SRF2019 - Classification: Cavities - Design / non-elliptical

Paper	Title	Page
FRTU1	Superconducting Cavities of Interesting Shapes (Non-Elliptical Cavities)
	S.U. De Silva ODU, Norfolk, Virginia, USA
	The Superconducting Cavities of Interesting Shapes¿ tutorial introduces the basics of non-elliptical cavities. The non-elliptical cavity types discussed includes cavities for accelerating particle beams and deflecting and crabbing beams. The types of cavities are categorized based on electromagnetic field profiles for easier understanding and characterization of cavity properties. The quarte wave resonator, half wave resonator and spoke cavities are discussed in detail. The practical applications of such cavities are also discussed for both accelerating and deflecting/crabbing cavities. Further details of cavity selection for different applications and mechanical properties are also presented.
	Slides FRTU1 [18.613 MB]
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP002	Modeling of Superconducting Spoke Cavity with its Control Loops Systems for the MYRRHA Linac Project	387
	M. Dominiczak ACS, Orsay, France F. Bouly LPSC, Grenoble Cedex, France N. Gandolfo, C. Joly Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
	In the construction framework of a future 600 MeV/4 mA CW Superconducting Linac accelerator for the MYRRHA project at SCK•CEN (Mol, Belgium), modeling works under Matlab/Simulink are carried out upstream to understand the behaviour of 352 MHz single Spoke cavity with its environment and its associated feedback control loops (LLRF and cold tuning system). One of the main goal is to assess the feasibility of cavity failure compensation in the Superconducting Linac. Indeed, stringent reliability requirements must be fulfilled to ensure an efficient operation of the MYRRHA Accelerator Driven System: unexpected beam interruptions, due to failures, must be compensated in less than 3 seconds. Our preliminary study focuses on the fast frequency re-tuning of the cavity and the power balances. Our goal is to prepare the R&D tests foreseen at IPN Orsay on a prototype cryomodule including two SC Spoke cavities equipped with couplers, tuners with feedback loop and connected to dedicate LLRF. Nicolas Gandolfo, IPNO, Orsay (France) Christophe Joly, IPNO, Orsay (France) Frédéric Bouly, LPSC, Grenoble (France)
	Poster TUP002 [1.335 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP002
About •	paper received ※ 23 June 2019 paper accepted ※ 04 July 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP004	Latest Cryogenic Test Results of the Superconducting β=0.069 CH-cavities for the HELIAC-project	392
	M. Basten, M. Busch, T. Conrad, H. Podlech, M. Schwarz IAP, Frankfurt am Main, Germany K. Aulenbacher, W.A. Barth, C. Burandt, F.D. Dziuba, V. Gettmann, M. Heilmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu, J. Salvatore, A. Schnase, S. Yaramyshev GSI, Darmstadt, Germany K. Aulenbacher, W.A. Barth, C. Burandt, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu HIM, Mainz, Germany K. Aulenbacher, S. Lauber IKP, Mainz, Germany F.D. Dziuba, J. List KPH, Mainz, Germany
	The upcoming FAIR (Facility for Antiproton and Ion Research) project at GSI will use the existing UNILAC (UNIversal Linear Accelerator) as an injector, reducing the beam time for the ambitious Super Heavy Element (SHE) program. To keep the UNILAC user program competitive a new superconducting (sc) continuous wave (cw) high intensity heavy ion LINAC should provide ion beams with max. duty factor above the coulomb barrier. The fundamental sc LINAC design comprises a low energy beam transport (LEBT)-section followed by a sc Drift Tube Linac (DTL) consisting of sc Crossbar-H-mode (CH) structures for acceleration up to 7.3 MeV/u. The latest milestones towards the new cw LINAC HELIAC (HELmholtz LInear ACcelerator) have been the successful tests and commissioning of the first demonstrator section with heavy ion beam in 2017 and 218 as well as the successful test under cryogenic conditions of the second CH-cavity in 2018. Now the third CH-cavity has been tested at cryogenic temperatures of 4 Kelvin at the Institute for Applied Physics (IAP) at Goethe University Frankfurt (GUF). The results of these measurements as well as the status of the HELIAC-project will be presented.
	Poster TUP004 [0.958 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP004
About •	paper received ※ 22 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP005	Cavity Designs for the CH3 to CH11 of the Superconducting Heavy Ion Accelerator HELIAC	396
SUSP009	use link to see paper's listing under its alternate paper code
	T. Conrad, M. Basten, M. Busch, H. Podlech, M. Schwarz IAP, Frankfurt am Main, Germany K. Aulenbacher, W.A. Barth, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu HIM, Mainz, Germany K. Aulenbacher KPH, Mainz, Germany W.A. Barth, M. Heilmann, A. Rubin, A. Schnase, S. Yaramyshev GSI, Darmstadt, Germany
