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J. Delayen

Publications and source records attributed to J. Delayen.

5 recordsLinked to original sources
arXiv2024

The Continuous Electron Beam Accelerator Facility at 12 GeV

This review paper describes the energy-upgraded CEBAF accelerator. This superconducting linac has achieved 12 GeV beam energy by adding 11 new high-performance cryomodules containing eighty-eight superconducting cavities that have operated CW at an average accelerating gradient of 20 MV/m. After reviewing the attributes and performance of the previous 6 GeV CEBAF accelerator, we discuss the upgraded CEBAF accelerator system in detail with particular attention paid to the new beam acceleration systems. In addition to doubling the acceleration in each linac, the upgrade included improving the beam recirculation magnets, adding more helium cooling capacity to allow the newly installed modules to run cold, adding a new experimental hall, and improving numerous other accelerator components. We review several of the techniques deployed to operate and analyze the accelerator performance, and document system operating experience and performance. In the final portion of the document, we present much of the current planning regarding projects to improve accelerator performance and enhance operating margins, and our plans for ensuring CEBAF operates reliably into the future. For the benefit of potential users of CEBAF, the performance and quality measures for beam delivered to each of the experimental halls is summarized in the appendix.

physics.acc-ph↗
arXiv2023

Development and Performance of RFD Crab Cavity Prototypes for HL-LHC AUP

The US will be contributing to the HL-LHC upgrade at CERN with the fabrication and qualification of RFD crabbing cavities in the framework of the HL-LHC Accelerator Upgrade Project (AUP) managed by Fermilab. AUP received Critical Decision 3 (CD-3) approval by DOE in December 2020 launching the project into the production phase. The electro-magnetic design of the cavity was inherited from the LHC Accelerator Research Program (LARP) but needed to be revised to meet new project requirements and to prevent issues encountered during beam tests performed at CERN in the R&D phase. Two prototype cavities were manufactured in industry and cold tested. Challenges specific to the RFD cavity were the stringent interface tolerances, the pole symmetry, and the higher-order-mode impedance spectrum. Chemical processing and heat treatments were performed initially at FNAL/ANL and are now being transferred to industry for the production phase. HOM dampers are manufactured and validated by JLAB. A summary of cold test results with and without HOM dampers is presented.

physics.acc-ph↗
arXiv2022

Key directions for research and development of superconducting radio frequency cavities

Radio frequency superconductivity is a cornerstone technology for many future HEP particle accelerators and experiments from colliders to proton drivers for neutrino facilities to searches for dark matter. While the performance of superconducting RF (SRF) cavities has improved significantly over the last decades, and the SRF technology has enabled new applications, the proposed HEP facilities and experiments pose new challenges. To address these challenges, the field continues to generate new ideas and there seems to be a vast room for improvements. In this paper we discuss the key research directions that are aligned with and address the future HEP needs.

physics.acc-ph↗
arXiv2022

Next-Generation Superconducting RF Technology based on Advanced Thin Film Technologies and Innovative Materials for Accelerator Enhanced Performance and Energy Reach

Superconducting RF is a key technology for future particle accelerators, now relying on advanced surfaces beyond bulk Nb for a leap in performance and efficiency. The SRF thin film strategy aims at transforming the current SRF technology by using highly functional materials, addressing all the necessary functions. The community is deploying efforts in three research thrusts to develop next-generation thin-film based cavities. Nb on Cu cavities are developed to perform as good as or better than bulk Nb at reduced cost and with better thermal stability. Recent results showing improved accelerating field and dramatically reduced Q slope show their potential for many applications. The second research thrust is to develop cavities coated with materials that can operate at higher temperatures or sustain higher fields. Proof of principle has been established for the merit of Nb3Sn for SRF application. Research is now needed to further exploit the material and reach its full potential with novel deposition techniques. The third line of research is to push SRF performance beyond the capabilities of the superconductors alone with multilayered coatings. In parallel, developments are needed to provide quality substrates, cooling schemes and cryomodule design tailored to thin film cavities. Recent results in these three research thrusts suggest that SRF thin film technologies are at the eve of a technological revolution. For them to mature, active community support and sustained funding are needed to address fundamental developments supporting material deposition techniques, surface and RF research, technical challenges associated with scaling and industrialization. With dedicated and sustained investment, next-generation thin-film based cavities will become a reality with high performance and efficiency, facilitating energy sustainable science while enabling higher luminosity, and higher energy.

physics.acc-ph↗