LINAC2012 - List of Keywords (SRF)

Paper	Title	Other Keywords	Page
SUPB001	Analyzing Surface Roughness Dependence of Linear RF Losses	superconductivity, scattering, niobium, radio-frequency	1
	C. Xu, M.J. Kelley The College of William and Mary, Williamsburg, USA C.E. Reece JLAB, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Topographic structure on Superconductivity Radio Frequency (SRF) surfaces can contribute additional cavity RF losses describable in terms of surface RF reflectivity and absorption indices of wave scattering theory. At isotropic homogeneous extent, Power Spectrum Density (PSD) of roughness is introduced and quantifies the random surface topographic structure. PSD obtained from different surface treatments of niobium, such as Buffered Chemical Polishing (BCP), Electropolishing (EP), Nano-Mechanical Polishing (NMP) and Barrel Centrifugal Polishing (CBP) are compared. A perturbation model is utilized to calculate the additional rough surface RF losses based on PSD statistical analysis. This model will not consider that superconductor becomes normal conducting at fields higher than transition field. One can calculate the RF power dissipation ratio between rough surface and ideal smooth surface within this field range from linear loss mechanisms.

SUPB020	Structural Analysis of the New-Shaped QWR for HIAF in IMP	cavity, simulation, superconducting-cavity, controls	53
	C. Zhang, S. He, Y. He, S.C. Huang, Y.L. Huang, T.C. Jiang, R.X. Wang, Y.Z. Yang, W.M. Yue, S.H. Zhang, S.X. Zhang, H.W. Zhao IMP, Lanzhou, People's Republic of China M.H. Xu IHEP, Beijing, People's Republic of China
	Since the QWR cavity is very successful for the operation with frequency of 48 to 160 MHz and beta value of 0.001 to 0.2, a new-shaped QWR is being designed for the low energy superconducting section of HIAF in the Institute of Modern Physics. The cavity will work at 81.25 MHz and \beta of 0.085，with a elliptical cylinder outer conductor to better its electro-magnetic performance and keep limited accelerating space. Structural design is an important aspect of the overall cavity implementation, and in order to minimize the frequency shift of the cavity due to the helium bath pressure fluctuations, the Lorentz force and microphonic excitation, stiffening elements have to be applied. In this paper, structural analyses of the new-shaped QWR are presented and stiffening methods are explored.

SUPB029	Impact of Trapped Flux and Systematic Flux Expulsion in Superconducting Niobium	niobium, cavity, controls, superconductivity	77
	J.M. Vogt, J. Knobloch, O. Kugeler HZB, Berlin, Germany
	The intrinsic quality factor Q₀ of superconducting cavities is known to depend on various factors like niobium material properties, treatment history and magnetic shielding. We already reported an additional impact of temperature gradients during the cool-down on the obtained Q₀. We believe cooling conditions can influence the level of flux trapping and hence the residual resistance. For further studies we have constructed a test stand using niobium rods to study flux trapping. Here we can precisely control the temperature and approach T_c in the superconducting state. Although the sample remains in the superconducting state a change in the amount of trapped flux is visible. The procedure can be applied repeatedly resulting in a significantly lowered level of trapped flux in the sample. Applying a similar procedure to a superconducting cavity could allow for reduction of the magnetic contribution to the surface resistance and result in a significant improvement of Q₀.

MO1A03	SRF Linac Technology Development at Fermilab	cavity, linac, cryogenics, status	110
	V.P. Yakovlev, C.M. Ginsburg Fermilab, Batavia, USA
	Superconducting linear accelerators are developing for different applications – for fundamental researches in High-Energy and High – Intensity Frontiers, nuclear physics, energetics, neutron spallation sources, synchrotron radiation sources, etc. The linac applications dictate the requirements for superconducting acceleration system, and, thus, for SRF technology. Fermilab is currently involved in two projects: ILC and Project X, both are based on SRF technology. For High-Intensity Frontier investigations, the Project X – a multi-experiment facility is developing based on 3 GeV, CW H⁻ linac in the frame of a wide collaboration of US National Laboratories. In a CW H⁻ linac several families of SC cavities are used: half-wave resonators (162.5 MHz); single-spoke cavities, SSR1 and SSR2 (325 MHz); elliptical 5-cell β=0.6 and β=0.9 cavities (650 MHz). Pulsed 3-8 GeV linac and ILC linac are based on 9-cell 1.3 GHz cavities. In the paper the basic requirements and the status of development of SC accelerating cavities, auxiliaries (couplers, tuners, etc.) and cryomodules are presented as well as technology challenges caused by their specifics.
	Slides MO1A03 [3.551 MB]

MOPLB07	Non-destructive Inspections for SC Cavities	cavity, target, laser, cryogenics	156
	Y. Iwashita, Y. Fuwa, M. Hashida, K. Otani, S. Sakabe, S. Tokita, H. Tongu Kyoto ICR, Uji, Kyoto, Japan H. Hayano, K. Watanabe, Y. Yamamoto KEK, Ibaraki, Japan
	Non-destructive Inspections play important roles to improve yield in production of high-performance SC Cavities. Starting from the high-resolution camera for inspection of the cavity inner surface, high resolution T-map, X-map and eddy current scanner have been developed. We are also investigating radiography to detect small voids inside the Nb EBW seam, where the target resolution is 0.1 mm. We are carrying out radiography tests with X-rays induced from an ultra short pulse intense laser. Recent progress will be presented.
	Slides MOPLB07 [5.810 MB]

MOPLB10	FRIB Technology Demonstration Cryomodule Test	cavity, cryomodule, resonance, solenoid	165
	J. Popielarski, E.C. Bernard, S. Bricker, S. Chouhan, C. Compton, A. Facco, A. Fila, L.L. Harle, M. Hodek, L. Hodges, S. Jones, M. Leitner, D. R. Miller, S.J. Miller, D. Morris, R. Oweiss, J.P. Ozelis, L. Popielarski, K. Saito, N.R. Usher, J. Weisend, Y. Zhang, S. Zhao, Z. Zheng FRIB, East Lansing, USA M. Klaus Technische Universität Dresden, Dresden, Germany
	A Technology Demonstration Cryomodule (TDCM) has been developed for a systems test of technology being developed for FRIB. The TDCM consists of two half wave resonators (HWRs) which have been designed for an optimum velocity of β=v/c=0.53 and a resonant frequency of 322 MHz. The resonators operate at 2 K. A superconducting 9 T solenoid is placed in close proximity to one of the installed HWRs. The 9 T solenoid operates at 4 K. A complete systems test of the cavities, magnets, and all ancillary components is presented in this paper. This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE SC0000661.
	Slides MOPLB10 [2.530 MB]

MOPB018	Analyzing Surface Roughness Dependence of Linear RF Losses	superconductivity, scattering, niobium, radio-frequency	210
	C. Xu The College of William and Mary, Williamsburg, USA M.J. Kelley, C.E. Reece JLAB, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Topographic structure on Superconductivity Radio Frequency (SRF) surfaces can contribute additional cavity RF losses describable in terms of surface RF reflectivity and absorption indices of wave scattering theory. At isotropic homogeneous extent, Power Spectrum Density (PSD) of roughness is introduced and quantifies the random surface topographic structure. PSD obtained from different surface treatments of niobium, such as Buffered Chemical Polishing (BCP), Electropolishing (EP), Nano-Mechanical Polishing (NMP) and Barrel Centrifugal Polishing (CBP) are compared. A perturbation model is utilized to calculate the additional rough surface RF losses based on PSD statistical analysis. This model will not consider that superconductor becomes normal conducting at fields higher than transition field. One can calculate the RF power dissipation ratio between rough surface and ideal smooth surface within this field range from linear loss mechanisms.

