NAPAC2016 - List of Keywords (SRF)

Paper	Title	Other Keywords	Page
MOPOB32	Design and Test of the Prototype Tuner for 3.9 GHz SRF Cavity for LCLS II Project	cavity, ion, cryomodule, FEL	140
	Y.M. Pischalnikov, E. Borissov, J.C. Yun Fermilab, Batavia, Illinois, USA
	Fermilab is responsible for the design of the 3.9GHz cryomodule for the LCLS-II that will operate in continuous wave (CW) mode. Bandwidth of the SRF cavities will be in the range of the 180Hz. In our tuner design, we adopted as the slow tuner-mechanism slim blade tuner originated by INFN for the European XFEL 3.9GHz. At the same time bandwidth of the SRF cavities for LCLS II will be in the range of the 180Hz and fine/fast tuning of the cavity frequency required. We added to the design fast/fine tuner made with 2 encapsulated piezos. First prototype tuner has been built and went through testing at warm conditions. Details of the design and summary of the tests will be presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB32
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MOPOB33	LCLS-II Tuner Assembly for the Prototype Cryomodule at FNAL	ion, cavity, cryomodule, operation	143
	Y.M. Pischalnikov, E. Borissov, T.N. Khabiboulline, J.C. Yun Fermilab, Batavia, Illinois, USA
	The tuner design for LCLS-II has been thoroughly verified and fabricated for used in the LCLS-II prototype modules. This paper will present the lessons learned during the installation of these tuners for the prototype modules at FNAL, including installation procedures, best practices, and challenges encountered.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB33
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MOPOB61	Updates of Vertical Electropolishing Studies at Cornell with KEK and Marui Galvanizing Co. Ltd .	cathode, ion, cavity, target	208
	F. Furuta, M. Ge, T. Gruber, J.J. Kaufman, M. Liepe, J. Sears Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA V. Chouhan, Y.I. Ida, K.N. Nii, T.Y. Yamaguchi MGH, Hyogo-ken, Japan H. Hayano, S. Kato, T. Saeki KEK, Ibaraki, Japan
	Cornell, KEK, and Marui Galvanizing Co. Ltd (MGI) have started new Vertical Electro-Polishing (VEP) R&D collaboration in 2014. MGI and KEK has developed their original VEP cathode named 'i-cathode Ninja'® which has four retractable wing-shape parts per cell for single-/9-cell cavities. One single cell cavity had processed with VEP using i-cathode Ninja at Cornell. Cornell also performed the vertical test on that cavity. We will present the details of process and RF test result at Cornell.
	Poster MOPOB61 [2.251 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB61
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MOPOB62	SRF Half Wave Resonator Activities at Cornell for the RAON Project	cavity, ion, pick-up, heavy-ion	211
	M. Ge, F. Furuta, T. Gruber, S.W. Hartman, C. Henderson, M. Liepe, S. Lok, T.I. O'Connell, P.J. Pamel, J. Sears, V. Veshcherevich Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA J. Joo, J.-W. Kim, W.K. Kim, J. Lee, I. Shin IBS, Daejeon, Republic of Korea
	The RAON heavy-ion accelerator requires ninety-eight 162.5MHz Half-Wave-Resonators (HWR) with a geometrical β=0.12. Cornell University will test a prototype HWR as well as develop a frequency tuner for this cavity. In this paper we report on the progress in designing, fabricating, and commissioning of new HWR preparation and testing infrastructure at Cornell. The HWR infrastructure work includes new input and pick-up couplers, a modified vertical test insert with a 162.5MHz RF system, a new High-Pressure-Water-Rinsing (HPR) setup, and a modified chemical etching system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB62
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MOPOB65	Investigation of the Origin of the Anti-Q-Slope	ion, cavity, ECR, experiment	218
	J.T. Maniscalco, M. Ge, D. Gonnella, M. Liepe Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	The surface resistance of a superconductor, a property very relevant to SRF accelerators, has long been known to depend on the strength of the surface magnetic field. A recent discovery showed that, for certain surface treatments, microwave cavities can be shown to have an inverse field dependence, dubbed the ‘‘anti-Q-slope'', in which the surface resistance decreases over an increasing field. Here we present an investigation into what causes the anti-Q-slope in nitrogen-doped niobium cavities, drawing a direct connection between the electron mean free path of the SRF material and the magnitude of the anti-Q-slope. Further, we incorporate residual resistance due to flux trapping to calculate an optimal mean free path for a given trapped flux.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB65
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MOPOB76	Field Emission Dark Current Simulation for eRHIC ERL Cavities	ion, cavity, electron, simulation	235
