Paper | Title | Other Keywords | Page |
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MO1A02 | An Overview of Recent Developments in SRF Technology | cavity, SRF, niobium, linac | 6 |
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Superconducting Radio-Frequency (SRF) is now the technology of choice for both large and small linac projects. Several challenging projects are in progress or planned that are pushing SRF technology and/or are enabled by SRF technology. This paper gives an overview of the present status of the field. | |||
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Slides MO1A02 [4.202 MB] | ||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MO1A02 | ||
About • | paper received ※ 16 September 2018 paper accepted ※ 31 October 2018 issue date ※ 18 January 2019 | ||
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MO1P01 | Status of the SNS Proton Power Upgrade Project | target, linac, injection, operation | 24 |
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SNS plans to double the power capability of the SNS proton beam by increasing the beam energy and the beam current. Accelerator scope includes additional superconducting RF cryo-modules and supporting RF systems, and upgrades to existing RF systems. Also the accumulator storage ring and the neutron source target will be upgraded to accommodate the additional power. The technical approach, project status and plans will be discussed. | |||
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Slides MO1P01 [6.457 MB] | ||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MO1P01 | ||
About • | paper received ※ 10 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019 | ||
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MOPO019 | Study on Cleaning of Copper Plated Bellows for LCLS-II | cavity, SRF, FEL, experiment | 71 |
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Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contracts DE-AC05-06OR23177 and DE-AC02-76SF00515 for the LCLS-II Project. Inter-cavity copper plated bellows are part of the LCLS-II cryomodule beamline components. Since the bellows are close to superconducting radio frequency (SRF) cavities during accelerator operation, it is desirable that these bellows have similar cleanliness as SRF cavi-ties. Studies have been done to help evaluate bellows interior cleanliness after the standard bellows cleaning procedure at Jefferson Lab. |
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Poster MOPO019 [1.326 MB] | ||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO019 | ||
About • | paper received ※ 28 August 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019 | ||
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MOPO130 | Magnetic Flux Generated by Thermal Current in CEBAF 5-Cell Cavity System | cavity, experiment, niobium, operation | 273 |
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The unloaded quality factor Q0 of many 5-cell CEBAF cavities were lowered by a factor of ~2 from their vertical qualification testing to their beam operation in CEBAF tunnel. Causes of this Q0 degradation were studied previously, including a more recent one addressing static fluxes arising from magnetic components near a 5-cell cavity. This paper reports on a preliminary study of the dynamic fluxes generated by a thermal current. Such a thermal current arises from the Seebeck effect and flows in closed loops formed by a niobium cavity and its surrounding tuner rods and liquid helium vessel that are made of stainless-steel. The behaviors of magnetic fluxes in response to various thermal profiles on a 5-cell CEBAF cavity with integrated tuner rods were studied in a JLAB VTA dewar. An outcome of this study is a proposed cool-down procedure for eliminating the thermal current generated magnetic fluxes around 5-cell cavities placed in CEBAF tunnels. This procedure may be useful to improve cavity Q0 in a cost-effective manner, which in turn saves cryogenic expenditures for sustaining CEBAF operation. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO130 | ||
About • | paper received ※ 01 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019 | ||
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TU1A01 | Challenges in Superconducting Accelerating Module Design and Construction for High Power Proton Accelerators | cavity, linac, vacuum, alignment | 280 |
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CEA is engaged in the construction of the IFMIF, SARAF and ESS superconducting linacs and in particular in the design and production of a their accelerating cryomodules: 1 low-beta half-wave 176 MHz resonators for IFMIF, 4 low-beta half-wave 176 MHz resonators for SARAF and 30 medium and high-beta elliptical cavity resonators for ESS. The developments of these RF cryomodules, although at various stages, are led in parallel by the cryomodule team at CEA-Saclay, including all RF, mechanical, thermal, cryogenic, integration and QA-QC aspects in a global approach which attempts to optimise synergies and lessons learnt between these projects. A status report will be presented describing the common approaches and methods, and the systemic particularities of each project. | |||