MOPB034	Novel Technique of Suppressing TBBU in High-energy ERLs	linac, HOM, electron, lattice	249
	V. Litvinenko BNL, Upton, Long Island, New York, USA
	Energy recovery linacs (ERLs) is emerging generation of accelerators promising revolutionize the fields of high-energy physics and photon sciences. One potential weakness of these devices is transverse beam-breakup instability, which may severely limit available beam current. In this paper I am presenting new idea [1] developed for high-energy ERL which could be used for eRHIC, LHeC and, potentially, ILC: a concept of using main ERL linacs and natural chromaticity to suppressing TBBU instabilities by simplifying an ERL lattice. As demonstration of this method, I present tow specific example of eRHIC and LHeC ERLs. [1] V.N. Litvinenko, Chromaticity of the lattice and beam stability in energy recovery linacs, submitted to PR ST-AB

MOPB053	Non-destructive Inspections for SC Cavities	cavity, target, laser, cryogenics	294
	Y. Iwashita, Y. Fuwa, M. Hashida, K. Otani, S. Sakabe, S. Tokita, H. Tongu Kyoto ICR, Uji, Kyoto, Japan H. Hayano, K. Watanabe, Y. Yamamoto KEK, Ibaraki, Japan
	Non-destructive Inspections play important roles to improve yield in production of high-performance SC Cavities. Starting from the high-resolution camera for inspection of the cavity inner surface, high resolution T-map, X-map and eddy current scanner have been developed. We are also investigating radiography to detect small voids inside the Nb EBW seam, where the target resolution is 0.1 mm. We are carrying out radiography tests with X-rays induced from an ultra short pulse intense laser. Recent progress will be presented.

MOPB054	Test Results of Tesla-style Cryomodules at Fermilab	cryomodule, cavity, controls, LLRF	297
	E.R. Harms, K. Carlson, B. Chase, D.J. Crawford, E. Cullerton, D.R. Edstrom, Jr, A. Hocker, M.J. Kucera, J.R. Leibfritz, O.A. Nezhevenko, D.J. Nicklaus, Y.M. Pischalnikov, P.S. Prieto, J. Reid, W. Schappert, P. Varghese Fermilab, Batavia, USA
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. Commissioning and operation of the first Tesla-style Cryomodule (CM-1) at Fermilab was concluded in recent months. It has now been replaced by a second Tesla Type III+ module, RFCA002. It is the first 8-cavity ILC style cryomodule to be built at Fermilab and also the first accelerating cryomodule of the Advanced Superconducting Test Accelerator (ASTA). We report on the operating results of both of these cryomodules.

MOPB060	RF Surface Impedance Characterization of Potential New Materials for SRF-based Accelerators	niobium, cavity, impedance, superconductivity	312
	B. P. Xiao, G.V. Eremeev, H.L. Phillips, C.E. Reece JLAB, Newport News, Virginia, USA M.J. Kelley, B. P. Xiao The College of William and Mary, Williamsburg, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. In the development of new superconducting materials for possible use in SRF-based accelerators, it is useful to work with small candidate samples rather than complete resonant cavities. The recently commissioned Jefferson Lab rf Surface Impedance Characterization (SIC) system* can presently characterize the central region of 50 mm diameter disk samples of various materials from 2 to 40 K exposed to RF magnetic fields up to 14 mT at 7.4 GHz. We report the measurement results from bulk Nb, thin film Nb on Cu and sapphire substrates, and thin film MgB₂ on sapphire substrate provided by colleagues at JLab and Temple University. We also report on efforts to extend the operating range to higher fields. * B.P. Xiao, et al., RSI, 2011. 82: p. 056104

MOPB061	The New 2nd Generation SRF R&D Facility at Jefferson Lab: TEDF	cryomodule, cavity, cryogenics, electron	315
	C.E. Reece, A.V. Reilly JLAB, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The US Department of Energy has funded a near-complete renovation of the SRF-based accelerator research and development facilities at Jefferson Lab. The project to accomplish this, the Technical and Engineering Development Facility (TEDF) Project has completed the first of two phases. An entirely new 3,300 m² purpose-built SRF technical work facility has been constructed and is being occupied in summer of 2012. All SRF work processes with the exception of cryogenic testing has been relocated into the new building. All cavity fabrication, processing, thermal treatment, chemistry, cleaning, and assembly work is collected conveniently into a new LEED-certified building. An innovatively designed 750 m² cleanroom/chemrooms suite provides long-term flexibility for support of multiple R&D and construction projects as well as continued process evolution. The detailed characteristics of this perhaps first 2nd-generation SRF facility will be described.

MOPB063	Superconducting RF Linac for eRHIC	cavity, linac, HOM, electron	321
	S.A. Belomestnykh, I. Ben-Zvi, J.C. Brutus, H. Hahn, D. Kayran, V. Litvinenko, G.J. Mahler, G.T. McIntyre, V. Ptitsyn, R. Than, J.E. Tuozzolo, W. Xu, A. Zaltsman BNL, Upton, Long Island, New York, USA S.A. Belomestnykh Stony Brook University, Stony Brook, USA
	Funding: Work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE. eRHIC will collide high-intensity hadron beams from RHIC with 50-mA electron beam from a six-pass 30-GeV Energy Recovery Linac (ERL), which will utilize 704 MHz superconducting RF accelerating structures. This presentation describes the eRHIC SRF linac requirements, layout and parameters, 5-cell SRF cavity with a new HOM damping scheme, project status and plans.

MOPB064	Developing of Superconducting RF Guns at BNL	gun, cathode, cavity, electron	324
	S.A. Belomestnykh, Z. Altinbas, I. Ben-Zvi, J.C. Brutus, D.M. Gassner, H. Hahn, L.R. Hammons, J.P. Jamilkowski, D. Kayran, J. Kewisch, V. Litvinenko, G.J. Mahler, G.T. McIntyre, D. Pate, D. Phillips, T. Rao, S.K. Seberg, T. Seda, B. Sheehy, J. Skaritka, K.S. Smith, R. Than, J.E. Tuozzolo, E. Wang, Q. Wu, W. Xu, A. Zaltsman BNL, Upton, Long Island, New York, USA S.A. Belomestnykh, J. Dai, M. Ruiz-Osés, T. Xin Stony Brook University, Stony Brook, USA C.H. Boulware, T.L. Grimm Niowave, Inc., Lansing, Michigan, USA A. Burrill JLAB, Newport News, Virginia, USA R. Calaga CERN, Geneva, Switzerland M.D. Cole, A.J. Favale, D. Holmes, J. Rathke, T. Schultheiss, A.M.M. Todd AES, Medford, NY, USA X. Liang SBU, Stony Brook, New York, USA
	Funding: Work is supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US DOE. The work at Niowave is supported by the US DOE under SBIR contract No. DE-FG02-07ER84861. BNL is developing several superconducting RF guns for different applications. The first gun is based on a half-cell 1.3 GHz elliptical cavity. This gun is used to study generation of polarized electrons from GaAs photocathodes. The second gun, also of a half-cell elliptical cavity design, operates at 704 MHz and is designed to produce high average current electron beam for the ERL prototype from a multi-alkali photocathodes. The third gun is of a quarter-wave resonator type, operating at 112 MHz. This gun will be used for photocathode studies, including a diamond-amplified cathode, and to generate high charge, low repetition rate beam for the coherent electron cooling experiment. In this presentation we will briefly describe the gun designs, present recent test results and discuss future plans.

MOPB065	Impact of Trapped Magnetic Flux and Systematic Flux Expulsion in Superconducting Niobium	niobium, cavity, controls, superconductivity	327
	J.M. Vogt, J. Knobloch, O. Kugeler HZB, Berlin, Germany
	The intrinsic quality factor Q₀ of superconducting cavities is known to depend on various factors like niobium material properties, treatment history and magnetic shielding. We already reported an additional impact of temperature gradients during the cool-down on the obtained Q₀. We believe cooling conditions can influence the level of flux trapping and hence the residual resistance. For further studies we have constructed a test stand using niobium rods to study flux trapping. Here we can precisely control the temperature and approach T_c in the superconducting state. Although the sample remains in the superconducting state a change in the amount of trapped flux is visible. The procedure can be applied repeatedly resulting in a significantly lowered level of trapped flux in the sample. Applying a similar procedure to a superconducting cavity could allow for reduction of the magnetic contribution to the surface resistance and result in a significant improvement of Q₀.

