User manual

1200 Series Variable Wavelength Detector User Manual 103
Maintenance 8
Wavelength Verification/Calibration
Wavelength calibration of the detector is done using the zero-order position
and 656 nm emission line position of the deuterium lamp. The calibration
procedure involves two steps. First the grating is calibrated on the zero-order
position. The stepper-motor step position where the zero-order maximum is
detected is stored in the detector. Next, the grating is calibrated against the
deuterium emission-line at 656 nm, and the motor position at which the
maximum occurs is stored in the detector.
In addition to the zero-order and 656 nm (alpha-emission line) calibration, the
beta-emission line at 486 nm and the three holmium lines are used for the
complete wavelength calibration process. These holmium lines are at
360.8 nm, 418.5 nm and 536.4 nm.
When the lamp is turned ON, the 656 nm emission line position of the
deuterium lamp is checked automatically.
Figure 35 Wavelength Verification/Calibration
NOTE
The wavelength verification/calibration takes about 2.5 minutes and is disabled within the
first 10 minutes after ignition of the lamp because initial drift may distort the measurement.