Software Based Peaking
For interval halving spectrometer peak centering, the peaking start size is the spectrometer step size used to begin the interval halving peak center assuming an LiF (200) crystal and a theta at the highest spectrometer setting. For example, K kα on an LiF crystal (SEMQ probe) or Ti kα on a LiF crystal (Cameca probe). Each time the interval halving peaking procedure reverses direction, the interval size is halved. When the interval size is less than the peaking stop size the spectrometer is considered to be properly peaked.
For parabolic fit peak centering, the peaking start size determines the offset used to measure the high and low side peak intensities. The peaking start size should be adjusted to yield an intensity approximately 1/2 the peak intensity for both the high and low side of the peak, to obtain a good fit to the peak shape. If the parabolic fit spectrometer positions need adjustment, the program shifts the middle, high and low positions by 1/2 the peaking start size and tries again.