Engineering Excellence for LBNL ALS-U: Dipole Chambers manufacturing
At SAES RIAL VACUUM, precision meets innovation.
SAES RIAL VACUUM’s contribution to the ALS-U project at Lawrence Berkeley National Laboratory (LBNL) represents the successful accomplishment of a challenging project.
Each dipole chamber for the Advanced Light Source Upgrade (ALS-U) – a project designed to push the boundaries of synchrotron research by delivering brighter, more coherent beams for the scientific community – required an novel approach to design integrity, surface quality, and dimensional precision.
Through collaboration, SAES RIAL VACUUM and SAES High Vacuum strengthen their role as trusted partners in enabling cutting-edge research around the world.
Watch the video to explore the main steps of the manufacturing process
01. Material procurement
For the LBNL dipole chambers, high-purity Cu alloys were procured to ensure excellent mechanical strength and minimal vacuum outgassing.
All materials underwent chemical and mechanical certification, guaranteeing traceability and compliance with the demanding requirements of accelerator technology.
02. Hydroforming
The chambers were shaped through hydroforming, a process that uses high-pressure fluid to form complex geometries from raw tubes.
This technique allows for a complex geometry, uniform wall thickness, and a superior surface finish — all critical parameters for maintaining UHV (Ultra-High Vacuum) conditions inside the chamber.
Achieving the exact curvature and dimensional tolerance along the entire tube length while avoiding micro-deformations that could compromise vacuum sealing was the main challenge.
03. Electron Beam Welding (EBW)
Once formed, the components were joined using electron beam welding.
This process, performed in vacuum, allows for deep, narrow, and contamination-free welds, essential for vacuum components that require a precise and clean inner-surface finish with leak-tight welds.
Maintaining alignment of component parts and controlling thermal distortion during welding, given the sub-millimeter dimensional precision required, was fundamental in this step.
04. Dimensional inspection with ZEISS technology
After welding, each chamber underwent 3D metrological inspection using ZEISS coordinate measuring machines (CMM).
This step ensured that every geometric parameter — from curvature to flange alignment — matched the strict design specifications required for ALS-U.
05. Ultrasonic cleaning
Cleanliness is fundamental to vacuum performance.
Each chamber was ultrasonically cleaned in a multi-stage process using controlled etchants, deionized water and alcaline detergents.
This procedure removes all particulate matter and hydrocarbon residues, and most importantly prepares internal surfaces for the final coating.
06. NEG Coating (Non Evaporable Getter)
NEG Coating is the final step of the manufacturing process of the ALS-U Dipole Chambers.
It consists of the deposition of a thin film of a Non Evaporable Getter material that, once activated, continuously absorbs residual gases inside the vacuum chamber, dramatically reducing at the same time PSD (Photon Stimulated Desorption) and ESD (Electron Stimulated Desorption).
This technology, mastered by SAES High Vacuum for more than 20 years, significantly improves long-term vacuum stability and beam reliability, and is an enabling technology for multibend achromat synchrotron light sources.
