FAINTDFE (Dec93)             ftools.asca             FAINTDFE (Dec93)



NAME
    faintdfe -- Calculate the dark frame error for SIS FAINT data
    
    
USAGE
    faintdfe infile binsec outfile dstfile
    
    
DESCRIPTION
      "faintdfe"  is  a  ftool  to  get  the Pulse Height channel of the
    'REAL' zero-level of each chip of SIS.  The  another  tool  will  be
    prepared  by  Goddard people in order to change the raw Pulse Height
    (PH) of events into correct PH. "faintdfe"  is  available  only  for
    the Faint mode data.
    
    The exact meaning of the result
    
      The  format  of  each  line  of  the output file is "ASCA-Time" in
    second, zero-level offsets of Chip0, Chip2, Chip2, and Chip3 in  the
    unit  of ADU.  ( See Table 1. ) The offset values are written not by
    integer, but by float, though the only integer values are  available
    to  correct  the  PH  value.     Each  offset  value  in the line is
    available after the time in the  same  line.  For  example,  in  the
    Table  1,  4  values of -2.69, -2.68, -2.92, -2.74 in the first line
    are available in the period from 17994050 to  17994114.   The  value
    in  the last values are available in the period from 17994178 to the
    latest time of event detection in the science file.
    
            ---------------------------------------------
                   Table 1.  Sample of output data
            ---------------------------------------------
            17994050        -2.69   -2.68   -2.92   -2.74
            17994114        -2.95   -3.04   -3.34   -3.20
            17994178        -2.82   -2.37   -2.34   -2.77
                  ..................................
                  ..................................
            17994498        -2.98   -4.00   -3.00   -1.78
            17994562        -3.03   -3.04   -2.14   -3.08
            ---------------------------------------------
    
      Each resulting offset value  shows  the  real  zero-level  channel
    when  we  adopt  the  0  channel  of  the  telemetry output as the 0
    channel. As a result, we should subtract each value from the  PH  of
    each  event  in  order  to  get  correct PH value for the event. For
    example, when we get 255 channel as the PH of  some  event  and  the
    offset  value in the period is -2.22, then we need to convert the PH
    (255) of the event into 257.
    
    If you find some problems, please mail me.
    ISAS  Chiko Otani
    otani@astro.isas.ac.jp
    


                                  -1-
FAINTDFE (Dec93)             ftools.asca             FAINTDFE (Dec93)



PARAMETERS
    
    infile [file name]
        The full name of science file for SIS/Faint-mode.
    
    (split = 40) [integer]
        Split  Threshold  :  I  recommend  to  use  "40"  as  the  split 
        threshold.   In  the sample file, I select the "hidden" mode for
        this key word. If you  need  to  select  another  value,  please
        change the mode "h" into "a" ( asking mode ).
    
    binsec = 64 [integer]
        The  unit  time  in second to calculate zero-level.  16 sec will
        be too short to calculate the zero-level in  enough  statistics.
        I recommend you to use more than 32 second, e.g. 64 sec.
    
    outfile  = stdout [filename]
        You  can  get  the  zero-level  result both in the file and into
        STDOUT. Though this result can be plotted by QDP, you have to  be
        careful  the  difference  of the written time and the real event
        time.
    
    dstfile = "/ftools/SUN/develop/testdata/faintdfe.qdp" [filename]
        This file "faintdfe.qdp" includes the reference PH  distribution
        to  search  the  real  zero-level.   This is just the average PH
        Distribution of corner pixels of SIS-0 collected  in  the  night
        region  for  the  satellite. As this file is also written in the
        QDP format, you can plot  the  typical  distribution  of  PH  of
        corner pixels.
    
    
EXAMPLES
    1.  Calculate  the  dark  frame  error  in  the FAINT mode FITS file
    faint.fits,    and then use it to make corrections  with  the  FAINT
    FTOOL.
    
        ft> faintdfe faint.fits 64 faintdfe.out /ftools/ftools/testdata/faintdfe.qdp
        ft> faint faint.fits outfile.fits 0 faintdfe.out  4
    
    
BUGS
    Not available under VMS.
    
    
SEE ALSO
    FAINT