SUBROUTINE PMTC18 ( DEBUG, LDEBUG, IRANGE, T, IWAVE )
C
C     PMTC18   Jan 2005  LKH
C
      include "pmtcat.inc"
      include "diswav.inc"
      include "r3mode.inc"
c    
      LOGICAL  DEBUG 
c
c --- set calibration parameters
      real*4 wave1,wave2,dGdT0_r3ccm,coefs(5),nominal_temp,response
      data wave1/252./, wave2/406./, nominal_temp/20.0/,
c --- prelaunch values
c     +  dGdT0_r3ccm/-8.92889e-2/, coefs/-9.09650e-2,
c     +            9.62278e-4,-3.80980e-6,6.47558e-9,-3.95456e-12/
c --- Revised as in A&E report.  The change is minor due to changed weighting in
c     the fitting.  
     +  dGdT0_r3ccm/-8.8635e-02/, coefs/-9.0312e-02,
     +            9.5413e-04,-3.7719e-06,6.3979e-09,-3.8954e-12/
c
      INTEGER*4  LDEBUG, IRANGE, ITEMP, IWAVE
      real*8 SUM, SUMSQ
      real*4 T, TLO, THI
      CHARACTER*1  CCOUNT, CBUFR (4)
      EQUIVALENCE ( PMTCNT, CBUFR )

C
      IF ( DEBUG )  WRITE ( LDEBUG, 6000 )  PMTCNT
C
C****   INITIALIZE VARIABLES
C
      TLO = -50.
      THI = 500.
      CCOUNT = CBUFR(4)
C
C****   CONVERT VOLTS TO DEGREES CELSIUS
C
      ITEMP = 3
      CALL SPTEMP  ( CCOUNT, ITEMP, T, TLO, THI, SUM, SUMSQ,
     1            NUM, TMIN, TMAX, NREC)

c ---  Wavelength dependent temperature response are hold to constant
c      at the calibrated wavelength range boundary
      if ( WLEN(IWAVE) .le. wave1 ) then
        wv=wave1
      elseif ( WLEN(IWAVE) .gt. wave2 ) then
        wv=wave2
      else
        wv=WLEN(IWAVE)
      endif

c ---  Range-3 cathode mode has the same wavelength dependence as in
c      the Range-3 anode mode, but with a constant shift to less 
c      temperature sensitivity.  
      if (IRANGE .eq. 3 .and. r3ccm) then
        response=dGdT0_r3ccm+coefs(2)*wv
      else
        response=coefs(1)+coefs(2)*wv
      endif
        wvp=wv
      do i=3,5
        wvp=wvp*wv
        response = response + coefs(i)*wvp
      enddo
 
C
      TMPCOR = 1.0 + response * (nominal_temp - T)

      IF ( DEBUG )  WRITE ( LDEBUG, 6999 )  T, TMPCOR
      if ( debug ) write (ldebug,7000) iwave,wlen(iwave),
     +  (coefs(i),i=1,4),response

 7000 format('debug: ',i3,1x,f6.2,1x,4(e13.6,1x),f9.6)
      RETURN
 6000 FORMAT(' ------------ SUBROUTINE PMTC17 ENTERED',/
     1       10X,'PMT CATHODE TEMPERATURE (COUNTS) =',I8)
 6999 FORMAT('  RETURN FROM SUBROUTINE PMTC17 ----------',/
     1       10X,'PMT CATHODE TEMPERATURE (C)=',1P,E15.5,10X,
     2       'CORRECTION FACTOR=',E15.5)
      END