	In collaboration of GSI, HIM and Goethe University Frankfurt new designs for the CH-DTL cavities of the proposed Helmholtz Linear Accelerator (HELIAC) are developed. The cw-mode operated linac with a final energy of 7.3 MeV/u is intended for various experiments, especially with heavy ions at energies near the coulomb barrier. Currently twelve superconducting CH-cavities are considered which will be split into four different cryostats. Each cavity will be equipped with dynamic bellow tuners. After successful beam tests with CH⁰ as well as last surface preparations and ongoing rf tests with CH1 and CH2, CH3 to CH11 will be designed. Based on the successful test results, individual optimizations are carried out on the cavity design. Attention was paid to reduce production costs, for example by keeping the cavity diameter in each cryostat constant despite varying particle velocities and gap numbers. In addition to reaching the resonance frequency of 216.816 MHz and the influence of the bellow tuners on the frequency, the mechanical stability of the bellow tuners, the thermal effects on the cavity and the measures to mitigate secondary electron emission are investigated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP005
About •	paper received ※ 19 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP007	Electromagnetic Design of the Prototype Spoke Cavity for the JAEA-ADS Linac	399
	J. Tamura, K. Hasegawa, Y. Kondo, F.M. Maekawa, S.I. Meigo, B. Yee-Rendón JAEA/J-PARC, Tokai-mura, Japan E. Kako, T. Konomi, H. Sakai, K. Umemori KEK, Ibaraki, Japan
	The Japan Atomic Energy Agency (JAEA) is proposing an accelerator-driven subcritical system (ADS) as a future project to transmute long-lived nuclides to short-lived or stable ones. In the JAEA-ADS, a high-power proton beam of 30 MW with a final beam energy of 1.5 GeV is required with a high reliability. Furthermore, the accelerator needs to be operated in a continuous wave mode in order to be compatible with the reactor operation. As the first step toward the detailed design of the JAEA-ADS linac, we are planning to demonstrate a high-field measurement by prototyping a low-beta single spoke resonator (SSR1). We performed the electromagnetic design, and confirmed that the cavity performances of the SSR1 model with and without dimensional constraint.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP007
About •	paper received ※ 02 July 2019 paper accepted ※ 04 July 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP008	HOMs Extraction Structure Design for HEPS 166.6 MHz Cavities	403
	X.R. Hao IHEP, Beijing, People’s Republic of China
	Higher order modes (HOMs) may af{}fect beam stability and refrigeration requirements of superconducting cavity such as the 166.6~MHz superconducting(SC) cavity, which is studied at IHEP. Under certain conditions beam-induced HOMs can accumulate suf{}f{}icient energy to destabilize the beam or quench the SC cavities. In order to limit these ef{}fects, we considers the use of coaxial HOM couplers on the cut-of{}f tubes of the SC cavity. However, HOMs cannot be ef{}fectively extracted by HOM couplers. Therefore, it is necessary to design a HOMs extraction structure to introduce the dangerous modes from the cavity into the bundle tube, which are designed to couple to potentially dangerous modes while suf{}ficiently rejecting the fundamental mode. The HOMs extraction structure consists of an enlarged tubes, a coaxial structure, and the petal. The extraction of the dangerous modes and the suppression of the fundamental mode are realized by the petal structure and the coaxial structure. In order to verify the designs, a rapid prototype for the favored structure was fabricated and characterized on a low-power test-stand.
	Poster TUP008 [1.665 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP008
About •	paper received ※ 22 June 2019 paper accepted ※ 01 July 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP010	Mechanical Design and Horizontal Tests of a Dressed 166.6 MHz Quarter-wave β=1 SRF Cavity System	408
	X.Y. Zhang, X.R. Hao, D.B. Li, Z.Q. Li, H.Y. Lin, Q. Ma, Z.H. Mi, Q.Y. Wang, P. Zhang IHEP, Beijing, People’s Republic of China
	Funding: This work has been supported by HEPS-TF project. A 166.6 MHz quarter-wave β=1 superconducting proof-of-principle cavity has been designed and recently been dressed with a helium jacket, fundamental power coupler and tuner. The cavity was subsequently installed in a modified cryomodule and tested in a horizontal manner at both 4.2 K and 2 K. The helium jacket was successfully developed with a focus on minimizing frequency shift due to helium pressure fluctuation while retaining a reasonable tuning range. The Lorentz force detuning (LFD) and microphonics were also optimized during the design. The df/dp and LFD coefficient were measured to be -3.1 Hz/mbar and -0.8 Hz/(MV/m)². These are in good agreement with simulations. Future work is mainly to reduce the stiffness of the cavity and further suppress the vibration mode of the inner conductor.
