The Advanced Photon Source (APS) continues developing novel SCUs, several of which have operated for a decade, delivering high-brightness, hard X-ray beams for scientific research. As part of the APS Upgrade, eight new NbTi SCUs were planned. While cryogenic and support systems were in place, challenges in scaling magnet lengths and reducing periods led to magnet failures and fabrication delays. The APS SCU team launched an R&D program to refine designs and materials, with two SCUs expected to be installed by late 2025 and six more to follow. Before the APS Upgrade, a novel Nb₃Sn SCU deployed and operated successfully for three months, validating its predicted performance. Building on this, the APS SCU team is developing a 14 mm period Nb₃Sn SCU with cryogen-free, conduction-cooled magnets and a thin-wall vacuum chamber, enhancing the field and simplifying cryogenics. Looking further ahead, the team is exploring implementation of high temperature superconductors for lower period undulators (~10 mm) to achieve unprecedented field strengths. This presentation will provide an overview of the APS SCU program, the challenges addressed, and ongoing efforts to advance SCU technology.

The 1st article NbTi SCU consists of two 1.5 m-long superconducting undulators (SCU) installed in a single cryostat that will occupy an entire straight section in the upgraded storage ring at the Advanced Photon Source. Installation is planned during the winter shutdown of 2025/2026. The initial design of the magnets proved to be difficult to successfully implement and a new design was pursued to resolve the issues that were identified. Manufacturing of the updated magnet design is scheduled to be completed in early 2025 after which the magnets will be tested in a vertical bath cryostat followed by installation into the production cryostat. A description of the magnet design modifications along with test results from the bath cryostat will be provided.