SUBROUTINE ZPD1(DATA,ET,MASK,DNUM,FRAME,SUM,SUMSQ,NADDS,
     &                          BRATE,ARATE,RRATE,EXPO,ONED,STATUS)
C
C Module Number: 13.5.1
C
C Module Name: ZPD1
C
C Keyphrase:
C ----------
C Compute statistics for evaluating HRS particle hits
C
C
C Description:
C ------------
C  This routine accumulates the sum and sum squared of the count
C  rates for all diodes in multiple frame data.  The average
C  bacground rate, radition diode rate, exposure, anticoincidence counter
C  rate per frame are also computed.
C
C
C FORTRAN Name: zpd1.for
C
C
C Keywords of Accessed Files :
C --------------------------
C none
C
C Modules Called:
C ---------------
C SDAS:
C    UMSPUT
C
C History:
C --------
C Version       Date      Author        Description
C    1          8/30/86  D. Lindler     Designed and coded
C    2          JAN 88   D. LINDLER     NEW SDAS I/O AND STANDARDS
C    3		Oct 89	 D. Lindler	Corrected expo. time computation
C------------------------------------------------------------------------
C     INCLUDE FILE FOR THE IRAF77 FORTRAN INTERFACE TO THE IRAF VOS
C
C
C     FILE I/O ACCESS MODES
C
      INTEGER   RDONLY
      PARAMETER (RDONLY = 1)
      INTEGER   RDWRIT
      PARAMETER (RDWRIT = 2)
      INTEGER   WRONLY
      PARAMETER (WRONLY = 3)
      INTEGER   APPEND
      PARAMETER (APPEND = 4)
C
C     CODES FOR DATA TYPES
C
      INTEGER   TYBOOL
      PARAMETER (TYBOOL = 1)
      INTEGER   TYCHAR
      PARAMETER (TYCHAR = 2)
      INTEGER   TYINT
      PARAMETER (TYINT = 4)
      INTEGER   TYREAL
      PARAMETER (TYREAL = 6)
      INTEGER   TYDOUB
      PARAMETER (TYDOUB = 7)
C
C     UMSPUT DESTINATIONS -- CB, DAO, 4-SEP-87
C
      INTEGER STDOUT
      PARAMETER (STDOUT = 1)
      INTEGER STDERR
      PARAMETER (STDERR = 2)
C
C     UHDAS HEADER PARM TYPES -- CB, DAO, 5-SEP-87
C
      INTEGER GENHDR
      PARAMETER (GENHDR = 0)
      INTEGER IMSPEC
      PARAMETER (IMSPEC = 1)
C
C     THIS SECTION IS FOR PARAMETERS RELEVANT TO TABLE I/O.
C
C     THESE MAY BE SET BY UTPPTI AND/OR READ BY UTPGTI:
C
C                                       LENGTH OF ROW (UNIT = SIZE OF REAL)
      INTEGER   TBRLEN
      PARAMETER (TBRLEN = 1)
C                                       INCREASE ROW LENGTH
      INTEGER   TBIRLN
      PARAMETER (TBIRLN = 2)
C                                       NUMBER OF ROWS TO ALLOCATE
      INTEGER   TBALLR
      PARAMETER (TBALLR = 3)
C                                       INCREASE ALLOC NUM OF ROWS
      INTEGER   TBIALR
      PARAMETER (TBIALR = 4)
C                                       WHICH TYPE OF TABLE? (ROW OR COLUMN)
      INTEGER   TBWTYP
      PARAMETER (TBWTYP = 5)
C                                       MAXIMUM NUMBER OF USER PARAMETERS
      INTEGER   TBMXPR
      PARAMETER (TBMXPR = 6)
C                                       MAXIMUM NUMBER OF COLUMNS
      INTEGER   TBMXCL
      PARAMETER (TBMXCL = 7)
C                                       TYPE = ROW-ORDERED TABLE
      INTEGER   TBTYPR
      PARAMETER (TBTYPR = 11)
C                                       TYPE = COLUMN-ORDERED TABLE
      INTEGER   TBTYPC
      PARAMETER (TBTYPC = 12)
C
C     THESE MAY BE READ BY UTPGTI BUT MAY NOT BE SET:
C
C                                       NUMBER OF ROWS WRITTEN TO
      INTEGER   TBNROW
      PARAMETER (TBNROW = 21)
C
C     END IRAF77.INC
