A small 50 K cooling device for a quarter-circle Eulerian cradle diffractometer

A one-stage He refrigerator (Displex CS1003) has been modified and installed on a quarter-circle Eulerian cradle of 250 mm diameter (AED Siemens) and has been operated down to 50 K. The mechanical interface, which can easily be mounted, is described as well as some alignment problems. The device is suitable for any Eulerian cradle 250 mm or larger. Structure redeterminations of two organic compounds were carried out at 52 K. R values of 2.2 and 3.6% were obtained and proved the quality of this set up.