Paper | Title | Page |
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FRIBA01 |
SRF R&D for FRIB Linac Energy Upgrade with High-performance Medium-beta Elliptical Cavity CW Cryomodules | |
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Funding: Work supported by the U.S. Department of Energy under Award Number DE-SC0000661. Further support provided by the US Department of Energy under Cooperative Agreement award number DE-SC0018362. Michigan State University is pursuing SRF R&D for FRIB400 upgrade, doubling the FRIB linac beam energy (400 MeV/u for the heaviest uranium beam) using ßopt=0.65 644 MHz 5-cell elliptical cavities. We have achieved unprecedented Q₀ in this cavity class, Q₀ = 3.5·1010 at Eacc of 17.5 MV/m in a nitrogen-doped bare niobium cavity in collaboration with FNAL and ANL. The next missions are achieving such high Q₀ in jacketed cavities and in cryomodules, achieving field-emission free performance at Epeak of 40 MV/m with reproducibility, developing a compact two-window high-power fundamental power coupler (15 kW CW), and achieving stable resonance control of cavities integrated with tuners in cryomodules. In this talk, we will present progress of the SRF R&D and discuss future plan. |
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Slides FRIBA01 [2.513 MB] | ||
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FRIBA02 | Instrumentation for High Performance Cavities and Cryomodule Field Emission Analysis | 978 |
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Field emission (FE) is one of the main reasons for the degradation of accelerator cryomodules, as field emitted current tends to become more severe during the beam operation. It is essential to better understand how this phenomenon is generated and evolves from the SRF cavity preparation in the clean room, through their assembly in the cryomodule until their final test and operation. Due to the shielding environment of a cavity in its vertical test stand, or the architecture of a cryomodule, the more faint radiation occurring at the FE onset remains undetected. More precise diagnostic and analysis tools are required to gain more information. We present the developpement of dedicated time-resolved detectors for the FE radiation which aim at improving its coverage in terms of solid angle and lower energy threshold sensitivity. We approach this topic through detailed simulation based on the Geant4 toolkit in order to analyse the interaction of FE radiation with the cavity environement and optimize the detectors with respect to their application in cryomodule or vertical test stands. We illustrate by analysing recent cryomodule experimental test data. | ||
Slides FRIBA02 [9.606 MB] | ||
DOI • | reference for this paper ※ doi:10.18429/JACoW-SRF2023-FRIBA02 | |
About • | Received ※ 27 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 05 July 2023 — Issue date ※ 09 July 2023 | |
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FRIBA03 | Heavily Damped Crab Cavities for High Luminosity Collisions | 986 |
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Funding: Work supported by BSA under U.S. DOE contract No. DE-SC0012704, by JSA under U.S. DOE Contract No. DE-SC0002769, and by DOE Contract No. DE-AC02-76SF00515. Next generation colliders require crab cavities to mitigate parasitic collisions caused by finite crossing angle for luminosity leveling and detector data pile up reduction. The Electron Ion Collider (EIC) crab cavity designs will be introduced as an example to fulfill the geometrical constraints, crabbing voltages, multipole components, Higher Order Mode (HOM) power and impedance budgets. Operational challenges such as tuning, high gain low delay control loop, amplitude and phase noises control will be discussed. |
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Slides FRIBA03 [3.666 MB] | ||
DOI • | reference for this paper ※ doi:10.18429/JACoW-SRF2023-FRIBA03 | |
About • | Received ※ 19 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 06 July 2023 | |
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FRIBA04 | Crab Cavities for ILC | 990 |
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For the 14 mrad crossing angle proposed, crab cavity systems are fundamentally anticipated for the viable operation of the International Linear Collider (ILC), in order to maximise its luminosity performance. Since 2021, a specialist development team have been defining optimum crab cavity technologies which can fulfil the operational requirements for ILC, both for its baseline centre-of-mass energy of 250 GeV, but also extending those requirements out to higher beam collision intensities. Five design teams have established crab cavity technology solutions, which have the capability to also operate up to 1 TeV centre-of-mass. This presentation showcases the key performance capabilities of these designs and their associated benefits for both manufacture and integration into the ILC Interaction Region. The recommended outcome of the recently conducted crab cavity technology down-selection, will also be highlighted. | ||