	C. Xu, I. Ben-Zvi, Y. Hao, V. Ptitsyn, K.S. Smith, B. P. Xiao, W. Xu BNL, Upton, Long Island, New York, USA
	The eRHIC project will be a electron and proton collider proposed in BNL. These high repetition rates will require Super-Conducting Radio-Frequency cavities with fundamental frequency of 650MHZ for high current applications. Each with a string of two of those cavities. The strong electromagnetic fields in the SRF cavities will extract electrons from the cavity walls and will accelerate those. Most dark current will be deposited locally, although some electrons may reach several neighbour cyromodules, thereby gaining substantial energy before they hit a collimator or other aperture. Simulation of these effects is therefore crucial for the design of the machine. Track3P code was used to simulate field-emission electrons from different SRF cavities setup to optimize the field emission dark current characterizes.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB76
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WEB1CO02	Investigation of Structural Development in the Two-Step Diffusion Coating of Nb3Sn on Niobium	ion, niobium, experiment, cavity	659
	U. Pudasaini, M.J. Kelley The College of William and Mary, Williamsburg, Virginia, USA G.V. Eremeev, M.J. Kelley, C.E. Reece JLab, Newport News, Virginia, USA M.J. Kelley, J. Tuggle Virginia Polytechnic Institute and State University, Blacksburg, USA
	Funding: Supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177 and Office of High Energy Physics under grant SC00144475. The potential for higher operating temperatures and increased accelerating gradient has attracted SRF researchers to Nb3Sn coatings on niobium for nearly 50 years. The two-step tin vapor diffusion: nucleation followed by deposition appears to be a promising technique to prepare Nb3Sn coatings on interior cavity surface. We have undertaken a fundamental materials study of the nucleation and deposition steps. Nucleation was accomplished within parameter ranges: 300 - 500 °C, 1 - 5 hrs duration, 5 mg - 1 g SnCl2 and 1 g Sn. The resulting deposit consists of (< 10%) coverage of tin particles, as determined by SEM/EDS, while XPS and SAM discovered extra tin film between these particles. Preliminary results by EBSD show no evident effect of substrate crystallography on the crystallography of the final coating. Substantial topography was found to develop during the coating growth.
	Slides WEB1CO02 [3.299 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEB1CO02
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WEB1CO03	Surface Impurity Content Optimization to Maximize Q-factors of Superconducting Resonators	ion, cavity, factory, niobium	663
	M. Martinello, M. Checchin, A. Grassellino, O.S. Melnychuk, S. Posen, A. Romanenko, D.A. Sergatskov Fermilab, Batavia, Illinois, USA M. Checchin Illinois Institute of Technology, Chicago, Illlinois, USA J. Zasadzinski IIT, Chicago, Illinois, USA
	Quality factor of superconducting radio-frequency (SRF) cavities is degraded whenever magnetic flux is trapped in the cavity walls during the cooldown. In this contribution we study how the trapped flux sensitivity, defined as the trapped flux surface resistance normalized for the amount of trapped flux, depends on the mean free path. A systematic study of a variety of 1.3 GHz cavities with different surface treatments (EP, 120 ^°C bake and different N-doping) is carried out. A bell shaped trend appears for the range of mean free path studied. Over-doped cavities fall at the maximum of this curve defining the largest values of sensitivity. In addition, we have studied the trend of the BCS surface resistance contribution as a function of mean free path, showing that N-doped cavities follow close to the theoretical minimum. Adding these results together we show that the 2/6 N-doping treatment gives the highest Q-factor values at 2 K and 16 MV/m, as long as the magnetic field fully trapped during the cavity cooldown is lower than 10 mG.
	Slides WEB1CO03 [4.500 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEB1CO03
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WEB3IO01	SRF Devlopment and Cryomodule Production for the FRIB Linac	ion, cavity, cryomodule, linac	847
	T. Xu, H. Ao, B. Bird, N.K. Bultman, E.E. Burkhardt, F. Casagrande, C. Compton, J.L. Crisp, K.D. Davidson, K. Elliott, A. Facco, V. Ganni, A. Ganshyn, P.E. Gibson, W. Hartung, M. Ikegami, P. Knudsen, S.M. Lidia, I.M. Malloch, S.J. Miller, D.G. Morris, P.N. Ostroumov, J.T. Popielarski, L. Popielarski, M.A. Reaume, K. Saito, G. Shen, M. Shuptar, S. Stark, J. Wei, J.D. Wenstrom, M. Xu, T. Xu, Y. Xu, Y. Yamazaki, Z. Zheng FRIB, East Lansing, Michigan, USA A. Facco INFN/LNL, Legnaro (PD), Italy K. Hosoyama KEK, Ibaraki, Japan M.P. Kelly ANL, Argonne, Illinois, USA R.E. Laxdal TRIUMF, Vancouver, Canada M. Wiseman JLab, Newport News, Virginia, USA
