Published online by Cambridge University Press: 06 March 2019
Lattice parameters, obtained by least-squares refinement of data from calibrated Guinier powder patterns, are compared in an effort to establish procedures for obtaining reproducible 2θ values with Guiniertype focusing camera techniques. The calibration procedure is discussed and a method of calculation to reduce loss of precision is proposed. Effects of particle size and crushing are also discussed as well as some sources of error such as use of only selected calibrant lines, film background, and mutual interference of powder lines.