Speaker
Description
SPring-8-II, a major upgrade of the third generation light source SPring-8, aims to achieve low emittance below 100 pm·rad and to reduce the power consumption of the light source machine. High magnetic field magnets for SPring-8-II naturally result in narrow bore diameters and are densely distributed. As a result, vacuum chambers along the entire storage ring are designed with narrow apertures, leading to low conductance, and space for vacuum equipment such as photon absorbers and vacuum pumps is limited. To meet these requirements, we employ small-diameter stainless steel chambers and discrete compact photon absorbers*. Non-Evaporable Getter (NEG) pumps are placed near photon absorbers to effectively evacuate photon stimulated desorption (PSD) gas. We simulated a pressure distribution within a SPring-8-II unit cell as a function of beam dose considering the degradation of a pumping speed of the NEG pump due to gas absorption. On the basis of these results, we evaluated the beam lifetime and formulated a commissioning strategy for increasing a stored current through systematic vacuum conditioning.
Footnotes
- K. Tamura et al., "Verification of SPring-8-II vacuum system prototype chamber", MEDSI2025 THP59 (2025).
| Paper status | Proceeding files received |
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