Simple Maintenance; Control Of The Lamp's Functionality; Checking Wavelength Accuracy; Sop 6 Checking Wavelength Accuracy - Knauer Smartlibe UV Detector 2500 Handbuch

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Simple Maintenance

Control of the lamp's functionality

Checking Wavelength Accuracy

Fig. 23

SOP 6

The deuterium lamp used in the UV-Detector 2500 has an extended life
time to ensure long-time functionality and reliable measurements with low
noise and baseline drift as well as high sensitivity. The current using time of
the lamp depends on different factors, like the number of lamp starts, the
average burning time and your requirements concerning noise and
sensitivity.
To check the functionality of the lamp, the two intensity values signal and
reference to be found in the SIGNAL menu on page 13 provide helpful
information. The reference value refers to the intensity of the light
measured in the reference channel and can be used for checking the
quality of the lamp.
INTENSITY signal:0.3836
♦ 1/8 reference:0.2264
On delivery of the Detector, the signal-value is set to the range of 0.39 to
0.78 and the reference-value to 0.2 to 0.4, measured with the dummy cell
at a wavelength of 240 nm.
We recommend to check the reference value at regular intervals under
the conditions mentioned above (dummy cell, λ = 240 nm). This applies
especially in case higher noise levels or decreased sensitivity are observed
on working with the Detector 2500. If these observations coincide with a
reference value of approx. 0.1 or less, a new deuterium lamp should be
installed, see "Changing the lamp" SOP 7 on page 28.
For tungsten halogen lamps this test is not needed because the light
intensity does not decrease so much.
Holmium Oxide glass is a glass with characteristic absorption maxima in
the range of 250 – 600 nm. The supplier of the glass adds a certificate to
the delivery of the glass showing the exact absorption maxima. Just by
comparison of measurements of the detector with the certificate of the
holmium oxide filter the accuracy can be determined.
filterholder with holmium oxide
Holmium oxide test cell, standard (left) and fiber optics (right)
To proof the wavelength accuracy of the Detector 2500 proceed a test
scan with a holmium oxide test cell according to SOP 6.
Checking Wavelength Accuracy
This instruction applies to the UV-Detector 2500.
1. Insert the holmium oxide test cell into the cell holder
2. Switch on the Detector and ignite the lamp. Wait for at least 10
minutes.
filter
screw to lock filter
Simple Maintenance