	Funding: Work supported by the U.S. Department of Energy Office of Sci-ence under Cooperative Agreement DE-SC0000661 The Facility for Rare Isotope Beams' heavy ion con-tinuous-wave (CW) linac extends superconducting RF to low beam energy of 500 keV/u. 332 low-beta cavities are housed in 48 cryomodules. Technical development of high performance subsystems including resonator, cou-pler, tuner, mechanical damper, solenoid and magnetic shielding is necessary. In 2015, the first innovatively designed FRIB bottom-up prototype cryomodule was tested meeting all FRIB specifications. In 2016, the first full production cryomodule is constructed and tested. The preproduction and production cryomodule procurements and in-house assembly are progressing according to the project plan.
	Slides WEB3IO01 [15.765 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEB3IO01
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WEB3CO03	650 MHz Elliptical Superconducting RF Cavities for PIP-II Project	cavity, ion, linac, simulation	859
	V. Jain, E. Borissov, I.V. Gonin, C.J. Grimm, S. Kazakov, T.N. Khabiboulline, V.A. Lebedev, C.S. Mishra, D.V. Mitchell, T.H. Nicol, Y.M. Pischalnikov, A.M. Rowe, N.K. Sharma, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. Proton Improvement Plan-II at Fermilab is an 800 MeV superconducting pulsed linac which is also capable of running in CW mode. The high energy section operates from 185 MeV to 800 MeV instigated using 650 MHz elliptical cavities. The low-beta (LB) βG =0.61 portion will accelerate protons from 185 MeV-500 MeV, while the high-beta (HB) βG = 0.92 portion of the linac will acceler-ate from 500 to 800 MeV. The development of both LB and HB cavities is taking place under the umbrella of the Indian Institutions Fermilab Collaboration (IIFC). This paper presents the design methodology adopted for both low-beta and high-beta cavities starting from the RF design yielding mechanical dimensions of the cavity cells and, then moving to the workable dressed cavity design. Designs of end groups (main coupler side and field probe side), helium vessel, coupler, and tuner are the same for both cavities everywhere where it is possible. The design, analysis and integration of dressed cavity are presented in detail.
	Slides WEB3CO03 [11.396 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEB3CO03
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WEPOB55	Simulation of Stray Electrons in the RHIC Low Energy Cooler	ion, electron, cathode, cavity	1012
	J. Kewisch BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. The Low Energy RHIC electron Cooler, under construction at BNL, accelerates electrons with a 400 kV DC gun and a 2.2 MeV SRF booster cavity. Electrons which leave the cathode at the wrong time will not be accelerated to the correct energies and will not reach the beam dump at the end of the accelerator. Thy may impact the beam pipe after incorrect deflection in dipoles or after being slowed down longitudinally in the booster while the transverse momentum is not affected. In some cases their direction is reversed in the booster and they will impact the cathode. We simulated the trajectories of these electrons using the GPT tracking code. The results are qualitative, not quantitative, since the sources and numbers of the stray electrons are unknown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB55
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THPOA65	Double Triple Bend Achromat for Next Generation 3 GeV Light Sources	ion, injection, lattice, optics	1237
	A. Alekou, R. Bartolini Oxford University, Physics Department, Oxford, Oxon, United Kingdom A. Alekou, R. Bartolini JAI, Oxford, United Kingdom A. Alekou, R. Bartolini, T. Pulampong, R.P. Walker DLS, Oxfordshire, United Kingdom N. Carmignani, S.M. Liuzzo, P. Raimondi ESRF, Grenoble, France
	The Double Triple Bend Achromat (DTBA) is a newly designed cell for a next generation 3 GeV synchrotron light source. DTBA is inspired by the Double-Double Bend Achromat (DDBA) cell designed for Diamond and originates from a modification of the ESRF HMBA 6 GeV cell, combining in this way the best characteristics of each lattice. The lattice achieves a natural emittance as low as 131 pm, together with a sufficient Dynamic Aperture (DA) for injection and lifetime. Two cells are designed with different end-drift lengths providing two different Long Straight Sections (LSS) for insertion devices, 5 and 7.5 m long, in addition to a new middle-straight section of 3 m. The characteristics of the lattice together with the results on emittance, DA and Touschek lifetime are presented after extensive linear and non-linear optimisations, with and without the presence of errors and corrections.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA65
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Paper

