This page contains a minimal user guide / information for a set of supplemental Vitess modules (tested with current Vitess 3.3a release), based on the following McStas 2.4.1 components/instruments:

Note: For more information about MCPL, please consult the website or publication.

Please bear in mind that:

1) “This is not Vitess” - but just a set of user-contributed, minimally documented modules,
2) I (Peter Willendrup) have discussed the solution with Klaus Lieutenant, who has on his mind/agenda to create a proper, official Vitess release with similar functionality at a later point

Download here: ESS_2017_Modules_for_Vitess_0.99.tgz or clone from the following repository

The tar.gz and the corresponding GitHub repo contain:

A) MODULES/ with binaries for Linux 64bit, Mac OS X (built on 10.12, should run on 10.9 and newer) and Windows (64 bit, should work on Win7 or newer) - corresponding to the following McStas components:

  1. ESS_butterfly.comp -> mcstas_ess_butterfly
  2. ESS_butterfly_MCPL_instr -> mcstas_ess_butterfly_mcpl
  3. MCPL_input -> mcstas_mcpl_input
  4. MCPL_output -> mcstas_mcpl_output

B) GUI/ contains a set of test Vitess gui files making use of the modules

C) SRC/ contains the original McStas code and some (light) documentation on the needed code changes


  1. Copy the modules corresponding to your platform from MODULES/ to your /where/ever/vitess/MODULES/
  2. Copy GUI/usermodule.tcl to your /where/ever/vitess/GUI/


Try the relevant .gui files found in subfolders of GUI/, respecting the following steps:

  1. Change of directory to that folder (i.e. GUI/ from the downloaded or cloned folder)
  2. The following "neutron-producing"/"neutron source" modules, will in the current version not produce any data when used from within the Vitess GUI:
    • ESS_butterfly
    • ESS_butterfly_mcpl
    • MCPL_input
    Please instead use the Vitess feature of File→ Export As to save a shell script or batch file, which you can afterwards execute from the command line. 
    On MacOS and Linux
    • Save an sh shell script e.g.
    • Give execute permission to the shell script by e.g. chmod u+x
    • Execute by ./
    On Windows
    • Save a bat file, e.g. Untitled.bat
    • Browse to the folder where the bat file is located
    • Double-click the bat file
  3. Please always specify a full path for the MCPL file when using the MCPL Input/Output modules
  4. When using the ESS_butterfly_MCPL module, please place the relevant beamport MCPL file from in the simulation folder

It may also be relevant to look at the presentation below: