IPAC2021 - List of Keywords (cryomodule)

Paper	Title	Other Keywords	Page
MOPAB190	An 8 GeV Linac as the Booster Replacement in the Fermilab Power Upgrade	linac, injection, cavity, booster	643
	D.V. Neuffer, S.A. Belomestnykh, M. Checchin, D.E. Johnson, S. Posen, E. Pozdeyev, V.S. Pronskikh, N. Solyak, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics. Increasing the Main Injector (MI) beam power above ~1.2 MW requires replacement of the 8 GeV Booster by a higher intensity alternative. Previously, rapid-cycling synchrotron (RCS) and Linac solutions were considered for this purpose. In this paper, we consider the Linac version that produces 8 GeV H⁻ beam for injection into the Recycler Ring (RR) or Main Injector (MI). The Linac takes ~1 GeV beam from the PIP-II Linac and accelerates it to ~2 GeV in a cw SRF linac, followed by a ~2-8 GeV pulsed linac using 1300 MHz cryomodules. The linac components incorporate recent improvements in SRF technology. The linac configuration and beam dynamics requirements are presented. Injection options are discussed. Research needed to implement the Booster replacement is described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB190
About •	paper received ※ 15 May 2021 paper accepted ※ 28 May 2021 issue date ※ 10 August 2021
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MOPAB232	Observation of Polarization-Dependent Changes in Higher-Order Mode Responses as a Function of Transverse Beam Position in Tesla-Type Cavities at FAST	cavity, HOM, electron, dipole	756
	R.M. Thurman-Keup, D.R. Edstrom, A.H. Lumpkin, P.S. Prieto, J. Ruan Fermilab, Batavia, Illinois, USA J.A. Diaz Cruz UNM-ECE, Albuquerque, USA J.A. Diaz Cruz, B.T. Jacobson, J.P. Sikora, F. Zhou SLAC, Menlo Park, California, USA
	Funding: FNAL supported by U.S. Department of Energy, Office of Science, under contract DE-AC02-07CH11359. SLAC supported by U.S. Department of Energy, Office of Science, under contract DE-AC02-76SF00515. Higher-order modes (HOMs) in superconducting rf cavities present problems for an electron bunch traversing the cavity in the form of long-range wakefields from previous bunches. These may dilute the emittance of the macropulse average, especially with low emittance beams at facilities such as the European X-ray Free-electron Laser (XFEL) and the upgraded Linac Coherent Light Source (LCLS-II). Here we present observations of HOMs driven by the beam at the Fermilab Accelerator Science and Technology (FAST) facility. The FAST facility features two independent TESLA-type cavities (CC1 and CC2) after a photocathode rf gun followed by an 8-cavity cryomodule. The HOM signals were acquired from cavities using bandpass filters of 1.75 ± 0.15 GHz, 2.5 ± 0.2 GHz, and 3.25 ± 0.2 GHz and recorded using an 8-GHz, 20 GSa/s oscilloscope. The frequency resolution obtained is sufficient to separate polarization components of many of the HOMs. These HOM signals were captured from CC1 and cavities 1 and 8 of the cryomodule for various initial trajectories through the cavities, and we observe correlations between trajectory, HOM signals, and which polarization component of a mode is affected.
	Poster MOPAB232 [2.144 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB232
About •	paper received ※ 20 May 2021 paper accepted ※ 25 May 2021 issue date ※ 10 August 2021
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MOPAB323	Commissioning of the LCLS-II Prototype HOM Detectors with Tesla-Type Cavities at Fast	cavity, HOM, electron, detector	996
	J.P. Sikora, J.A. Diaz Cruz, B.T. Jacobson SLAC, Menlo Park, California, USA J.A. Diaz Cruz UNM-ECE, Albuquerque, USA D.R. Edstrom, A.H. Lumpkin, P.S. Prieto, J. Ruan, R.M. Thurman-Keup Fermilab, Batavia, Illinois, USA
	Funding: Work supported by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy. Work supported by the U.S. Department of Energy, contract DE-AC02-76SF00515. Experiments at the Fermilab Accelerator Science and Technology (FAST) facility detected electron beam-induced high order mode (HOM) signals from Tesla superconducting cavities. This paper describes some of the signal detection hardware used in this experiment, as well as measurements of the HOM signal magnitude versus beam trajectory. These measurements were made both with a single bunch and with a train of 50 bunches at bunch charges from 400 pC/b down to 10 pC/b. The detection hardware is designed for use with the Tesla superconducting cavities of LCLS-II at SLAC** and is based on a prototype already in use at Fermilab. The HOM signal passes through a bandpass filter that is centered on several cavity dipole modes and a zero bias Schottky diode detects its magnitude. Direct comparisons were made between the FNAL chassis and the SLAC prototype for identical beam steering conditions. To support measurements with bunch charges as low as 10 pC, the SLAC detector has RF amplification between the bandpass filter and the diode detector. With this hardware, usable HOM signal measurements are obtained with a single bunch of 10 pC in cryomodule cavities as will be needed for LCLS-II.
	Poster MOPAB323 [2.076 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB323
About •	paper received ※ 17 May 2021 paper accepted ※ 07 June 2021 issue date ※ 14 August 2021
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MOPAB388	Status of the High Power Couplers for ESS Elliptical Cavities	cavity, simulation, vacuum, SRF	1186
	C. Arcambal, P. Bosland, G. Devanz, T. Hamelin, C. Madec, C. Marchand, M. Oublaid, G. Perreu, C. Servouin, C. Simon CEA-IRFU, Gif-sur-Yvette, France M. Baudrier, C. Mayri, S. Regnaud, T.V. Vacher CEA-DRF-IRFU, France
	In the framework of the European Spallation Source (ESS), CEA Paris-Saclay is responsible for the delivery of 30 cryomodules (9 medium beta (β = 0.67) and 21 high beta (β = 0.86) ones). Each cryomodule contains 4 elliptical cavities equipped with a radio frequency power coupler. The ESS nominal pulse is 1.1 MW maximum peak power over a width of 3.6 ms at a repetition rate of 14 Hz. The design of the couplers for medium beta and for high beta cavities is the same, except a small difference of the antenna penetration to adjust the Q_ext. The mass production of the 120 couplers started and all the medium beta couplers have been conditioned at room temperature. The first cryomodules equipped with the power couplers were successfully tested at high RF power and with cavities at 2K reaching the ESS nominal pulse. The main issue at the start of the series production could be fixed and it was due to bad TiN coatings that caused abnormal dielectric losses in the window. Thus, this paper deals with the TiN coating defect, presents the conditioning procedure and gives a conditioning report of these 36 couplers.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB388
About •	paper received ※ 19 May 2021 paper accepted ※ 24 May 2021 issue date ※ 18 August 2021
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MOPAB393	Design of an RF-Dipole Crabbing Cavity System for the Electron-Ion Collider	cavity, HOM, impedance, electron	1200
	S.U. De Silva, J.R. Delayen ODU, Norfolk, Virginia, USA J. Henry, F. Marhauser, H. Park, R.A. Rimmer JLab, Newport News, Virginia, USA
