6
•
Operation
Page 112
Fluorescence Detectors (VC-D50, VC-D51, VF-D50, VF-D51)
Operating Manual
6.9.5
Filter Wheel (VF detectors only)
To prevent stray light from reaching the PMT, additional optical edge
filters are installed on a filter wheel in the light path between the flow
cell and the emission monochromator. This reduces direct scattering of
light from the light source. In addition, a grating monochromator lets
unwanted fractions (the half, one third, ...) of a selected wavelength
pass. If the monochromator is set to 500 nm, for example, second-order
light at 250 nm from the sample may reach the PMT. The filters also
eliminate this higher-order stray light.
Ideally, these filters can be passed by wavelengths above their cut-off
wavelength, while light with a smaller wavelength than the cut-off
wavelength is blocked. In practice, there is a transition area where the
transmission of the light increases from the lower wavelengths near the
range where the light is cut off to the higher wavelengths near the range
where the light passes. At the cut-off wavelength, the filters let 50% of
the light pass. The figure shows the transmission behavior of the 280 nm
filter as an example.
Figure 35: Transmission behavior of the 280 nm filter
The filter wheel setting can be selected automatically or manually:
•
If the filter wheel mode is set to
Auto
, the detector automatically
selects a filter wheel position. It selects the first filter with a cut-off
wavelength below the selected emission wavelength. This mode is
selected by default and provides best results for most applications.
•
You can manually select the filter wavelength (that is, the cut-off
wavelength). Available filters are 280 nm, 370 nm, 435 nm or
530 nm. In special situations (for example, if the emission
Содержание Vanquish VC-D50
Страница 4: ...Contacting Us Page 4 Fluorescence Detectors VC D50 VC D51 VF D50 VF D51 Operating Manual...
Страница 10: ...Contents Page 10 Fluorescence Detectors VC D50 VC D51 VF D50 VF D51 Operating Manual...
Страница 30: ...2 Safety Page 30 Fluorescence Detectors VC D50 VC D51 VF D50 VF D51 Operating Manual...
Страница 42: ...3 Device Overview Page 42 Fluorescence Detectors VC D50 VC D51 VF D50 VF D51 Operating Manual...
Страница 88: ...5 Installation Page 88 Fluorescence Detectors VC D50 VC D51 VF D50 VF D51 Operating Manual...
Страница 122: ...6 Operation Page 122 Fluorescence Detectors VC D50 VC D51 VF D50 VF D51 Operating Manual...
Страница 154: ...7 Maintenance and Service Page 154 Fluorescence Detectors VC D50 VC D51 VF D50 VF D51 Operating Manual...
Страница 170: ...9 Specifications Page 170 Fluorescence Detectors VC D50 VC D51 VF D50 VF D51 Operating Manual...
Страница 187: ...Index Fluorescence Detectors VC D50 VC D51 VF D50 VF D51 Operating Manual Page 187...
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