Slides FRIBA04 [2.526 MB] | ||
DOI • | reference for this paper ※ doi:10.18429/JACoW-SRF2023-FRIBA04 | |
About • | Received ※ 19 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 20 July 2023 | |
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FRIBA05 | Automation of FRIB SRF Cavities and SC Solenoids Turn-on/off | 999 |
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The superconducting driver Linac for the Facility for Rare Isotope Beams (FRIB) is a heavy ion accelerator that accelerate ions to 200 MeV per nucleon. The Linac has 46 cryomodules that contain 324 superconducting radio frequency (SRF) cavities and 69 superconducting (SC) solenoid packages. For operation of all cryomodules with high efficiency and reliability, automation for SRF cavity and SC solenoid fast turn-on/off is essentially. Based on cryomodule commissioning results and expert experience, all manual cavity and solenoid turn-on/off procedures and steps have been replaced by automatic programs for FRIB linac operation. This allows the operators to turn the systems on and off without expert-level training. Automation reduces the risk of human error, speeds up beam recovery after user access to experimental areas, and increases beam availability. The cavity turn-on procedure makes sure that the cavity can operate at low field with expected read backs, ramps up the field, and makes sure that the RF amplitude and phase are stable. The design, implementation, and operating experience with automation will be presented. | ||
Slides FRIBA05 [3.503 MB] | ||
DOI • | reference for this paper ※ doi:10.18429/JACoW-SRF2023-FRIBA05 | |
About • | Received ※ 29 June 2023 — Revised ※ 16 August 2023 — Accepted ※ 21 August 2023 — Issue date ※ 21 August 2023 | |
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FRIBA06 |
Operational Experience From 8 Years of ELBE SRF-Gun II | |
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At the electron accelerator for beams with high brilliance and low emittance (ELBE), the second version of a superconducting radio-frequency (SRF) photoinjector was brought into operation in 2014. After a period of commissioning, a gradual transfer to routine operation took place in 2017, so that now more than 1800h of user beam are generated every year. Since the commission, a total of 24 cathodes (2 Cu, 12 Mg, 10 Cs₂Te) have been used, without observing serious cavity degradation. The contribution summarizes commissioning and operational experience of the last 8 years of gun operation, with special emphasis on SRF properties but also on specialties such as dark current and multipacting that are directly linked to the integration of a normal conducting cathode into the SRF cavity. | ||
Slides FRIBA06 [6.709 MB] | ||
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FRIBA07 | Status of the SLAC/MSU SRF Gun Development Project | 1003 |
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Funding: Work supported by the Department of Energy under Contract DE-AC02-76SF00515 The Linac Coherent Light Source II High Energy (LCLS-II-HE) Project at SLAC includes the construction of a low-emittance injector (LEI) and a superconducting quarter-wave resonator (QWR) at 185.7 MHz. Several alternatives to a superconducting radio frequency (SRF) QWR gun were considered for the LEI, including nor-mal-conducting RF guns evolved from the LCLS-II gun design. Compared to normal-conducting designs, the combination of an intrinsically outstanding vacuum environment (for cathode lifetime), and the potential for a larger ultimate performance envelope, led to the deci-sion to pursue development of the QWR-SRF gun. A prototype gun is currently being designed and fabricated at the Facility for Rare Isotope Beams (FRIB) at Michi-gan State University (MSU). This paper presents perfor-mance goals for the new gun design, an overview of the prototype development effort, status, and future plans including fabrication. |
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Slides FRIBA07 [9.655 MB] | ||
DOI • | reference for this paper ※ doi:10.18429/JACoW-SRF2023-FRIBA07 | |
About • | Received ※ 15 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 11 July 2023 | |
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