pxrd op• Data kinds: scalar × scalar × scalar → scalar
• Call: import fullseye as fs; fs.ledger.scherrer_size(fwhm, two_theta, wavelength, K=0.9, instrumental_fwhm=0.0, combine='gauss') (to call the implementation directly, import pxrd; pxrd.scherrer_size(fwhm, two_theta, wavelength, K=0.9, instrumental_fwhm=0.0, combine='gauss'); from the registry, opsdrive.get("scherrer_size"))
Crystallite size [Å] by the Scherrer equation (L = K λ / (β cos θ)).
fwhm and instrumental_fwhm are full widths at half maximum in 2θ [deg], two_theta [deg], wavelength [Å]. The sample broadening β is combine="gauss" with sqrt(fwhm² − inst²) and "lorentz" with fwhm − inst. Passing arrays returns arrays. The Scherrer equation is a rough measure of the volume-weighted column length and does not distinguish strain broadening (proportional to tan θ) — when strain is suspected, look at the dependence on tan θ across multiple peaks, as in Williamson–Hall.
Raises ValueError: fwhm <= instrumental_fwhm (peak narrower than the instrument = size cannot be determined), non-positive values, misspellings.
• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).
• Operator provenance and references — the sources of the research/methods this op family came from.
• The canonical algorithm (author, year) and its uses are named in the family usage guide above.
• poc_pxrd_phase_peel — py -3.11 examples/poc_pxrd_phase_peel.py
scalar as input)spin_from_marker_sequence · carla_transform_matrix · carla_pose_to_world · carla_camera_pose · carla_xy_yaw · carla_scene_load · town_chain · osm_parse
pxrd)cif_read · cubic_prototype · powder_reflections · debye_ring_image · detector_two_theta · detector_calibrate · azimuthal_integrate · diffraction_peaks
*Provenance: pxrd.py — DRIVE operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.