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Garfield Version 6.05 - Forthcoming Release

  Rob Veenhof, CEA Saclay

The forthcoming release of Garfield (W5050), version 6.05, has a major new feature: an interface with the Heed program written by Igor Smirnov, PNPI St Petersburg. This program simulates the ionisation of gas molecules when a charged particle traverses the chamber. The addition of this interface has implications for the format of many commands in various sections.

CELL section:

Wires were plotted at incorrect positions when polar coordinates were used, this has now been fixed.


No changes


A mistake has been found in the electrostatic force calculation routines for potential types B2X and B2Y: the mirror charge of the wire on which the force is calculated, was not taken into account (Almut Tadsen). The mistake, which has been corrected, had no effect on field calculations.

The forces acting in chambers with a tube were so far not available. They have now been added.

FIELD section:

No changes

GAS section:

To take advantage of the Heed interface, you have to initialise the ionisation properties of the gas mixture. This is achieved via a new command called HEED.

An option has been added to the MAGBOLTZ command to request plots of the energy distribution functions F0, F1, F2, F3.

The transverse diffusion as returned by Magboltz is, in some cases, 20 % lower then in previous releases. This is the result of a modification in the interface, recommended by the author of Magboltz.

The Lorentz angle as computed in the absence of Magboltz generated data had a wrong sign for the `E' times `B' term. This has been corrected.

DRIFT section:

A routine has been added that performs Monte-Carlo style integration of drift lines, taking diffusion into account on a step-by-step basis.

Various instructions in this section have a modified format with a view to the Heed interface and to Monte Carlo drift line integration. In particular, the behaviour of the DRIFT TRACK command has changed.

In a couple of commands, the conversion of internal to polar coordinates has been cleaned up - although the absence of some conversions was inconvenient, results such as drift times, diffusion, etc., are not believed to have been incorrect.

SIGNAL section:

The drift lines used for signal computation can now optionally be computed with the Monte Carlo integration routine.

The buffer for intermediate results now uses an algorithm to re-use entries that were little used or used long ago. This buffer is not directly accessible to the user; error messages related to buffer overflow appeared. It might be appropriate to recall that, at compile time, two versions of this buffer are offered: one optimised for hardware that has a lot of memory, and one for hardware with a large cache.

The assignment of electron induced signals to the classes "direct" and "cross induced" has been slightly modified in view of the optional Monte Carlo integration.


Better treatment of the case of no terminal graphics output when using the HIGZ interface.

Histograms, Matrices, Formulae and Calls:

A couple of new procedures have been added: PLOT_CELL, PLOT_DRIFT_LINE. Also, the Monte Carlo drift line calculation routines as well as the Heed cluster generation routines can be accessed via calls.

Plotting of histograms with a total weight equal to zero gave a divide by zero, and this has been corrected. Filling of auto-range histograms with weighted entries has been improved.

When iterating and leaving a loop from within a conditional block, the IF context was sometimes incorrectly restored, giving rise to an addressing error, and this has been corrected.

The interpretation of A-B-C (and similar for divisions and exponentiations) has been brought in line with what is usual in Fortran, namely A-(B+C) rather than A-(B-C).

Datasets and input / output:

No changes

Global options:

No changes.


The compilation procedures have been changed as a result of the addition of the Heed interface.


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, lacking SGML at CERN. A set of examples and various information can be found on the Web.

next up previous
Next: Questions and Answers from the UCO Up: cnl226.html Previous: HEED version 1.01: Detailed Simulation of the Initial Ionization in Gases