Kipp & Zonen BREWER MK IV, Instruction Manual

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16-10-200716-10-2007
MKIV OPERATOR’S MANUAL 105
The Stray Light Rejection is calulated by:
R
peak count rate
background count rate
=
_ _
_ _
Counts per second are calculated from raw counts.
( )
counts
raw counts dark counts
cycles
/ sec
_ _
.
=
−
×
2
0 1147
The counts must be corrected for the PMT dead time. This correction is insignificant for background
counts but can reach as high as 8% for peak values.
( )
[ ]
corrected counts counts dead time counts _ / sec / sec exp _ / sec
⇒
×
The errors involved are mostly statistical counting errors witch can be reduced by increasing the
number of slitmask cycles.
( )
δ
δ δ
R
peak count rate
background count rate
peak count rate background count rate
background count rate
= +
×
_ _
_ _
_ _ _ _
_ _
2
( )
δ
δ δ
counts
raw counts dark counts
cycles
/ sec
_ _
.
=
+
×
2
0 1147
δ
raw counts raw counts _ _
=
δ
dark counts dark counts _ _
=
Thermal Tests
The Thermal Tests consist of a battery of diagnostics which determine the extent to which the
spectrophotometer's performance is affected by temperature.
Measurements are made with the quartz-halogen (standard) lamp. Light intensity measurements
are taken at a number of points which span the temperature range -10 to +50
°
C. The wavelength
setting must be recalibrated (via the HG command) at each new temperature before the standard-
lamp intensities are measured. These intensity data are analyzed to yield the absolute temperature
coefficients for each of the five operational wavelengths; the negative of each coefficient is stored in
the instrument Constants File for subsequent use during data reduction.
During the course of the Thermal Tests all of the Brewer electromechanical subsystems should be
thoroughly exercised, and any malfunction corrected.
The PRFILE.BAT program is used to process the data and determine the temperature coefficients
for the brewer.
Method:
The instrument is placed in a chamber where the ambient temperature is set to values between -10
and +46
°
C. (These temperature settings cause the internal Brewer temperature monitor to register
between approximately -5 and +55
°
C.) The temperature is set for 2 hours at +46
°
C and then
APPENDIX F FACTORY TESTS