X-Ray Diffractometers
Possibilities and Characteristics

CHESS has two large Huber 6-circle diffractometers for doing crystallographic and diffraction studies. They are mounted to diffract in the vertical plane atop a movable CHESS optical table for precision alignment in height, rotation and translation perpendicular to the incident beam direction. These diffractometers can be utilized in stations A2, F2, and D1, providing a wide variety of experimental possibilities with the various beam characteristics. A Displex cryostat (Model CSA-202A) can be mounted on either of the diffractometers to provide temperature regulation from 10 to 350K to allow further investigative studies. We are presently looking into the purchase of an additional cryostat for these types of experiments.

Crystallographic work can also be performed at the A1, B2, C2, F1, and F3 stations using a small Huber or Picker 4-circle diffractometer. There are small Displex cryostats on the market that can be mounted on the small Huber 4-circle which are being considered for purchase.

There are two Picker 2-axis diffracto-meters mounted to diffract in the vertical plane which can be used in any of the stations when a 4-circle instrument is unnecessary. The Displex cryostat we now possess can be mounted on these Picker diffracto-meters to allow studies at a variety of temperatures. One can also orient in CHI and PHI through the use of a General Electric 1/4 circle goniostat mounted to these units but not while utilizing the Displex cryostat.

For rotations in one dimension we have four Huber 410 (138 mm diameter mounting plate) single circle goniometers mounted on vertical and horizontal linear translation stages to manipulate samples, analyzing crystals, mirrors, etc.

The degree of polarization of the incident beam can be determined by a polarimeter for a beam of less than 2 mm diameter and up to 30 keV. Fast shutters are also available for beams of less than 1 mm allowing opening times from DC to the sub-millisecond time scale.

Last Update: 2006-09-21