MOPB069	Study of HPR Created Oxide Layer at Nb Surfaces	vacuum, cavity, electron, ion	336
	P.V. Tyagi Sokendai, Ibaraki, Japan H. Hayano, S. Kato, T. Saeki, M. Sawabe KEK, Ibaraki, Japan
	The performance of superconducting radio frequency (SRF) niobium (Nb) cavities strongly depends on final surface condition. Therefore the surface preparation of these SRF cavities often becomes critical. The preparation of surface includes two steps; surface chemistry (in order to get a smooth surface) and cleaning/rinsing (in order to remove contaminants left after the surface chemistry). As high pressure rinsing (HPR) with ultra pure water (UPW) is most commonly used surface cleaning method after the surface chemistry, it's very interesting to characterize the Nb surfaces after HPR. Results of our surface characterization done by XPS (x-ray photoelectron spectroscopy) with depth profiling show the presence of a thicker oxide surface characterization results show the presence of a thicker oxide layer at Nb surface as an outcome of HPR. In this article, we report the production of oxide layer (FWHM thickness) based on different conditions such as the pressures and doses.

MOPB070	Quality Control of Cleanroom Processing Procedures of SRF Cavities for Mass Production	cavity, controls, acceleration, diagnostics	339
	R. Oweiss, K. Elliott, A. Facco, M. Hodek, I.M. Malloch, J. Popielarski, L. Popielarski, K. Saito FRIB, East Lansing, Michigan, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661. Quality control is a key factor in the success of SRF cavity mass production. This paper summarizes ongoing research at the Facility for Rare Isotope Beams FRIB to validate the quality assurance of SRF cavities meanwhile optimizing processing procedures for mass production. Experiments are conducted to correlate surface cleanliness for niobium surfaces with high pressure rinse time using β=0.085 quarter-wave resonators (QWR) cavities. Diagnostic devices; liquid particle counter, surface particle detector and TOC analyzer are used to monitor key parameters for quality control. Rinse water samples are collected during high pressure rinsing to measure liquid particle counts. The SLS 1200 Sampler is used to detect the presence of liquid particles of 0.2 microns and up to 1 micron to set standards for acceptable cleaning thresholds and optimize high pressure rinse time. The QIII+ surface particle detector is used to scan high electric field region for the β=0.085 QWR to ensure high pressure rinsing efficiency. The β=0.085 QWR RF testing data are analyzed and results are presented to demonstrate the correlation between attained acceleration gradients and surface cleanliness.

MOPB071	Process Developments for Superconducting RF Low Beta Resonators for the ReA3 LINAC and Facility for Rare Isotope Beams	cavity, vacuum, controls, linac	342
	L. Popielarski, C. Compton, L.J. Dubbs, K. Elliott, A. Facco, L.L. Harle, I.M. Malloch, R. Oweiss, J.P. Ozelis, J. Popielarski, K. Saito FRIB, East Lansing, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE SC0000661. The Facility for Rare Isotope Beams (FRIB) will utilize over 330 superconducting radio frequency (SRF) low beta cavities for its heavy ion driver linac. The SRF department will process and test all cavities prior to string assembly in the cleanroom. The baseline cavity surface and bulk niobium processing procedures have been established. The methods are being optimized for production process rate benchmarking. Additional processes are being developed to increase flexibility and reduce technical risks. This paper will describe procedure developments and experimental results. Topics include high temperature heat treatment for hydrogen degassing, selective chemical etching for cavity frequency tuning, low-temperature bake out and process quality control.

MOPB077	Lorentz Force Detuning Compensation Studies for Long Pulses in ILC type SRF Cavities	cavity, cryomodule, controls, linac	354
	N. Solyak, G.I. Cancelo, B. Chase, D.J. Crawford, D.R. Edstrom, Jr, E.R. Harms, Y.M. Pischalnikov, W. Schappert Fermilab, Batavia, USA
	Project-X 3-8 GeV pulsed linac is based on ILC type 1.3 GHz elliptical cavities. The cavity will operate at 25 MV/m accelerating gradient, but in contrast with XFEL and ILC projects the required loaded Q is much higher (Q=10⁷) and RF pulse is much longer (~8ms). For these parameters Lorence force detuning (LFD) and microphonics should be controlled at the level <30 Hz. A new algorithm of LFD compensation, developed at Fermilab for ILC cavities was applied for Lorentz force compensation studies for 8ms pulses. In these studies two cavities inside TESLA-type cryomodule at Fermilab NML facility have been powered by one klystron. Studies done for different cavity gradients and different values of loaded Q demonstrated that required compensation are achievable. Detuning measurements and compensation results are presented.

MOPB090	FRIB Technology Demonstration Cryomodule Test	cavity, cryomodule, resonance, solenoid	386
	J. Popielarski, E.C. Bernard, S. Bricker, S. Chouhan, C. Compton, A. Facco, A. Fila, L.L. Harle, M. Hodek, L. Hodges, S. Jones, M. Leitner, D. R. Miller, S.J. Miller, D. Morris, R. Oweiss, J.P. Ozelis, L. Popielarski, K. Saito, N.R. Usher, J. Weisend, Y. Zhang, S. Zhao, Z. Zheng FRIB, East Lansing, USA M. Klaus Technische Universität Dresden, Dresden, Germany
	A Technology Demonstration Cryomodule (TDCM) has been developed for a systems test of technology being developed for FRIB. The TDCM consists of two half wave resonators (HWRs) which have been designed for an optimum velocity of β=v/c=0.53 and a resonant frequency of 322 MHz. The resonators operate at 2 K. A superconducting 9 T solenoid is placed in close proximity to one of the installed HWRs. The 9 T solenoid operates at 4 K. A complete systems test of the cavities, magnets, and all ancillary components is presented in this paper. This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE SC0000661.

MOPB095	Design of MEBT for the Project X Injector Experiment at Fermilab	kicker, vacuum, quadrupole, diagnostics	398
	A.V. Shemyakin, C.M. Baffes, A.Z. Chen, Y.I. Eidelman, B.M. Hanna, V.A. Lebedev, S. Nagaitsev, J.-F. Ostiguy, R.J. Pasquinelli, D.W. Peterson, L.R. Prost, G.W. Saewert, V.E. Scarpine, B.G. Shteynas, N. Solyak, D. Sun, M. Wendt, V.P. Yakovlev Fermilab, Batavia, USA T. Tang SLAC, Menlo Park, California, USA
	Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE The Project X Injector Experiment (PXIE), a test bed for the Project X front end, will be completed at Fermilab at FY12-16. One of the challenging goals of PXIE is demonstration of the capability to form a 1 mA H⁻ beam with an arbitrary selected bunch pattern from the initially 5 mA 162.5 MHz CW train. The bunch selection will be made in the Medium Energy Beam Transport (MEBT) at 2.1 MeV by diverting undesired bunches to an absorber. This paper will present the MEBT scheme and describe development of its elements, including the kickers and absorber.

