4.4.9 SUBROUTINE ZTTDST(P, V, DST, FIRST, IPRP, IPZ, PHI, PEND, VEND, TRACK, ERROR) : Follow Track helix a DiSTance

This routine tracks a particle with momentum p from v to the the distance DST. It returns the momentum (pend) and position (vend) at this point. It also returns the TKR parameters at the point.

ARGUMENTS:

INPUT :

    P : Momentum of track
    V  : Position where P is given
    DST : Distance to follow track from V.
    FIRST : TRUE if first call for this track.
    IPRP : true IP in R-Phi (input if FIRST = FALSE)
    IPZ : true IP in Z (input if FIRST = FALSE)
    PHI : Phi angle to perigee point in R-phi plane
            (input if FIRST = FALSE)

OUTPUT :

    IPRP : true IP in R-Phi (output if FIRST = TRUE)
    IPZ : true IP in Z (output if FIRST = TRUE)
    PHI : Phi angle to perigee point in R-phi plane
            (output if FIRST = TRUE)
    PEND: Momentum of track (if ERROR <>0 then PEND=P)
    VEND  : Position where PEND is given (if ERROR <>0 then VEND=V)
    TRACK : TKR parameters for the track.
                 for the track
    ERROR : error flag :
             0 - no error
             1 - no intersection in barrel.
             2 - track turns back.
             3 - other error.

IMPLICIT INPUTS:

    none

IMPLICIT OUTPUTS:

    none

CALLED BY :

ZDETSI, DETector SImulation (see 4.3.1).

CALLED ROUTINE(S):

ZTTPLA (see 4.4.8)

(To track a to a PLAne given by its z)

VMOD

(CERNLIB routine)

SIDE EFFECTS:

none

AUTHORS:

M. Berggren, UFRJ

CREATION DATE:

10-DEC-1995