| Paper | Title | Page |
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| WEEPPB010 | RF Modeling Using Parallel Codes ACE3P for the 400-MHz Parallel-Bar/Ridged-Waveguide Compact Crab Cavity for the LHC HiLumi Upgrade | 2185 |
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Funding: Work partially supported by the US DOE through the US LHC Accelerator Research Program (LARP), and by US DOE under contract number DE-AC02-76SF00515. Schemes utilizing crab cavities to achieve head-on beam-beam collisions were proposed for the LHC HiLumi upgrade. These crabbing schemes require that the crab cavities be compact in order to fit into the tight spacing available in the existing LHC beamlines at the location where the crab cavities will be installed. Under the support of US LARP program, Old Dominion University and SLAC have joint efforts to develop a 400-MHz compact superconducting crab cavity to meet the HiLumi upgrade requirements. In this paper, we will present the RF modeling and analysis of a parallel-bar/ridged-waveguide shaped 400-MHz compact cavity design that can be used for both the horizontal and vertical crabbing schemes. We will also present schemes for HOM damping and multipacting analysis for such a design. |
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| WEPPC084 | Development of a Superconducting 500 MHz Multi-Spoke Cavity for Electron Linacs | 2408 |
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Funding: This work is supported by the US Department of Energy SBIR/STTR program through the Office of Nuclear Physics. Multi-spoke cavities are well-known options for acceleration of heavy and light ions. A recently developed multi-spoke cavity for β=1 presents an attractive opportunity to use this cavity type for electron accelerators. One of the main attractive features of this cavity type is its compactness for relatively low frequency. A simplified design at 500 MHz allowed building of a multi-spoke cavity and cryomodule in a 2-year time frame with confidence and development of effective manufacturing techniques. It also constitutes an important step in proving the usefulness of this kind of cavity design for new applications in the electron machines. Niowave is now in a position to build on the success of this cavity to help advance the design of superconducting electron accelerators. Accelerating voltage of more then 4.3 MV in a single cavity at 4.5 K is expected with peak electric field of less then 21.7 MV/m, and peak magnetic field of less then 80 mT. The paper discusses the fabrication challenges of the complete cavity and the cryomodule, as well as room temperature and cryogenic test results. |
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| WEPPC085 | Engineering of a Superconducting 400 MHz Crabbing Cavity for the LHC HiLumi Upgrade | 2411 |
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Funding: This work is supported by the US DOE-HEP SBIR/STTR program and the US DOE through the US LHC Accelerator Research Program (LARP). The recently developed new simplified design for the 400 MHz LHC crabbing cavity presents attractive properties compared to conventional designs. The proposed approach can be equally compact in both transverse dimensions and allows horizontal as well as vertical deflection of the beam in the collider. The significant modification of the parallel-bar design with the bars merged to the side walls of the cavity gives improved properties, such as better mode separation and reduced surface fields*. A transverse deflecting voltage of 3 to 5 MV in a single cavity can be expected with the peak surface electric field lower then 50 MV/m and peak magnetic field below 100 mT. This paper presents engineering issues of the proof-of-concept crabbing cavity design and discusses the manufacturing techniques. The paper discusses present status of the project including fabrication of the niobium cavity, as well as room temperature and cryogenic testing. * J.R. Delayen, S.U. De Silva, "Design of Superconducting Parallel-Bar Deflecting/Crabbing Cavities with Improved Properties," Proc. of 2011 PAC, New York, NY, USA, 2011, p. 1021. |
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| WEPPC100 | Design of Electron and Ion Crabbing Cavities for an Electron-Ion Collider | 2447 |
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| Beyond the 12 GeV upgrade at the Jefferson Lab a Medium Energy Electron-Ion Collider (MEIC) has been considered. In order to achieve the desired high luminosities at the Interaction Points (IP), the use of crabbing cavities is under study. In this work, we will present to-date designs of superconducting cavities, considered for crabbing both ion and electron bunches. A discussion of properties such as peak surface fields and higher-order mode separation will be presented. | ||
| WEPPC101 | Characteristics and Fabrication of a 499 MHz Superconducting Deflecting Cavity for the Jefferson Lab 12 GeV Upgrade | 2450 |
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| A 499 MHz parallel bar superconducting deflecting cavity has been designed and optimized for a possible implementation at the Jefferson Lab 12 GeV upgrade. This paper will present the analysis of the mechanical characteristics of the cavity (pressure sensitivity and tunability) and will detail the fabrication process. The unique geometry of the cavity–which is currently being fabricated at Jefferson Lab–and its required mechanical strength present interesting manufacturing challenges. | ||
| WEPPC102 | Design and Development of Superconducting Parallel-bar Deflecting/Crabbing Cavities | 2453 |
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| The superconducting parallel-bar cavity is a deflecting/crabbing cavity with attractive properties that is being considered for a number of applications. We present the designs of a 499 MHz deflecting cavity developed for the Jefferson Lab 12 GeV Upgrade and a 400 MHz crabbing cavity for the LHC High Luminosity Upgrade. Prototypes of these two cavities are now under development and fabrication. | ||
| WEPPC103 | Development of Spoke Cavities for High-velocity Applications | 2456 |
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| In response to recent interest in alternatives to elliptical cavities for low-frequency, high-velocity applications we have initiated a program for the development of multi-spoke superconducting cavities. We have completed the electromagnetic design for two-spoke cavities operating at 352 and 325 MHz and a design velocity of β = 0.82 and β = 1. We present the results of the optimization, higher order mode (HOM) analysis, multipacting analysis, and an initial multipole expansion study of the fundamental accelerating mode. | ||
| THPPR030 | High Power Test of RF Separator For 12 GeV Upgrade of CEBAF at Jefferson Lab | 4032 |
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Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. CEBAF at JLab is in the process of an energy upgrade from 6 GeV to 12 GeV. The existing setup of the RF separator cavities in the 5th pass will not be adequate enough to extract the highest energy (11 GeV) beam to any two existing halls (A, B or C) while simultaneously delivering to the new hall D in the case of the proposed 12 GeV upgrade of the machine. To restore this capability, several options including the extension of existing normal conducting (NC) and a potential 499 MHz TEM-type superconducting (SC) cavity design have been investigated using computer simulations. Detailed numerical studies suggest that six 2-cell normal conducting structures meet the requirements; each 2-cell structure will require up to 4 kW RF input power in contrast with the current nominal operating power of 1.0 to 2.0 kW. A high power test to 4 kW is required to confirm the cavity’s operate-ability at these elevated gradient and power levels. We have assembled a 2-cell cavity, pumped down to 2.0·10-9 torr using ion pump and confirmed the low level RF performance. A high power test is in progress and will be completed soon. The detailed numerical and experimental results will be discussed in the paper. |
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