Evaluation of photocathode materials in combination with commercial fiber-coupled UV photon sources as a compact electron source in mass spectrometry

Abstract The design of a compact electron source for mass spectrometry applications based on commercially available plug-and-play light sources and sturdy materials is presented, and its performance of photo-electron production is evaluated. We report quantum yields ranging between 1–2.5 × 10 –5 for aluminum, 9 × 10 –8 –3 × 10 –6 for stainless steel, 1– 2.2 × 10 –6 for molybdenum, 6.3 × 10 –7 –5.1 × 10 –6 for tantalum, and 1.4–2.1 × 10 –6 for titanium, depending on the wavelength range of the irradiation source. In terms of quantum yield, the deuterium lamp provided better results compared to the two UV LEDs for all metals. However, due to their higher optical output power, the LEDs nevertheless yield a higher photoelectron current for all metals except for stainless steel. The measured photocurrents ranged from 1-2 nA for aluminum to 0.01 nA for Stainless Steel samples.