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Slides TU1A01 [11.896 MB] | ||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TU1A01 | ||
About • | paper received ※ 14 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019 | ||
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TU1A05 | Seamless Quarter Wave Resonators for HIE ISOLDE | cavity, ISOL, niobium, linac | 292 |
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The HIE-ISOLDE post accelerator consists of 4 cryomodules with 5 niobium-coated Quarter Wave Reso-nators (QWR) each. The standard manufacturing tech-nique was to machine the inner and outer conductor sepa-rately, to shrink-fit the 2 pieces and to apply an electron beam welding at the interface. Due toμcracks, ob-served on some of the cavities around the welds, we took the decision to explore the possibility of a seamless de-sign. First cavities became available in late 2017 and were then cold-tested in the vertical cryostat. These seam-less coated quarter wave resonators have shown some of the highest Q-values of all HIE-ISOLDE cavities in the acceptance tests. Furthermore, we studied the cavity per-formance with different compensations of the earth mag-netic field and different temperature gradients upon cool down. These tests have demonstrated record-breaking RF surface fields for the Nb/Cu technology. This paper re-views the design and fabrication and reports on the cold tests results of seamless quarter wave resonators, and of possible future applications | |||
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Slides TU1A05 [30.518 MB] | ||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TU1A05 | ||
About • | paper received ※ 11 September 2018 paper accepted ※ 08 October 2018 issue date ※ 18 January 2019 | ||
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TUPO019 | SPIRAL2 Cryogenic System Thermodynamic Behavior Prediction Through Dynamic Modeling | cryogenics, cavity, controls, experiment | 366 |
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SPIRAL 2 (Caen, France) is a state of the art superconducting linear accelerator composed of 26 quarter wave accelerating cavities. Each cavity is plunged in a liquid helium bath at 4.4 K itself surrounded by a thermal shield at 70 K. In this paper, a dynamic model of the cryogenic systemof the LINAC is proposed. Thismodel simulates the dynamic behaviour of the 19 cryomodules and their respective valves box connected through the cryodistribution. Model accuracy is evaluated through a comparison between simulation and experimental data. Using the model we should be able to predict the behaviour of the cryogenic system for different beam operating conditions of the accelerator. The model also highlights the link between the cryogenic system and the cavity RF losses through a dynamic estimator of those RF losses in the cavity walls. The latter could be used as a rough estimator of the quality factor of a cavity. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO019 | ||
About • | paper received ※ 13 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019 | ||
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TUPO020 | Microphonics Investigation of ARIEL e-Linac Cryomodules | cavity, pick-up, damping, linac | 370 |
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Now the stage of the 30MeV portion of ARIEL (The Advanced Rare Isotope Laboratory) e-Linac is under commissioning which includes an injector cryomodule (ICM) and the 1st accelerator cryomodule (ACM1) with two cavities configuration. In this paper, the progress of the microphonics investigation and suppression of ICM and ACM1 is presented. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO020 | ||
About • | paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019 | ||
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TUPO027 | Series Production of the Specific Waveguide Distribution for the European XFEL at DESY | GUI, cavity, FEL, LLRF | 380 |
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Series Production of the Specific Waveguide Distribution for the European XFEL at DESY B.Yildirim, S.Choroba, V.Katalev, P.Morozov, Y.Nachtigal, E.Apostolov The European XFEL uses 100 accelerating cryomodules. One RF station with 10 MW klystron supplies four cryomodules, each with eight cavities, through a waveguide distribution system. The RF station operates at 1.3 GHz, 1.37 ms pulse width and 10 Hz repetition rate. The results of the cryomodule test have shown however different maximum gradients for each cavity. The maximum gradient has been measured between 11 MV/m and 31 MV/m, which requires the cavity power from 29 kW to 230 kW. To operate with the maximum energy for every cryomodule, it is necessary to supply individual power to the cavity. In this case the weakest cavity problem can be avoided. For this goal a specific waveguide distribution has been developed. 100 waveguide distributions have been successfully tailored, produced and tested at the Waveguide Assembly Test Facility (WATF) at DESY and finally assembled to the cryomodules. We present the series production of the specific waveguide distributions at the WATF. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO027 | ||