	Poster TUP010 [1.245 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP010
About •	paper received ※ 23 June 2019 paper accepted ※ 29 June 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP011	QWR085 Design for Bisol Post Accelerator SCL2	413
	M. Chen, S. Chen, A.Q. Cheng, J.K. Hao, K.X. Liu, Y.Q. Liu, D.M. Ouyang, S.W. Quan, F. Zhu PKU, Beijing, People’s Republic of China Z. Peng CIAE, Beijing, People’s Republic of China
	BISOL(Beijing Isotope-Separation-On-Line Neutron-Rich Beam Facility) is a new generation radioactive ion beam(RIB) facility[1]. It consists a CARR nuclear reactor, a high intensity deuteron accelerator and a post accelera-tor. QWR085 cavity is supposed to be used in SCL2 of post accelerator. This paper mainly talks about the elec-tromagnetic design, mechanical design and vibration damper design of QWR085.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP011
About •	paper received ※ 23 June 2019 paper accepted ※ 29 June 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP014	Mechanical Design and Fabrication Aspects of Prototype SSR2 Jacketed Cavities	424
	M. Parise, D. Passarelli, F. Ruiu Fermilab, Batavia, Illinois, USA P. Duchesne, D. Longuevergne, D. Reynet Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
	A total of 35 Superconducting SSR2 spoke cavities will be installed in the PIP II SRF linac at Fermilab and a total of 8 prototype SSR2 cavities will be manufactured for the prototype cryomodule. In this paper, the mechanical design and fabrication aspects of the prototype jacketed SSR2 cavity will be presented. RF and mechanical design activities were conducted in parallel directly on the jacketed cavity in order to minimize the number of design iterations. Also, the lessons learned from other spoke cavities experiences (i.e. SSR1 at Fermilab and ESS double spoke at IPNO) were considered since the early stage of the design.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP014
About •	paper received ※ 23 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP016	Quarter-wave Resonator with the Optimized Shape for Quantum Information Systems	430
	S.V. Kutsaev, R.B. Agustsson, P.R. Carriere, A. Moro, A.Yu. Smirnov, K.V. Taletski RadiaBeam, Santa Monica, California, USA A.N. Cleland, É. Dumur The University of Chicago, Chicago, Illinois, USA Z.A. Conway ANL, Lemont, Illinois, USA K.V. Taletski MEPhI, Moscow, Russia
	Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics, under SBIR grant DE-SC0018753 Quantum computers (QC), if realized, could disrupt many computationally intense fields of science. The building block element of a QC is a quantum bit (qubit). Qubits enable the use of quantum superposition and multi-state entanglement in QC calculations, allowing a QC to simultaneously calculate millions of computations at once. However, quantum states stored in a qubit degrade with decreased quality factors and interactions with the environment. One technical solution to improve qubit lifetimes and network interactions is a circuit comprised of a Josephson junction located inside of a high Q-factor superconducting 3D cavity. RadiaBeam, in collaboration with Argonne National Laboratory and The University of Chicago, has developed a superconducting radio-frequency quarter-wave resonant cavity (QWR) for quantum computation. Here a 6 GHz QWR was optimized to include tapering of the inner and outer conductors, a toroidal shape for the resonator shorting plane, and the inner conductor to reduce parasitic capacitance. In this paper, we present the results of the qubit cavity design optimization, fabrication, processing and testing in a single-photon regime at mK temperatures.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP016
About •	paper received ※ 23 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP032	Modal Analysis and Vibration Test for Quarter Wave Resonator for RAON	485
	M.O. Hyun, H.C. Jung, Y. Kim, M. Lee IBS, Daejeon, Republic of Korea
	Funding: This paper was supported by the Rare Isotope Science Project (RISP), which is funded by the Ministry of Science and ICT (MSIT) and National Research Foundation (NRF) of the Republic of Korea. The Rare Isotope Science Project (RISP) in the Institute of Basic Science (IBS), Korea, is developing and con-structing the multi-purpose linear accelerator at the north side of Daejeon, South Korea. RISP accelerator (RAON) is composed with low-energy region (SCL3) and high-energy region (SCL2), and low-energy region is made with quarter-wave resonator (QWR) and half-wave resonator (HWR) when high-energy region is made with single spoke resonator type-1 (SSR1) and type-2 (SSR2). This paper shows about the initial resonance issues of QWR superconducting (SC) cavity during cold test and SRF disturbance measurement. Afterwards, this paper shows the modal analysis and vibration test of QWR SC cavity.
