Suppression of Secondary Electron Emission from Stainless-Steel Surface by Laser Etching:An Experimental Study

We addressed the suppression of secondary electron emission yield(SEY) from stainless-steel vacuum-chamber wall of charged-particle accelerator by laser etching in ambient environment.The influence of the etching conditions,including the energy density/beam-width/spacing/speed of scanning laser beam on the microstructures and SEY was investigated with scanning electron microscopy and high-precision SEY measurement.The results show that the laser etching significantly suppressed the secondary electron emission.The highest SEY of the laser-etched surfaces was found to decrease from 2.71 to 0.89.The parallel ridge-furrow structures formed on the surfaces,15~25 μm in width.The differently-sized tiny “hairy goose-bumps” on the ridge-surfaces considerably decreased the secondary electron emission yield.