Cooling to 10 K on a four-circle diffractometer by means of a double-stage cryorefrigerator

The cooling of single-crystal samples down to 10 K within the Mark VI Eulerian cradle of a neutron four-circle diffractometer has been achieved by means of a two-stage cryorefrigerator fixed to the offset chi circle and coupled to the phi shaft. There is no blind spot for the phi rotation but the chi rotation must be restricted to the -100 < chi < 500 range to avoid collisions of the cryorefrigerator with the detector shielding. The major advantages of this device are its low running cost and its ease of use, no liquid nitrogen or helium being required. (Auth.)