Engineering topics

Larrieu, T.

Publications and source records attributed to Larrieu, T..

4 records

DOE OSTI2024

The Continuous Electron Beam Accelerator Facility at 12 GeV

This review paper describes the energy-upgraded Continuous Electron Beam Accelerator Facility (CEBAF) accelerator. This superconducting linac has achieved 12 GeV beam energy by adding 11 new high-performance cryomodules containing 88 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 the beam delivered to each of the experimental halls are summarized in the Appendix. Published by the American Physical Society 2024

43 PARTICLE ACCELERATORS↗

DOE OSTI2024

Graph Analytics for CEBAF Operations

We report on the progress achieved during a 2-year Laboratory Directed Research and Development (LDRD) project titled “Graph Analytics for CEBAF Operations”. The objective of this project is to leverage deep learning on graph representations of CEBAF’s injector beamline in order to create a tool for improving the efficiency of beam tuning tasks. Specifically, we use graphs to represent the injector beamline at any arbitrary date and time and invoke a graph neural network (GNN) to extract a low-dimensional, informative representation that can be visualized in two-dimensions. By analyzing years of operational data from the CEBAF archiver, good and bad regions of parameter space can be identified. The goal is to exercise this framework as a real-time tool to aid beam tuning, which represents the dominant source of machine downtime.

43 PARTICLE ACCELERATORS↗

DOE OSTI2016

Design and Evaluation of joint resistance in SSC Rutherford type cable splices for Torus magnet for the Jefferson Lab 12 GeV Upgrade

The Hall B 3.6-T superconducting torus magnet is being designed and built as part of the Jefferson Lab 12-GeV upgrade. The magnet consists of six trapezoidal coils connected in series, with an operating current of 3770 A. The magnet and the joints (or splices) connecting the coils are all conduction cooled by supercritical 4.6-K helium. This paper studies the design and manufacturing process of the splices made between two SSC Rutherford-type cables and discusses the tests performed to evaluate the performance of the splices under varying incident magnetic fields.

Ghoshal, Probir K.↗

DOE OSTI2015

The Role of the CEBAF Element Database in Commissioning the 12GeV Accelerator Upgrade

The CEBAF Element Database (CED) was first developed in 2010 as a resource to support model-driven configuration of the Jefferson Lab Continuous Electron Beam Accelerator (CEBAF). Since that time, its uniquely flexible schema design, robust programming interface, and support for multiple concurrent versions has permitted it to evolve into a more broadly useful operational and control system tool. The CED played a critical role before and during the 2013 startup and commissioning of CEBAF following its 18-month long shutdown and upgrade. Information in the CED about hardware components and their relations to one-another facilitated a thorough Hot Checkout process involving more than 18,000 system checks. New software relies on the CED to generate EDM screens for operators on-demand thereby ensuring that the information on those screens is correct and up-to-date. The CED also continues to fulfill its original mission of supporting model-driven accelerator setup. Using the new ced2elegant and eDT (elegant Download Tool), accelerator physicists have proven able to compute and apply energy-dependant set points with greater efficiency than ever before.

Larrieu, T.↗