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--- n [2009/08/06 14:39] – created clare
+++ n [2025/09/19 15:18] (current) – external edit 127.0.0.1
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+====== n ======
+**[//neutron_data//]**
+Signals the use of neutron atomic scattering lengths.Scattering lengths for isotopes can be used by placing the isotope name after “//occ//” as in:
+occ 6Li 1
+occ 36Ar 1
+The scattering lengths data, contained in the file NEUTSCAT.CPP, is from
+www.ccp14.ac.uk/ccp/web-mirrors/neutrons/n-scatter/n-lengths/LIST~1.HTM
+Constant wavelength neutron diffraction requires a Lorentz correction using the Lorentz_Factor  macro (defined in TOPAS.INC); it is defined as follows:
+scale_pks = 1 / (Sin(Th)^2 Cos(Th));
+**[//no_LIMIT_warnings//]**
+Surpresses [[#k157|LIMIT_MIN]] and LIMIT_MAX warning messages.
+**[//normalize_FCs//]**
+If defined then site fractional coordinates are normalized. Normalization of a particular fractional coordinate does not occur if it has //min/////max// limits, is part of a //rigid// body or part of a site constraint of any kind.
+**[//numerical_area// E]**
+Returns the numerically calculated area under the phase.