LINAC2014 - List of Keywords (niobium)

Paper	Title	Other Keywords	Page
MOPP001	First Experimental Results for the Superconducting Half-Wave Resonators for PXIE	cavity, proton, cryomodule, accelerating-gradient	46
	Z.A. Conway, A. Barcikowski, G.L. Cherry, R.L. Fischer, S.M. Gerbick, M. Kedzie, M.P. Kelly, S.H. Kim, S.W.T. MacDonald, R.C. Murphy, P.N. Ostroumov, T. Reid, K.W. Shepard ANL, Argonne, Illinois, USA
	Funding: This work was supported by the U.S. Department of energy, Offices of High-Energy Physics and Nuclear Physics, under Contract No. DE-AC02-76-CH03000 and DE-AC02-06CH11357. The first pair of superconducting niobium half-wave resonators operating at 162.5 MHz for the FNAL PIP-II project are complete and this poster reports the cold test results. These cavities are optimized to accelerate protons/H⁻ from 2 to 10 MeV and build upon optimized electromagnetic designs and processing techniques developed at Argonne for the Intensity Upgrade of the ATLAS superconducting heavy ion accelerator.

MOPP002	Design of a Superconducting Quarter-Wave Resonator for eRHIC	cavity, electron, linac, SRF	49
	S.V. Kutsaev, Z.A. Conway, M.P. Kelly, B. Mustapha, P.N. Ostroumov ANL, Argonne, USA S.A. Belomestnykh, I. Ben-Zvi Stony Brook University, Stony Brook, USA S.A. Belomestnykh, I. Ben-Zvi, Q. Wu, W. Xu BNL, Upton, Long Island, New York, USA B. P. Xiao SBU, Stony Brook, New York, USA
	Funding: Work is supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 and by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357 The electron-ion collider project (eRHIC) at Brookhaven National Laboratory requires a 50 mA 12 MeV electron injector linac for eRHIC main linac and an SRF electron gun for a Coherent electron Cooling (CeC) linac. The necessity to deal with long electron bunches required for both the eRHIC injector and the coherent electron cooler sets the frequency requirement of 84.5 MHz. Quarter wave resonator is a perfect choice for this frequency because of its dimensions, RF parameters and good experience with manufacturing and using them at ANL. Here we present the design and optimization of an 84.5 MHz 2.5 MV superconducting quarter-wave cavity suitable for both machines. One such QWR will be used as a bunching cavity in the injector linac, the other one as the photoemission electron source for the CeC linac. In addition to the optimization of the QWR electromagnetic design we will discuss the tuner design, approaches to cavity fabrication and processing.

MOPP019	Nb3Sn Materials Studies	SRF, cavity, electron, ion	92
	S. Posen, M. Liepe Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA Th. Proslier ANL, Argonne, Illinois, USA
	Nb₃Sn is a very promising material for use in SRF cavity applications, potentially offering significant improvements in quality factor and energy gradient compared to niobium. In order to better understand how to optimize this material for SRF applications, Nb₃Sn samples were prepared at Cornell via vapor deposition, using varying parameters in the coating process. Microscopic studies were performed with SEM/EDX, and studies were performed on bulk samples to measure secondary electron yield, energy gap, and upper critical magnetic field. The results are presented here, with discussion for how they might point the way towards reaching even higher fields in Nb₃Sn cavities.
	Poster MOPP019 [2.742 MB]

MOPP081	The ECT System for RAON's Cavities	SRF, cavity, experiment, controls	242
	M.J. Joung, Y. Jung, H.J. Kim IBS, Daejeon, Republic of Korea
	The ECT system is in use for Nb surface control in many laboratories. This system can inspect Nb surface quickly using high resolution. The ECT system for RAON's cavity was made with the feature : It has 3-axis acting probe movement system, It can inspect big size of Nb sheet, which is 1m by 1m and It contain the analysis program that can show the result as 2D and 3D image as well as relative figure of surface level. The standard sample was made with various sizes of defects using the same Nb sheet that was used to make RISP cavity. The ECT system conditioining was carried out to optimize ECT operation on the frequency, the range is from 300kHz to 2MHz. The result of 900 kHz shows the strongest signal. The conditioning experiment on other parameter will be carried out in near future. .

