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Garfield Version 6.21

  Rob Veenhof, NIKHEF (Amsterdam, the Netherlands)

Garfield is a computer program originally written for the detailed simulation of two-dimensional drift chambers. The PaRC service has taken over the production of executables at CERN. The following article describes the list of modifications since the latest official release (previous releases have been described in past CNL articles).

CELL section:

A new command, SOLIDS, has been added which can be used to define the 3-dimensional objects present in the chamber in case the field is derived from a field map. Entering these objects is not mandatory, but is helpful when studying collection efficiencies, computing calibration curves and signals. Some commands like RESET have been modified in line with the addition of the SOLIDS command. It is hoped that this information can in the future be derived from files produced by the finite element programs.


No changes.


Field maps can now also be used for the background field.

FIELD section:

As part of the on-going extension to three dimensional structures, a new scheme has been introduced for selecting the visualisation of the chamber. Apart from the traditional x-y view, it is now possible to produce plots for cut planes and three dimensional impressions of the chamber. The main command affected is AREA which now accepts a considerably extended argument list.

GAS section:

Ion diffusion coefficients have been added - they can be set with the PARAMETERS statement and are taken into account when performing Monte Carlo drift line integration for ions. The diffusion coefficients are for the time being assumed not to depend on the field, but this limitation can be lifted if needed.

The TEMPERATURE and PRESSURE statements now accept a unit following the temperature and pressure. The latter, for instance, can therefore be entered in more common units like the atm or the hPa rather tha in Torr.

Steve Biagi has released a Monte Carlo version of Magboltz which should have a substantially higher accuracy. An interface with this program is being written - meanwhile, interested users should contact Steve Biagi/University of Liverpool ( directly.

DRIFT section:

The same extended AREA command as in the field section has been introduced here.

SIGNAL section:

No changes.


No changes.

Histograms, Matrices, Formulae and Calls:

The argument list of PLOT_TRACK and PLOT_DRIFT_LINE has been modified to match the new projection scheme.

Procedures for drifting negatively charged ions have been added.

A procedure that integrates the charge contained in a cylindrical or spherical area has been added. There is now also a procedure that computes the flux of the electric field through a parallelogram.

Intrinsic functions called MINIMUM and MAXIMUM have been added. They operate on histograms and matrices and return the minimum and the maximum number of entries or value of the argument histogram or matrix.

Datasets and input / output:

No changes.

Global options:

No changes.


Executables are built on PaRC and can be accessed as /afs/ For further information, please contact or Juan Manuel Guijarro (


Currently, the most accurate description of the program can be found in the on-line help. The printed manual is not available at the moment, for lack of SGML at CERN. A set of examples can be found on the Web, as described at URL:

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