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GEANT Release (3.21)

  Simone Giani CN/ASD and Sven Ravndal CN/ASD

A new release of GEANT, GEANT3.21, will be submitted together with the 94a release of the CERN Library. Also for the future it is foreseen to submit GEANT releases and update/correction cradles together with the CERN Library releases.

The new release of GEANT3.21 has new features and contains substantial improvements concerning the geometry and tracking package:

New ray tracing package.

The new tracking of GEANT3.21 is also used to visualize the detectors. This technique allows a realistic rendering with light processing, the speed being largely independent of the number of the visible volumes and with no need for large memory allocation. The main advantage is that it is a quick tool to investigate the correctness of the geometrical description and of the tracking parameters of a detector (the image reflects the detector "seen" by the tracked particles).

Boolean operations between geometrical shapes.

In the geometry part of GEANT it is now possible to extend the definition of various geometrical shapes from the previous 16 different types to a larger number. This is obtained by the definition of boolean operations between the existing shapes. The implementation of the boolean operations is backward compatible, so that existing geometries are treated as in the previous versions of GEANT.

New tracking based on ``virtual divisions''.

The tracking is now able to handle overlapping volumes in the most general sense: the concept of MANY volumes has been extended to automatic clipping for producing objects. Thanks to this MANY technique, any 3-D or 2-D geometrical pattern can be reduced to a single dimensional structure, basically cancelling the need for GUNEAR at tracking time.

Improvement in tracking.

Modifications in routines GTELEC, GTGAMA and GDRAY.

Janne Saarela
Tue May 16 14:52:44 METDST 1995