	Poster TUP032 [0.584 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP032
About •	paper received ※ 23 June 2019 paper accepted ※ 01 July 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP066	New Design of SSR2 Spoke Cavity for PIP II SRF Linac	600
	P. Berrutti, I.V. Gonin, T.N. Khabiboulline, M. Parise, D. Passarelli, G.V. Romanov, F. Ruiu, A.I. Sukhanov, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	Funding: US Department of Energy Superconducting SSR2 spoke cavities provide acceleration of the H⁻ in PIP II SRF linac from 35 to 185 MeV. The RF and mechanical design of the SSR2 cavities has been completed and satisfies the technical requirements. However, our resent results of the high RF power tests of fully dressed SSR1 cavities show considerably strong multipacting (MP), which took significant time to process. On the other hand, the new results of the tests of balloon cavity showed significant mitigation of MP. In this paper we present the results of the improved design of the SSR2 cavity, based on the balloon cavity concept. The electromagnetic design is presented, including RF parameter optimization, MP simulations, field asymmetry analysis, High Order Mode (HOM) calculations. Mechanical analysis of the dressed cavity is presented also, which includes Lorentz Force Detuning optimization, and reduction of the cavity resonance frequency sensitivity versus He pressure fluctuations. The design completely satisfies the PIP II technical requirements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP066
About •	paper received ※ 21 June 2019 paper accepted ※ 01 July 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRCAA2	Balloon Single Spoke Resonator - A New Variant for Reduced Multipacting
	Z.Y. Yao, R.E. Laxdal TRIUMF, Vancouver, Canada
	Spoke resonators have been widely proposed and optimized for various applications. Good performance has been demonstrated by many cavity tests. Accompanying the great progress, the adverse impact of strong multipacting (MP) is also noted, consistent with modern 3D simulations. This paper will discuss MP behaviors in the single spoke resonator (SSR). In particular a phenomenological theory is developed to highlight the details of the geometry that affect MP. The analysis leads to an optimized geometry of a single spoke resonator defined here as the ’balloon’ geometry. TRIUMF has designed, fabricated and tested the first balloon SSR at 325 MHz and β=0.3. Cold tests proved the principle of the balloon concept, the elimination of MP barriers around the operational gradient. This paper will also report the details of the mechanical and RF design, the fabrication steps and recent cold test results.
	Slides FRCAA2 [19.831 MB]
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRCAA4	Progress in SRF CH-Cavities for the HELIAC CW Linac at GSI	1206
	M. Miski-Oglu, K. Aulenbacher, W.A. Barth, C. Burandt, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, J. List, S. Yaramyshev HIM, Mainz, Germany K. Aulenbacher, W.A. Barth, C. Burandt, F.D. Dziuba, V. Gettmann, M. Heilmann, T. Kürzeder, S. Lauber, J. List, A. Rubin, A. Schnase, S. Yaramyshev GSI, Darmstadt, Germany K. Aulenbacher, F.D. Dziuba, J. List KPH, Mainz, Germany M. Basten, M. Busch, T. Conrad, H. Podlech, M. Schwarz IAP, Frankfurt am Main, Germany S. Lauber IKP, Mainz, Germany
	The machine beam commissioning is a major milestone of the R&D for the superconducting heavy ion continuous wave linear accelerator HELIAC of Helmholtz Institute Mainz (HIM) and GSI developed in collaboration with IAP Goethe-University Frankfurt. During successful beam commissioning of the superconducting 15-gap Crossbar H-mode cavity at GSI Helmholtzzentrum für Schwerionenforschung heavy ions up to the design beam energy have been accelerated. The design acceleration gain of 3.5 MeV has been reached with full transmission for heavy ion beams of up to 1.5 particle mueA. We present fabrication experience and results of off-line and on-line cavity performance. The next step is the procurement and commissioning of so called ’Advanced Demonstrator’ - the first of series cryomodule for the entire accelerator HELIAC. Results of further Demonstrator beam tests, as well as the status of the Advanced demonstrator project will be reported.
	Slides FRCAA4 [9.864 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-FRCAA4
About •	paper received ※ 23 June 2019 paper accepted ※ 02 July 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

