Secondary electron emission yield (SEY) in amorphous and graphitic carbon films prepared by PLD

Abstract

High secondary emission yield (SEY), and the subsequent build‐up of a secondary electron cloud, may severely limit the stability of high‐intensity particle beams inside particle accelerators. One of the best candidates of beam pipe coating for reduced SEY has been amorphous carbon (a‐C) produced by direct current (D.C.) magnetron sputtering. Here we used pulsed laser deposition (PLD), to prepare a‐C films from a pure carbon target at substrate temperatures ranging from 300 K to 773 K. The ablating laser was a Nd:YAG system operating at 1064 nm wavelength. With increasing temperature the optical band gap dropped from about 2.1 eV to 1.0 eV. This trend indicates transition from predominantly a‐C films to films with more graphitic content, which was also confirmed by Raman measurements. SEY spectra were taken upto 1732 eV of primary electron energy. The maximum SEY value decreased from 1.9 in a‐C films down to 1.4 in highly graphitic films deposited at higher temperatures (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Enhancing image contrast of carbon nanotubes on cellular background using helium ion microscope by varying helium ion fluence

“…B). It is known that the SE yield for carbon structures varies and is higher in amorphous carbon films (∼1.95) (Alberti et al ., ) than for crystalline MWCNTs (∼0.6) (Alam et al ., ). This suggests that the brightness of cells should be higher than the MWCNTs; indeed, the situation is possible as indicated by the overlapping error bars in Figure (C) (data for image in Fig.…”

Substrate Temperature Dependent Microstructure and Electron-Induced Secondary Electron Emission Properties of Magnetron Sputter-Deposited Amorphous Carbon Films

“…In recent decades, large amounts of related research about a-C film have been carried out because of its relatively low SEY and simple deposition process. For example, M. Alberti et al produced an a-C film by pulsed laser deposition, and its maximum SEY is as low as 1.4 [28]. Vallgren et al prepared an a-C film by direct current magnetron sputtering and found that the SEY rose by 10–20% after this film exposed to air for one month [29].…”

Secondary electron emission characteristics of graphene films with copper substrate

“…The build-up of electron cloud generated by residual gas ionization, synchrotron radiation, etc., in the beam pipes considerably affects the stability of particle beams in a particle accelerator. For example, the suppression of secondary electron emission is important for the Super Proton Synchrotron (SPS) accelerator and the future super proton-proton collider (SPPC) [1][2][3][4]. Therefore, it is critical to look for stable and very low SEY material for future high intensity accelerators.…”