DEVELOPMENT OF A COMPACT 6-CIRCLE GONIOMETER

A compact versatile six-axis goniometer has been built which can be us ed with the scattering plane vertical or horizontal for anomalous X-ra y diffraction and diffraction X-ray absorption fine structure using a tunable X-ray undulator at SPring-X. The diffractometer consists of a four-circle goniometer for the standard omega, 2 theta, phi and chi mo tions and a two-circle goniometer on the 28 arm for mounting the detec tor and analyser crystal. The goniometer is controlled via Ethernet, a nd standard data-acquisition software with a graphical user interface has been developed. A closed-cycle helium cryostat is mounted on the o mega axis for temperature-dependent experiments from 330 K to 14 K. Pr eliminary experiments on a Bi2Sr2CaCu2O8 single crystal demonstrate th e performance. Superstructure peaks due to the one-dimensional spatial modulations in the b axis were recorded as a function of temperature above 20 K using an image plate.