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# Coincidence correction options
define CC_PHOTO_MODE 1 # Photometer style correction
define CC_IIDS_MODE 2 # IIDS style
define CC_POWER_MODE 3 # Power law correction
define CC_USER_MODE 4 # User supplies a function
# COINCOR -- Coincidence correction for detector deadtime
procedure coincor (input, output, npts, expo, coflag, dt, power, mode)
real input[npts]
real output[npts]
real expo
int coflag
real dt
real power
int mode, npts
begin
# Check that exposure time is legit
if (expo <= 0.0)
return
# Select the method by which the correction is performed
switch (mode) {
case CC_PHOTO_MODE:
# Photoelectric photometer
call ccphoto (input, output, npts, expo, coflag, dt)
case CC_IIDS_MODE:
# IIDS style correction
if (coflag == -1) {
call cciids (input, output, npts, expo, coflag, dt)
if (power != 1.0)
call ccpower (output, output, npts, expo, coflag,
power)
} else if ((coflag == 0) && (power != 1.0))
call ccpower (input, output, npts, expo, coflag, power)
else
call amovr (input, output, npts)
case CC_USER_MODE:
# Provided by the user
call ccuser (input, output, npts, expo, coflag, dt)
}
end
# CCPHOTO -- Photoelectric photometer coincidence correction
procedure ccphoto (input, output, npts, expo, coflag, dt)
real input[npts], output[npts], expo, dt
int coflag
int npts
int i
begin
do i = 1, npts
output[i] = input[i] * exp (input[i] * dt / expo)
coflag = 2
end
# CCUSER -- User supplied correction scheme
procedure ccuser (input, output, npts, expo, coflag, dt)
real input[npts], output[npts], expo, dt
int coflag
int npts
begin
coflag = 3
end
# CCIIDS -- IIDS style correction scheme
# From Instrumentation for Astronomy III (SPIE Vol 172) p.88 by Larry Goad
#
# Note that only the "Detect" mode of observation is supported.
procedure cciids (input, output, npts, expo, coflag, dt)
real input[npts], output[npts], expo, dt
int npts, coflag
int i
real tsweep, value
begin
# Allow tsweep to be the deadtime so that a different value
# may be entered for other instruments.
# For the IIDS, tsweep = 1.424e-3 sec
tsweep = dt
do i = 1, npts {
value = 1 - input[i] / expo * tsweep
if ((value < 0.) || (value > 1.))
output[i] = input[i]
else
output[i] = -expo * log (value)/ tsweep
}
coflag = 0
end
# CCPOWER -- Power law correction
# Power law correction from Massey and De Veny, NOAO Newsletter #6.
procedure ccpower (input, output, npts, expo, coflag, power)
real input[npts], output[npts], expo, power
int npts, coflag
int i
begin
do i = 1, npts
if (input[i] > 0.)
output[i] = expo * (input[i] / expo) ** power
else
output[i] = input[i]
coflag = 1
end
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