	The Electron-Ion Collider requires several crabbing systems to facilitate head-on collisions between electron and proton beams in increasing the luminosity at the interaction point. One of the critical rf systems is the 197 MHz crabbing system that will be used in crabbing the proton beam. Many factors such as the low operating frequency, large transverse voltage requirement, tight longitudinal and transverse impedance thresholds, and limited beam line space makes the crabbing cavity design challenging. The rf-dipole cavity design is considered as one of the crabbing cavity options for the 197 MHz crabbing system. The cavity is designed including the HOM couplers, FPC and other ancillaries. This paper presents the detailed electromagnetic design, mechanical analysis, and conceptual cryomodule design of the crabbing system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB393
About •	paper received ※ 26 May 2021 paper accepted ※ 02 June 2021 issue date ※ 26 August 2021
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MOPAB400	Development of Helium Vessel Welding Process for SNS PPU Cavities	cavity, proton, neutron, accelerating-gradient	1212
	P. Dhakal, E. Daly, G.K. Davis, J.F. Fischer, N.A. Huque, K. Macha, P.D. Owen, K.M. Wilson, M. Wiseman JLab, Newport News, Virginia, USA
	Funding: This manuscript has been authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The Spallation Neutron Source Proton Power Upgrade cavities are produced by Research Instrument with all the cavity processing done at vendor sites with final chemistry applied to the cavity to be electropolishing. Cavities are delivered to Jefferson Lab, ready to be tested. One of the tasks to be completed before the arrival of production-ready PPU cavities is to develop a robust helium vessel welding protocol. We have successfully developed the process and applied it to three six-cell high beta cavities. Here, we present the summary of RF results, welding process development, and post helium vessel RF results.
	Poster MOPAB400 [1.313 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB400
About •	paper received ※ 18 May 2021 paper accepted ※ 26 May 2021 issue date ※ 01 September 2021
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TUPAB167	Status of Conduction Cooled SRF Photogun for UEM/UED	gun, SRF, cavity, shielding	1773
	R.A. Kostin, C. Jing Euclid Beamlabs, Bolingbrook, USA P.V. Avrakhov, A. Liu, Y. Zhao Euclid TechLabs, Solon, Ohio, USA
	Funding: DOE #DE-SC0018621 Benefiting from the rapid progress on RF photogun technologies in the past two decades, the development of MeV range ultrafast electron diffraction/microscopy (UED and UEM) has been identified as an enabling instrumentation. UEM or UED use low power electron beams with modest energies of a few MeV to study ultrafast phenomena in a variety of novel and exotic materials. SRF photoguns become a promising candidate to produce highly stable electrons for UEM/UED applications because of the ultrahigh shot-to-shot stability compared to room temperature RF photoguns. SRF technology was prohibitively expensive for industrial use until two recent advancements: Nb₃Sn and conduction cooling. The use of Nb₃Sn allows to operate SRF cavities at higher temperatures (4K) with low power dissipation which is within the reach of commercially available closed-cycle cryocoolers. Euclid is developing a continuous wave (CW), 1.5-cell, MeV-scale SRF conduction cooled photogun operating at 1.3 GHz. In this paper, the technical details of the design and first experimental data are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB167
About •	paper received ※ 29 May 2021 paper accepted ※ 21 June 2021 issue date ※ 01 September 2021
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TUPAB199	Progress on the Proton Power Upgrade at the Spallation Neutron Source	target, klystron, linac, proton	1876
	M.S. Champion, C.N. Barbier, M.S. Connell, J. Galambos, M.P. Howell, S.-H. Kim, J.S. Moss, B.W. Riemer, K.S. White ORNL, Oak Ridge, Tennessee, USA E. Daly JLab, Newport News, Virginia, USA N.J. Evans, G.D. Johns ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. This research was supported by the DOE Office of Science, Basic Energy Science. The Proton Power Upgrade Project at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory will double the proton power capability from 1.4 to 2.8 MW. This will be accomplished through an energy increase from 1.0 to 1.3 GeV and a beam current increase from 26 to 38 mA. The energy increase will be accomplished through the addition of 7 cryomodules to the linear accelerator (Linac). The beam current increase will be supported by upgrading several radio-frequency systems in the normal-conducting section of the Linac. Upgrades to the accumulator ring injection and extraction regions will accommodate the increase in beam energy. A new 2-MW-capable target and supporting systems will be developed and installed. Conventional facility upgrades include build-out of the existing klystron gallery and construction of a tunnel stub to facilitate future beam transport to the second target station. The project received approval to proceed with construction in October 2020. Procurements are in progress, and some installation activities have already occurred. Most of the installation will take place during three outages in 2022-2023. The project early finish is planned for 2025.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB199
About •	paper received ※ 10 May 2021 paper accepted ※ 28 May 2021 issue date ※ 21 August 2021
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TUPAB211	The Accelerator System of IFMIF-DONES Multi-MW Facility	linac, cavity, rfq, SRF	1910
	I. Podadera, A. Ibarra, D. Jimenez-Rey, J. Mollá, C. Oliver, D. Regidor, R. Varela, C. de la Morena CIEMAT, Madrid, Spain F. Arbeiter, V. Hauer KIT, Eggenstein-Leopoldshafen, Germany N. Bazin, J. Dumas, L. Seguí CEA-IRFU, Gif-sur-Yvette, France L. Bellan, E. Fagotti, A. Palmieri, A. Pisent INFN/LNL, Legnaro (PD), Italy N. Chauvin, S. Chel, J. Plouin CEA-DRF-IRFU, France G. Duglue, H. Dzitko F4E, Germany W.C. Grabowski, A. Wysocka-Rabin NCBJ, Świerk/Otwock, Poland M. Jaksic, T. Tadic RBI, Zagreb, Croatia W. Królas IFJ-PAN, Kraków, Poland R. López, A. Muñoz, C. Prieto Empresarios Agrupados, Madrid, Spain O. Nomen, M. Sanmartí, F.J. Saura Esteban, B.K. Singh, D. Sánchez-Herranz IREC, Sant Adria del Besos, Spain
	Funding: Work carried out within EUROfusion Consortium and DONES-PreP and received funding from the Euratom research and training programme 2014-2018 & 2019-2020 under grants agreement No. 633053 & 870186 The IFMIF-DONES (DEMO-Oriented Neutron Early Source) facility has passed the preliminary design phase and the detailed design phase is very much advanced. Next step will be the preparation phase for the construction of the facility. The DONES facility aims at developing a database of fusion-like radiation effects on materials to be used in future fusion reactors up to damage levels expected in the EU DEMO. It will be based on an intense neutron source created by an accelerated deuteron beam (125 mA CW, 40 MeV) impinging on a liquid lithium curtain. The DONES Accelerator Systems (AS) will be responsible of delivering this 5 MW D⁺ beam with very high availability. The beam acceleration will be performed by several stages: an ion source and LEBT, an RFQ, a MEBT, an SRF Linac and a HEBT transporting and delivering an optimized profile down to the target. A high power RF system and several ancillaries will ensure the equipment is properly operated. This contribution will report the present status of the AS design, the main challenges faced, the R&D programme to overcome them, and the prospects for the construction and commissioning of the DONES accelerator in Granada (Spain).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB211
