This directory contains an updated ESS source component for use with McStas 2.x and 1.12c - dated December 2015!

The component comes with a library of ESS source brilliances, including:

• 2001, legacy "Mezei moderators" from the original F. Mezei documents, rescaled to ESS TDR frequency, pulselength and power.
• TDR, Mezei moderators, with a wavelength-dependent correction term to the cold flux, derived from 2012 MCNPX calculations by ESS neutronics group. Corrections calculated by K Lieutenant (Vitess) NOTE: uses the 2001 brilliance for the thermal moderator!
• 2013, post-TDR update with non-Maxwellian cold spectrum, Troels Schoenfeldt, BEFORE the ESS pancake geometry was introduced.
• 2014 updated brilliance using formulation by Troels Schoenfeldt, including support for the "pancacke", i.e. flat geometry and geometrical brilliance over the moderator surface.
• 2015 updated brilliance using formulation by Troels Schoenfeldt, including support for the "butterfly" moderator in 3 and 6cm height versions. This formulation further includes local variation of the brilliance over the moderator surface, and variation with selected beamport angle.
• We further provide a set of example instruments for producing curves corresponding to each of the brilliance settings.
• ... as well as an updated version of the Brilliance_monitor.comp with controllable size and distance from the source - for free calculation of the solid angle covered.

Please also read the "usage recommendations" provided in the enclosed PDF

Peter Willendrup