Laser-processing of grinded and mechanically abraded Nb-surfaces

TL;DR

This study explores pulsed laser polishing of rough niobium surfaces, demonstrating how laser treatment can create tailored surface textures and correlate electrical signals with surface roughness and defects.

Contribution

It introduces a method to control niobium surface roughness using nanosecond laser pulses and correlates electrical signals with surface topography and defects.

Findings

Achieved uniform rough and smooth surfaces with specific fractal dimensions.

Correlated electrical signals with initial roughness and laser-induced defects.

Provided detailed analysis of particle behavior during laser processing.

Abstract

The effect of pulsed laser polishing on rough niobium surfaces was investigated. We created different well-defined roughness profiles with standard emery papers and subsequently remelted random surface areas with a size of about 2x2 mm^2 with nanosecond laser pulses (wavelength of 1064 nm, pulse length of 10 ns). Pristine as well as laser-treated surfaces were investigated using optical profilometry and atomic force microscopy, and the surface topography was described by means of correlation functions. Uniformly rough and highly smooth surface geometries were achieved for fractals above and below 7 {\mu}m, respectively. Moreover, the behavior of foreign particles during the laser processing was investigated in detail. The polishing procedure was also monitored point by point by detecting electrical signals, i.e., sample charging, which resulted from the intense laser illumination. The measured electrical charges were found to be correlated with the local surface texture. Thus, regions with initially high roughness profiles and regions with extensive laser-induced defects could be directly identified from the detected electrical signals.