4.4.5 SUBROUTINE ZTTISC(P, V, REND, FIRST, SIPRP, IPZ, PHI0, PEND, VEND, DST, RCYL, TRACK, REQX0, X0INT, IGEOM, ERROR) : TRacK InterSection with Cylinder

This routine tracks a particle with momentum p from v to the last detector element (cylinder) inside REND. It returns the momentum (pend) and position (vend) at this point. It also returns the TKR parameters at the point, the radius of the detector cylinder and the integrated radiation length over the path from v to vend.

ARGUMENTS:

INPUT :

    P : Momentum of track
    V  : Position where P is given
    REND : The routine will return the values on the last detector
           cylinder inside REND.
           If REND=0, the perigee parameters will be returned.
    FIRST : TRUE if first call for this track.
    SIPRP : true IP in R-Phi (input if FIRST = FALSE on input)
    IPZ : true IP in Z (input if FIRST = FALSE on input)
    PHI0 : Phi angle to perigee point in R-phi plane
            (input if FIRST = FALSE on input)
    REQX0 : TRUE if the integrated number of radiation length between
            V and VEND is requested.
    IGEOM : Index of the detector description to be used.

OUTPUT :

    FIRST : set to FALSE if any tracking done for this track.
    SIPRP : true IP in R-Phi (output if FIRST = TRUE on input)
    IPZ : true IP in Z (output if FIRST = TRUE on input)
    PHI0 : Phi angle to perigee point in R-phi plane
            (output if FIRST = TRUE on input)
    PEND: Momentum of track (if ERROR <>0 then PEND=P)
    VEND  : Position where PEND is given (if ERROR <>0 then VEND=V)
    DST : Distance travled from V to VEND.
    RCYL : Radius of cylinder on which the result is.
           If RCYL=0, the perigee parameters are returned.
    TRACK : TKR parameters for the track.
                 for the track
    X0INT : Integrated number of radiation-lengths along the track
              negative if tracking was done from the outside going in.
    ERROR : error flag :
             0 - no error
             1 - no intersection in barrel.
             2 - track turns back.
             3 - other error.

IMPLICIT INPUTS:

    from /ZTBAR/ : the radii and lateral extents of the barrel detectors
    from /ZTGPT/ : Pointers in /ZTBAR/
    From /PXCONS/ : BMAG, the magnetic field; CONSA, Speed of light.

IMPLICIT OUTPUTS:

    none

CALLED BY :

ZDBREM, generate BREMsstrahlung (see 4.3.9). ZDDHIT, Detector HITs. (see 4.3.7).

CALLED ROUTINE(S):

ZTTCYL (see 4.4.6)

(To get Track intersection with CYLinder.)

VMOD

(CERNLIB routine.)

SIDE EFFECTS:

none

AUTHORS:

M. Berggren, LAL

CREATION DATE:

27-jul-1992