TU1A01	Status of the IFMIF-EVEDA 9 MeV 125 mA Deuteron Linac	rfq, cavity, linac, solenoid	407
	A. Mosnier Fusion for Energy, Garching, Germany
	The scope of IFMIF/EVEDA has been recently revised to set priority on the validation activities, especially on the Accelerator Prototype (LIPAc) with extending the duration up to mid 2017 in order to better fit the development of the challenging components and the commissioning of the whole accelerator. The present status of LIPAc, currently under construction at Rokkasho in Japan, outlines of the engineering design and of the developments of the major components will be reported. In conclusion, the expected outcomes of the engineering work, associated with the experimental program will be presented.
	Slides TU1A01 [7.602 MB]

TU2A04	High Current ERL at BNL	electron, linac, gun, cavity	437
	I. Ben-Zvi BNL, Upton, Long Island, New York, USA
	The electron hadron collider eRHIC will collide polarized and unpolarized electrons with a current of 50 mA and energy in the range of 5 GeV to 30 GeV with hadron beams, including heavy ions or polarized light ions of the RHIC storage ring. The electron beam will be generated in an energy recovery linac contained inside the RHIC tunnel, comprising six passes through two linac section of about 2.5 GeV each. The electron ERL poses many challenges in term of a high-current high-polarization electron gun, HOM damping in the linac, crab cavities, harmonic cavities and beam stability.
	Slides TU2A04 [2.227 MB]

TUPB040	Status of the Linac SRF Acquisition for FRIB	linac, cryomodule, cavity, status	564
	M. Leitner, E.C. Bernard, J. Binkowski, B. Bird, S. Bricker, S. Chouhan, C. Compton, K. Elliott, B. Enkhbat, A.D. Fox, L.L. Harle, M. Hodek, M.J. Johnson, I.M. Malloch, D. R. Miller, S.J. Miller, T. Nellis, D. Norton, R. Oweiss, J.P. Ozelis, J. Popielarski, L. Popielarski, K. Saito, M. Shuptar, G.J. Velianoff, J. Wei, M. Williams, K. Witgen, Y. Xu, Y. Yamazaki, Y. Zhang FRIB, East Lansing, USA A. Facco INFN/LNL, Legnaro (PD), Italy
	Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE SC0000661. The Facility for Rare Isotope Beams (FRIB) will utilize a high-intensity, superconducting heavy-ion driver linac to provide stable ion beams from protons to uranium up to energies of >200 MeV/u and at a beam power of up to 400 kW. The ions are accelerated to about 0.5 MeV/u using a room-temperature 80.5 MHz RFQ and injected into a superconducting cw linac consisting of 330 individual low-beta cavities in 49 cryomodules operating at 2 K. This paper discusses the current status of the linac SRF acquisition strategy as the project phases into construction mode.

TUPB047	Status of the Superconducting RF Activities for the HIE ISOLDE Project	cavity, factory, linac, niobium	582
	W. Venturini Delsolaro, L. Alberty Vieira, S. Calatroni, O. Capatina, A. D'Elia, B. Delaup, M.A. Fraser, N.M. Jecklin, Y. Kadi, P. Maesen, I. Mondino, E. Montesinos, M. Therasse, D. Valuch CERN, Geneva, Switzerland
	The planned upgrade of the REX ISOLDE facility at CERN will boost the energy of the machine from 3 MeV/u up to 10 MeV/u with beams of mass-to-charge ratio 2.5 < A/q < 4. For this purpose, a new superconducting post accelerator based on independently phased 10¹.28 MHz Quarter Wave Resonators (QWR) will replace part of the normal conducting Linac. The QWRs make use of the Niobium sputtering on Copper technology which was successfully applied to LEP2, LHC and to the energy upgrade of the ALPI Linac at INFN-LNL. The status of advancement of the project will be detailed, limited to the SRF activities.

TUPB057	Structural Analysis of the New-Shaped QWR for HIAF in IMP	cavity, simulation, superconducting-cavity, controls	606
	C. Zhang, S. He, Y. He, S.C. Huang, Y.L. Huang, T.C. Jiang, R.X. Wang, M.X. Xu, Y.Z. Yang, W.M. Yue, S.H. Zhang, S.X. Zhang, H.W. Zhao IMP, Lanzhou, People's Republic of China
	Since the QWR cavity is very successful for the operation with frequency of 48 to 160 MHz and \beta value of 0.001 to 0.2, a new-shaped QWR is being designed for the low energy superconducting section of HIAF in the Institute of Modern Physics. The cavity will work at 81.25 MHz and \beta of 0.085，with a elliptical cylinder outer conductor to better its electro-magnetic performance and keep limited accelerating space. Structural design is an important aspect of the overall cavity implementation, and in order to minimize the frequency shift of the cavity due to the helium bath pressure fluctuations, the Lorentz force and microphonic excitation, stiffening elements have to be applied. In this paper, structural analyses of the new-shaped QWR are presented and stiffening methods are explored.

TH1A03	Superconducting Spoke Cavities for Electron and High-Velocity Proton Linacs	cavity, linac, impedance, electron	758
	J.R. Delayen ODU, Norfolk, Virginia, USA
	Spoke resonantors are currently under development for many proton machines but these structures are also considered for high beta electron linacs as well. These structures compare well to traditional elliptical cavities.
	Slides TH1A03 [3.570 MB]

THPLB05	R&D Activities on High Intensity Superconducting Proton Linac at RRCAT	cavity, ion, niobium, linac	819
	S.C. Joshi, J. Dwivedi, P.D. Gupta, P.R. Hannurkar, P. Khare, P.K. Kush, G. Mundra, A. Puntambekar, S.B. Roy, P. Shrivastava RRCAT, Indore (M.P.), India
	Raja Ramanna Centre for Advanced Technology (RRCAT), Indore has taken up a program on development of 1 GeV high intensity superconducting proton linac for Spallation Neutron Source. This will require several multi-cell superconducting cavities operating at different RF frequencies. To start with, a number of single-cell prototype cavities at 1.3 GHz have been developed in high RRR bulk niobium. These single-cell cavities have exhibited high quality factor and accelerating gradients. Superconducting properties of niobium are being studied for varying composition of impurities and different processing conditions. Development activity on solid state RF amplifiers to power the SCRF cavities at various RF frequencies is being pursued. A building has been constructed to house the SCRF cavity fabrication and processing facility. To characterize SCRF cavity, a 2 K Vertical Test Stand is being set up including a 2 K cryostat, RF power supply and data acquisition system. Design activities for cryomodule and large 2 K cryostat for Horizontal Test Stand are also under progress. The paper will discuss the status of above R&D activities and infrastructure development at RRCAT.
	Slides THPLB05 [1.614 MB]

THPB003	R&D Activities on High Intensity Superconducting Proton Linac at RRCAT	cavity, ion, niobium, linac	843
	S.C. Joshi, J. Dwivedi, P.D. Gupta, P.R. Hannurkar, P. Khare, P.K. Kush, G. Mundra, A. Puntambekar, S.B. Roy, P. Shrivastava RRCAT, Indore (M.P.), India
	Raja Ramanna Centre for Advanced Technology (RRCAT), Indore has taken up a program on development of 1 GeV high intensity superconducting proton linac for Spallation Neutron Source. This will require several multi-cell superconducting cavities operating at different RF frequencies. To start with, a number of single-cell prototype cavities at 1.3 GHz have been developed in high RRR bulk niobium. These single-cell cavities have exhibited high quality factor and accelerating gradients. Superconducting properties of niobium are being studied for varying composition of impurities and different processing conditions. Development activity on solid state RF amplifiers to power the SCRF cavities at various RF frequencies is being pursued. A building has been constructed to house the SCRF cavity fabrication and processing facility. To characterize SCRF cavity, a 2 K Vertical Test Stand is being set up including a 2 K cryostat, RF power supply and data acquisition system. Design activities for cryomodule and large 2 K cryostat for Horizontal Test Stand are also under progress. The paper will discuss the status of above R&D activities and infrastructure development at RRCAT.

THPB069	Beam Dynamics Studies for SRF Photoinjectors	emittance, gun, cavity, booster	999
	T. Kamps, A. Neumann, J. Völker HZB, Berlin, Germany
	The SRF photoinjector combines the advantages of photo-assisted production of high brightness, short electron pulses and high gradient, low-loss continuous wave (CW) operation of a superconducting radiofrequency (SRF) cavity. The paper discusses beam dynamics considerations for FEL and ERL class applications of SRF photoinjectors. One case of particular interest is the design of the SRF photoinjector for BERLinPro, an ERL test facility demanding a high brightness beam with an emittance better than 1 mm mrad at 77 pC and average current of 100 mA.