About •	paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 27 August 2021
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TUPAB274	Investigations of Long-Range Wakefield Effects in a TESLA-type Cryomodule at FAST	HOM, cavity, electron, wakefield	2109
	A.H. Lumpkin, D.R. Edstrom, P.S. Prieto, J. Ruan, R.M. Thurman-Keup Fermilab, Batavia, Illinois, USA J.A. Diaz Cruz UNM-ECE, Albuquerque, USA J.A. Diaz Cruz, B.T. Jacobson, J.P. Sikora, F. Zhou SLAC, Menlo Park, California, USA
	Funding: Work supported by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics. The preservation of low emittance of electron beams during transport in the accelerating structures of large facilities is an ongoing challenge. In the cases of the TESLA-type superconducting rf cavities currently used in the European X-ray Free-electron Laser (XFEL) and the under-construction Linac Coherent Light Source upgrade (LCLS-II), off-axis beam transport may result in emittance dilution due to transverse long-range wakefields (LRWs) and short-range wakefields (SRW). To investigate such effects, experiments were performed at the Fermilab Accelerator Science and Technology (FAST) facility with its unique configuration of two TESLA-type cavities after the photocathode rf gun followed by an 8-cavity cryomodule CM). We generated beam trajectory changes with the H/V125 corrector set located 4 m upstream of the cryomodule. At 125 pC/bunch, 50 bunches, 25-MeV input, and 100-MeV exit energy, we observed for the first time submacropulse position slews of up to 500 microns at locations ~3 m after the CM and a centroid oscillation at a difference frequency of 240 kHz further downstream. Both are emittance-dilution effects which we mitigated with selective upstream beam steering. *W.K.H. Panofsky and M. Bander, Rev. Sci. Instr. 39, 206 (1968).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB274
About •	paper received ※ 18 May 2021 paper accepted ※ 09 June 2021 issue date ※ 31 August 2021
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TUPAB333	Status of PIP-II 650 MHz Prototype Dressed Cavity Qualification	cavity, SRF, status, superconductivity	2279
	G.V. Eremeev, D.J. Bice, C. Boffo, S.K. Chandrasekaran, S. Cheban, F. Furuta, I.V. Gonin, C.J. Grimm, S. Kazakov, T.N. Khabiboulline, A. Lunin, M. Martinello, N. Nigam, J.P. Ozelis, Y.M. Pischalnikov, K.S. Premo, O.V. Prokofiev, O.V. Pronitchev, G.V. Romanov, N. Solyak, A.I. Sukhanov, G. Wu Fermilab, Batavia, Illinois, USA M. Bagre, V. Jain, A. Puntambekar, S. Raghvendra, P. Shrivastava RRCAT, Indore (M.P.), India P. Bhattacharyya, S. Ghosh, S. Seth VECC, Kolkata, India R. Kumar BARC, Mumbai, India J. Lewis, P.A. McIntosh, A.E. Wheelhouse STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom C. Pagani, R. Paparella INFN/LASA, Segrate (MI), Italy C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy T. Reid ANL, Lemont, Illinois, USA A.D. Shabalina STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics. Low-beta and high-beta sections of PIP-II linac will use nine low-beta cryomodules with four cavities each and four high-beta cryomodules with six cavities each. These cavities will be produced and qualified in collaboration between Fermilab and the international partner labs. Prior to their installation into prototype cryomodules, several dressed cavities, which include jacketed cavities, high power couplers, and tuners, will be qualified in STC horizontal test bed at Fermilab. After qualification of bare β = 0.9 cavities at Fermilab, several pre-production β = 0.92 and β = 0.61 cavities have been and are being fabricated and qualified. Procurements have also been started for high power couplers and tuners. In this contribution we present the current status of prototype dressed cavity qualification for PIP-II.
	Poster TUPAB333 [6.247 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB333
About •	paper received ※ 23 May 2021 paper accepted ※ 19 July 2021 issue date ※ 19 August 2021
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WEXB01	The ESS Elliptical Cavity Cryomodules Production at CEA	cavity, status, site, vacuum	2536
	C. Madec CEA, Gif-sur-Yvette, France C. Arcambal, S. Berry, A. Bouygues, G. Devanz, C. Mayri, P. Sahuquet, T. Trublet CEA-DRF-IRFU, France P. Bosland, E. Cenni, C. Cloué, T. Hamelin, O. Piquet CEA-IRFU, Gif-sur-Yvette, France P. Pierini ESS, Lund, Sweden
	CEA in Kind contribution to the ESS superconducting LINAC includes 30 elliptical medium and high-beta cryomodules. CEA is in charge of the production of all the components (except the cavities delivered by LASA and STFC) as well as the assembly of the cryomodules and a few cryogenic and RF tests. The power couplers operating at a maximum power of 1.1MW on a 3.6ms pulse at 14Hz are conditioned at high RF power on a dedicated stand. The assembly of the cryomodules is performed at CEA by a private Company under the supervision of CEA. This paper presents the status of the cryomodules production and the infrastructure dedicated to this project at CEA Saclay.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEXB01
About •	paper received ※ 18 May 2021 paper accepted ※ 19 July 2021 issue date ※ 30 August 2021
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THPAB271	JLAB LLRF 3.0 Development and Tests	cavity, LLRF, controls, FPGA	4340
	T.E. Plawski, R. Bachimanchi, S. Higgins, C. Hovater, J. Latshaw, C.I. Mounts, D.J. Seidman, J. Yan JLab, Newport News, Virginia, USA
	The Jefferson Lab LLRF 3.0 system is being developed to replace legacy LLRF systems in the CEBAF accelerator. The new design builds upon 25 years of design and operational RF control experience, and our recent collaboration in the design of the LCLSII LLRF system. The new cavity control algorithm is a fully functional phase and amplitude locked Self Exciting Loop (SEL). This paper discusses the progress of the LLRF 3.0 hardware design, FPGA firmware development, User Datagram Protocol (UDP) operation, and recent LLRF 3.0 system tests on the CEBAF Booster cryomodule in the Upgrade Injector Test Facility (UITF).
	Poster THPAB271 [1.940 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB271
About •	paper received ※ 14 May 2021 paper accepted ※ 06 July 2021 issue date ※ 20 August 2021
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THPAB337	Resonance Control System for the PIP-II IT HWR Cryomodule	cavity, controls, feedback, resonance	4446
	P. Varghese, B.E. Chase, P.M. Hanlet, H. Maniar, D.J. Nicklaus, S. Sankar Raman Fermilab, Batavia, Illinois, USA L.R. Doolittle, S. Paiagua, C. Serrano LBNL, Berkeley, California, USA
