Multi-Chamber TiZrV Coating in OFS Copper Vacuum Chamber for HALF

NEG coating is a competitive candidate to achieve ultra-high vacuum in narrow gap vacuum chambers, which is very important for diffraction-limited storage ring. To get enough NEG coated chambers in schedule for HALF, a multi-chamber coating system was employed, and some multi-coating research was performed based on previous work. The NEG film was characterized and analyzed by scanning electron microscopy, atomic force microscopy, and energy dispersive X-ray energy spectroscopy, and the activation characteristics of NEG films were analyzed by X-ray photoelectron spectroscopy. The results show that the surface morphology, cross-sectional morphology, surface roughness, and composition of the film coated by different chambers are about the same. After activation at 180°C for 2 h, the high oxidation state of the surface metal was transferred to a low oxidation state or metallic state, which is similar to that of the previous single-chamber coating. Three NEG coated chambers were equipped with SIP to simulate work status, and after activation at 180°C for 24 h, the pressure at the end of chambers was 4.13×10⁻⁸ Pa, which reached 3.74×10⁻⁸ Pa after about 260 h, which would benefit future HALF vacuum system.