| AVS 55th International Symposium & Exhibition | |
| Vacuum Technology | Tuesday Sessions |
| Session VT-TuM |
| Session: | Vacuum Pumping Technologies, Large Vacuum Systems, Vacuum Modeling |
| Presenter: | M.J. Ferreira, Brazilian Synchrotron Light Laboratory - LNLS |
| Authors: | M.J. Ferreira, Brazilian Synchrotron Light Laboratory - LNLS R.M. Seraphim, Brazilian Synchrotron Light Laboratory - LNLS P.A.P. Nascente, Federal University of Sao Carlos - UFSCAR, Brazil |
| Correspondent: | Click to Email |
The construction of ultra-high vacuum chambers (UHV) for particle accelerator demands pressure in the range of 10-8 Pa. It is particularly more difficult to obtain this vacuum level in chambers with a length to traverse section rate of 150:1. Among several methods used to obtain this condition, it stands out the internal coating with a metallic film capable of absorbing gases, called NEG (non-evaporable getter). Metallic films used in synchrotron accelerators cannot have gas molecules adsorbed on the surface and should be deposited on the internal surface of the chamber, making it a vacuum pump. Usually these materials are constituted by elements of great reactivity and solubility (such as Ti, Zr, and V) at room temperature, for oxygen and other gases typically found in UHV (H2, CO, and CO2), besides having considerable diffusibility at low temperature (< 700 K), the so-called activation temperature. The objective of this work is to prepare and evaluate films of TiZrV alloy and Au produced by magnetron sputtering. The film structure, morphology, and aging have been characterized in order to know how much of the gas absorption property at low temperature can be attributed to the chemical reactivity of the elements and to the structure formed by the deposition process. The morphological, structural, and chemical characterization was carried out by atomic force microscopy (AFM), high-resolution scanning electron microscopy (FEG-SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and photon stimulated desorption (PSD). The produced materials were compared with commercial TiZrV samples, and this comparison made clear that the desired characteristics are related to the nanometric structure of the films and that the structure is clearly sensitive to the heating treatments.
Acknowledgements: we would like to thank Vinicius L. Pimentel and Roosevel Droppa Jr. for their assistance on some of the experiments.