WP6 – Advanced RF Technologies
Adolfo Velez Saiz
“Our work package is important because it develops key enabling technologies, such as advanced HTS magnet systems, fast reactive tuning solutions, and efficient RF sources. These can improve the performance, efficiency, and flexibility of next-generation particle accelerators.
We are aiming to have integrated technologies for improved accelerator operation, including high-field HTS-based components and rapid beam loading compensation strategies that enhance RF stability and accelerator performance.”
WP6 will develop magnetrons and ferroelectric fast reactive tuners (FE-FRTs) for sustainable accelerator applications, alongside high-temperature superconducting (HTS) wide tapes for high-gradient accelerator RF systems. The detailed objectives are to design and construct improved magnetrons and test them with developed novel control techniques; develop FE-FRTs to mitigate transient beam loading at high repetition rates; and scale up HTS tapes width beyond 48 mm to support larger RF devices and enable operation in the S-band frequency regime.
This work package includes three tasks.
Task 6.1: Locked Magnetron Sources for SRF Systems
Magnetrons, compact and cost-effective microwave sources, are a promising alternative to solid-state amplifiers (SSAs) and klystrons for efficient, low-cost RF power delivery, particularly in systems requiring multiple RF sources, such as linacs. This task will design, construct and test a 1.3 GHz magnetron prototype optimised for high efficiency and power, focusing on efficiency, phase stability, and compatibility with modern accelerator architectures. QMUL will design the cathode, while Tekniker will focus on anode design and fabrication. UPV/EHU will develop phase-locking techniques to enable cost-effective amplitude and phase noise stabilisation. HZB will conduct prototype testing with SRF cavities, supported by UPV/EHU for low-level RF (LLRF) implementation.
Task 6.2: FE-FRT Ultra High Rep-Rate Frequency Shifting Applications
The high repetition rate (1.25 MHz) needed for beam loading compensation in 4th generation light sources like BESSY III at HZB, crucial for boosting beam lifetime and physics output per dissipated Watt, requires the development of novel FE-FRTs and ultra-high repetition rate pulsers. HZB will lead the design, construction, and testing of FE-FRTs, while VITAVE will focus on pulser design, applying their expertise to optimise rep-rate and rise times at the voltage and load capacitance required by the FE-FRT. Continuous feedback between HZB’s RF design and test results and VITAVE’s pulser development will enable iterative improvements.
Task 6.3: High-Temperature Superconductors for High-Gradient RF
CSIC-ICMAB will evaluate the RF performance of large HTS tapes (>48 mm in width and targeting sizes up to 100 mm), starting at low RF power (8 GHz), with the goal of extending both the frequency range and the applied power, also in presence of external magnetic fields. They will also provide soldering of tapes onto appropriate substrates for all subsequent testing. UU will characterise the field-emission properties of HTS tapes at low temperature, along with their field-holding capabilities and breakdown resistance. In parallel, CERN will test HTS samples at 3 GHz using in-house RF setup and, together with SLAC, will design an S-band RF structure tailored for HTS tape coating without joints across tapes, overcoming current state-of-the-art limitations. The external partner SLAC will also carry out cryogenic high-power testing of samples and devices at X- and S-band frequencies, possibly with an applied external magnetic field.