Title

Other Keywords

Page

MOPOB32

Design and Test of the Prototype Tuner for 3.9 GHz SRF Cavity for LCLS II Project

cavity, ion, cryomodule, FEL

140

Y.M. Pischalnikov, E. Borissov, J.C. Yun
Fermilab, Batavia, Illinois, USA

Fermilab is responsible for the design of the 3.9GHz cryomodule for the LCLS-II that will operate in continuous wave (CW) mode. Bandwidth of the SRF cavities will be in the range of the 180Hz. In our tuner design, we adopted as the slow tuner-mechanism slim blade tuner originated by INFN for the European XFEL 3.9GHz. At the same time bandwidth of the SRF cavities for LCLS II will be in the range of the 180Hz and fine/fast tuning of the cavity frequency required. We added to the design fast/fine tuner made with 2 encapsulated piezos. First prototype tuner has been built and went through testing at warm conditions. Details of the design and summary of the tests will be presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB32

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MOPOB33

LCLS-II Tuner Assembly for the Prototype Cryomodule at FNAL

ion, cavity, cryomodule, operation

143

Y.M. Pischalnikov, E. Borissov, T.N. Khabiboulline, J.C. Yun
Fermilab, Batavia, Illinois, USA

The tuner design for LCLS-II has been thoroughly verified and fabricated for used in the LCLS-II prototype modules. This paper will present the lessons learned during the installation of these tuners for the prototype modules at FNAL, including installation procedures, best practices, and challenges encountered.

