The lattice comparator uses two silver KL3 (Kα) radiation beams, which are monchromated and collimated by a 450 μm thick central transfer crystal, operating simultaneously in positive and negative order, to nearly simultaneously measure the angle at which non-dispersive diffraction is achieved between the transfer and specimen crystals. This angle offset is affected by the lattice spacing difference between the transfer crystal and the specimen.
The instrument is optimized to operate on silicon specimens 455 μm thick in the analysis region, and approximately 10 mm wide. Using samples such as this, sharp pendellösung fringes appear in the diffraction pattern, resulting in the highest resolution.
However, due to the high energy the the photon source, it is capable of working with much thicker specimens, although with reduced resolution. Thus, it can be used to compare the lattice spacing and strain in a wide variety of silicon samples, including simple cut wafers.
By taking advantage of the crossed beams in various geometries, it can also measure the curvature of the lattice of silicon specimens.