Paper

Title

Other Keywords

Page

SUPB001

Analyzing Surface Roughness Dependence of Linear RF Losses

superconductivity, scattering, niobium, radio-frequency

1

C. Xu, M.J. Kelley
The College of William and Mary, Williamsburg, USA
C.E. Reece
JLAB, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Topographic structure on Superconductivity Radio Frequency (SRF) surfaces can contribute additional cavity RF losses describable in terms of surface RF reflectivity and absorption indices of wave scattering theory. At isotropic homogeneous extent, Power Spectrum Density (PSD) of roughness is introduced and quantifies the random surface topographic structure. PSD obtained from different surface treatments of niobium, such as Buffered Chemical Polishing (BCP), Electropolishing (EP), Nano-Mechanical Polishing (NMP) and Barrel Centrifugal Polishing (CBP) are compared. A perturbation model is utilized to calculate the additional rough surface RF losses based on PSD statistical analysis. This model will not consider that superconductor becomes normal conducting at fields higher than transition field. One can calculate the RF power dissipation ratio between rough surface and ideal smooth surface within this field range from linear loss mechanisms.

SUPB020

Structural Analysis of the New-Shaped QWR for HIAF in IMP

cavity, simulation, superconducting-cavity, controls

53

C. Zhang, S. He, Y. He, S.C. Huang, Y.L. Huang, T.C. Jiang, R.X. Wang, Y.Z. Yang, W.M. Yue, S.H. Zhang, S.X. Zhang, H.W. Zhao
IMP, Lanzhou, People's Republic of China
M.H. Xu
IHEP, Beijing, People's Republic of China

Since the QWR cavity is very successful for the operation with frequency of 48 to 160 MHz and beta value of 0.001 to 0.2, a new-shaped QWR is being designed for the low energy superconducting section of HIAF in the Institute of Modern Physics. The cavity will work at 81.25 MHz and \beta of 0.085，with a elliptical cylinder outer conductor to better its electro-magnetic performance and keep limited accelerating space. Structural design is an important aspect of the overall cavity implementation, and in order to minimize the frequency shift of the cavity due to the helium bath pressure fluctuations, the Lorentz force and microphonic excitation, stiffening elements have to be applied. In this paper, structural analyses of the new-shaped QWR are presented and stiffening methods are explored.

SUPB029

Impact of Trapped Flux and Systematic Flux Expulsion in Superconducting Niobium

niobium, cavity, controls, superconductivity

77

J.M. Vogt, J. Knobloch, O. Kugeler
HZB, Berlin, Germany

The intrinsic quality factor Q₀ of superconducting cavities is known to depend on various factors like niobium material properties, treatment history and magnetic shielding. We already reported an additional impact of temperature gradients during the cool-down on the obtained Q₀. We believe cooling conditions can influence the level of flux trapping and hence the residual resistance. For further studies we have constructed a test stand using niobium rods to study flux trapping. Here we can precisely control the temperature and approach T_c in the superconducting state. Although the sample remains in the superconducting state a change in the amount of trapped flux is visible. The procedure can be applied repeatedly resulting in a significantly lowered level of trapped flux in the sample. Applying a similar procedure to a superconducting cavity could allow for reduction of the magnetic contribution to the surface resistance and result in a significant improvement of Q₀.

MO1A03

SRF Linac Technology Development at Fermilab

cavity, linac, cryogenics, status

110

V.P. Yakovlev, C.M. Ginsburg
Fermilab, Batavia, USA

Superconducting linear accelerators are developing for different applications – for fundamental researches in High-Energy and High – Intensity Frontiers, nuclear physics, energetics, neutron spallation sources, synchrotron radiation sources, etc. The linac applications dictate the requirements for superconducting acceleration system, and, thus, for SRF technology. Fermilab is currently involved in two projects: ILC and Project X, both are based on SRF technology. For High-Intensity Frontier investigations, the Project X – a multi-experiment facility is developing based on 3 GeV, CW H⁻ linac in the frame of a wide collaboration of US National Laboratories. In a CW H⁻ linac several families of SC cavities are used: half-wave resonators (162.5 MHz); single-spoke cavities, SSR1 and SSR2 (325 MHz); elliptical 5-cell β=0.6 and β=0.9 cavities (650 MHz). Pulsed 3-8 GeV linac and ILC linac are based on 9-cell 1.3 GHz cavities. In the paper the basic requirements and the status of development of SC accelerating cavities, auxiliaries (couplers, tuners, etc.) and cryomodules are presented as well as technology challenges caused by their specifics.

Slides MO1A03 [3.551 MB]

MOPLB07

Non-destructive Inspections for SC Cavities

cavity, target, laser, cryogenics

156

Y. Iwashita, Y. Fuwa, M. Hashida, K. Otani, S. Sakabe, S. Tokita, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
H. Hayano, K. Watanabe, Y. Yamamoto
KEK, Ibaraki, Japan

Non-destructive Inspections play important roles to improve yield in production of high-performance SC Cavities. Starting from the high-resolution camera for inspection of the cavity inner surface, high resolution T-map, X-map and eddy current scanner have been developed. We are also investigating radiography to detect small voids inside the Nb EBW seam, where the target resolution is 0.1 mm. We are carrying out radiography tests with X-rays induced from an ultra short pulse intense laser. Recent progress will be presented.

Slides MOPLB07 [5.810 MB]

MOPLB10

FRIB Technology Demonstration Cryomodule Test

cavity, cryomodule, resonance, solenoid

165

J. Popielarski, E.C. Bernard, S. Bricker, S. Chouhan, C. Compton, A. Facco, A. Fila, L.L. Harle, M. Hodek, L. Hodges, S. Jones, M. Leitner, D. R. Miller, S.J. Miller, D. Morris, R. Oweiss, J.P. Ozelis, L. Popielarski, K. Saito, N.R. Usher, J. Weisend, Y. Zhang, S. Zhao, Z. Zheng
FRIB, East Lansing, USA
M. Klaus
Technische Universität Dresden, Dresden, Germany

A Technology Demonstration Cryomodule (TDCM) has been developed for a systems test of technology being developed for FRIB. The TDCM consists of two half wave resonators (HWRs) which have been designed for an optimum velocity of β=v/c=0.53 and a resonant frequency of 322 MHz. The resonators operate at 2 K. A superconducting 9 T solenoid is placed in close proximity to one of the installed HWRs. The 9 T solenoid operates at 4 K. A complete systems test of the cavities, magnets, and all ancillary components is presented in this paper.
This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE SC0000661.

Slides MOPLB10 [2.530 MB]

MOPB018

Analyzing Surface Roughness Dependence of Linear RF Losses

superconductivity, scattering, niobium, radio-frequency

210

C. Xu
The College of William and Mary, Williamsburg, USA
M.J. Kelley, C.E. Reece
JLAB, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Topographic structure on Superconductivity Radio Frequency (SRF) surfaces can contribute additional cavity RF losses describable in terms of surface RF reflectivity and absorption indices of wave scattering theory. At isotropic homogeneous extent, Power Spectrum Density (PSD) of roughness is introduced and quantifies the random surface topographic structure. PSD obtained from different surface treatments of niobium, such as Buffered Chemical Polishing (BCP), Electropolishing (EP), Nano-Mechanical Polishing (NMP) and Barrel Centrifugal Polishing (CBP) are compared. A perturbation model is utilized to calculate the additional rough surface RF losses based on PSD statistical analysis. This model will not consider that superconductor becomes normal conducting at fields higher than transition field. One can calculate the RF power dissipation ratio between rough surface and ideal smooth surface within this field range from linear loss mechanisms.

