| Paper | Title | Page |
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| MOPAB216 | 20-24 GeV FFA CEBAF Energy Upgrade | 715 |
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Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177 A proposal was formulated to increase the CEBAF energy from the present 12 GeV to 20-24 GeV by replacing the highest-energy arcs with Fixed Field Alternating Gradient (FFA) arcs. The new pair of arcs would provide six or seven new beam passes, going through this magnet array, allowing the energy to be nearly doubled using the existing CEBAF SRF cavity system. One of the immediate accelerator design tasks is to develop a proof-of-principle FFA arc magnet lattice that would support simultaneous transport of 6-7 passes with energies spanning a factor of two. We also examine the possibility of using combined function magnets to configure a cascade, six-way beam split switchyard. Finally, a novel multi-pass linac optics based on a weakly focusing lattice is being explored. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB216 | |
| About • | paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 29 August 2021 | |
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| TUPAB079 | Using ER@CEBAF to Show that a Multipass ERL Can Drive an XFEL | 1555 |
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| A multi-pass recirculating superconducting CW linac offers a cost effective path to a multi-user facility with unprecedented scientific and industrial reach over a wide range of disciplines. We propose such a facility as an option for a potential UK-XFEL. Energy Recovery enables multi-MHz FEL sources, for example, an X-ray FEL oscillator or regenerative amplifier FEL. Additionally, combining with external lasers and/or self-interaction would provide access to MeV and GeV gamma-rays via inverse Compton scattering at high average power for nuclear and particle physics applications. An opportunity exists to demonstrate the necessary point-to-parallel longitudinal matches to drive an XFEL and successfully energy recover at the upcoming 5-pass up, 5-pass down Energy Recovery experiment on CEBAF at JLab termed ER@CEBAF. We show candidate matches and simulations supporting the minimal necessary modifications to CEBAF this will require. This includes linearisation of the longitudinal phase space in the injector and a reduction in the dispersion of the arcs, both of which increase the energy acceptance of CEBAF. We expect to commence initial tests of these adaptations on CEBAF during 2021. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB079 | |
| About • | paper received ※ 17 May 2021 paper accepted ※ 27 July 2021 issue date ※ 17 August 2021 | |
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| WEPAB001 | Accelerator Challenges of the LHeC Project | 2570 |
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| The LHeC project studies the design of a future electron-proton collider at CERN that will run in parallel to the standard LHC operation. For this purpose, the existing LHC storage ring will be combined with an Energy Recovery Linac (ERL), to accelerate electrons up to kinetic energy of 50 GeV. This concept - also applicable to the FCC-eh collider and studied at the PERLE project as prototype version - allows a peak luminosity of 1034 cm-2 s-1. A sophisticated design of the RF structures, linacs, arcs, and interaction region is required. The electrons are accelerated and, after the interaction point, their energy is recovered through the same RF structures. While this energy recovery concept is a very promising approach, severe challenges are set by the layout of the interaction region, the beam separation concept and the design of the linac and arc lattice for the highest possible momentum acceptance. Emittance control and beam-beam effect of both, electron and proton beams, have been studied in front-to-end simulations and will be presented. We summarise the design principles of the ERL, the optimization of the arc lattice, and the main parameters of the project. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB001 | |
| About • | paper received ※ 17 May 2021 paper accepted ※ 21 June 2021 issue date ※ 21 August 2021 | |
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| WEPAB065 | Studies of the Energy Recovery Performance of the PERLE Project | 2744 |
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| The Powerful Energy Recovery Linac for Experiments (PERLE) is an accelerator facility for the development and application of the energy recovery technique for an intense 500 MeV electron beam. The paper presents the studies that have been performed to assess the quality of the ERL lattice design and beam optics. The studies include the Coherent Synchrotron Radiation (CSR) emission and wakefields in the superconducting radio-frequency structures of the linacs. The lattice design and optics principles of the ERL structure are discussed, involving the vertical deflection system and the 180° arcs. Finally, the results of the front-to-end tracking simulations that consider the complete multi-turn energy recovery process are presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB065 | |
| About • | paper received ※ 18 May 2021 paper accepted ※ 24 June 2021 issue date ※ 30 August 2021 | |
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| WEPAB383 | An Evolutionary Algorithm Approach to Multi-Pass ERL Optics Design | 3610 |
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Funding: This material is based upon work supported by the U.S. Department of Energy under contract DE-AC05-06OR23177. An Energy Recovery Experiment at CEBAF (ER@CEBAF) is aimed at demonstrating high energy, low current, multi-pass energy recovery at the existing 12 GeV CEBAF accelerator. The beam break-up instability, limiting the maximum beam current, can be controlled through minimizing beta functions for the lowest energy pass, which gives a preference to strongly focusing optics, e.g. a semi-periodic FODO lattice. On the other hand, one needs to limit beta function excursions, caused by under focusing, at the higher energy passes, which in turn favors weakly focusing linac optics. Balancing both effects is the main objective of proposed multi-pass linac optics optimization. Here, we discuss an optics design process for ER@CEBAF transverse optics using a genetic algorithm. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB383 | |
| About • | paper received ※ 19 May 2021 paper accepted ※ 02 July 2021 issue date ※ 15 August 2021 | |
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| THPAB106 | Optimization of a High Bunch Charge ERL Injection Merger for PERLE | 3983 |
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| Delivery of high charge electron bunches into the main loop of an ERL (energy recovery linac) while preserving the emittance is challenging. This is because at the typical injection momentum, space charge forces still have a significant effect on the beam dynamics. In this work we consider the design of the merger for PERLE, an ERL test facility to be based at IJCLab in France. Previous simulations have shown that the baseline DC gun based injector can achieve the required emittance at the booster linac exit. The quality of the 500 pC bunches must then be preserved with space charge through the merger at total beam energy of 7 MeV keeping the emittance below 6 mm mrad. The beam dynamics in the merger were simulated using the code OPAL and optimised using a genetic algorithm. Three possible merger schemes were investigated. The goal of the optimisation was to minimise the emittance growth while also achieving the required Twiss parameters to match onto the spreader at the main linac exit. A three dipole solution is then examined in more detail. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB106 | |
| About • | paper received ※ 19 May 2021 paper accepted ※ 16 July 2021 issue date ※ 12 August 2021 | |
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