X-ray photoelectron spectroscopy and secondary electron yield analysis of Al and Cu samples exposed to an accelerator environment

Abstract

Articles you may be interested inInfluence of electron irradiation and heating on secondary electron yields from non-evaporable getter films observed with in situ x-ray photoelectron spectroscopy

Effect of the surface processing on the secondary electron yield of Al alloy samples

“…The only change evident with respect to the as-received spectrum consists in the decrease of both O1s and C1s intensities with a preferential desorption of oxygen with respect to carbon; indeed the O1s and C1s spectral intensities measured on the scrubbed surface were 22% and 14% lower, respectively, than those of the asreceived surface. The max value of 1.8 measured on the scrubbed surface is consistent with those reported for experiments performed by electron bombarding similar Al alloy samples [14,15]. In contrast the max value measured on the sputter cleaned Al alloy 6061 surface is around 1 [6].…”

“…The investigations carried out so far on technical Al samples have emphasized the impossibility to obtain surfaces with a low SEY even after extensive conditioning [14,15], indicating the difficulty to modify in the desired direction the state of the Al surface via the impact of charged particles. On the other hand the large spread of the max values reported in the literature for different Al and Al alloys [6,8,[14][15][16] ( max being the maximum of the measured SEY curves) denotes the importance of the chemical state of the metal surface, but also to the properties of the specific alloy, in determining the secondary electron yield. This poses a crucial issue as the simulation codes developed to correctly analyze, predict, and possibly mitigate the EC-related unwanted effects for PETRA III necessitate, among other input parameters, a reliable max value.…”

Electron Conditioning of Technical Aluminium Surfaces

“…As the fluorine disappears from the surface, the spectrum shifts to lower binding energy and presents the characteristic of a thin aluminium oxide film (less than 5 nm) on an aluminium substrate. Very similar curves on an Al 6063 alloy sample can be found in [8], where the peaks are representatives of the pure and the oxidized Al. Moreover, the relative intensities of the peaks changes during the conditioning.…”

“…In some other data, collected at ANL (Argonne National Laboratory) on an Al 6063 sample, the δ max achieved after an electron dose exposure of 350 nA/cm 2 for 5h (equivalent to 63 µC/mm 2 ) at an energy of 100 eV is around 2.1 [8]. Figure 9: SEY of baked technical surfaces conditioned by electrons from ref.…”

Electron Conditioning of Technical Aluminium Surfaces: Effect on the Secondary Electron Yield

“…The shift in energy, is also accompanied with a change in intensities between the peaks, as it was observed on the Al 1100, Fig.15. In [7], the XPS spectra from the technical Al 6063 sample, exposed to the effect of a running accelerator beam, shows a shift toward lower BE of the oxidized peak. The intensity of the oxidized Al peak before running the beam is higher than the pure Al peak.…”