	The HWR (half-wave-resonator) cryomodule is the first one in the superconducting section of the PIP-II LINAC project at Fermilab. PIP-II IT is a test facility for the project where the injector, warm front-end, and the first two superconducting cryomodules are being tested. The HWR cryomodule comprises 8 cavities operating at a frequency of 162.5 MHz and accelerating beam up to 10 MeV. Resonance control of the cavities is performed with a pneumatically operated slow tuner which compresses the cavity at the beam ports. Helium gas pressure in a bellows mounted to an end wall of the cavity is controlled by two solenoid valves, one on the pressure side and one on the vacuum side. The resonant frequency of the cavity can be controlled in one of two modes. A pressure feedback control loop can hold the cavity tuner pressure at a fixed value for the desired resonant frequency. Alternately, the feedback loop can regulate the cavity tuner pressure to bring the RF detuning error to zero. The resonance controller is integrated into the LLRF control system for the cryomodule. The control system design and performance of the resonance control system are described in this paper.
	Poster THPAB337 [4.426 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB337
About •	paper received ※ 12 May 2021 paper accepted ※ 26 July 2021 issue date ※ 27 August 2021
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THPAB338	Performance of the LLRF System for the Fermilab PIP-II Injector Test	cavity, controls, LLRF, resonance	4450
	P. Varghese, B.E. Chase, P.M. Hanlet, H. Maniar, D.J. Nicklaus Fermilab, Batavia, Illinois, USA L.R. Doolittle, C. Serrano LBNL, Berkeley, California, USA
	PIP-II IT is a test facility for the PIP-II project where the injector, warm front-end, and the first two superconducting cryomodules are being tested. The 8-cavity half-wave-resonator (HWR) cryomodule operating at 162.5 MHz is followed by the 8-cavity single-spoke resonator(SSR1) cryomodule operating at 325 MHz. The LLRF systems for both cryomodules are based on a common SOC FPGA-based hardware platform. The resonance control systems for the two cryomodules are quite different, the first being a pneumatic system based on helium pressure and the latter a piezo/stepper motor type control. The data acquisition and control system can support both CW and Pulsed mode operations. Beam loading compensation is available which can be used for both manual/automatic control in the LLRF system. The user interfaces include EPICS, Labview, and ACNET. Testing of the RF system has progressed to the point of being ready for a 2 mA beam to be accelerated to 25 MeV. The design and performance of the field control and resonance control system operation with beam are presented in this paper.
	Poster THPAB338 [5.482 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB338
About •	paper received ※ 13 May 2021 paper accepted ※ 27 July 2021 issue date ※ 24 August 2021
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THPAB343	Test Results of the Prototype SSR1 Cryomodule for PIP-II at Fermilab	cavity, SRF, vacuum, focusing	4461
	D. Passarelli, J. Bernardini, C. Boffo, B.M. Hanna, S. Kazakov, T.N. Khabiboulline, A. Lunin, J.P. Ozelis, M. Parise, Y.M. Pischalnikov, V. Roger, B. Squires, A.I. Sukhanov, G. Wu, V.P. Yakovlev, S. Zorzetti Fermilab, Batavia, Illinois, USA C. Contreras-Martinez FRIB, East Lansing, Michigan, USA
	Funding: Work supported by Fermi Research Alliance, LLC under Contract No. DEAC02- 07CH11359 with the United States Department of Energy A prototype cryomodule containing eight Single Spoke Resonators type-1 (SSR1) operating at 325 MHz and four superconducting focusing lenses has been successfully assembled and cold tested in the framework of PIP-II project at Fermilab. The performance of cavities and focusing lenses along with test results of other cryomodule’s key parameters are presented in this contribution.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB343
About •	paper received ※ 20 May 2021 paper accepted ※ 08 August 2021 issue date ※ 28 August 2021
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THPAB352	Computer Vision Techniques Used to Monitor the Alignment of Cavities and Solenoids in the PIP-II Prototype SSR1 Cryomodule	cavity, solenoid, alignment, target	4485
	S. Zorzetti, J. Bernardini, D. Passarelli Fermilab, Batavia, Illinois, USA
	The alignment of the SRF PIP-II string components is studied as the acceptable beam deflection, offset and defocusing, which may otherwise cause beam loss. Simulations and measurements established that the maximum deviation of the beam pipe from the reference orbit should not exceed a small fraction of the beam aperture. To observe the translations and rotations of each single component within the cryomodule, optical instruments (H-BCAM) surveying highly reflective targets, installed in the internal assembly of the module were used. The alignment monitoring concept for the PIP II SSR1 prototype cryomodule, along with relevant measurements of the components’ position monitoring during coldmass cooldown is presented in this contribution. This development paves the way to new computer vision applications in the field of cryomodule assemblies in cleanroom environment, in which robotically-assisted operations have the potential to dramatically reduce the risk of chemical and particulate contamination.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB352
About •	paper received ※ 19 May 2021 paper accepted ※ 02 August 2021 issue date ※ 31 August 2021
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FRXC01	Superconducting Radio-Frequency Cavity Fault Classification Using Machine Learning at Jefferson Laboratory	cavity, network, SRF, radio-frequency	4535
	C. Tennant, A. Carpenter, T. Powers, L.S. Vidyaratne JLab, Newport News, Virginia, USA K.M. Iftekharuddin, M. Rahman ODU, Norfolk, Virginia, USA A.D. Shabalina STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: This work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Contract No. DE-AC05-06OR23177. We report on the development of machine learning models for classifying C100 superconducting radiofrequency (SRF) cavity faults in the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab. Of the 418 SRF cavities in CEBAF, 96 are designed with a digital low-level RF system configured such that a cavity fault triggers recordings of RF signals for each of eight cavities in the cryomodule. Subject matter experts analyze the collected time-series data and identify which of the eight cavities faulted first and classify the type of fault. This information is used to find trends and strategically deploy mitigations to problematic cryomodules. However, manually labeling the data is laborious and time-consuming. By leveraging machine learning, near real-time - rather than postmortem - identification of the offending cavity and classification of the fault type has been implemented. We discuss the performance of the machine learning models during a recent physics run. We also discuss efforts for further insights into fault types through unsupervised learning techniques and present preliminary work on cavity and fault prediction using data collected prior to a failure event.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-FRXC01
About •	paper received ※ 16 May 2021 paper accepted ※ 01 July 2021 issue date ※ 13 August 2021
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Paper