TUIOC03	Nb3Sn - Present Status and Potential as an Alternative SRF Material	cavity, linac, SRF, cryogenics	431
	S. Posen, M. Liepe Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Nb₃Sn is a material that has the potential to have a transformative impact on SRF linacs. Due to its large critical temperature of approximately 18 K, Nb₃Sn cavities can have far smaller surface resistances at a given temperature than standard Nb cavities. This could significantly reduce the costs for infrastructure and power in cryoplants for large CW linacs. In addition, the predicted superheating field of Nb₃Sn is approximately double that of Nb, potentially doubling the maximum energy gradient. This would significantly decrease the size and cost of high energy linacs. In this work, we present recent progress in research and development for this promising material.
	Slides TUIOC03 [3.357 MB]
	Poster TUIOC03 [2.046 MB]

TUPP018	Analysis of Systematic and Random Error in SRF Material Parameter Calculations	simulation, cavity, extraction, SRF	465
	S.J. Meyers, M. Liepe, S. Posen Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA M. Liepe Cornell University, Ithaca, New York, USA
	Funding: NSF Career award PHY-0841213 and DOE award ER41628 To understand the relationship between an RF cavity’s performance and the material on its surface, one must look at various parameters, including energy gap, mean free path, and residual resistance. Though SRIMP fits for seven parameters, three parameters are eliminated using measurement and literature values, and the uncertainty of the fit of the remaining four parameters is further reduced by synthesizing two 3-parameter fits, each from a different data set. To study random error, Monte Carlo simulations were performed of ideal data with added noise; for systematic error, contour plots of normalized residual sum of squares (RSS) of the polymorphic fit on inputted data were generated.
	Poster TUPP018 [1.183 MB]

TUPP055	Progress on Euclid SRF Conical Half-Wave Resonator Project	cavity, vacuum, SRF, proton	547
	E.N. Zaplatin FZJ, Jülich, Germany T.L. Grimm Niowave, Inc., Lansing, Michigan, USA A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio, USA V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	Funding: This Work is supported by the DOE SBIR Program, contract # DE-SC0006302. Euclid conical Half-Wave Resonator (cHWR) project develops 162.5 MHz β=v/c=0.11 accelerator structure for the high-intensity proton accelerator complex proposed at Fermi National Accelerator Laboratory. The main idea of this project is to provide a self-compensation cavity design together with its helium vessel to minimize the resonant frequency dependence on external loads. A unique cavity side-tuning option is also under development. Niowave, Inc. proposed a complete cavity production procedure including preparation of technical drawings, processing steps and resonator high-gradient tests to demonstrate such possibility for the private company. Here we present the procedure of the cavity and helium vessel fabrication, cavity preparation and initial experimental results.

TUPP083	Design and Analysis of Slow Tuner in the Superconducting Cavity of RISP	cavity, superconducting-cavity, target, SRF	616
	M.O. Hyun, H.C. Jung, H.J. Kim IBS, Daejeon, Republic of Korea
	Funding: This work was supported by the Rare Isotope Science Project of Institute of Basic Science funded by the Ministry of Science, ICT and Future Planning and National Research Foundation. Superconducting cavity is one of the most complex systems from the view of mechanical engineering, which is installed and operated in the superconducting linear accelerator. In order to operate SC cavity properly and precisely, superconducting cavity needs many sub-systems, including power coupler for applying RF power inside cavity, and liquid helium jacket for cooling cavity until reaching to the superconducting conditions. And, also cavity needs frequency tuning system for adjusting operating frequency when RF frequency of cavity is changed with outer disturbances such as liquid helium fluctuation, mechanical deformation due to vacuum condition of cavity. Generally, this tuning system is called as a tuner. There are two types of tuner, one is slow tuner which operates with motor, and the other is fast tuner which operates with piezo-electric actuator. This paper describes about design process and analysis results about slow tuner.

TUPP084	Surface Treatment Facilities for SCRF Cavities at RISP	cavity, vacuum, superconducting-cavity, superconducting-RF	619
	J. Joo, D. Jeon, M.J. Joung, Y. Jung, H.J. Kim, M. Lee IBS, Daejeon, Republic of Korea
	Rare Isotope Science Project is engaged in the fabrication of four types of superconducting RF cavities. The surface treatment is one of the important processes of superconducting RF cavity fabrication. New superconducting RF cavity processing systems have been designed and developed for the etching of niobium in buffered chemical polish at RISP. The safety precautions used in protecting the operator from the acids used in the etchant and from the fumes given of during the process are discussed. All of the new hardware will be located in RISP Munji Superconducting Cavity Test Facility.

TUPP088	The Fabrication of the β=0.12 HWR at RISP	cavity, target, vacuum, electron	628
	G.-T. Park, H.J. Cha, Y. Jung, H. Kim, W.K. Kim IBS, Daejeon, Republic of Korea
	At RISP, the superconducting cavities have been developed to construct RAON, the heavy ion accelerator. Among the cavities, the fabrication of the QWR (Quarter wave resonator) and the HWR (Half wave resonator)are complete. The detailed fabrication processes including material inspection, forming, the electron beam welding, and the clamp up test are described.

