International
Tables for
Crystallography
Volume F
Crystallography of biological macromolecules
Edited by E. Arnold, D. M. Himmel and M. G. Rossmann

International Tables for Crystallography (2012). Vol. F, ch. 10.1, p. 247   | 1 | 2 |

Section 10.1.4.4. Transfer of the crystal to the diffractometer

H. Hopea* and S. Parkinb

aDepartment of Chemistry, University of California, Davis, One Shields Ave, Davis, CA 95616–5295, USA, and bDepartment of Chemistry, University of Kentucky, Lexington, Kentucky, USA
Correspondence e-mail:  hhope@ucdavis.edu

10.1.4.4. Transfer of the crystal to the diffractometer

| top | pdf |

Inspection of Figs. 10.1.4.1[link][link][link]–10.1.4.4[link] reveals that the mounting of a crystal on a mounting pin via the traditional placement of the pin in the hole of a standard goniometer head is not simple, because the cooling nozzle is in the way. The solution to the problem is a design that allows side entry. This is most commonly achieved with a magnetic platform on the goniometer head and a corresponding magnetic base on the mounting pin, but an alternative means of side entry employs a slot on a modified goniometer head; the slot is equipped with a spring-loaded catch that allows a very smooth, but stable, catch of the pin.

The use of liquid-N2 cooling and side entry, and the requirement of reproducible knowledge of crystal temperature at all times, led to the development of a set of tools for crystal mounting as described by Parkin & Hope (1998[link]). The tools include special transfer tongs used for moving crystals from liquid N2 to the goniometer head. The temperature of the crystal is maintained by the heat capacity and low heat conductance of the tongs. The operation is independent of the orientation of the goniometer head because there is no liquid to contain.

References

Parkin, S. & Hope, H. (1998). Macromolecular cryocrystallography: cooling, mounting, storage and transportation of crystals. J. Appl. Cryst. 31, 945–953.








































to end of page
to top of page