MOPB034

Novel Technique of Suppressing TBBU in High-energy ERLs

linac, HOM, electron, lattice

249

V. Litvinenko
BNL, Upton, Long Island, New York, USA

Energy recovery linacs (ERLs) is emerging generation of accelerators promising revolutionize the fields of high-energy physics and photon sciences. One potential weakness of these devices is transverse beam-breakup instability, which may severely limit available beam current. In this paper I am presenting new idea [1] developed for high-energy ERL which could be used for eRHIC, LHeC and, potentially, ILC: a concept of using main ERL linacs and natural chromaticity to suppressing TBBU instabilities by simplifying an ERL lattice. As demonstration of this method, I present tow specific example of eRHIC and LHeC ERLs.
[1] V.N. Litvinenko, Chromaticity of the lattice and beam stability in energy recovery linacs, submitted to PR ST-AB

MOPB053

Non-destructive Inspections for SC Cavities

cavity, target, laser, cryogenics

294

Y. Iwashita, Y. Fuwa, M. Hashida, K. Otani, S. Sakabe, S. Tokita, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
H. Hayano, K. Watanabe, Y. Yamamoto
KEK, Ibaraki, Japan

Non-destructive Inspections play important roles to improve yield in production of high-performance SC Cavities. Starting from the high-resolution camera for inspection of the cavity inner surface, high resolution T-map, X-map and eddy current scanner have been developed. We are also investigating radiography to detect small voids inside the Nb EBW seam, where the target resolution is 0.1 mm. We are carrying out radiography tests with X-rays induced from an ultra short pulse intense laser. Recent progress will be presented.

MOPB054

Test Results of Tesla-style Cryomodules at Fermilab

cryomodule, cavity, controls, LLRF

297

E.R. Harms, K. Carlson, B. Chase, D.J. Crawford, E. Cullerton, D.R. Edstrom, Jr, A. Hocker, M.J. Kucera, J.R. Leibfritz, O.A. Nezhevenko, D.J. Nicklaus, Y.M. Pischalnikov, P.S. Prieto, J. Reid, W. Schappert, P. Varghese
Fermilab, Batavia, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
Commissioning and operation of the first Tesla-style Cryomodule (CM-1) at Fermilab was concluded in recent months. It has now been replaced by a second Tesla Type III+ module, RFCA002. It is the first 8-cavity ILC style cryomodule to be built at Fermilab and also the first accelerating cryomodule of the Advanced Superconducting Test Accelerator (ASTA). We report on the operating results of both of these cryomodules.

MOPB060

RF Surface Impedance Characterization of Potential New Materials for SRF-based Accelerators

niobium, cavity, impedance, superconductivity

312

B. P. Xiao, G.V. Eremeev, H.L. Phillips, C.E. Reece
JLAB, Newport News, Virginia, USA
M.J. Kelley, B. P. Xiao
The College of William and Mary, Williamsburg, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
In the development of new superconducting materials for possible use in SRF-based accelerators, it is useful to work with small candidate samples rather than complete resonant cavities. The recently commissioned Jefferson Lab rf Surface Impedance Characterization (SIC) system* can presently characterize the central region of 50 mm diameter disk samples of various materials from 2 to 40 K exposed to RF magnetic fields up to 14 mT at 7.4 GHz. We report the measurement results from bulk Nb, thin film Nb on Cu and sapphire substrates, and thin film MgB₂ on sapphire substrate provided by colleagues at JLab and Temple University. We also report on efforts to extend the operating range to higher fields.
* B.P. Xiao, et al., RSI, 2011. 82: p. 056104

MOPB061

The New 2nd Generation SRF R&D Facility at Jefferson Lab: TEDF

cryomodule, cavity, cryogenics, electron

315

C.E. Reece, A.V. Reilly
JLAB, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The US Department of Energy has funded a near-complete renovation of the SRF-based accelerator research and development facilities at Jefferson Lab. The project to accomplish this, the Technical and Engineering Development Facility (TEDF) Project has completed the first of two phases. An entirely new 3,300 m² purpose-built SRF technical work facility has been constructed and is being occupied in summer of 2012. All SRF work processes with the exception of cryogenic testing has been relocated into the new building. All cavity fabrication, processing, thermal treatment, chemistry, cleaning, and assembly work is collected conveniently into a new LEED-certified building. An innovatively designed 750 m² cleanroom/chemrooms suite provides long-term flexibility for support of multiple R&D and construction projects as well as continued process evolution. The detailed characteristics of this perhaps first 2nd-generation SRF facility will be described.

MOPB063

Superconducting RF Linac for eRHIC

cavity, linac, HOM, electron

321

S.A. Belomestnykh, I. Ben-Zvi, J.C. Brutus, H. Hahn, D. Kayran, V. Litvinenko, G.J. Mahler, G.T. McIntyre, V. Ptitsyn, R. Than, J.E. Tuozzolo, W. Xu, A. Zaltsman
BNL, Upton, Long Island, New York, USA
S.A. Belomestnykh
Stony Brook University, Stony Brook, USA

Funding: Work is supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
eRHIC will collide high-intensity hadron beams from RHIC with 50-mA electron beam from a six-pass 30-GeV Energy Recovery Linac (ERL), which will utilize 704 MHz superconducting RF accelerating structures. This presentation describes the eRHIC SRF linac requirements, layout and parameters, 5-cell SRF cavity with a new HOM damping scheme, project status and plans.

MOPB064

Developing of Superconducting RF Guns at BNL

gun, cathode, cavity, electron

324

S.A. Belomestnykh, Z. Altinbas, I. Ben-Zvi, J.C. Brutus, D.M. Gassner, H. Hahn, L.R. Hammons, J.P. Jamilkowski, D. Kayran, J. Kewisch, V. Litvinenko, G.J. Mahler, G.T. McIntyre, D. Pate, D. Phillips, T. Rao, S.K. Seberg, T. Seda, B. Sheehy, J. Skaritka, K.S. Smith, R. Than, J.E. Tuozzolo, E. Wang, Q. Wu, W. Xu, A. Zaltsman
BNL, Upton, Long Island, New York, USA
S.A. Belomestnykh, J. Dai, M. Ruiz-Osés, T. Xin
Stony Brook University, Stony Brook, USA
C.H. Boulware, T.L. Grimm
Niowave, Inc., Lansing, Michigan, USA
A. Burrill
JLAB, Newport News, Virginia, USA
R. Calaga
CERN, Geneva, Switzerland
M.D. Cole, A.J. Favale, D. Holmes, J. Rathke, T. Schultheiss, A.M.M. Todd
AES, Medford, NY, USA
X. Liang
SBU, Stony Brook, New York, USA

Funding: Work is supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US DOE. The work at Niowave is supported by the US DOE under SBIR contract No. DE-FG02-07ER84861.
BNL is developing several superconducting RF guns for different applications. The first gun is based on a half-cell 1.3 GHz elliptical cavity. This gun is used to study generation of polarized electrons from GaAs photocathodes. The second gun, also of a half-cell elliptical cavity design, operates at 704 MHz and is designed to produce high average current electron beam for the ERL prototype from a multi-alkali photocathodes. The third gun is of a quarter-wave resonator type, operating at 112 MHz. This gun will be used for photocathode studies, including a diamond-amplified cathode, and to generate high charge, low repetition rate beam for the coherent electron cooling experiment. In this presentation we will briefly describe the gun designs, present recent test results and discuss future plans.

