The aims of this module are to enable students to gain a working knowledge of oscillation, Weissenberg and precession photography, and the use of the CAD4 diffractometer.

The programme involves the selection and mounting of crystal specimens and subsequent setting on each of the three cameras. Students come across practical difficulties which are probably glossed over in the lecture course. For example, crystal size and quality. Often a promising looking crystal will exhibit defects in its diffraction pattern, such as evidence of disorder, splitting or streaking. By teaching students the use of various cameras they form a critical working attitude which is invaluable for future project work in single crystal analysis. Students select several crystals for study and aim at the determination of crystal unit cells and space groups using methods introduced in other modules of the course.

For the CAD4, the aim is to give each student one weeks personal use of the instrument under the guidance and tuition of an academic member of staff.

The aim is to give each student is given a different crystalline substance from which he/she has to choose and mount a suitable crystal. The objectives of the practical are as follows: To collect a few reflections via random searching, to centre reflections, to index the reflections and hence determine a possible unit cell, to check the Laue symmetry of the crystal, to collect a data set containing equivalent reflections, to learn how to choose reflections for psi scans, and then measure them.