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Beamline geometries and optics information

FRS data sets for new target chamber valid from November 2006 on



These web pages provide the different files for MOCADI and to set and operate several beamlines at GSI and at some other places.
  • *.in : MOCADI input file - download examples for the desired geometry on your account and adapt them to your own special setup
  • *.dat: Each ion optical setting is based on a GICOSY calculation with the corresponding GICOSY input file. GICOSY is used to generate the matrix files for MOCADI. If you need to change the ion optics you can download this file, modify it and use GICOSY to create your own matrix files.
  • *.csv: A list of field values (only for FRS). This file can be read into the LSA data base of the GSI/FAIR accelerator control.
  • *.mtx: Transfer matrices of going from one functional block of the beamline to another. Especially the dispersion coefficients are important for shifting the beam.
  • *.pdf: Some plots illustrating the optics of the beamline.
  • *.MAT: Matrix files describing the magnets. For each geometry several optical settings are available, which have to be specified in the MOCADI input file. For each magnet there is at least one matrix file. The beginning of the filename specifies the optics setting, while the end of the filename is a three digit number indicating the continuous numbering of the magnets along the beam line. The MOCADI example input files use one of these optical settings but you might want to use another one and change the path name and the names of the matrix files.

Caution: Effective Drift Lengths

To calculate the trajectory of a particle through the system often effective lengths of the magnets are used which differ slightly from the geometric ones. In this case the drift lengths used in MOCADI are also not the geometric ones but effective lengths in order to keep the sum of all lengths constant. In principle the effective lengths depend on the strength of the magnetic fields and should be adapted according to the setting of the magnetic rigidity. In the provided MOCADI input files the effective lengths of the FRS quadrupoles is about 4cm longer than the geometric length. In case of high field strength saturation may shorten the effective length by a few centimeters but the transfer matrix will almost not change. But one should not mix up input files with geometric lengths and matrices for effective lengths. Otherwise the overall length will be wrong.

This page was last modified by Dr. Helmut Weick,25th May 2018, contact h.weick(at),  Imprint (Impressum), Privacy Policy (Datenschutzerklärung)