Photomultiplier connector boxes are generally supplied with preinstalled dichroic mirror holders, emission filter holders, and photomultipliers. The delivery note should detail the wavelengths of the filters and mirrors supplied. The dichroic mirror holders are factory aligned to ensure that reflections are correctly centred on the appropriate detection devices. Mirrors can be removed from the light path if required by loosening the two knurled screws on the side of the box. The mirror plate can then be released and the rest of assembly replaced.
Fine adjustment of the dichroic mirror holders is possible by first loosening the two knurled corner screws and the three central fixing screws. The angle of the mirror can then be controlled using the two sets of opposing grub screws. User adjustment is not generally required, as all units are factory aligned prior to despatch.
The emission filter holders operate on a sliding mechanism with two locking positions. Filters can be changed by simply pulling the slider fully out of its holder. The factory default is to fit the required emission filter in one position with a blank in the other to act as a manual shutter for the photomultiplier when not in use. If a detector other than a photomultiplier (e.g. an imaging camera) is fitted then the system may be configured with 25mm rather than 12.5mm filters. In this case the emission filter will not be in a sliding arm and the photodetector must be removed to change filters.
