US accelerator projects: Lab reports

28 September 2021

• Earlier this summer, the Advanced Light Source (ALS), a synchrotron user facility at the US Department of Energy’s (DOE) Lawrence Berkeley National Laboratory, received federal approval (known as Critical Decision 2) for the $590 million budget, schedule and technical scope of a major upgrade project (ALS-U) that will boost the brightness of its X-ray beams at least a hundredfold. In addition to the replacement of the existing electron storage ring, the upgrade involves construction of two new beamlines to take full advantage of ALS-U’s enhanced beam properties. The project will also provide for the realignment of existing beamlines and a seismic and shielding upgrade of the storage-ring tunnel. A key challenge with ALS-U is the construction of a second concentric ring, called an accumulator, inside the already-cramped concrete tunnels that house the storage ring. This unique feature enables a technique called on-axis, swap-out injection, which allows the electron beam to be injected into the storage ring with minimal perturbation.

Fast-corrector magnet

• While construction work for the $815 million upgrade of Argonne National Laboratory’s Advanced Photon Source (APS) is already well under way, the replacement of the facility’s existing electron storage ring – which will require a year-long shutdown of the APS experimental programme – is now scheduled to kick off in April 2023. That represents a 10-month delay versus the original planned refit owing to the operational impacts of the COVID-19 pandemic. The upgrade of the APS, a national synchrotron research facility funded by the US DOE, will reduce electron beam emittance by a factor of 70 from its present value which, together with a doubling of stored beam current and the introduction of high-performance insertion devices (some superconducting), will yield X-ray beams two to three orders of magnitude brighter than the current machine. Delaying the shutdown for the storage-ring upgrade will allow the APS to continue operating for all three experimental runs in 2022.

• The US DOE’s Brookhaven National Laboratory (BNL) has named Wolfram Fischer as chair of its Collider–Accelerator Department (C-AD). C-AD develops, improves and operates BNL’s suite of particle and heavy-ion accelerators – including the Relativistic Heavy Ion Collider (RHIC) and Alternating Gradient Synchrotron (AGS) – and will also play a key role in supporting the upcoming construction of the Electron-Ion Collider (see Partnership yields big wins for the EIC). Fischer previously served as accelerator division head in C-AD.

bright-rec iop pub iop-science physcis connect