A novel vacuum ultra violet lamp for metastable rare gas experiments

TL;DR

This paper introduces a new VUV lamp design for exciting metastable rare gas atoms, featuring improved lifetime and compatibility with ultra high vacuum environments, driven by a microwave source and using a magnesium fluoride window.

Contribution

The paper presents a novel VUV lamp design that significantly extends operational lifetime and can be directly mounted in ultra high vacuum systems for atomic physics experiments.

Findings

VUV lamp lifetime increased by two orders of magnitude.

Detected signal remained at 25% after 550 hours of operation.

Compatible with ultra high vacuum environments.

Abstract

We report on a new design of a vacuum ultra violet (VUV) lamp for direct optical excitation of high laying atomic states e.g. for excitation of metastable rare gas atoms. The lamp can be directly mounted to ultra high vacuum vessels (p <= 10^(-10) mbar). It is driven by a 2.45 GHz microwave source. For optimum operation it requires powers of approximately 20 W. The VUV light is transmitted through a magnesium fluoride window, which is known to have a decreasing transmittance for VUV photons with time. In our special setup, after a run-time of the VUV lamp of 550 h the detected signal continuously decreased to 25 % of its initial value. This corresponds to a lifetime increase of two orders of magnitude compared to previous setups or commercial lamps.