Characterisation of copper and stainless steel surfaces treated with laser ablation surface engineering

Abstract

In the past few years, it has been established that Laser Ablation Surface Engineering (LASE) is a very effective way of producing surfaces which have Secondary Electron Yields (SEY)¿<¿1. This can be achieved with a variety of laser pulse durations from nano-to picoseconds. However, the features (i.e. moderately deep grooves and nano-particulates) that help to reduce the SEY can produce undesirable effects such as an increase in the RF surface resistance. In this paper we discuss the methods employed utilising the dielectric resonator technique to quantify the surface resistance of laser treated copper and stainless steel samples. The quantification is based on a non-destructive measurement of high-frequency losses on the conducting surface. It has been demonstrated that the LASE surface can be produced with SEY<1 and an RF surface resistance of only ~6% higher than that on untreated surfaces. Furthermore, a comparative study of electron stimulated desorption (ESD) between the LASE treated and untreated samples of copper and stainless steel is reported for H2, CH4, CO and CO2. It has been shown that there are negligible differences in ESD between LASE treated and untreated stainless steel. It has been demonstrated that LASE-treated copper samples have a considerable reduction in ESD as compared with untreated sample.