TUPP092	Developmental and Operational Aspects of Nb QWR Based Heavy Ion LINAC System at IUAC Delhi	linac, controls, operation, ion	640
	S. Ghosh, R. Ahuja, J. Antony, S. Babu, J. Chacko, G.K. Chaudhari, A. Chaudhary, T.S. Datta, R.N. Dutt, R. Joshi, D. Kanjilal, S. Kar, J. Karmakar, M. Kumar, R. Kumar, D.S. Mathuria, K.K. Mistri, A. Pandey, P. Patra, P.N. Potukuchi, A. Rai, J. Sacharias, B.K. Sahu, A. Sarkar, S.S.K. Sonti, S. K. Suman IUAC, New Delhi, India A. Roy VECC, Kolkata, India
	The superconducting linac of IUAC consists of five cryostats containing 27 niobium quarter wave resonators. The prototype and the first 12 resonators were fabricated in collaboration with Argonne National Laboratory. The fabrication of the remaining resonators were carried out using in-house facilities available at IUAC. During the initial period of linac operations, problems were faced to generate higher accelerating fields in the resonators inside the linac cryostat and to reproduce the high fields at the time of beam acceleration. With systemetic efforts, all the major problems are solved and the complete linac is now operational. Since last few years, energized ion beams from linac are being delivered routinely for scheduled experiments. Among the major developmental works related to the linac operation, the vibrational damping mechansim by SS-balls, use of piezo actuator as mechanical tuner and the calculation of optimum phase focussing to control the time width of the beam bunches are noteworthy. Other two developments e.g. automatic phase locking of the resonators and auto beam tuning of the complete linac will be tested during the next beam acceleration.

TUPP138	Analysis of New High-Q0 SRF Cavity Tests by Nitrogen Gas Doping at Jefferson Lab	cavity, injection, SRF, vacuum	736
	A.D. Palczewski, R.L. Geng, C.E. Reece JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. In order to refine systematic understanding and establish confident process control, Jefferson Lab has joined with partners to investigate and thoroughly characterize the dramatically higher Q0 of 1.3 GHz niobium cavities first reported by FNAL in 2013[1]. With partial support from the LCLS-II project, JLab has undertaken a parametric study of nitrogen doping in vacuum furnace at 800 C followed by variable depth surface removal in the 5 - 20 μm range. Q0 above 3×10¹⁰ are typical at 2.0 K and 16 MV/m accelerating field. We report observations from the single cell study and current interpretations. In addition to the parametric single cell study, we also report on the ongoing serial testing of six nitrogen-doped 9-cell cavities as baseline prototypes for LCLS-II. [1] A. Grassellino, et al., Supercon. Sci.and Tech., 2013. 26(10): p. 102001
	Poster TUPP138 [4.214 MB]

THPP016	Nitrogen-Treated Cavity Testing at Cornell	cavity, SRF, linac, vacuum	866
	D. Gonnella, F. Furuta, G.M. Ge, M. Liepe Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: U.S. Department of Energy Recent results from Cornell, FNAL, and TJNAF have shown that superconducting RF cavities given a heat treatment in a nitrogen atmosphere show higher Q₀ at operating gradients at 2.0 K than standard SRF cavities. Here we present on recent results at Cornell in which five single cell cavities and three 9-cell cavities were tested after receiving various nitrogen-doping treatments. Cavity performance was correlated with treatment, and samples treated with the cavities were analyzed with SIMS. These results provide new insights into the science behind the excellent performance that is observed in these cavities.

THPP018	Sample Plate Studies Using a High Field TE Cavity With Thermometry Mapping System	cavity, coupling, SRF, experiment	873
	D.L. Hall, C.D. Burton, M. Liepe Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: NSF Career Grant PHY-0841213 A TE-Mode sample plate cavity capable of sustaining peak fields of >90 mT on the surface of a 10cm diameter sample plate has been developed and tested at Cornell. A thermometry mapping system composed of 40 Allen-Bradley resistors, mounted on the outside of the sample plate, is capable of measuring the surface resistance of the sample with a resolution of 1 nOhm and a spatial resolution of 0.5 cm. In this paper we present the design and expected performance of this high field TE cavity, and show data taken with a sample plate of niobium as well as results from tests qualifying the performance of the thermometry mapping system.

THPP029	Electropolishing Simulation on Full Scale Radio Frequency Elliptical Structures	cavity, simulation, cathode, radio-frequency	898
	L.M.A. Ferreira CERN, Geneva, Switzerland H. Rana, J.A. Shirra Loughborough University, Leicestershre, United Kingdom
	This paper describes a methodology to simulate the electropolishing of a full scale radio frequency (RF) accelerating elliptical cavity through data acquired by means of a rotating disc electrode (RDE) in a three electrode set-up. The method combines laboratorial data from the RDE with computational simulation performed with Comsol Multiphysics® either for the primary and secondary current distribution as well as to account for the local effect of hydrodynamic perturbations. The results are compared with experimental data from the electropolishing of niobium 704 MHz and five cell cavity from the Superconducting Proton Linear Accelerator (SPL) R&D project at CERN.
	Poster THPP029 [0.177 MB]

