ALBA is working on the upgrade project that shall transform the actual storage ring, in operation since 2012, into a 4th generation light source, in which the soft X-rays part of the spectrum shall be diffraction limited. The project was launched in 2021 with an R&D budget to build prototypes of the more critical components. The storage ring upgrade is based on a MBA lattice which has to comply with several constraints imposed by the decision of maintaining the same circumference (269m), the same number of cells (16), the same beam energy (3GeV), and as many of the source points as possible unperturbed. At present, the lattice optimization, iterating with the technical constraints of space and performance, is ongoing. This paper presents the situation of the project, with the present proposed lattice and equipment design; the status of the prototyping of magnets, pulsed elements. vacuum chambers, buttons BPMs, and girders; the proposed RF system with fundamental and harmonics cavities; and the general context of the upgrade.

ALBA is a 3rd generation synchrotron light source located in Barcelona, Spain. The circumference is 268.8 meters and electrons are stored at 3 GeV. In the framework of the upgrade towards the 4th generation light source ALBA II, an active 3rd harmonic RF system at 1.5 GHz is foreseen to increase the Touschek lifetime component. The system will be installed and available for operation in the current machine, which will allow to gather experience before the upgrade. Four normal conducting HOM damped harmonic cavities will be placed in the storage ring, each of it including a complete WR650 waveguide system with circulator and load, a 20 kW high power SSPA amplifier and a Low Level RF control system. We are presenting in this contribution the complete design of the active harmonic RF system for ALBA and the expected performance during operation.

ALBA Low-Level RF (LLRF) system has provided over a decade of reliable operation and has been adopted by other synchrotron facilities. To meet the evolving requirements of ALBA and ALBA-II, a new LLRF system has been developed. This system features FPGA and ADC/DAC MTCA boards designed by SAFRAN, enabling direct 500 MHz signal sampling without down/up-conversion. These enhancements reduce system complexity, minimize noise, and simplify maintenance. SAFRAN also supplies peripheral modules and the Tango device server generator, while ALBA implemented it and developed a new GUI. Upgraded GPIO and RF signal patch panels complement the new hardware. The legacy VHDL code has been updated to improve readability and functionality, incorporating advanced features such as octant selection and a harmonic direct feedback selection method. The latter, based on IIR filtering, isolates positive and negative revolution harmonics in the I/Q domain, feeding them back to amplifiers to effectively mitigate transient beam loading caused by the storage ring bunch train gaps. This upgraded LLRF system delivers enhanced performance and greater flexibility to address the future needs of ALBA and ALBA-II.