About • | paper received ※ 06 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019 | ||
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TUPO029 | Highlights of the XM-3 Cryomodule Tests at DESY | cavity, FEL, operation, feedback | 388 |
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To investigate the feasibility of the continuous wave (cw) upgrade of the European XFEL (E-XFEL) DESY, on-going tests are performed on E-XFEL prototype and production cryomodules since 2011. For these studies, DESY’s Cryo-Module Test Bench (CMTB) has been equipped with a 105 kW cw operating IOT in addition to the 10MW pulsed klystron, making CMTB a very flexible test stand, enabling both cw and pulse operation. For these tests, E-XFEL-like LLRF electronics is used to stabilize amplitude and phase of the voltage Vector Sum (VS) of all 8 cavities of the cryomodule under test. The cryomodule most often tested is the pre-series XM-3, unique since it is housing one fine grain niobium and seven large grain niobium cavities. In autumn 2017, additional spacers were installed on all 8 input couplers to increase the maximum reachable loaded quality factor Ql beyond 2·107. With higher Ql, up to 6·107 for 6 cavities and 2.7·107 for 2 cavities, we have investigated the VS stability and SRF-performance of this cryomodule under various conditions of cooling down rate and operation temperature 1.65K, 1.8K and 2K, at gradients up to ca. 18MV/m. The results of these tests are presented in this paper. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO029 | ||
About • | paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019 | ||
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TUPO041 | LCLS-II Cavity Higher Order Modes Coupler Tuning Optimization and Challenges at Jefferson Lab | HOM, cavity, vacuum, target | 423 |
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LCLS-II is a new XFEL linac based on 1.3GHz SRF linac. Half of the LCLS-II cryomodules are being produced at Jefferson Lab. This paper summarizes the Higher Order Mode filter tuning challenges at Jefferson Lab and describes optimization of the procedure for a 9-cell Tesla type cavity and its integration into a cryomodule production line. | |||
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Poster TUPO041 [0.719 MB] | ||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO041 | ||
About • | paper received ※ 11 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019 | ||
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TUPO058 | Cool Down Studies for the LCLS-II Project | cavity, network, SRF, linac | 470 |
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The quality factor of the nitrogen-doped SRF cavities for the LCLS-II project are strongly impacted by cool down speed. A sufficiently fast cool down speed can produce large thermal gradient across a cavity and sufficiently expel magnetic flux when the cavity wall passes from the normal-conducting to the superconducting state. However, instrumentation in LCLS-II production cryomodules has been kept at a minimum, and additional information during the cool down of the modules is therefore desirable. In this work, we study if and how RF data can be used during cavity cool-down to determine the transition speeds of the individual cavities in the LCLS-II linac. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO058 | ||
About • | paper received ※ 19 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019 | ||
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TUPO064 | Pre-study of CEPC SRF Cavity | cavity, SRF, collider, electron | 476 |
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Funding: This study was supported by National Key Programme for S&T Research and Development (Grant NO.: 2016YFA0400400) and National Natural Science Foundation of China (Grant NO.:11505197). CEPC will use 650 MHz cavities for the collider and 1.3 GHz cavities for the Booster. Each booster cryomod-ule contains eight 1.3 GHz 9-cell cavities, which is simi-lar as LCLS-II, E-XFEL and ILC. Each collider cryo-module contains six 650 MHz 2-cell cavities, which is totally new. Therefore, the pre-study mainly focuses on the 650 MHz 2-cell cavity. N-doping and vertical tests of 650 MHz 1-cell and 2-cell cavities have been carried out at IHEP, which have achieved good results. A test cryomodule, which consists of two 650 MHz 2-cell cavities, has also begun as the first step to the full-scale cryomodule. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO064 | ||
About • | paper received ※ 31 August 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019 | ||
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TUPO084 | Beam Dynamics Simulations for the New Superconducting CW Heavy Ion LINAC at GSI | linac, cavity, heavy-ion, experiment | 525 |
