No reader parsed a polarization, and ApplyRugnuxExperimentDefaults then set
P = 0.99 (an undulator value) unconditionally, so laboratory-source data were
corrected as if from a synchrotron. Every d*TREK (Rigaku Saturn/A200) header in
the open arm states SOURCE_POLARZ=0.5 1 0 0, i.e. unpolarized; at Cu K-alpha and
2 A the wrong factor puts a +-33% azimuthal modulation on the intensities.
- d*TREK SMV: SOURCE_POLARZ is the fraction f followed by the plane normal (as
dxtbx's FormatSMVRigaku reads it); stored as degree 2f - 1, negative where the
normal lies along lab x (plane containing y).
- miniCBF: "# Polarization f" is the fraction in the horizontal plane; stored as
2f - 1 ("None" or a missing line leave it unset).
- ApplyRugnuxExperimentDefaults sets 0.99 only where the file stated none;
--polarization still overrides. ADSC SMV, marCCD and NXmx state nothing and
keep 0.99.
- The "Header:" log line reports the stated polarization.
RESULT-CHANGING: d*TREK home-source sets (0.99 -> 0), one Rigaku miniCBF set
(0.99 -> 0), miniCBF sets stating 0.99 (0.99 -> 0.98).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PXc1zD1yxHqaR1DGdCTHL4
leonarski_fandClaude Opus 5.5
b17b643bd9