Permanent cooling of protein crystals by a collinear air flow

In order to cool protein crystals a commercially available airstream cooling apparatus was remodeled to fit the Enraf-Nonius precession camera and the Arndt-Wonacott rotation camera for simultaneous use. The device is mechanically refrigerated. The operating temperatures are in the range of 242 to 335 K. Permanent operation for many months causes no freezing problems.