THPP039	Electron Beam Welding and Vacuum Brazing Characterization for SRF Cavities	vacuum, cavity, electron, interface	932
	N. Valverde Alonso, S. Atieh, I. Aviles Santillana, S. Calatroni, O. Capatina, L.M.A. Ferreira, F. Pillon, M. Redondas Monteserin, T. Renaglia, K.M. Schirm, T. Tardy, A. Vacca CERN, Geneva, Switzerland
	In the framework of the SPL R&D effort at CERN, development design efforts study the joining of dissimilar metals: bulk niobium for the superconducting RF cavities and stainless steel (316LN) or titanium alloys (Ti-6Al-4V and Nb55Ti) for the cryostats. Joining techniques of electron beam welding (EBW) and vacuum brazing are particularly important for these applications. These processes have been used in the accelerator community and developed into generally accepted “best practice”. Studies were performed to update the existing knowledge, and comprehensively characterise these joints via mechanical and metallurgical investigations using modern available technologies. The developed solutions are described in detail, some currently being applied uniquely at CERN.
	Poster THPP039 [5.324 MB]

THPP099	Status of Superconducting Cavity and Cryomodule Development at MHI	cavity, cryomodule, vacuum, superconducting-cavity	1084
	T. Yanagisawa, H. Hara, N. Ikeda, K. Sennyu MHI, Hiroshima, Japan
	MHI's activities for ｓuperconducting accelerator are reported. MHI had developed several procedure and method of ILC cavity production for stable quality and cost reduction. And we had fabricated and installed cryomodules for ILC and ERL R&D. These activities are reported in detail.

THPP122	Development of Superconducting Cavities and Related Infrastructure for High Intensity Proton Linac for Spallation Neutron Source	cavity, laser, linac, proton	1140
	S.C. Joshi, J. Dwivedi, P.D. Gupta, P.R. Hannurkar, V. Jain, P. Khare, P.K. Kush, G. Mundra, A. Puntambekar, S. Raghvendra, S.B. Roy, P. Shrivastava RRCAT, Indore (M.P.), India
	Raja Ramanna Centre for Advanced Technology has taken up a program on R&D activities of a 1 GeV, high intensity superconducting proton linac for a spallation neutron source. The proton linac will require a large number of superconducting Radio Frequency cavities ranging from low beta spoke resonators to medium and high beta multi-cell elliptical cavities at different RF frequencies. A dedicated facility is being set up for development of multi-cell superconducting cavities and their performance characterization. 1.3 GHz single-cell niobium cavities have been developed to establish the fabrication procedure. These cavities has exhibited high quality factor with an accelerating gradients up to 37 MV/m. A novel technique of laser welding of 1.3 GHz niobium cavity has been developed and demonstrated performance comparable to electron beam welded cavity. A dedicated facility for SCRF cavity forming, machining, electron beam welding, RF characterization, cavity tuning and cavity processing is being set up. To characterize a SCRF cavity at 2K, a vertical test stand has been developed and a horizontal test stand has been designed.

THPP124	Wakefields in the Superconducting RF Cavities of LCLS-II	cavity, linac, wakefield, electron	1147
	K.L.F. Bane, T.O. Raubenheimer SLAC, Menlo Park, California, USA A. Romanenko, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	Funding: Work supported by Department of Energy contract DE–AC02–76SF00515. The superconducting cavities in the linacs of LCLS-II are designed to operate at 2K, where cooling costs are very expensive. In addition to an unavoidable static load and the dynamic load of the fundamental 1.3 GHz accelerating rf, there will be higher order mode (HOM) power deposited by the beam. Due to the very short bunch length the LCLS-II beam spectrum extends into the THz range. Ceramic absorbers, cooled to 70K and located between cryomodules, are meant to absorb much of this power; understanding their effectiveness, however, is a challenging task. In this report we calculate the amount of power radiated by the beam in the different portions of the linac as the bunch length is changed by the bunch compressors. We consider both the steady state radiation as well as transients that arise at the beginning of the linac structures. In addition, transitions due to changes in the vacuum chamber aperture at the ends of the linacs are also considered. Finally, under the assumption that all the wake power ends up in the SRF cavity walls, we estimate the wall heating and the possibility of breaking the Cooper pairs and quenching the cavities.

THPP131	Series Superconducting Cavity Production for the HIE-ISOLDE Project at CERN	cavity, cryomodule, vacuum, pick-up	1165
	M. Therasse, L. Alberty, K. Artoos, S. Calatroni, O. Capatina, A. D'Elia, N.M. Jecklin, Y. Kadi, I. Mondino, K.M. Schirm, A. Sublet, W. Venturini Delsolaro, P. Zhang CERN, Geneva, Switzerland
	In the context of the HIE-ISOLDE linac upgrade at CERN, the phase 1 planned to boost the energy of the machine from 3 MeV/u to 5 MeV/u. For this purpose, it is planned to install 2 cryomodules based on quarter waves resonators (QWRs) made by Niobium sputtering on Copper. The poster will present the different steps of the cavity series production since the reception from the industry to the cavity storage before cryomodule assembly. We will describe the cavity preparation included the resonance frequency measurement, the chemical treatment, the cavity rinsing, the Niobium coating and the RF test at 4.5K.

