Strategy of Development of Beamline Optics for SPring-8-II

Abstract The SPring-8 facility is scheduled for an upgrade to SPring-8-II in FY2028, transforming it into the fourth-generation synchrotron radiation source based on a multi-bend achromat design. This upgrade will deliver enhanced beam performance, characterized by a significant increase in coherent flux and a reduction in partial power to approximately one-third of that in SPring-8. To support these advancements, compact in-vacuum undulators will replace the existing insertion devices, ensuring compatibility with the upgraded lattice while preserving the current energy range. To fully exploit these improvements, the development of X-ray optics with exceptional thermal and mechanical stability is critical. Building on the success of key components at SPring-8, such as cryogenically cooled double-crystal monochromators and Kirkpatrick-Baez focusing mirrors, we are developing next-generation optical systems specifically designed for SPring-8-II. These include channel-cut monochromators and monolithic Wolter mirrors, engineered to provide ultimate stability and meet the stringent demands of the upgraded light source. This integrated effort is crucial to achieving the advanced beamline performance required for the next-generation synchrotron radiation facility.