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MOPAB190

An 8 GeV Linac as the Booster Replacement in the Fermilab Power Upgrade

linac, injection, cavity, booster

643

D.V. Neuffer, S.A. Belomestnykh, M. Checchin, D.E. Johnson, S. Posen, E. Pozdeyev, V.S. Pronskikh, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
Increasing the Main Injector (MI) beam power above ~1.2 MW requires replacement of the 8 GeV Booster by a higher intensity alternative. Previously, rapid-cycling synchrotron (RCS) and Linac solutions were considered for this purpose. In this paper, we consider the Linac version that produces 8 GeV H⁻ beam for injection into the Recycler Ring (RR) or Main Injector (MI). The Linac takes ~1 GeV beam from the PIP-II Linac and accelerates it to ~2 GeV in a cw SRF linac, followed by a ~2-8 GeV pulsed linac using 1300 MHz cryomodules. The linac components incorporate recent improvements in SRF technology. The linac configuration and beam dynamics requirements are presented. Injection options are discussed. Research needed to implement the Booster replacement is described.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB190

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paper received ※ 15 May 2021 paper accepted ※ 28 May 2021 issue date ※ 10 August 2021

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MOPAB232

Observation of Polarization-Dependent Changes in Higher-Order Mode Responses as a Function of Transverse Beam Position in Tesla-Type Cavities at FAST

cavity, HOM, electron, dipole

756

R.M. Thurman-Keup, D.R. Edstrom, A.H. Lumpkin, P.S. Prieto, J. Ruan
Fermilab, Batavia, Illinois, USA
J.A. Diaz Cruz
UNM-ECE, Albuquerque, USA
J.A. Diaz Cruz, B.T. Jacobson, J.P. Sikora, F. Zhou
SLAC, Menlo Park, California, USA

Funding: FNAL supported by U.S. Department of Energy, Office of Science, under contract DE-AC02-07CH11359. SLAC supported by U.S. Department of Energy, Office of Science, under contract DE-AC02-76SF00515.
Higher-order modes (HOMs) in superconducting rf cavities present problems for an electron bunch traversing the cavity in the form of long-range wakefields from previous bunches. These may dilute the emittance of the macropulse average, especially with low emittance beams at facilities such as the European X-ray Free-electron Laser (XFEL) and the upgraded Linac Coherent Light Source (LCLS-II). Here we present observations of HOMs driven by the beam at the Fermilab Accelerator Science and Technology (FAST) facility. The FAST facility features two independent TESLA-type cavities (CC1 and CC2) after a photocathode rf gun followed by an 8-cavity cryomodule. The HOM signals were acquired from cavities using bandpass filters of 1.75 ± 0.15 GHz, 2.5 ± 0.2 GHz, and 3.25 ± 0.2 GHz and recorded using an 8-GHz, 20 GSa/s oscilloscope. The frequency resolution obtained is sufficient to separate polarization components of many of the HOMs. These HOM signals were captured from CC1 and cavities 1 and 8 of the cryomodule for various initial trajectories through the cavities, and we observe correlations between trajectory, HOM signals, and which polarization component of a mode is affected.

Poster MOPAB232 [2.144 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB232

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paper received ※ 20 May 2021 paper accepted ※ 25 May 2021 issue date ※ 10 August 2021

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MOPAB323

Commissioning of the LCLS-II Prototype HOM Detectors with Tesla-Type Cavities at Fast

cavity, HOM, electron, detector

996

J.P. Sikora, J.A. Diaz Cruz, B.T. Jacobson
SLAC, Menlo Park, California, USA
J.A. Diaz Cruz
UNM-ECE, Albuquerque, USA
D.R. Edstrom, A.H. Lumpkin, P.S. Prieto, J. Ruan, R.M. Thurman-Keup
Fermilab, Batavia, Illinois, USA

Funding: *Work supported by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy. **Work supported by the U.S. Department of Energy, contract DE-AC02-76SF00515.
Experiments at the Fermilab Accelerator Science and Technology* (FAST) facility detected electron beam-induced high order mode (HOM) signals from Tesla superconducting cavities. This paper describes some of the signal detection hardware used in this experiment, as well as measurements of the HOM signal magnitude versus beam trajectory. These measurements were made both with a single bunch and with a train of 50 bunches at bunch charges from 400 pC/b down to 10 pC/b. The detection hardware is designed for use with the Tesla superconducting cavities of LCLS-II at SLAC** and is based on a prototype already in use at Fermilab. The HOM signal passes through a bandpass filter that is centered on several cavity dipole modes and a zero bias Schottky diode detects its magnitude. Direct comparisons were made between the FNAL chassis and the SLAC prototype for identical beam steering conditions. To support measurements with bunch charges as low as 10 pC, the SLAC detector has RF amplification between the bandpass filter and the diode detector. With this hardware, usable HOM signal measurements are obtained with a single bunch of 10 pC in cryomodule cavities as will be needed for LCLS-II.

Poster MOPAB323 [2.076 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB323

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paper received ※ 17 May 2021 paper accepted ※ 07 June 2021 issue date ※ 14 August 2021

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MOPAB388

Status of the High Power Couplers for ESS Elliptical Cavities

cavity, simulation, vacuum, SRF

1186

C. Arcambal, P. Bosland, G. Devanz, T. Hamelin, C. Madec, C. Marchand, M. Oublaid, G. Perreu, C. Servouin, C. Simon
CEA-IRFU, Gif-sur-Yvette, France
M. Baudrier, C. Mayri, S. Regnaud, T.V. Vacher
CEA-DRF-IRFU, France

In the framework of the European Spallation Source (ESS), CEA Paris-Saclay is responsible for the delivery of 30 cryomodules (9 medium beta (β = 0.67) and 21 high beta (β = 0.86) ones). Each cryomodule contains 4 elliptical cavities equipped with a radio frequency power coupler. The ESS nominal pulse is 1.1 MW maximum peak power over a width of 3.6 ms at a repetition rate of 14 Hz. The design of the couplers for medium beta and for high beta cavities is the same, except a small difference of the antenna penetration to adjust the Q_ext. The mass production of the 120 couplers started and all the medium beta couplers have been conditioned at room temperature. The first cryomodules equipped with the power couplers were successfully tested at high RF power and with cavities at 2K reaching the ESS nominal pulse. The main issue at the start of the series production could be fixed and it was due to bad TiN coatings that caused abnormal dielectric losses in the window. Thus, this paper deals with the TiN coating defect, presents the conditioning procedure and gives a conditioning report of these 36 couplers.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB388

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paper received ※ 19 May 2021 paper accepted ※ 24 May 2021 issue date ※ 18 August 2021

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MOPAB393

Design of an RF-Dipole Crabbing Cavity System for the Electron-Ion Collider

cavity, HOM, impedance, electron

1200

S.U. De Silva, J.R. Delayen
ODU, Norfolk, Virginia, USA
J. Henry, F. Marhauser, H. Park, R.A. Rimmer
JLab, Newport News, Virginia, USA

