[15p-419-1~8] Recent Progress and Future Perspective on Vacuum Technology for Accelerator and Space Sciences

[15p-419-8] Application of NEG-coating Technology in New Generation Light Sources

〇Yasunori Tanimoto¹ (1.KEK)

Keywords:non-evaporable getter coating, synchrotron radiation, photon stimulated desorption

In new-generation high-brightness light sources, it has been getting difficult to achieve an ultrahigh vacuum of 10^–8 Pa under which the electron beams can be sufficiently long-stored. This is mainly because the beam ducts in such low-emittance rings have to be restrained to have an inner aperture of 25 mm or less and outgassing by the Photon Stimulated Desorption (PSD) cannot be effectively pumped out. One of the most promising ways to cope with this problem is the so-called NEG coatings developed at CERN, in which the Non-Evaporable Getter (NEG) materials of TiZrV are deposited on the inner surface of the beam ducts. Once the NEG coatings are activated by heating at 180–250 ^oC, the thin film can provide high sticking probabilities (e.g. 0.03 for H₂ and 0.6 for CO), as well as a low PSD yield of 2×10^–6 molecules/photon at an accumulated photo dose of 1×10²² photons/m. With the aim of applying NEG coatings to the proposed KEK-LS project, we have been studying the vacuum properties of NEG coatings at KEK with the collaboration of CERN.