[NOBUGS] Updated ESS source component available

[Peter Kjær Willendrup]

Dear McStas users,


Unfortunately we are still hunting a few bugs in the development tree, and are (still!!) not ready to release the official McStas 2.1.

In the meantime, those of you simulating ESS instruments can try out our new ESS moderator component, available through the
download share (http://www.mcstas.org/download/share) for use with both McStas 2.x and 1.12c.

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 variation over the moderator surface.

An important detail about the 2014-pancake moderator is that the component origin is NOT at the centre of the cylindrical cold source, but
instead at the middle of the front face of the cylinder. For technical reasons, neutrons are in this case propagated from a tangential plane through
that point.

• 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, allowing multiple instances within an instrument file

We hope you will find this useful even though the official McStas 2.1 is still pending…


Vacation greetings on behalf of the McStas team

Peter Willendrup


Peter Kjær Willendrup
Senior Research Engineer, Special Advisor

DTU Physics



Technical University of Denmark



[cid:image002.gif at 01CCCAF1.5E6331F0]

Department of Physics
Fysikvej

Building 307

DK-2800 Kongens Lyngby

Direct +45 2125 4612

Mobil +45 2125 4612
Fax +45 4593 2399


pkwi at fysik.dtu.dk<mailto:pkwi at fysik.dtu.dk>




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