Paper

Title

Other Keywords

Page

MOPP001

First Experimental Results for the Superconducting Half-Wave Resonators for PXIE

cavity, proton, cryomodule, accelerating-gradient

46

Z.A. Conway, A. Barcikowski, G.L. Cherry, R.L. Fischer, S.M. Gerbick, M. Kedzie, M.P. Kelly, S.H. Kim, S.W.T. MacDonald, R.C. Murphy, P.N. Ostroumov, T. Reid, K.W. Shepard
ANL, Argonne, Illinois, USA

Funding: This work was supported by the U.S. Department of energy, Offices of High-Energy Physics and Nuclear Physics, under Contract No. DE-AC02-76-CH03000 and DE-AC02-06CH11357.
The first pair of superconducting niobium half-wave resonators operating at 162.5 MHz for the FNAL PIP-II project are complete and this poster reports the cold test results. These cavities are optimized to accelerate protons/H⁻ from 2 to 10 MeV and build upon optimized electromagnetic designs and processing techniques developed at Argonne for the Intensity Upgrade of the ATLAS superconducting heavy ion accelerator.

MOPP002

Design of a Superconducting Quarter-Wave Resonator for eRHIC

cavity, electron, linac, SRF

49

S.V. Kutsaev, Z.A. Conway, M.P. Kelly, B. Mustapha, P.N. Ostroumov
ANL, Argonne, USA
S.A. Belomestnykh, I. Ben-Zvi
Stony Brook University, Stony Brook, USA
S.A. Belomestnykh, I. Ben-Zvi, Q. Wu, W. Xu
BNL, Upton, Long Island, New York, USA
B. P. Xiao
SBU, Stony Brook, New York, USA

Funding: Work is supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 and by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357
The electron-ion collider project (eRHIC) at Brookhaven National Laboratory requires a 50 mA 12 MeV electron injector linac for eRHIC main linac and an SRF electron gun for a Coherent electron Cooling (CeC) linac. The necessity to deal with long electron bunches required for both the eRHIC injector and the coherent electron cooler sets the frequency requirement of 84.5 MHz. Quarter wave resonator is a perfect choice for this frequency because of its dimensions, RF parameters and good experience with manufacturing and using them at ANL. Here we present the design and optimization of an 84.5 MHz 2.5 MV superconducting quarter-wave cavity suitable for both machines. One such QWR will be used as a bunching cavity in the injector linac, the other one as the photoemission electron source for the CeC linac. In addition to the optimization of the QWR electromagnetic design we will discuss the tuner design, approaches to cavity fabrication and processing.

MOPP019

Nb3Sn Materials Studies

SRF, cavity, electron, ion

92

S. Posen, M. Liepe
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
Th. Proslier
ANL, Argonne, Illinois, USA

Nb₃Sn is a very promising material for use in SRF cavity applications, potentially offering significant improvements in quality factor and energy gradient compared to niobium. In order to better understand how to optimize this material for SRF applications, Nb₃Sn samples were prepared at Cornell via vapor deposition, using varying parameters in the coating process. Microscopic studies were performed with SEM/EDX, and studies were performed on bulk samples to measure secondary electron yield, energy gap, and upper critical magnetic field. The results are presented here, with discussion for how they might point the way towards reaching even higher fields in Nb₃Sn cavities.

Poster MOPP019 [2.742 MB]

MOPP081

The ECT System for RAON's Cavities

SRF, cavity, experiment, controls

242

M.J. Joung, Y. Jung, H.J. Kim
IBS, Daejeon, Republic of Korea

The ECT system is in use for Nb surface control in many laboratories. This system can inspect Nb surface quickly using high resolution. The ECT system for RAON's cavity was made with the feature : It has 3-axis acting probe movement system, It can inspect big size of Nb sheet, which is 1m by 1m and It contain the analysis program that can show the result as 2D and 3D image as well as relative figure of surface level. The standard sample was made with various sizes of defects using the same Nb sheet that was used to make RISP cavity. The ECT system conditioining was carried out to optimize ECT operation on the frequency, the range is from 300kHz to 2MHz. The result of 900 kHz shows the strongest signal. The conditioning experiment on other parameter will be carried out in near future. .

TUIOC03

Nb3Sn - Present Status and Potential as an Alternative SRF Material

cavity, linac, SRF, cryogenics

431

S. Posen, M. Liepe
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Nb₃Sn is a material that has the potential to have a transformative impact on SRF linacs. Due to its large critical temperature of approximately 18 K, Nb₃Sn cavities can have far smaller surface resistances at a given temperature than standard Nb cavities. This could significantly reduce the costs for infrastructure and power in cryoplants for large CW linacs. In addition, the predicted superheating field of Nb₃Sn is approximately double that of Nb, potentially doubling the maximum energy gradient. This would significantly decrease the size and cost of high energy linacs. In this work, we present recent progress in research and development for this promising material.

