A Precision Goniometer for Use in Accelerators

Author(s): E. A. Thebado
Sponsor(s): IEEE Nuclear and Plasma Sciences Society
Publisher: IEEE - Institute of Electrical and Electronics Engineers, Inc.
Publication Date: 1 June 1969
Volume: 16
Page(s): 648 - 649
ISSN (Paper): 0018-9499
ISSN (Online): 1558-1578
DOI: 10.1109/TNS.1969.4325324



This paper will describe a Goniometer built to hold a diamond crystal which has been operated by twelve scientists approximately 2000 hours within 140 milliradians (8-¦) in two crystal axes and one longitudinal axis, reproducible within 5x10-5 radian with an average backlash of 5x10-4 inches in an ultra-high vacuum and high radiation environment. This Goniometer will precisely position a diamond crystal so that the circulating electron beam of the synchrotron will strike the crystal at a particular angle to the crystal axes. For certain values of this angle, coherent effects produce modifications to the nonnal brenmsstrahlung spectrum resulting in a quasi-monochromatic polarized photon beam.1-5