Description of the routines

CALL GSTMED (ITMED,NATMED,NMAT,ISVOL,IFIELD,FIELDM,TMAXFD,STEMAX, DEEMAX,EPSIL,STMIN,UBUF,NWBUF) This routine associates a set of tracking parameters to a material, defining a so-called tracking medium. Every GEANT volume must be associated to an existing tracking medium. The routine stores the parameters of the tracking medium ITMED in the data structure JTMED.

ITMED

( INTEGER) tracking medium number;

NATMED

( CHARACTER*20) tracking medium name;

NMAT

( INTEGER) material number corresponding to ITMED;

ISVOL

( INTEGER) sensitivity flag (see later):

$\le$ 0

not a sensitive volume;

>0

sensitive volume;

IFIELD

( INTEGER) magnetic field flag:

=0

no magnetic field;

=1

strongly inhomogeneous magnetic field (returned by the user function GUFLD): tracking performed with the Runge-Kutta method by the routine GRKUTA;

=2

inhomogeneous magnetic field (returned by the user function GUFLD), tracking along a helix performed by the routine GHELIX;

=3

uniform magnetic field along the z axis of strength FIELDM, tracking performed along a helix by the routine GHELX3;

FIELDM

( REAL) maximum field value (in Kilogauss);

TMAXFD

( REAL) maximum angular deviation due to the magnetic field permitted in one step (in degrees);

STEMAX

( REAL) maximum step permitted (cm);

DEEMAX

( REAL) maximum fractional energy loss in one step (0< DEEMAX $\le 1$ );

EPSIL

( REAL) boundary crossing precision (cm);

STMIN

( REAL) minimum value for the maximum step imposed by energy loss, multiple scattering, Cerenkov or magnetic field effects (cm);

UBUF

( REAL) array of NWBUF additional user parameters;

NWBUF

( INTEGER) number of additional user parameters.

Note: the tracking medium number can in principle be any positive integer from 1 to 65,535. However this number is used directly by GEANT as the number of the pointer to the data structure where the information is stored. When a pointer is defined, all pointers from 1 to the one allocated are created, if not already existing. Every time data structures are moved in memory, all the links are potentially scanned for update. This can be time consuming and it can seriously affect performances. So a continuous range of numbers should be used for tracking media.

CALL GFTMED (ITMED,NATMED*,NMAT*,ISVOL*,IFIELD*,FIELDM*,TMAXFD*, STEMAX*,DEEMAX*,EPSIL*,STMIN*,UBUF*,NWBUF*)

Extracts the parameters of the tracking medium ITMED from the data structure JTMED.

CALL GPTMED (ITMED)

Prints the tracking medium parameters for the given medium.

ITMED

( INTEGER) tracking medium to be printed, all tracking media if ITMED=0.