Note: Hollow cathode lamp with integral, high optical efficiency isolation valve: A modular vacuum ultraviolet source

The design and operating conditions of a hollow cathode discharge lamp for the generation of vacuum ultraviolet radiation, suitable for ultrahigh vacuum (UHV) application, are described in detail. The design is easily constructed, and modular, allowing it to be adapted to different experimental requirements. A thin isolation valve is built into one of the differential pumping stages, isolating the discharge section from the UHV section, both for vacuum safety and to allow lamp maintenance without venting the UHV chamber. The lamp has been used both for ultraviolet photoelectron spectroscopy of surfaces and as a "soft" photoionization source for gas-phase mass spectrometry