C
C INPUT PARAMETERS
C
        REAL    DATA(500)
C                                    --->DATA FROM MAIN DIODE ARRAY
        REAL    ET(24)
C                                    --->EXT. ENG. TRAILER DATA
        REAL    MASK(500)
C                                    --->DATA MASK
        INTEGER DNUM
C                                    --->ISOLATED DIODE NUMBER
C
C INPUT/OUTPUT PARAMETERS
C
        INTEGER FRAME
C                                    --->FRAME COUNTER
        REAL    SUM(500)
C                                    --->ARRAY OF DATA RATE SUMS
        REAL    SUMSQ(500)
C                                    --->ARRAY OF SUMS DATA RATE SQUARED
        INTEGER NADDS(500)
C                                    --->NUMBER OF ADDS TO EACH POINT
C
C OUTPUT PARAMETERS
C
        REAL    BRATE(1)
C                                    --->BACKGROUND RATE FOR EACH FRAME
        REAL    ARATE(1)
C                                    --->ANTI-COIN. RATE FOR EACH FRAME
        REAL    RRATE(1)
C                                    --->RADIATION DIODE RATE FRO EACH FRAME
        REAL    EXPO(1)
C                                    --->EXPOSURE TIME PER FRAME
        REAL    ONED(1)
C                                    --->ISOLATED DIODE COUNT RATE
        INTEGER STATUS
C
C LOCAL VARIABLES
C
        REAL    ETIME,RATE
C                                    --->EXPOSURE AND COUNT RATE
        INTEGER I
C                                    --->COUNTER
        CHARACTER*130 CONTXT
C                                    --->WHAT HAPPENED
        INTEGER ITEMP
C
C INITIALIZATION WHEN FRAME=0
C
        IF(FRAME.EQ.0) THEN
                DO 10 I=1,500
                        SUM(I)=0.0
                        SUMSQ(I)=0.0
                        NADDS(I)=0
10              CONTINUE
        ENDIF
C
C COMPUTE EXPOSURE TIME
C
        ITEMP=ET(21)
C                                    ---> INTEGRATION PERIOD
        ETIME=0.05*MOD(ITEMP,256)
        IF(ET(23).GT.0.0)ETIME=ETIME*ET(23)
C                                    --->TIMES # OF COADDS
        IF(ETIME.LE. 0.0)THEN
                CONTXT='INVALID EXPOSURE TIME IN TRAILER'
                GO TO 999
        ENDIF
C
C INCREMENT FRAME COUNTER
C
        FRAME=FRAME+1
        IF(FRAME.GT.10000)THEN
                CONTXT='MAX NUMBER FOR FRAMES PROCESSED'
                GO TO 999
        ENDIF
C
C COMPUTE BACKGROUND, ANTI-COIN. RATE, AND RADIATION RATE
C
        BRATE(FRAME)=(ET(1)+ET(2)+ET(11)+ET(12))/4.0/ETIME
C                                    --->AVE. 4 BACK DIODE
        RRATE(FRAME)=(ET(3)+ET(10))
C                                    --->AVE. 2 RADIATION DIODES
        ARATE(FRAME)=ET(15)
C                                    --->ANTI-COINCIDENCE RATE
        EXPO(FRAME)=ETIME
C
C ACCUMLATE SUMS AND SUM SQUARED
C
        DO 20 I=1,500
                IF(MASK(I).EQ.1)THEN
                        RATE=DATA(I)/ETIME
                        SUM(I)=SUM(I)+RATE
                        SUMSQ(I)=SUMSQ(I)+RATE*RATE
                        NADDS(I)=NADDS(I)+1
                ENDIF
20      CONTINUE
C
C KEEP RESULTS FOR ISOLATED DIODE IF SUPPLIED
C
        IF(DNUM.GT.0)ONED(FRAME)=DATA(DNUM-6)/ETIME
C
C DONE
C
        STATUS=0
        GO TO 1000
999     CALL UMSPUT(CONTXT,STDOUT+STDERR,0,STATUS)
        STATUS=1
1000    RETURN
        END