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MOPOB61

Updates of Vertical Electropolishing Studies at Cornell with KEK and Marui Galvanizing Co. Ltd .

cathode, ion, cavity, target

208

F. Furuta, M. Ge, T. Gruber, J.J. Kaufman, M. Liepe, J. Sears
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
V. Chouhan, Y.I. Ida, K.N. Nii, T.Y. Yamaguchi
MGH, Hyogo-ken, Japan
H. Hayano, S. Kato, T. Saeki
KEK, Ibaraki, Japan

Cornell, KEK, and Marui Galvanizing Co. Ltd (MGI) have started new Vertical Electro-Polishing (VEP) R&D collaboration in 2014. MGI and KEK has developed their original VEP cathode named 'i-cathode Ninja'® which has four retractable wing-shape parts per cell for single-/9-cell cavities. One single cell cavity had processed with VEP using i-cathode Ninja at Cornell. Cornell also performed the vertical test on that cavity. We will present the details of process and RF test result at Cornell.

Poster MOPOB61 [2.251 MB]

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MOPOB62

SRF Half Wave Resonator Activities at Cornell for the RAON Project

cavity, ion, pick-up, heavy-ion

211

M. Ge, F. Furuta, T. Gruber, S.W. Hartman, C. Henderson, M. Liepe, S. Lok, T.I. O'Connell, P.J. Pamel, J. Sears, V. Veshcherevich
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J. Joo, J.-W. Kim, W.K. Kim, J. Lee, I. Shin
IBS, Daejeon, Republic of Korea

The RAON heavy-ion accelerator requires ninety-eight 162.5MHz Half-Wave-Resonators (HWR) with a geometrical β=0.12. Cornell University will test a prototype HWR as well as develop a frequency tuner for this cavity. In this paper we report on the progress in designing, fabricating, and commissioning of new HWR preparation and testing infrastructure at Cornell. The HWR infrastructure work includes new input and pick-up couplers, a modified vertical test insert with a 162.5MHz RF system, a new High-Pressure-Water-Rinsing (HPR) setup, and a modified chemical etching system.

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MOPOB65

Investigation of the Origin of the Anti-Q-Slope

ion, cavity, ECR, experiment

218

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

The surface resistance of a superconductor, a property very relevant to SRF accelerators, has long been known to depend on the strength of the surface magnetic field. A recent discovery showed that, for certain surface treatments, microwave cavities can be shown to have an inverse field dependence, dubbed the ‘‘anti-Q-slope'', in which the surface resistance decreases over an increasing field. Here we present an investigation into what causes the anti-Q-slope in nitrogen-doped niobium cavities, drawing a direct connection between the electron mean free path of the SRF material and the magnitude of the anti-Q-slope. Further, we incorporate residual resistance due to flux trapping to calculate an optimal mean free path for a given trapped flux.

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB65

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MOPOB76

Field Emission Dark Current Simulation for eRHIC ERL Cavities

ion, cavity, electron, simulation

235

C. Xu, I. Ben-Zvi, Y. Hao, V. Ptitsyn, K.S. Smith, B. P. Xiao, W. Xu
BNL, Upton, Long Island, New York, USA

The eRHIC project will be a electron and proton collider proposed in BNL. These high repetition rates will require Super-Conducting Radio-Frequency cavities with fundamental frequency of 650MHZ for high current applications. Each with a string of two of those cavities. The strong electromagnetic fields in the SRF cavities will extract electrons from the cavity walls and will accelerate those. Most dark current will be deposited locally, although some electrons may reach several neighbour cyromodules, thereby gaining substantial energy before they hit a collimator or other aperture. Simulation of these effects is therefore crucial for the design of the machine. Track3P code was used to simulate field-emission electrons from different SRF cavities setup to optimize the field emission dark current characterizes.

