CERN Program Library Long Writeup W5013 - CERNLIB ...

Geant 3.16 GEANT User’s Guide HITS500
Origin : GEANT2 Submitted: 01.10.81
Revision : Revised: 19.12.93
Documentation :
Digitisation for drift- or MWP- Chambers
CALL GPDRIF
(DETREP,HITREP,IOUT*)
DETREP
HITREP
IOUT
(REAL) array of 6 with detector description:
1 number of wires;
2 wire spacing in cm;
3 sin(α);
4 cos(α);
5 distance of wire 1 from the origin in cm;
6 drift velocity (cm/nsec)
(REAL) array of 2 with track description:
1 x coordinate of intersection;
2 y coordinate of intersection;
(INTEGER) result of digitisation:
1 wire number;
2 drift time (signed to avoid left/right ambiguity).
Digitisation routine for a plane drift chamber. The drift chamber is supposed to be in the x − y plane. The
normal to the wires in the x − y plane and the z axis form an angle α.
CALL GCMWPC
(DETREP,HITREP,IOUT*)
DETREP
HITREP
IOUT
(REAL) array of 6 with detector description:
1 number of wires;
2 wire spacing (radians);
3 dθ/dz along the wires;
4 θ of a point on wire 1;
5 z of a point on wire 1 corresponding to θ=DETREP(4);
6 gap width;
(REAL) array of 4 with track description:
1 θ coordinate of intersection;
2 z coordinate;
3 dθ/dr;
4 dz/dr;
(INTEGER) array of 4 with result of digitisation:
1 wire number (-1 if missing);
2 cluster size;
3 wire number of second cluster if any;
4 cluster size;
Routine to compute one or two digitisations produced by a hit on a cylindrical MWPC. The chamber is a
cylinder of thickness DETREP(6) which should be small compared with the radius.
171 HITS500 – 1