FRTU1

Superconducting Cavities of Interesting Shapes (Non-Elliptical Cavities)

S.U. De Silva
ODU, Norfolk, Virginia, USA

The Superconducting Cavities of Interesting Shapes¿ tutorial introduces the basics of non-elliptical cavities. The non-elliptical cavity types discussed includes cavities for accelerating particle beams and deflecting and crabbing beams. The types of cavities are categorized based on electromagnetic field profiles for easier understanding and characterization of cavity properties. The quarte wave resonator, half wave resonator and spoke cavities are discussed in detail. The practical applications of such cavities are also discussed for both accelerating and deflecting/crabbing cavities. Further details of cavity selection for different applications and mechanical properties are also presented.

Slides FRTU1 [18.613 MB]

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP002

Modeling of Superconducting Spoke Cavity with its Control Loops Systems for the MYRRHA Linac Project

387

M. Dominiczak
ACS, Orsay, France
F. Bouly
LPSC, Grenoble Cedex, France
N. Gandolfo, C. Joly
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France

In the construction framework of a future 600 MeV/4 mA CW Superconducting Linac accelerator for the MYRRHA project at SCK•CEN (Mol, Belgium), modeling works under Matlab/Simulink are carried out upstream to understand the behaviour of 352 MHz single Spoke cavity with its environment and its associated feedback control loops (LLRF and cold tuning system). One of the main goal is to assess the feasibility of cavity failure compensation in the Superconducting Linac. Indeed, stringent reliability requirements must be fulfilled to ensure an efficient operation of the MYRRHA Accelerator Driven System: unexpected beam interruptions, due to failures, must be compensated in less than 3 seconds. Our preliminary study focuses on the fast frequency re-tuning of the cavity and the power balances. Our goal is to prepare the R&D tests foreseen at IPN Orsay on a prototype cryomodule including two SC Spoke cavities equipped with couplers, tuners with feedback loop and connected to dedicate LLRF.
Nicolas Gandolfo, IPNO, Orsay (France)
Christophe Joly, IPNO, Orsay (France)
Frédéric Bouly, LPSC, Grenoble (France)

