Calculations of the diffraction intensities from a small specimen on a counter diffractometer show that, with a 10–20 mg specimen, the intensities should be 50% or more of those obtained from a normal specimen. Observed values are in reasonable agreement with the calculations. With small quantities the strategy is to disperse the sample evenly as a fine powder over the whole irradiated area. This is especially important at the lower diffraction angles. A glass support is usually suitable. With specimens < 1 mg in weight dispersion difficulties can be eased by mixing with diamond powder, and background scattering can be considerably reduced by using a single crystal as a support. The lower limit of detection of quartz by this method has been shown to be probably < 1 μg. Quantitative estimates of 10% quartz in a few milligrams of sample and crystallite size measurements on 50 μg of nickel oxide are examples of work with these experimental arrangements.
No takes yet. Share an insight, caveat, or question.
Baldock et al. (1973) studied this question.