The Electron-Ion Collider requires several crabbing systems to facilitate head-on collisions between electron and proton beams in increasing the luminosity at the interaction point. One of the critical rf systems is the 197 MHz crabbing system that will be used in crabbing the proton beam. Many factors such as the low operating frequency, large transverse voltage requirement, tight longitudinal and transverse impedance thresholds, and limited beam line space makes the crabbing cavity design challenging. The rf-dipole cavity design is considered as one of the crabbing cavity options for the 197 MHz crabbing system. The cavity is designed including the HOM couplers, FPC and other ancillaries. This paper presents the detailed electromagnetic design, mechanical analysis, and conceptual cryomodule design of the crabbing system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB393

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paper received ※ 26 May 2021 paper accepted ※ 02 June 2021 issue date ※ 26 August 2021

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MOPAB400

Development of Helium Vessel Welding Process for SNS PPU Cavities

cavity, proton, neutron, accelerating-gradient

1212

P. Dhakal, E. Daly, G.K. Davis, J.F. Fischer, N.A. Huque, K. Macha, P.D. Owen, K.M. Wilson, M. Wiseman
JLab, Newport News, Virginia, USA

Funding: This manuscript has been authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The Spallation Neutron Source Proton Power Upgrade cavities are produced by Research Instrument with all the cavity processing done at vendor sites with final chemistry applied to the cavity to be electropolishing. Cavities are delivered to Jefferson Lab, ready to be tested. One of the tasks to be completed before the arrival of production-ready PPU cavities is to develop a robust helium vessel welding protocol. We have successfully developed the process and applied it to three six-cell high beta cavities. Here, we present the summary of RF results, welding process development, and post helium vessel RF results.

Poster MOPAB400 [1.313 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB400

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paper received ※ 18 May 2021 paper accepted ※ 26 May 2021 issue date ※ 01 September 2021

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TUPAB167

Status of Conduction Cooled SRF Photogun for UEM/UED

gun, SRF, cavity, shielding

1773

R.A. Kostin, C. Jing
Euclid Beamlabs, Bolingbrook, USA
P.V. Avrakhov, A. Liu, Y. Zhao
Euclid TechLabs, Solon, Ohio, USA

Funding: DOE #DE-SC0018621
Benefiting from the rapid progress on RF photogun technologies in the past two decades, the development of MeV range ultrafast electron diffraction/microscopy (UED and UEM) has been identified as an enabling instrumentation. UEM or UED use low power electron beams with modest energies of a few MeV to study ultrafast phenomena in a variety of novel and exotic materials. SRF photoguns become a promising candidate to produce highly stable electrons for UEM/UED applications because of the ultrahigh shot-to-shot stability compared to room temperature RF photoguns. SRF technology was prohibitively expensive for industrial use until two recent advancements: Nb₃Sn and conduction cooling. The use of Nb₃Sn allows to operate SRF cavities at higher temperatures (4K) with low power dissipation which is within the reach of commercially available closed-cycle cryocoolers. Euclid is developing a continuous wave (CW), 1.5-cell, MeV-scale SRF conduction cooled photogun operating at 1.3 GHz. In this paper, the technical details of the design and first experimental data are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB167

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paper received ※ 29 May 2021 paper accepted ※ 21 June 2021 issue date ※ 01 September 2021

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TUPAB199

Progress on the Proton Power Upgrade at the Spallation Neutron Source

target, klystron, linac, proton

1876

M.S. Champion, C.N. Barbier, M.S. Connell, J. Galambos, M.P. Howell, S.-H. Kim, J.S. Moss, B.W. Riemer, K.S. White
ORNL, Oak Ridge, Tennessee, USA
E. Daly
JLab, Newport News, Virginia, USA
N.J. Evans, G.D. Johns
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. This research was supported by the DOE Office of Science, Basic Energy Science.
The Proton Power Upgrade Project at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory will double the proton power capability from 1.4 to 2.8 MW. This will be accomplished through an energy increase from 1.0 to 1.3 GeV and a beam current increase from 26 to 38 mA. The energy increase will be accomplished through the addition of 7 cryomodules to the linear accelerator (Linac). The beam current increase will be supported by upgrading several radio-frequency systems in the normal-conducting section of the Linac. Upgrades to the accumulator ring injection and extraction regions will accommodate the increase in beam energy. A new 2-MW-capable target and supporting systems will be developed and installed. Conventional facility upgrades include build-out of the existing klystron gallery and construction of a tunnel stub to facilitate future beam transport to the second target station. The project received approval to proceed with construction in October 2020. Procurements are in progress, and some installation activities have already occurred. Most of the installation will take place during three outages in 2022-2023. The project early finish is planned for 2025.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB199

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paper received ※ 10 May 2021 paper accepted ※ 28 May 2021 issue date ※ 21 August 2021

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TUPAB211

The Accelerator System of IFMIF-DONES Multi-MW Facility

linac, cavity, rfq, SRF

1910

I. Podadera, A. Ibarra, D. Jimenez-Rey, J. Mollá, C. Oliver, D. Regidor, R. Varela, C. de la Morena
CIEMAT, Madrid, Spain
F. Arbeiter, V. Hauer
KIT, Eggenstein-Leopoldshafen, Germany
N. Bazin, J. Dumas, L. Seguí
CEA-IRFU, Gif-sur-Yvette, France
L. Bellan, E. Fagotti, A. Palmieri, A. Pisent
INFN/LNL, Legnaro (PD), Italy
N. Chauvin, S. Chel, J. Plouin
CEA-DRF-IRFU, France
G. Duglue, H. Dzitko
F4E, Germany
W.C. Grabowski, A. Wysocka-Rabin
NCBJ, Świerk/Otwock, Poland
M. Jaksic, T. Tadic
RBI, Zagreb, Croatia
W. Królas
IFJ-PAN, Kraków, Poland
R. López, A. Muñoz, C. Prieto
Empresarios Agrupados, Madrid, Spain
O. Nomen, M. Sanmartí, F.J. Saura Esteban, B.K. Singh, D. Sánchez-Herranz
IREC, Sant Adria del Besos, Spain

Funding: Work carried out within EUROfusion Consortium and DONES-PreP and received funding from the Euratom research and training programme 2014-2018 & 2019-2020 under grants agreement No. 633053 & 870186
The IFMIF-DONES (DEMO-Oriented Neutron Early Source) facility has passed the preliminary design phase and the detailed design phase is very much advanced. Next step will be the preparation phase for the construction of the facility. The DONES facility aims at developing a database of fusion-like radiation effects on materials to be used in future fusion reactors up to damage levels expected in the EU DEMO. It will be based on an intense neutron source created by an accelerated deuteron beam (125 mA CW, 40 MeV) impinging on a liquid lithium curtain. The DONES Accelerator Systems (AS) will be responsible of delivering this 5 MW D⁺ beam with very high availability. The beam acceleration will be performed by several stages: an ion source and LEBT, an RFQ, a MEBT, an SRF Linac and a HEBT transporting and delivering an optimized profile down to the target. A high power RF system and several ancillaries will ensure the equipment is properly operated. This contribution will report the present status of the AS design, the main challenges faced, the R&D programme to overcome them, and the prospects for the construction and commissioning of the DONES accelerator in Granada (Spain).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB211

