Two-axis Goniometer Research Articles

A liquid He cooled two-axis goniometer for channeling measurements down to 5 K

A liquid He cooled two-axis goniometer was built to perform channeling measurements at temperatures down to 5 K. The rotation about the vertical axis is achieved by a rotatable He-vessel. The rotation about the sample surface normal is possible by a sample holder which is pressed against the He-vessel and driven via a worm gear. The precision of the vertical rotation is ±0.02°, the precision of the horizontal rotation is ±0.2°. To test the goniometer channeling measurements with 2 MeV He + ions on a Mo-single crystal at temperatures of 295 K, 77 K and 5 K have been performed. The measured minimum yields and critical angles are compared with calculated parameters obtained by Monte Carlo methods.

A precise specimen manipulator for a LEED camera with a two-axis goniometer

A simple specimen manipulator is described which allows precise tilting and location of the specimen in a low energy electron diffraction camera. The rotating shafts which drive the two tilt axes of the manipulator are sealed by PTFE grommets. The manipulator is bakeable to 250°C and the specimen may be heated to 1500°C by electron bombardment of the specimen supporting plate.