The main part of the diffractometer is the high resolution spindle. The air bearing axis has a sphere of confusion less than 2 microns allowing accurate rotation of the sample in the X-ray beam. This axis is also mounted on a three axes translation table (phix, phiy and phiz) allowing changes to the rotation axis position remotely to bring the rotation axis in to the X-ray beam. In order to align the sample on the center of rotation, there is an additional 2 axis table (sampx and sampy) equivalent to the two translations on a standard goniometer head.

 

Minidiff-phi

 

The diffractometer also has a remotely controlled light you can move in and out controlled from the exes_sc_prodc and exes_hutch interfaces or in spec (lightin and lightout) using pneumatic actuators and you can change the intensity of the light via exes_sc_prodc and exes_hutch or by using a pseudo-motor called light in spec.

The phi axis is fitted with either a smart magnet when used in conjunction with the sample changer or a metal rod and magnet to fix metallic pins (Hampton system or equivalent). In this configuration the pin length (from base bottom to loop) must be between 17.5 mm and 27.5 mm. It is also possible to remove this standard magnet and put on a traditional goniometer head. Then the size of goniometer head (+ cryo-arc) + pin must be between 61 and 72 mm.

The backstop is made of tungsten carbide with a G ring shape with a thickness of 300 microns. It is mounted on a two axis translation stage (bstopz and bstopy respectively vertical and horizontal). The alignement is performed by fitting accurately the metal pin on the backstop support right at the center of the V shape by a strong magnet. The collimator aperture is 300 microns diameter. The alignment of the backstop is performed remotely by moving bstopy and bstopz and also manually if needed with the two rotation screws on the backstop support (see trouble shooting section for more information).