Thermo Finnigan SpectraSYSTEM UV6000LP, Reference Manual

Page: 94 / 137

5-18 Thermo Electron January 2004
PERFORMING A
DARK CURRENT
CALIBRATION
To perform the dark current calibration, do the following:
1. Turn on both lamps and wait 1 hour for the lamps to warm-up.
Because the dark current is a function of temperature, you want
to perform this calibration after the detector has reached its
typical operating temperature.
2. Pump water at 1 mL/minute through the flowcell.
3. Place the filter wheel in position 1, Open.
4. Press the Execute button. An information box opens
(Figure 5.11) to remind you of the necessary pre-conditions.
5. If all of the pre-conditions have been met, press the OK button.
Figure 5.11 Dark Current Calibration Start
As the calibration proceeds, its status is shown in the status
group at the bottom of the page. During the dark current
calibration, intensity scans are collected under four sets of
conditions; with both lamps on, D
2
lamp only on, W lamp only
on and both lamps off. After the last event is completed, the
lamps are turned back on and the Calibration Complete info
box shown in Figure 5.12 appears.
Figure 5. 12 Dark Current Calibration Complete
6. Click on the OK button.
7. Press the Apply button to apply the calibration results to the
detector. Date and time of calibration are displayed and stored
in memory.