Slides TUIOC03 [3.357 MB]

Poster TUIOC03 [2.046 MB]

TUPP018

Analysis of Systematic and Random Error in SRF Material Parameter Calculations

simulation, cavity, extraction, SRF

465

S.J. Meyers, M. Liepe, S. Posen
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
M. Liepe
Cornell University, Ithaca, New York, USA

Funding: NSF Career award PHY-0841213 and DOE award ER41628
To understand the relationship between an RF cavity’s performance and the material on its surface, one must look at various parameters, including energy gap, mean free path, and residual resistance. Though SRIMP fits for seven parameters, three parameters are eliminated using measurement and literature values, and the uncertainty of the fit of the remaining four parameters is further reduced by synthesizing two 3-parameter fits, each from a different data set. To study random error, Monte Carlo simulations were performed of ideal data with added noise; for systematic error, contour plots of normalized residual sum of squares (RSS) of the polymorphic fit on inputted data were generated.

Poster TUPP018 [1.183 MB]

TUPP055

Progress on Euclid SRF Conical Half-Wave Resonator Project

cavity, vacuum, SRF, proton

547

E.N. Zaplatin
FZJ, Jülich, Germany
T.L. Grimm
Niowave, Inc., Lansing, Michigan, USA
A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA
V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Funding: This Work is supported by the DOE SBIR Program, contract # DE-SC0006302.
Euclid conical Half-Wave Resonator (cHWR) project develops 162.5 MHz β=v/c=0.11 accelerator structure for the high-intensity proton accelerator complex proposed at Fermi National Accelerator Laboratory. The main idea of this project is to provide a self-compensation cavity design together with its helium vessel to minimize the resonant frequency dependence on external loads. A unique cavity side-tuning option is also under development. Niowave, Inc. proposed a complete cavity production procedure including preparation of technical drawings, processing steps and resonator high-gradient tests to demonstrate such possibility for the private company. Here we present the procedure of the cavity and helium vessel fabrication, cavity preparation and initial experimental results.

TUPP083

Design and Analysis of Slow Tuner in the Superconducting Cavity of RISP

cavity, superconducting-cavity, target, SRF

616

M.O. Hyun, H.C. Jung, H.J. Kim
IBS, Daejeon, Republic of Korea

Funding: This work was supported by the Rare Isotope Science Project of Institute of Basic Science funded by the Ministry of Science, ICT and Future Planning and National Research Foundation.
Superconducting cavity is one of the most complex systems from the view of mechanical engineering, which is installed and operated in the superconducting linear accelerator. In order to operate SC cavity properly and precisely, superconducting cavity needs many sub-systems, including power coupler for applying RF power inside cavity, and liquid helium jacket for cooling cavity until reaching to the superconducting conditions. And, also cavity needs frequency tuning system for adjusting operating frequency when RF frequency of cavity is changed with outer disturbances such as liquid helium fluctuation, mechanical deformation due to vacuum condition of cavity. Generally, this tuning system is called as a tuner. There are two types of tuner, one is slow tuner which operates with motor, and the other is fast tuner which operates with piezo-electric actuator. This paper describes about design process and analysis results about slow tuner.

TUPP084

Surface Treatment Facilities for SCRF Cavities at RISP

cavity, vacuum, superconducting-cavity, superconducting-RF

619

J. Joo, D. Jeon, M.J. Joung, Y. Jung, H.J. Kim, M. Lee
IBS, Daejeon, Republic of Korea

Rare Isotope Science Project is engaged in the fabrication of four types of superconducting RF cavities. The surface treatment is one of the important processes of superconducting RF cavity fabrication. New superconducting RF cavity processing systems have been designed and developed for the etching of niobium in buffered chemical polish at RISP. The safety precautions used in protecting the operator from the acids used in the etchant and from the fumes given of during the process are discussed. All of the new hardware will be located in RISP Munji Superconducting Cavity Test Facility.

TUPP088

The Fabrication of the β=0.12 HWR at RISP

cavity, target, vacuum, electron

628

G.-T. Park, H.J. Cha, Y. Jung, H. Kim, W.K. Kim
IBS, Daejeon, Republic of Korea

At RISP, the superconducting cavities have been developed to construct RAON, the heavy ion accelerator. Among the cavities, the fabrication of the QWR (Quarter wave resonator) and the HWR (Half wave resonator)are complete. The detailed fabrication processes including material inspection, forming, the electron beam welding, and the clamp up test are described.

