Photographing the reciprocal lattice with the axis of the film cylinder intersecting the rotation axis of the crystal at 45°

By allowing the axis of the film cylinder to intersect the rotation axis of the crystal at 45°, it is possible to design a compact camera which can be place into a Dewar vessel of diameter 115 mm that can be made of glass. This feature allows the diffraction study of single crystals to be carried out at liquid-helium temperature. A modified equi-inclination method is used and distorted Weissenberg patterns are obtained. The geometrical analyses lead to a comprehensive interpretation of the resulting patterns. Reflections can be indexed by graphical methods. Diagrams for indexing rotation, zero and nth-layer photographs are given.