Olivier Callot
                                                             December 22, 1988





                         The CDC event display package
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    The CDC display package is used since one year in EVTMON for the Stony-Brook
cosmic ray analysis. It has now being adapted to the new Event Display framework
( PXMAIN, PXEXEC ) and is  released in the PIXIE  library. Here is a description
of the   routines  you can  call  as  'action   routines', and  of  the specific
parameters. Refer to D0$TRACKING_UTIL:CDC_D0USER.MEM for informations on how the
data are  processed,  and   D0$ZEB:CDC*_ZEBANKS.MEM  for the  description of the
relevant bank structures. 

1) CDC Action Routines
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    PDRPHI draws a side view of the CDC ( R - Phi view ) in 2D, with ( and under
control of some  parameters ) sector  limits, wire  position, hits, segments and
ISAJET tracks for Geant events. A good set of value for the center and size is :
Center = (0.,0.), size = 200. 

    PD3SEC  uses the  same  subroutine  as  PDRPHI, but  for only  the 3 sectors
centered  around the  value of  the  parameter "CDC  SECTOR". The  center of the
window is shifted  to be centered on  the center of the 3  sectors internally. A
good set of value is center = (0.,0.), size = 40. 

    PDFSEC draws the  11 FADC datas of a  sector, with the  delay lines ( one on
top, one on the bottom of  the picture ) drawn with  one side upwards, the other
side   downwards. A  global  title  shows the  value of  the  sector and layer (
parameters "CDC LAYER" and "CDC SECTOR"  ). The window limits are overwritten by
this routine, and thus the window values and the BLOW-UP action are ignored. 

    PDFADC draws the data  of one FADC, and the  derivative of these data ( i.e.
the difference between a bin content and the previous bin content ). The FADC is
selected by the values of  "CDC LAYER", "CDC  SECTOR" and "CDC FADC". The window
limits are also ignored. 

    An  example  of  screens  using  these   routines can  be  found in the file
    D0$PIXIE$DATA:CDC.SCREEN 

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2) CDC specific Parameters
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    - "CDC LAYER" defines the layer number [0:3] for the FADC displays ( PDFSEC,
      PDFADC) 

    - "CDC  SECTOR" defines  the sector  number  [0:31] for the  FADC displays (
      PDFSEC, PDFADC ) and the center of the 3 sector display ( PD3SEC ) 

    - "CDC FADC" defines the FADC number [0:10] ( PDFADC ) 

    - "CDC ISAJET  TRACK" defines if we  want to draw the  ISAJET tracks ( for a
      simulated event only, of course ). 0 = No, 1 = Yes. 

    - "CDC DRAW  SECTORS" defines  if we want to  draw the  sector boundaries in
      PDRPHI and PD3SEC. T means yes, F means no. 

    - "CDC DRAW WIRES" defines if we want to draw the sense wire position in the
      PDRPHI and PD3SEC routines. T means yes, F means no. 

    - "CDC DRAW  HITS" defines if  we want to  draw a small  segment to show the
      reconstructed hit  position. We  show both solutions,  i.e. the right-left
      ambiguity is not solved. T means yes, F means no. 

    - "CDC DRAW SEGMENT"  defines if and how we want  to draw the track segments
      reconstructed by the program. 0 =  no, 1 = all segments, 2 = only those on
      full tracks, 3 = only those NOT on full tracks. 


    An example of values is given in D0$PIXIE$DATA:CDC.PXPARA