Important Information

The Cairn spectrophotometry system is an extremely flexible and powerful research tool, and as such must be handled with care. The system is potentially dangerous if not operated correctly. In addition to this the lifespan of several key components will depend greatly on how the system is used. The following points are of particular importance.

1. When changing the xenon arc lamp please follow the procedure outlined in the relevant section of this manual.
2. There is no speed limit on our rotary filter changer. We've run it successfully at about 300 revs/sec, but we would strongly advise against using it at speeds in excess of 200 revs/sec without consulting us first. For most experiments typical speeds of 32 or 64 revs/sec give perfectly satisfactory time resolution.
3. When fitting filters in the wheel always ensure that the mounting grub screw is as tight as possible without causing damage to the filter. The colour-coded bands should be visible with the filters fitted and the rotor wheel should be orientated with these bands facing away from the light source.
4. Our arc lamps are very powerful and can easily damage optical filters if allowed to overheat. Never stop a filter in the light path without ensuring that there is some neutral density gauze in place in the optical adapter (preferably two or three pieces). Always shutter the light source when not recording. Even if the rotor is spinning then neutral density gauze should be used if possible (usually one or two pieces are fine during experiments). For single excitation experiments we recommend that 25mm filters are used and that the rotary filter changer is removed from the light path.
5. On most of our microscope based systems an infrared filter is fitted to the integral brightfield halogen light source to allow CCD camera viewing during experiments. If this filter is removed, without first diverting light away from photometric output port, then the camera and photomultipliers will be subjected to extremely high light levels. This has been known to destroy sensitive detection electronics, and may lead to instability in the photomultipliers for several hours.

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