GEOM120 Positioning a volume inside its mother with parameters

CALL GSPOSP (CHNAME,NR,CHMOTH,X,Y,Z,IROT,CHONLY,PAR,NPAR)

Position a copy of volume CHNAME inside its mother CHMOTH assigning its parameters.

CHNAME

( CHARACTER*4) name of the volume being positioned;

NR

( INTEGER) copy number of the volume CHNAME being positioned;

CHMOTH

( CHARACTER*4) name of the volume in which copy NR of CHNAME is positioned;

X

( REAL) x position of the volume in the mother reference system;

Y

( REAL) y position of the volume in the mother reference system;

Z

( REAL) z position of the volume in the mother reference system;

IROT

( INTEGER) rotation matrix number describing the orientation of the volume relative to the coordinate system of the mother;

CHONLY

( CHARACTER*4) flag to indicate whether a point found to be in this volume may also be in other volumes which are not direct descendants of it -- possible values are ONLY and MANY;

PAR

( REAL) array of parameters for the volume being positioned;

NPAR

( INTEGER) number of parameters.

It is often the case in a detector to have a family of similar objects, differing only by their dimensions. A typical example are the crystals of an electromagnetic calorimeter. In this case it is convenient and logically consistent to give them all the same name, but assign to each copy a different set of parameters.

This can be done defining the volume with 0 parameters through the routine GSVOLU and then assigning the parameters to each copy via the routine GSPOSP.

GSPOSP is similar in all other aspects to GSPOS and the user is referred to the description of this routine for more information. An obvious limitation is that a volume defined with 0 parameters can only be positioned via GSPOSP, because otherwise its dimensions will be undefined.

GEOM130