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Funding: Work supported by BMBF contr. No. 05P15RFRBA, EU Framework Programme H2020 662186 (MYRTE) and HIC for FAIR For future experiments with heavy ions near the coulomb barrier within the super-heavy element (SHE) research project a multi-stage R&D program of GSI/HIM and IAP is currently in progress. It aims for developing a supercon-ducting (sc) continuous wave (CW) LINAC with multiple CH cavities as key components downstream the High Charge State Injector (HLI) at GSI. The LINAC design is challenging due to the requirement of intense beams in CW mode up to a mass-to-charge ratio of 6, while covering a broad output energy range from 3.5 to 7.3 MeV/u with unchanged minimum energy spread. Testing of the first CH-cavity in 2016 demonstrated a promising maximum accelerating gradient of Ea = 9.6 MV/m; the worldwide first beam test with this sc multi-gap CH-cavity in 2017 was a milestone in the R&D work of GSI/HIM and IAP. In the light of experience gained in this research so far, the beam dynamics layout for the entire LINAC has recently been updated and optimized. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO084 | ||
About • | paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019 | ||
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WE2A01 | First Acceleration at FRIB | rfq, MMI, linac, emittance | 615 |
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FRIB is now moving to commissioning interleaved with installation. The ECR, low energy transport and RFQ have been commissioned with beam By the time of the conference the 4K cryogenic system and first three beta 0.041 QWR cryomodules will be commissioned with first cold acceleration. The talk would focus on the hardware and beam performance. | |||
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Slides WE2A01 [11.425 MB] | ||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-WE2A01 | ||
About • | paper received ※ 17 September 2018 paper accepted ※ 09 October 2018 issue date ※ 18 January 2019 | ||
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WE2A03 | Construction Status of the Superconducting Linac at RIKEN RIBF | cavity, vacuum, linac, DTL | 620 |
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An upgrade project of the RIKEN Heavy-Ion Linac, RILAC, is under going, which aims at the further investigation of the super-heavy elements and production of radioactive isotopes for medical applications. In this project, a new superconducting ECR ion source and superconducting RF (SRF) booster linac are being developed and constructed. The SRF linac consists of 10 quarter-wavelength resonator operated at 73 MHz, that are contained in three cryomodules. The construction status, including the first vertical test results, will be given in this paper. | |||
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Slides WE2A03 [23.169 MB] | ||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-WE2A03 | ||
About • | paper received ※ 14 September 2018 paper accepted ※ 17 October 2018 issue date ※ 18 January 2019 | ||
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THPO008 | Long-term 0peration with Beam and Cavity Performance Degradation in Compact-ERL Main Linac at KEK | cavity, operation, linac, vacuum | 695 |
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We developed ERL main linac cryomodule for Compact ERL (cERL) in KEK. The module consists of two 9-cell 1.3 GHz superconducting cavities. After construction of cERL recirculation loop, beam operation was started in 2013 Dec. First electron beam of 20 MeV successfully passed the main linac cavities. Beam current increased step by step and currently reached to 1mA (CW). Energy recovery has successfully achieved. However, field emission was one of the problems for long term operation. Therefore, the performance of the SRF cavities through long term beam operation has been investigated. In this paper, we express the measurement of the cavity performances and its degradation during long term beam operation. We also described the details of the cavity performance degradation and some trial for the cavity performance recovery. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO008 | ||
About • | paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019 | ||
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THPO067 | Control System and Experiment for RAON HWR Cryomodules | cavity, controls, PLC, cryogenics | 845 |
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A prototype of half-wave resonator (HWR) cryomodules is fabricated and tested. Cables and tray are installed for horizontal test. The design and the piping and instrumentation diagram (P&ID) of the HWR cryomodule are presented. The HWR cryomodule is tested with developed programmable logic controller (PLC) and experimental physics and industrial control system (EPICS) control systems. The heat loads of the HWR cryomodule for static and dynamic are measured. | |||
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Poster THPO067 [0.631 MB] | ||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO067 | ||
About • | paper received ※ 10 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019 | ||
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