| Paper | Title | Page |
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| MOPAB138 | Dielectric Wakefield Acceleration with a Laser Injected Witness Beam | 481 |
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Funding: Work supported by DOE grant DE-SC0017690 The plasma photocathode concept, whereby a two-species gas mixture is used to generate a beam -driven accelerating wakefield and a laser-ionized generation of a witness beam, was recently experimentally demonstrated. In a variation of this concept, a beam-driven dielectric wakefield accelerator is employed, filled with a neutral gas for laser-ionization and creation of a witness beam. The dielectric wakefields, in the terahertz regime, provide comparatively modest timing requirements for the injection phase of the witness beam. In this paper, we provide an update on the progress of the experimental realization of the hybrid dielectric wakefield accelerator with laser injected witness beam at the Argonne Wakefield Accelerator (AWA), including engineering considerations for gas delivery, and preliminary simulations. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB138 | |
| About • | paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 31 August 2021 | |
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| MOPAB140 | Gas Sheet Ionization Diagnostic for High Intensity Electron Beams | 489 |
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Funding: Work supported by DOE grant DE-SC0019717 The characterization of high intensity charged particle beams in a minimally interceptive, and non-destructive manner is performed using an ionization diagnostic. In this application, a neutral gas is tailored into a thin sheet, or curtain-like, distribution at the interaction point with an electron beam. The electron beam ionizes the neutral gas in localized space, leaving a footprint of the beam transverse distribution. The ion cloud is subseqeuntly imaged with a series of electrostatic lenses to a detector plane. The resultant image is used in a reconstruction algorithm to reconstruct the beam profile at the interaction point. In this paper, we present progress on the development of this diagnostic for the characterization of high charge, 10GeV electron beams with small transverse distributions. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB140 | |
| About • | paper received ※ 20 May 2021 paper accepted ※ 10 June 2021 issue date ※ 01 September 2021 | |
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| TUPAB153 | Modeling of Capillary Discharge Plasmas for Wakefield Accelerators and Beam Transport | 1740 |
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Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award Number DE-SC0018719. Next generation accelerators demand sophisticated beam sources to reach ultra-low emittances at large accelerating gradients, along with improved optics to transport these beams without degradation. Capillary discharge plasmas can address each of these challenges. As sources, capillaries have been shown to increase the energy and quality of wakefield accelerators, and as active plasma lenses they provide orders-of-magnitude increases in peak magnetic field. Capillaries are sensitive to energy deposition, heat transfer, ionization dynamics, and magnetic field penetration; therefore, capillary design requires careful modeling. We present simulations of capillary discharge plasmas using FLASH, a publicly-available multi-physics code developed at the University of Chicago. We report on the implementation of 2D and 3D models of capillary plasma density and temperature evolution with realistic boundary and discharge conditions. We then demonstrate laser energy deposition to model channel formation for guiding intense laser pulses. Lastly, we examine active capillary plasmas with varying fill species and compare our simulations against experimental studies. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB153 | |
| About • | paper received ※ 24 May 2021 paper accepted ※ 29 July 2021 issue date ※ 30 August 2021 | |
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| WEXC04 | Simulations of Beam Strikes on Advanced Photon Source Upgrade Collimators using FLASH, MARS, and elegant | 2562 |
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Funding: Work supported by the U.S. D.O.E.,Office of Science, Office of Basic Energy Sciences, under contract number DE-AC02- 06CH11357. Modeling of high-energy-density electron beams on collimators proposed for the Advanced Photon Source Upgrade (APS-U) storage ring (SR) is carried out with codes FLASH, MARS, and elegant. Code results are compared with experimental data from two separate beam dump studies conducted in the present APS SR. Whole beam dumps of the 6-GeV, 200 mA, ultra-low emittance beam will deposit acute doses of 30 MGy within 10 to 20 microseconds, leading to hydrodynamic behavior in the collimator material. Goals for coupling the codes include accurate modeling of the hydrodynamic behavior, methods to mitigate damage, and understanding the effects of the resulting shower downstream of the collimator. Relevant experiments, though valuable, are difficult and expensive to conduct. The coupled codes will provide a method to model differing geometries, materials, and loss scenarios. Efforts thus far have been directed toward using FLASH to reproduce observed damage seen in aluminum test pieces subjected to varying beam strike currents. Stabilizing the Eulerian mesh against large energy density gradients as well as establishing release criteria from solid to fluid forms are discussed. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEXC04 | |
| About • | paper received ※ 19 May 2021 paper accepted ※ 23 July 2021 issue date ※ 30 August 2021 | |
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