MOPB065

Impact of Trapped Magnetic Flux and Systematic Flux Expulsion in Superconducting Niobium

niobium, cavity, controls, superconductivity

327

J.M. Vogt, J. Knobloch, O. Kugeler
HZB, Berlin, Germany

The intrinsic quality factor Q₀ of superconducting cavities is known to depend on various factors like niobium material properties, treatment history and magnetic shielding. We already reported an additional impact of temperature gradients during the cool-down on the obtained Q₀. We believe cooling conditions can influence the level of flux trapping and hence the residual resistance. For further studies we have constructed a test stand using niobium rods to study flux trapping. Here we can precisely control the temperature and approach T_c in the superconducting state. Although the sample remains in the superconducting state a change in the amount of trapped flux is visible. The procedure can be applied repeatedly resulting in a significantly lowered level of trapped flux in the sample. Applying a similar procedure to a superconducting cavity could allow for reduction of the magnetic contribution to the surface resistance and result in a significant improvement of Q₀.

MOPB069

Study of HPR Created Oxide Layer at Nb Surfaces

vacuum, cavity, electron, ion

336

P.V. Tyagi
Sokendai, Ibaraki, Japan
H. Hayano, S. Kato, T. Saeki, M. Sawabe
KEK, Ibaraki, Japan

The performance of superconducting radio frequency (SRF) niobium (Nb) cavities strongly depends on final surface condition. Therefore the surface preparation of these SRF cavities often becomes critical. The preparation of surface includes two steps; surface chemistry (in order to get a smooth surface) and cleaning/rinsing (in order to remove contaminants left after the surface chemistry). As high pressure rinsing (HPR) with ultra pure water (UPW) is most commonly used surface cleaning method after the surface chemistry, it's very interesting to characterize the Nb surfaces after HPR. Results of our surface characterization done by XPS (x-ray photoelectron spectroscopy) with depth profiling show the presence of a thicker oxide surface characterization results show the presence of a thicker oxide layer at Nb surface as an outcome of HPR. In this article, we report the production of oxide layer (FWHM thickness) based on different conditions such as the pressures and doses.

MOPB070

Quality Control of Cleanroom Processing Procedures of SRF Cavities for Mass Production

cavity, controls, acceleration, diagnostics

339

R. Oweiss, K. Elliott, A. Facco, M. Hodek, I.M. Malloch, J. Popielarski, L. Popielarski, K. Saito
FRIB, East Lansing, Michigan, USA

Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
Quality control is a key factor in the success of SRF cavity mass production. This paper summarizes ongoing research at the Facility for Rare Isotope Beams FRIB to validate the quality assurance of SRF cavities meanwhile optimizing processing procedures for mass production. Experiments are conducted to correlate surface cleanliness for niobium surfaces with high pressure rinse time using β=0.085 quarter-wave resonators (QWR) cavities. Diagnostic devices; liquid particle counter, surface particle detector and TOC analyzer are used to monitor key parameters for quality control. Rinse water samples are collected during high pressure rinsing to measure liquid particle counts. The SLS 1200 Sampler is used to detect the presence of liquid particles of 0.2 microns and up to 1 micron to set standards for acceptable cleaning thresholds and optimize high pressure rinse time. The QIII+ surface particle detector is used to scan high electric field region for the β=0.085 QWR to ensure high pressure rinsing efficiency. The β=0.085 QWR RF testing data are analyzed and results are presented to demonstrate the correlation between attained acceleration gradients and surface cleanliness.

MOPB071

Process Developments for Superconducting RF Low Beta Resonators for the ReA3 LINAC and Facility for Rare Isotope Beams

cavity, vacuum, controls, linac

342

L. Popielarski, C. Compton, L.J. Dubbs, K. Elliott, A. Facco, L.L. Harle, I.M. Malloch, R. Oweiss, J.P. Ozelis, J. Popielarski, K. Saito
FRIB, East Lansing, USA

Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE SC0000661.
The Facility for Rare Isotope Beams (FRIB) will utilize over 330 superconducting radio frequency (SRF) low beta cavities for its heavy ion driver linac. The SRF department will process and test all cavities prior to string assembly in the cleanroom. The baseline cavity surface and bulk niobium processing procedures have been established. The methods are being optimized for production process rate benchmarking. Additional processes are being developed to increase flexibility and reduce technical risks. This paper will describe procedure developments and experimental results. Topics include high temperature heat treatment for hydrogen degassing, selective chemical etching for cavity frequency tuning, low-temperature bake out and process quality control.

MOPB077

Lorentz Force Detuning Compensation Studies for Long Pulses in ILC type SRF Cavities

cavity, cryomodule, controls, linac

354

N. Solyak, G.I. Cancelo, B. Chase, D.J. Crawford, D.R. Edstrom, Jr, E.R. Harms, Y.M. Pischalnikov, W. Schappert
Fermilab, Batavia, USA

Project-X 3-8 GeV pulsed linac is based on ILC type 1.3 GHz elliptical cavities. The cavity will operate at 25 MV/m accelerating gradient, but in contrast with XFEL and ILC projects the required loaded Q is much higher (Q=10⁷) and RF pulse is much longer (~8ms). For these parameters Lorence force detuning (LFD) and microphonics should be controlled at the level <30 Hz. A new algorithm of LFD compensation, developed at Fermilab for ILC cavities was applied for Lorentz force compensation studies for 8ms pulses. In these studies two cavities inside TESLA-type cryomodule at Fermilab NML facility have been powered by one klystron. Studies done for different cavity gradients and different values of loaded Q demonstrated that required compensation are achievable. Detuning measurements and compensation results are presented.

MOPB090

FRIB Technology Demonstration Cryomodule Test

cavity, cryomodule, resonance, solenoid

386

J. Popielarski, E.C. Bernard, S. Bricker, S. Chouhan, C. Compton, A. Facco, A. Fila, L.L. Harle, M. Hodek, L. Hodges, S. Jones, M. Leitner, D. R. Miller, S.J. Miller, D. Morris, R. Oweiss, J.P. Ozelis, L. Popielarski, K. Saito, N.R. Usher, J. Weisend, Y. Zhang, S. Zhao, Z. Zheng
FRIB, East Lansing, USA
M. Klaus
Technische Universität Dresden, Dresden, Germany

A Technology Demonstration Cryomodule (TDCM) has been developed for a systems test of technology being developed for FRIB. The TDCM consists of two half wave resonators (HWRs) which have been designed for an optimum velocity of β=v/c=0.53 and a resonant frequency of 322 MHz. The resonators operate at 2 K. A superconducting 9 T solenoid is placed in close proximity to one of the installed HWRs. The 9 T solenoid operates at 4 K. A complete systems test of the cavities, magnets, and all ancillary components is presented in this paper.
This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE SC0000661.

MOPB095

Design of MEBT for the Project X Injector Experiment at Fermilab

kicker, vacuum, quadrupole, diagnostics

398

A.V. Shemyakin, C.M. Baffes, A.Z. Chen, Y.I. Eidelman, B.M. Hanna, V.A. Lebedev, S. Nagaitsev, J.-F. Ostiguy, R.J. Pasquinelli, D.W. Peterson, L.R. Prost, G.W. Saewert, V.E. Scarpine, B.G. Shteynas, N. Solyak, D. Sun, M. Wendt, V.P. Yakovlev
Fermilab, Batavia, USA
T. Tang
SLAC, Menlo Park, California, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE
The Project X Injector Experiment (PXIE), a test bed for the Project X front end, will be completed at Fermilab at FY12-16. One of the challenging goals of PXIE is demonstration of the capability to form a 1 mA H⁻ beam with an arbitrary selected bunch pattern from the initially 5 mA 162.5 MHz CW train. The bunch selection will be made in the Medium Energy Beam Transport (MEBT) at 2.1 MeV by diverting undesired bunches to an absorber. This paper will present the MEBT scheme and describe development of its elements, including the kickers and absorber.