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-MOPOB76

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WEB1CO02

Investigation of Structural Development in the Two-Step Diffusion Coating of Nb3Sn on Niobium

ion, niobium, experiment, cavity

659

U. Pudasaini, M.J. Kelley
The College of William and Mary, Williamsburg, Virginia, USA
G.V. Eremeev, M.J. Kelley, C.E. Reece
JLab, Newport News, Virginia, USA
M.J. Kelley, J. Tuggle
Virginia Polytechnic Institute and State University, Blacksburg, USA

Funding: Supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177 and Office of High Energy Physics under grant SC00144475.
The potential for higher operating temperatures and increased accelerating gradient has attracted SRF researchers to Nb3Sn coatings on niobium for nearly 50 years. The two-step tin vapor diffusion: nucleation followed by deposition appears to be a promising technique to prepare Nb3Sn coatings on interior cavity surface. We have undertaken a fundamental materials study of the nucleation and deposition steps. Nucleation was accomplished within parameter ranges: 300 - 500 °C, 1 - 5 hrs duration, 5 mg - 1 g SnCl2 and 1 g Sn. The resulting deposit consists of (< 10%) coverage of tin particles, as determined by SEM/EDS, while XPS and SAM discovered extra tin film between these particles. Preliminary results by EBSD show no evident effect of substrate crystallography on the crystallography of the final coating. Substantial topography was found to develop during the coating growth.

Slides WEB1CO02 [3.299 MB]

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WEB1CO03

Surface Impurity Content Optimization to Maximize Q-factors of Superconducting Resonators

ion, cavity, factory, niobium

663

M. Martinello, M. Checchin, A. Grassellino, O.S. Melnychuk, S. Posen, A. Romanenko, D.A. Sergatskov
Fermilab, Batavia, Illinois, USA
M. Checchin
Illinois Institute of Technology, Chicago, Illlinois, USA
J. Zasadzinski
IIT, Chicago, Illinois, USA

Quality factor of superconducting radio-frequency (SRF) cavities is degraded whenever magnetic flux is trapped in the cavity walls during the cooldown. In this contribution we study how the trapped flux sensitivity, defined as the trapped flux surface resistance normalized for the amount of trapped flux, depends on the mean free path. A systematic study of a variety of 1.3 GHz cavities with different surface treatments (EP, 120 ^°C bake and different N-doping) is carried out. A bell shaped trend appears for the range of mean free path studied. Over-doped cavities fall at the maximum of this curve defining the largest values of sensitivity. In addition, we have studied the trend of the BCS surface resistance contribution as a function of mean free path, showing that N-doped cavities follow close to the theoretical minimum. Adding these results together we show that the 2/6 N-doping treatment gives the highest Q-factor values at 2 K and 16 MV/m, as long as the magnetic field fully trapped during the cavity cooldown is lower than 10 mG.

Slides WEB1CO03 [4.500 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEB1CO03

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WEB3IO01

SRF Devlopment and Cryomodule Production for the FRIB Linac

ion, cavity, cryomodule, linac

847

T. Xu, H. Ao, B. Bird, N.K. Bultman, E.E. Burkhardt, F. Casagrande, C. Compton, J.L. Crisp, K.D. Davidson, K. Elliott, A. Facco, V. Ganni, A. Ganshyn, P.E. Gibson, W. Hartung, M. Ikegami, P. Knudsen, S.M. Lidia, I.M. Malloch, S.J. Miller, D.G. Morris, P.N. Ostroumov, J.T. Popielarski, L. Popielarski, M.A. Reaume, K. Saito, G. Shen, M. Shuptar, S. Stark, J. Wei, J.D. Wenstrom, M. Xu, T. Xu, Y. Xu, Y. Yamazaki, Z. Zheng
FRIB, East Lansing, Michigan, USA
A. Facco
INFN/LNL, Legnaro (PD), Italy
K. Hosoyama
KEK, Ibaraki, Japan
M.P. Kelly
ANL, Argonne, Illinois, USA
R.E. Laxdal
TRIUMF, Vancouver, Canada
M. Wiseman
JLab, Newport News, Virginia, USA

Funding: Work supported by the U.S. Department of Energy Office of Sci-ence under Cooperative Agreement DE-SC0000661
The Facility for Rare Isotope Beams' heavy ion con-tinuous-wave (CW) linac extends superconducting RF to low beam energy of 500 keV/u. 332 low-beta cavities are housed in 48 cryomodules. Technical development of high performance subsystems including resonator, cou-pler, tuner, mechanical damper, solenoid and magnetic shielding is necessary. In 2015, the first innovatively designed FRIB bottom-up prototype cryomodule was tested meeting all FRIB specifications. In 2016, the first full production cryomodule is constructed and tested. The preproduction and production cryomodule procurements and in-house assembly are progressing according to the project plan.