TUPP092

Developmental and Operational Aspects of Nb QWR Based Heavy Ion LINAC System at IUAC Delhi

linac, controls, operation, ion

640

S. Ghosh, R. Ahuja, J. Antony, S. Babu, J. Chacko, G.K. Chaudhari, A. Chaudhary, T.S. Datta, R.N. Dutt, R. Joshi, D. Kanjilal, S. Kar, J. Karmakar, M. Kumar, R. Kumar, D.S. Mathuria, K.K. Mistri, A. Pandey, P. Patra, P.N. Potukuchi, A. Rai, J. Sacharias, B.K. Sahu, A. Sarkar, S.S.K. Sonti, S. K. Suman
IUAC, New Delhi, India
A. Roy
VECC, Kolkata, India

The superconducting linac of IUAC consists of five cryostats containing 27 niobium quarter wave resonators. The prototype and the first 12 resonators were fabricated in collaboration with Argonne National Laboratory. The fabrication of the remaining resonators were carried out using in-house facilities available at IUAC. During the initial period of linac operations, problems were faced to generate higher accelerating fields in the resonators inside the linac cryostat and to reproduce the high fields at the time of beam acceleration. With systemetic efforts, all the major problems are solved and the complete linac is now operational. Since last few years, energized ion beams from linac are being delivered routinely for scheduled experiments. Among the major developmental works related to the linac operation, the vibrational damping mechansim by SS-balls, use of piezo actuator as mechanical tuner and the calculation of optimum phase focussing to control the time width of the beam bunches are noteworthy. Other two developments e.g. automatic phase locking of the resonators and auto beam tuning of the complete linac will be tested during the next beam acceleration.

TUPP138

Analysis of New High-Q0 SRF Cavity Tests by Nitrogen Gas Doping at Jefferson Lab

cavity, injection, SRF, vacuum

736

A.D. Palczewski, R.L. Geng, C.E. Reece
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
In order to refine systematic understanding and establish confident process control, Jefferson Lab has joined with partners to investigate and thoroughly characterize the dramatically higher Q0 of 1.3 GHz niobium cavities first reported by FNAL in 2013[1]. With partial support from the LCLS-II project, JLab has undertaken a parametric study of nitrogen doping in vacuum furnace at 800 C followed by variable depth surface removal in the 5 - 20 μm range. Q0 above 3×10¹⁰ are typical at 2.0 K and 16 MV/m accelerating field. We report observations from the single cell study and current interpretations. In addition to the parametric single cell study, we also report on the ongoing serial testing of six nitrogen-doped 9-cell cavities as baseline prototypes for LCLS-II.
[1] A. Grassellino, et al., Supercon. Sci.and Tech., 2013. 26(10): p. 102001

Poster TUPP138 [4.214 MB]

THPP016

Nitrogen-Treated Cavity Testing at Cornell

cavity, SRF, linac, vacuum

866

D. Gonnella, F. Furuta, G.M. Ge, M. Liepe
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: U.S. Department of Energy
Recent results from Cornell, FNAL, and TJNAF have shown that superconducting RF cavities given a heat treatment in a nitrogen atmosphere show higher Q₀ at operating gradients at 2.0 K than standard SRF cavities. Here we present on recent results at Cornell in which five single cell cavities and three 9-cell cavities were tested after receiving various nitrogen-doping treatments. Cavity performance was correlated with treatment, and samples treated with the cavities were analyzed with SIMS. These results provide new insights into the science behind the excellent performance that is observed in these cavities.

THPP018

Sample Plate Studies Using a High Field TE Cavity With Thermometry Mapping System

cavity, coupling, SRF, experiment

873

D.L. Hall, C.D. Burton, M. Liepe
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: NSF Career Grant PHY-0841213
A TE-Mode sample plate cavity capable of sustaining peak fields of >90 mT on the surface of a 10cm diameter sample plate has been developed and tested at Cornell. A thermometry mapping system composed of 40 Allen-Bradley resistors, mounted on the outside of the sample plate, is capable of measuring the surface resistance of the sample with a resolution of 1 nOhm and a spatial resolution of 0.5 cm. In this paper we present the design and expected performance of this high field TE cavity, and show data taken with a sample plate of niobium as well as results from tests qualifying the performance of the thermometry mapping system.

THPP029

Electropolishing Simulation on Full Scale Radio Frequency Elliptical Structures

cavity, simulation, cathode, radio-frequency

898

L.M.A. Ferreira
CERN, Geneva, Switzerland
H. Rana, J.A. Shirra
Loughborough University, Leicestershre, United Kingdom

This paper describes a methodology to simulate the electropolishing of a full scale radio frequency (RF) accelerating elliptical cavity through data acquired by means of a rotating disc electrode (RDE) in a three electrode set-up. The method combines laboratorial data from the RDE with computational simulation performed with Comsol Multiphysics® either for the primary and secondary current distribution as well as to account for the local effect of hydrodynamic perturbations. The results are compared with experimental data from the electropolishing of niobium 704 MHz and five cell cavity from the Superconducting Proton Linear Accelerator (SPL) R&D project at CERN.

