axis parallel to its face and around the beam direction. In this paper preliminary measurement data obtained from Advanced Photon Source and the detail of the instrument design are presented