Slides WEB3IO01 [15.765 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEB3IO01

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WEB3CO03

650 MHz Elliptical Superconducting RF Cavities for PIP-II Project

cavity, ion, linac, simulation

859

V. Jain, E. Borissov, I.V. Gonin, C.J. Grimm, S. Kazakov, T.N. Khabiboulline, V.A. Lebedev, C.S. Mishra, D.V. Mitchell, T.H. Nicol, Y.M. Pischalnikov, A.M. Rowe, N.K. Sharma, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
Proton Improvement Plan-II at Fermilab is an 800 MeV superconducting pulsed linac which is also capable of running in CW mode. The high energy section operates from 185 MeV to 800 MeV instigated using 650 MHz elliptical cavities. The low-beta (LB) βG =0.61 portion will accelerate protons from 185 MeV-500 MeV, while the high-beta (HB) βG = 0.92 portion of the linac will acceler-ate from 500 to 800 MeV. The development of both LB and HB cavities is taking place under the umbrella of the Indian Institutions Fermilab Collaboration (IIFC). This paper presents the design methodology adopted for both low-beta and high-beta cavities starting from the RF design yielding mechanical dimensions of the cavity cells and, then moving to the workable dressed cavity design. Designs of end groups (main coupler side and field probe side), helium vessel, coupler, and tuner are the same for both cavities everywhere where it is possible. The design, analysis and integration of dressed cavity are presented in detail.

Slides WEB3CO03 [11.396 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEB3CO03

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WEPOB55

Simulation of Stray Electrons in the RHIC Low Energy Cooler

ion, electron, cathode, cavity

1012

J. Kewisch
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
The Low Energy RHIC electron Cooler, under construction at BNL, accelerates electrons with a 400 kV DC gun and a 2.2 MeV SRF booster cavity. Electrons which leave the cathode at the wrong time will not be accelerated to the correct energies and will not reach the beam dump at the end of the accelerator. Thy may impact the beam pipe after incorrect deflection in dipoles or after being slowed down longitudinally in the booster while the transverse momentum is not affected. In some cases their direction is reversed in the booster and they will impact the cathode. We simulated the trajectories of these electrons using the GPT tracking code. The results are qualitative, not quantitative, since the sources and numbers of the stray electrons are unknown.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-WEPOB55

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THPOA65

Double Triple Bend Achromat for Next Generation 3 GeV Light Sources

ion, injection, lattice, optics

1237

A. Alekou, R. Bartolini
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
A. Alekou, R. Bartolini
JAI, Oxford, United Kingdom
A. Alekou, R. Bartolini, T. Pulampong, R.P. Walker
DLS, Oxfordshire, United Kingdom
N. Carmignani, S.M. Liuzzo, P. Raimondi
ESRF, Grenoble, France

The Double Triple Bend Achromat (DTBA) is a newly designed cell for a next generation 3 GeV synchrotron light source. DTBA is inspired by the Double-Double Bend Achromat (DDBA) cell designed for Diamond and originates from a modification of the ESRF HMBA 6 GeV cell, combining in this way the best characteristics of each lattice. The lattice achieves a natural emittance as low as 131 pm, together with a sufficient Dynamic Aperture (DA) for injection and lifetime. Two cells are designed with different end-drift lengths providing two different Long Straight Sections (LSS) for insertion devices, 5 and 7.5 m long, in addition to a new middle-straight section of 3 m. The characteristics of the lattice together with the results on emittance, DA and Touschek lifetime are presented after extensive linear and non-linear optimisations, with and without the presence of errors and corrections.

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA65

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