TU1A01

Status of the IFMIF-EVEDA 9 MeV 125 mA Deuteron Linac

rfq, cavity, linac, solenoid

407

A. Mosnier
Fusion for Energy, Garching, Germany

The scope of IFMIF/EVEDA has been recently revised to set priority on the validation activities, especially on the Accelerator Prototype (LIPAc) with extending the duration up to mid 2017 in order to better fit the development of the challenging components and the commissioning of the whole accelerator. The present status of LIPAc, currently under construction at Rokkasho in Japan, outlines of the engineering design and of the developments of the major components will be reported. In conclusion, the expected outcomes of the engineering work, associated with the experimental program will be presented.

Slides TU1A01 [7.602 MB]

TU2A04

High Current ERL at BNL

electron, linac, gun, cavity

437

I. Ben-Zvi
BNL, Upton, Long Island, New York, USA

The electron hadron collider eRHIC will collide polarized and unpolarized electrons with a current of 50 mA and energy in the range of 5 GeV to 30 GeV with hadron beams, including heavy ions or polarized light ions of the RHIC storage ring. The electron beam will be generated in an energy recovery linac contained inside the RHIC tunnel, comprising six passes through two linac section of about 2.5 GeV each. The electron ERL poses many challenges in term of a high-current high-polarization electron gun, HOM damping in the linac, crab cavities, harmonic cavities and beam stability.

Slides TU2A04 [2.227 MB]

TUPB040

Status of the Linac SRF Acquisition for FRIB

linac, cryomodule, cavity, status

564

M. Leitner, E.C. Bernard, J. Binkowski, B. Bird, S. Bricker, S. Chouhan, C. Compton, K. Elliott, B. Enkhbat, A.D. Fox, L.L. Harle, M. Hodek, M.J. Johnson, I.M. Malloch, D. R. Miller, S.J. Miller, T. Nellis, D. Norton, R. Oweiss, J.P. Ozelis, J. Popielarski, L. Popielarski, K. Saito, M. Shuptar, G.J. Velianoff, J. Wei, M. Williams, K. Witgen, Y. Xu, Y. Yamazaki, Y. Zhang
FRIB, East Lansing, USA
A. Facco
INFN/LNL, Legnaro (PD), Italy

Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE SC0000661.
The Facility for Rare Isotope Beams (FRIB) will utilize a high-intensity, superconducting heavy-ion driver linac to provide stable ion beams from protons to uranium up to energies of >200 MeV/u and at a beam power of up to 400 kW. The ions are accelerated to about 0.5 MeV/u using a room-temperature 80.5 MHz RFQ and injected into a superconducting cw linac consisting of 330 individual low-beta cavities in 49 cryomodules operating at 2 K. This paper discusses the current status of the linac SRF acquisition strategy as the project phases into construction mode.

TUPB047

Status of the Superconducting RF Activities for the HIE ISOLDE Project

cavity, factory, linac, niobium

582

W. Venturini Delsolaro, L. Alberty Vieira, S. Calatroni, O. Capatina, A. D'Elia, B. Delaup, M.A. Fraser, N.M. Jecklin, Y. Kadi, P. Maesen, I. Mondino, E. Montesinos, M. Therasse, D. Valuch
CERN, Geneva, Switzerland

The planned upgrade of the REX ISOLDE facility at CERN will boost the energy of the machine from 3 MeV/u up to 10 MeV/u with beams of mass-to-charge ratio 2.5 < A/q < 4. For this purpose, a new superconducting post accelerator based on independently phased 10¹.28 MHz Quarter Wave Resonators (QWR) will replace part of the normal conducting Linac. The QWRs make use of the Niobium sputtering on Copper technology which was successfully applied to LEP2, LHC and to the energy upgrade of the ALPI Linac at INFN-LNL. The status of advancement of the project will be detailed, limited to the SRF activities.

TUPB057

Structural Analysis of the New-Shaped QWR for HIAF in IMP

cavity, simulation, superconducting-cavity, controls

606

C. Zhang, S. He, Y. He, S.C. Huang, Y.L. Huang, T.C. Jiang, R.X. Wang, M.X. Xu, Y.Z. Yang, W.M. Yue, S.H. Zhang, S.X. Zhang, H.W. Zhao
IMP, Lanzhou, People's Republic of China

Since the QWR cavity is very successful for the operation with frequency of 48 to 160 MHz and \beta value of 0.001 to 0.2, a new-shaped QWR is being designed for the low energy superconducting section of HIAF in the Institute of Modern Physics. The cavity will work at 81.25 MHz and \beta of 0.085，with a elliptical cylinder outer conductor to better its electro-magnetic performance and keep limited accelerating space. Structural design is an important aspect of the overall cavity implementation, and in order to minimize the frequency shift of the cavity due to the helium bath pressure fluctuations, the Lorentz force and microphonic excitation, stiffening elements have to be applied. In this paper, structural analyses of the new-shaped QWR are presented and stiffening methods are explored.

TH1A03

Superconducting Spoke Cavities for Electron and High-Velocity Proton Linacs

cavity, linac, impedance, electron

758

J.R. Delayen
ODU, Norfolk, Virginia, USA

Spoke resonantors are currently under development for many proton machines but these structures are also considered for high beta electron linacs as well. These structures compare well to traditional elliptical cavities.

Slides TH1A03 [3.570 MB]

THPLB05

R&D Activities on High Intensity Superconducting Proton Linac at RRCAT

cavity, ion, niobium, linac

819

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

Raja Ramanna Centre for Advanced Technology (RRCAT), Indore has taken up a program on development of 1 GeV high intensity superconducting proton linac for Spallation Neutron Source. This will require several multi-cell superconducting cavities operating at different RF frequencies. To start with, a number of single-cell prototype cavities at 1.3 GHz have been developed in high RRR bulk niobium. These single-cell cavities have exhibited high quality factor and accelerating gradients. Superconducting properties of niobium are being studied for varying composition of impurities and different processing conditions. Development activity on solid state RF amplifiers to power the SCRF cavities at various RF frequencies is being pursued. A building has been constructed to house the SCRF cavity fabrication and processing facility. To characterize SCRF cavity, a 2 K Vertical Test Stand is being set up including a 2 K cryostat, RF power supply and data acquisition system. Design activities for cryomodule and large 2 K cryostat for Horizontal Test Stand are also under progress. The paper will discuss the status of above R&D activities and infrastructure development at RRCAT.

Slides THPLB05 [1.614 MB]

THPB003

R&D Activities on High Intensity Superconducting Proton Linac at RRCAT

cavity, ion, niobium, linac

843

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

Raja Ramanna Centre for Advanced Technology (RRCAT), Indore has taken up a program on development of 1 GeV high intensity superconducting proton linac for Spallation Neutron Source. This will require several multi-cell superconducting cavities operating at different RF frequencies. To start with, a number of single-cell prototype cavities at 1.3 GHz have been developed in high RRR bulk niobium. These single-cell cavities have exhibited high quality factor and accelerating gradients. Superconducting properties of niobium are being studied for varying composition of impurities and different processing conditions. Development activity on solid state RF amplifiers to power the SCRF cavities at various RF frequencies is being pursued. A building has been constructed to house the SCRF cavity fabrication and processing facility. To characterize SCRF cavity, a 2 K Vertical Test Stand is being set up including a 2 K cryostat, RF power supply and data acquisition system. Design activities for cryomodule and large 2 K cryostat for Horizontal Test Stand are also under progress. The paper will discuss the status of above R&D activities and infrastructure development at RRCAT.

THPB069

Beam Dynamics Studies for SRF Photoinjectors

emittance, gun, cavity, booster

999

T. Kamps, A. Neumann, J. Völker
HZB, Berlin, Germany

The SRF photoinjector combines the advantages of photo-assisted production of high brightness, short electron pulses and high gradient, low-loss continuous wave (CW) operation of a superconducting radiofrequency (SRF) cavity. The paper discusses beam dynamics considerations for FEL and ERL class applications of SRF photoinjectors. One case of particular interest is the design of the SRF photoinjector for BERLinPro, an ERL test facility demanding a high brightness beam with an emittance better than 1 mm mrad at 77 pC and average current of 100 mA.