Poster THPP029 [0.177 MB]

THPP039

Electron Beam Welding and Vacuum Brazing Characterization for SRF Cavities

vacuum, cavity, electron, interface

932

N. Valverde Alonso, S. Atieh, I. Aviles Santillana, S. Calatroni, O. Capatina, L.M.A. Ferreira, F. Pillon, M. Redondas Monteserin, T. Renaglia, K.M. Schirm, T. Tardy, A. Vacca
CERN, Geneva, Switzerland

In the framework of the SPL R&D effort at CERN, development design efforts study the joining of dissimilar metals: bulk niobium for the superconducting RF cavities and stainless steel (316LN) or titanium alloys (Ti-6Al-4V and Nb55Ti) for the cryostats. Joining techniques of electron beam welding (EBW) and vacuum brazing are particularly important for these applications. These processes have been used in the accelerator community and developed into generally accepted “best practice”. Studies were performed to update the existing knowledge, and comprehensively characterise these joints via mechanical and metallurgical investigations using modern available technologies. The developed solutions are described in detail, some currently being applied uniquely at CERN.

Poster THPP039 [5.324 MB]

THPP099

Status of Superconducting Cavity and Cryomodule Development at MHI

cavity, cryomodule, vacuum, superconducting-cavity

1084

T. Yanagisawa, H. Hara, N. Ikeda, K. Sennyu
MHI, Hiroshima, Japan

MHI's activities for ｓuperconducting accelerator are reported. MHI had developed several procedure and method of ILC cavity production for stable quality and cost reduction. And we had fabricated and installed cryomodules for ILC and ERL R&D. These activities are reported in detail.

THPP122

Development of Superconducting Cavities and Related Infrastructure for High Intensity Proton Linac for Spallation Neutron Source

cavity, laser, linac, proton

1140

S.C. Joshi, J. Dwivedi, P.D. Gupta, P.R. Hannurkar, V. Jain, P. Khare, P.K. Kush, G. Mundra, A. Puntambekar, S. Raghvendra, S.B. Roy, P. Shrivastava
RRCAT, Indore (M.P.), India

Raja Ramanna Centre for Advanced Technology has taken up a program on R&D activities of a 1 GeV, high intensity superconducting proton linac for a spallation neutron source. The proton linac will require a large number of superconducting Radio Frequency cavities ranging from low beta spoke resonators to medium and high beta multi-cell elliptical cavities at different RF frequencies. A dedicated facility is being set up for development of multi-cell superconducting cavities and their performance characterization. 1.3 GHz single-cell niobium cavities have been developed to establish the fabrication procedure. These cavities has exhibited high quality factor with an accelerating gradients up to 37 MV/m. A novel technique of laser welding of 1.3 GHz niobium cavity has been developed and demonstrated performance comparable to electron beam welded cavity. A dedicated facility for SCRF cavity forming, machining, electron beam welding, RF characterization, cavity tuning and cavity processing is being set up. To characterize a SCRF cavity at 2K, a vertical test stand has been developed and a horizontal test stand has been designed.

THPP124

Wakefields in the Superconducting RF Cavities of LCLS-II

cavity, linac, wakefield, electron

1147

K.L.F. Bane, T.O. Raubenheimer
SLAC, Menlo Park, California, USA
A. Romanenko, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Funding: Work supported by Department of Energy contract DE–AC02–76SF00515.
The superconducting cavities in the linacs of LCLS-II are designed to operate at 2K, where cooling costs are very expensive. In addition to an unavoidable static load and the dynamic load of the fundamental 1.3 GHz accelerating rf, there will be higher order mode (HOM) power deposited by the beam. Due to the very short bunch length the LCLS-II beam spectrum extends into the THz range. Ceramic absorbers, cooled to 70K and located between cryomodules, are meant to absorb much of this power; understanding their effectiveness, however, is a challenging task. In this report we calculate the amount of power radiated by the beam in the different portions of the linac as the bunch length is changed by the bunch compressors. We consider both the steady state radiation as well as transients that arise at the beginning of the linac structures. In addition, transitions due to changes in the vacuum chamber aperture at the ends of the linacs are also considered. Finally, under the assumption that all the wake power ends up in the SRF cavity walls, we estimate the wall heating and the possibility of breaking the Cooper pairs and quenching the cavities.

THPP131

Series Superconducting Cavity Production for the HIE-ISOLDE Project at CERN

cavity, cryomodule, vacuum, pick-up

1165

M. Therasse, L. Alberty, K. Artoos, S. Calatroni, O. Capatina, A. D'Elia, N.M. Jecklin, Y. Kadi, I. Mondino, K.M. Schirm, A. Sublet, W. Venturini Delsolaro, P. Zhang
CERN, Geneva, Switzerland

In the context of the HIE-ISOLDE linac upgrade at CERN, the phase 1 planned to boost the energy of the machine from 3 MeV/u to 5 MeV/u. For this purpose, it is planned to install 2 cryomodules based on quarter waves resonators (QWRs) made by Niobium sputtering on Copper. The poster will present the different steps of the cavity series production since the reception from the industry to the cavity storage before cryomodule assembly. We will describe the cavity preparation included the resonance frequency measurement, the chemical treatment, the cavity rinsing, the Niobium coating and the RF test at 4.5K.