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paper received ※ 19 May 2021 paper accepted ※ 17 June 2021 issue date ※ 27 August 2021

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TUPAB274

Investigations of Long-Range Wakefield Effects in a TESLA-type Cryomodule at FAST

HOM, cavity, electron, wakefield

2109

A.H. Lumpkin, D.R. Edstrom, P.S. Prieto, J. Ruan, R.M. Thurman-Keup
Fermilab, Batavia, Illinois, USA
J.A. Diaz Cruz
UNM-ECE, Albuquerque, USA
J.A. Diaz Cruz, B.T. Jacobson, J.P. Sikora, F. Zhou
SLAC, Menlo Park, California, USA

Funding: *Work supported by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
The preservation of low emittance of electron beams during transport in the accelerating structures of large facilities is an ongoing challenge. In the cases of the TESLA-type superconducting rf cavities currently used in the European X-ray Free-electron Laser (XFEL) and the under-construction Linac Coherent Light Source upgrade (LCLS-II), off-axis beam transport may result in emittance dilution due to transverse long-range wakefields (LRWs) and short-range wakefields (SRW)***. To investigate such effects, experiments were performed at the Fermilab Accelerator Science and Technology (FAST) facility with its unique configuration of two TESLA-type cavities after the photocathode rf gun followed by an 8-cavity cryomodule CM). We generated beam trajectory changes with the H/V125 corrector set located 4 m upstream of the cryomodule. At 125 pC/bunch, 50 bunches, 25-MeV input, and 100-MeV exit energy, we observed for the first time submacropulse position slews of up to 500 microns at locations ~3 m after the CM and a centroid oscillation at a difference frequency of 240 kHz further downstream. Both are emittance-dilution effects which we mitigated with selective upstream beam steering.
***W.K.H. Panofsky and M. Bander, Rev. Sci. Instr. 39, 206 (1968).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB274

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paper received ※ 18 May 2021 paper accepted ※ 09 June 2021 issue date ※ 31 August 2021

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TUPAB333

Status of PIP-II 650 MHz Prototype Dressed Cavity Qualification

cavity, SRF, status, superconductivity

2279

G.V. Eremeev, D.J. Bice, C. Boffo, S.K. Chandrasekaran, S. Cheban, F. Furuta, I.V. Gonin, C.J. Grimm, S. Kazakov, T.N. Khabiboulline, A. Lunin, M. Martinello, N. Nigam, J.P. Ozelis, Y.M. Pischalnikov, K.S. Premo, O.V. Prokofiev, O.V. Pronitchev, G.V. Romanov, N. Solyak, A.I. Sukhanov, G. Wu
Fermilab, Batavia, Illinois, USA
M. Bagre, V. Jain, A. Puntambekar, S. Raghvendra, P. Shrivastava
RRCAT, Indore (M.P.), India
P. Bhattacharyya, S. Ghosh, S. Seth
VECC, Kolkata, India
R. Kumar
BARC, Mumbai, India
J. Lewis, P.A. McIntosh, A.E. Wheelhouse
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
C. Pagani, R. Paparella
INFN/LASA, Segrate (MI), Italy
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy
T. Reid
ANL, Lemont, Illinois, USA
A.D. Shabalina
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
Low-beta and high-beta sections of PIP-II linac will use nine low-beta cryomodules with four cavities each and four high-beta cryomodules with six cavities each. These cavities will be produced and qualified in collaboration between Fermilab and the international partner labs. Prior to their installation into prototype cryomodules, several dressed cavities, which include jacketed cavities, high power couplers, and tuners, will be qualified in STC horizontal test bed at Fermilab. After qualification of bare β = 0.9 cavities at Fermilab, several pre-production β = 0.92 and β = 0.61 cavities have been and are being fabricated and qualified. Procurements have also been started for high power couplers and tuners. In this contribution we present the current status of prototype dressed cavity qualification for PIP-II.

Poster TUPAB333 [6.247 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB333

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paper received ※ 23 May 2021 paper accepted ※ 19 July 2021 issue date ※ 19 August 2021

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WEXB01

The ESS Elliptical Cavity Cryomodules Production at CEA

cavity, status, site, vacuum

2536

C. Madec
CEA, Gif-sur-Yvette, France
C. Arcambal, S. Berry, A. Bouygues, G. Devanz, C. Mayri, P. Sahuquet, T. Trublet
CEA-DRF-IRFU, France
P. Bosland, E. Cenni, C. Cloué, T. Hamelin, O. Piquet
CEA-IRFU, Gif-sur-Yvette, France
P. Pierini
ESS, Lund, Sweden

CEA in Kind contribution to the ESS superconducting LINAC includes 30 elliptical medium and high-beta cryomodules. CEA is in charge of the production of all the components (except the cavities delivered by LASA and STFC) as well as the assembly of the cryomodules and a few cryogenic and RF tests. The power couplers operating at a maximum power of 1.1MW on a 3.6ms pulse at 14Hz are conditioned at high RF power on a dedicated stand. The assembly of the cryomodules is performed at CEA by a private Company under the supervision of CEA. This paper presents the status of the cryomodules production and the infrastructure dedicated to this project at CEA Saclay.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEXB01

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paper received ※ 18 May 2021 paper accepted ※ 19 July 2021 issue date ※ 30 August 2021

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THPAB271

JLAB LLRF 3.0 Development and Tests

cavity, LLRF, controls, FPGA

4340

T.E. Plawski, R. Bachimanchi, S. Higgins, C. Hovater, J. Latshaw, C.I. Mounts, D.J. Seidman, J. Yan
JLab, Newport News, Virginia, USA

The Jefferson Lab LLRF 3.0 system is being developed to replace legacy LLRF systems in the CEBAF accelerator. The new design builds upon 25 years of design and operational RF control experience, and our recent collaboration in the design of the LCLSII LLRF system. The new cavity control algorithm is a fully functional phase and amplitude locked Self Exciting Loop (SEL). This paper discusses the progress of the LLRF 3.0 hardware design, FPGA firmware development, User Datagram Protocol (UDP) operation, and recent LLRF 3.0 system tests on the CEBAF Booster cryomodule in the Upgrade Injector Test Facility (UITF).

Poster THPAB271 [1.940 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB271

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paper received ※ 14 May 2021 paper accepted ※ 06 July 2021 issue date ※ 20 August 2021

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THPAB337

Resonance Control System for the PIP-II IT HWR Cryomodule

cavity, controls, feedback, resonance

4446

P. Varghese, B.E. Chase, P.M. Hanlet, H. Maniar, D.J. Nicklaus, S. Sankar Raman
Fermilab, Batavia, Illinois, USA
L.R. Doolittle, S. Paiagua, C. Serrano
LBNL, Berkeley, California, USA

The HWR (half-wave-resonator) cryomodule is the first one in the superconducting section of the PIP-II LINAC project at Fermilab. PIP-II IT is a test facility for the project where the injector, warm front-end, and the first two superconducting cryomodules are being tested. The HWR cryomodule comprises 8 cavities operating at a frequency of 162.5 MHz and accelerating beam up to 10 MeV. Resonance control of the cavities is performed with a pneumatically operated slow tuner which compresses the cavity at the beam ports. Helium gas pressure in a bellows mounted to an end wall of the cavity is controlled by two solenoid valves, one on the pressure side and one on the vacuum side. The resonant frequency of the cavity can be controlled in one of two modes. A pressure feedback control loop can hold the cavity tuner pressure at a fixed value for the desired resonant frequency. Alternately, the feedback loop can regulate the cavity tuner pressure to bring the RF detuning error to zero. The resonance controller is integrated into the LLRF control system for the cryomodule. The control system design and performance of the resonance control system are described in this paper.

Poster THPAB337 [4.426 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB337

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paper received ※ 12 May 2021 paper accepted ※ 26 July 2021 issue date ※ 27 August 2021

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THPAB338

Performance of the LLRF System for the Fermilab PIP-II Injector Test

cavity, controls, LLRF, resonance

4450

P. Varghese, B.E. Chase, P.M. Hanlet, H. Maniar, D.J. Nicklaus
Fermilab, Batavia, Illinois, USA
L.R. Doolittle, C. Serrano
LBNL, Berkeley, California, USA

PIP-II IT is a test facility for the PIP-II project where the injector, warm front-end, and the first two superconducting cryomodules are being tested. The 8-cavity half-wave-resonator (HWR) cryomodule operating at 162.5 MHz is followed by the 8-cavity single-spoke resonator(SSR1) cryomodule operating at 325 MHz. The LLRF systems for both cryomodules are based on a common SOC FPGA-based hardware platform. The resonance control systems for the two cryomodules are quite different, the first being a pneumatic system based on helium pressure and the latter a piezo/stepper motor type control. The data acquisition and control system can support both CW and Pulsed mode operations. Beam loading compensation is available which can be used for both manual/automatic control in the LLRF system. The user interfaces include EPICS, Labview, and ACNET. Testing of the RF system has progressed to the point of being ready for a 2 mA beam to be accelerated to 25 MeV. The design and performance of the field control and resonance control system operation with beam are presented in this paper.

Poster THPAB338 [5.482 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB338

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paper received ※ 13 May 2021 paper accepted ※ 27 July 2021 issue date ※ 24 August 2021

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THPAB343

Test Results of the Prototype SSR1 Cryomodule for PIP-II at Fermilab

cavity, SRF, vacuum, focusing

4461

D. Passarelli, J. Bernardini, C. Boffo, B.M. Hanna, S. Kazakov, T.N. Khabiboulline, A. Lunin, J.P. Ozelis, M. Parise, Y.M. Pischalnikov, V. Roger, B. Squires, A.I. Sukhanov, G. Wu, V.P. Yakovlev, S. Zorzetti
Fermilab, Batavia, Illinois, USA
C. Contreras-Martinez
FRIB, East Lansing, Michigan, USA

Funding: Work supported by Fermi Research Alliance, LLC under Contract No. DEAC02- 07CH11359 with the United States Department of Energy
A prototype cryomodule containing eight Single Spoke Resonators type-1 (SSR1) operating at 325 MHz and four superconducting focusing lenses has been successfully assembled and cold tested in the framework of PIP-II project at Fermilab. The performance of cavities and focusing lenses along with test results of other cryomodule’s key parameters are presented in this contribution.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB343

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paper received ※ 20 May 2021 paper accepted ※ 08 August 2021 issue date ※ 28 August 2021

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THPAB352

Computer Vision Techniques Used to Monitor the Alignment of Cavities and Solenoids in the PIP-II Prototype SSR1 Cryomodule

cavity, solenoid, alignment, target

4485

S. Zorzetti, J. Bernardini, D. Passarelli
Fermilab, Batavia, Illinois, USA

The alignment of the SRF PIP-II string components is studied as the acceptable beam deflection, offset and defocusing, which may otherwise cause beam loss. Simulations and measurements established that the maximum deviation of the beam pipe from the reference orbit should not exceed a small fraction of the beam aperture. To observe the translations and rotations of each single component within the cryomodule, optical instruments (H-BCAM) surveying highly reflective targets, installed in the internal assembly of the module were used. The alignment monitoring concept for the PIP II SSR1 prototype cryomodule, along with relevant measurements of the components’ position monitoring during coldmass cooldown is presented in this contribution. This development paves the way to new computer vision applications in the field of cryomodule assemblies in cleanroom environment, in which robotically-assisted operations have the potential to dramatically reduce the risk of chemical and particulate contamination.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB352

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paper received ※ 19 May 2021 paper accepted ※ 02 August 2021 issue date ※ 31 August 2021

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FRXC01

Superconducting Radio-Frequency Cavity Fault Classification Using Machine Learning at Jefferson Laboratory

cavity, network, SRF, radio-frequency

4535

C. Tennant, A. Carpenter, T. Powers, L.S. Vidyaratne
JLab, Newport News, Virginia, USA
K.M. Iftekharuddin, M. Rahman
ODU, Norfolk, Virginia, USA
A.D. Shabalina
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

Funding: This work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Contract No. DE-AC05-06OR23177.
We report on the development of machine learning models for classifying C100 superconducting radiofrequency (SRF) cavity faults in the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab. Of the 418 SRF cavities in CEBAF, 96 are designed with a digital low-level RF system configured such that a cavity fault triggers recordings of RF signals for each of eight cavities in the cryomodule. Subject matter experts analyze the collected time-series data and identify which of the eight cavities faulted first and classify the type of fault. This information is used to find trends and strategically deploy mitigations to problematic cryomodules. However, manually labeling the data is laborious and time-consuming. By leveraging machine learning, near real-time - rather than postmortem - identification of the offending cavity and classification of the fault type has been implemented. We discuss the performance of the machine learning models during a recent physics run. We also discuss efforts for further insights into fault types through unsupervised learning techniques and present preliminary work on cavity and fault prediction using data collected prior to a failure event.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-FRXC01

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paper received ※ 16 May 2021 paper accepted ※ 01 July 2021 issue date ※ 13 August 2021

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