Poster TUP002 [1.335 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP002

About •

paper received ※ 23 June 2019 paper accepted ※ 04 July 2019 issue date ※ 14 August 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP004

Latest Cryogenic Test Results of the Superconducting β=0.069 CH-cavities for the HELIAC-project

392

M. Basten, M. Busch, T. Conrad, H. Podlech, M. Schwarz
IAP, Frankfurt am Main, Germany
K. Aulenbacher, W.A. Barth, C. Burandt, F.D. Dziuba, V. Gettmann, M. Heilmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu, J. Salvatore, A. Schnase, S. Yaramyshev
GSI, Darmstadt, Germany
K. Aulenbacher, W.A. Barth, C. Burandt, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu
HIM, Mainz, Germany
K. Aulenbacher, S. Lauber
IKP, Mainz, Germany
F.D. Dziuba, J. List
KPH, Mainz, Germany

The upcoming FAIR (Facility for Antiproton and Ion Research) project at GSI will use the existing UNILAC (UNIversal Linear Accelerator) as an injector, reducing the beam time for the ambitious Super Heavy Element (SHE) program. To keep the UNILAC user program competitive a new superconducting (sc) continuous wave (cw) high intensity heavy ion LINAC should provide ion beams with max. duty factor above the coulomb barrier. The fundamental sc LINAC design comprises a low energy beam transport (LEBT)-section followed by a sc Drift Tube Linac (DTL) consisting of sc Crossbar-H-mode (CH) structures for acceleration up to 7.3 MeV/u. The latest milestones towards the new cw LINAC HELIAC (HELmholtz LInear ACcelerator) have been the successful tests and commissioning of the first demonstrator section with heavy ion beam in 2017 and 218 as well as the successful test under cryogenic conditions of the second CH-cavity in 2018. Now the third CH-cavity has been tested at cryogenic temperatures of 4 Kelvin at the Institute for Applied Physics (IAP) at Goethe University Frankfurt (GUF). The results of these measurements as well as the status of the HELIAC-project will be presented.

Poster TUP004 [0.958 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP004

About •

paper received ※ 22 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP005

Cavity Designs for the CH3 to CH11 of the Superconducting Heavy Ion Accelerator HELIAC

396

SUSP009

use link to see paper's listing under its alternate paper code

T. Conrad, M. Basten, M. Busch, H. Podlech, M. Schwarz
IAP, Frankfurt am Main, Germany
K. Aulenbacher, W.A. Barth, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, J. List, M. Miski-Oglu
HIM, Mainz, Germany
K. Aulenbacher
KPH, Mainz, Germany
W.A. Barth, M. Heilmann, A. Rubin, A. Schnase, S. Yaramyshev
GSI, Darmstadt, Germany

In collaboration of GSI, HIM and Goethe University Frankfurt new designs for the CH-DTL cavities of the proposed Helmholtz Linear Accelerator (HELIAC) are developed. The cw-mode operated linac with a final energy of 7.3 MeV/u is intended for various experiments, especially with heavy ions at energies near the coulomb barrier. Currently twelve superconducting CH-cavities are considered which will be split into four different cryostats. Each cavity will be equipped with dynamic bellow tuners. After successful beam tests with CH⁰ as well as last surface preparations and ongoing rf tests with CH1 and CH2, CH3 to CH11 will be designed. Based on the successful test results, individual optimizations are carried out on the cavity design. Attention was paid to reduce production costs, for example by keeping the cavity diameter in each cryostat constant despite varying particle velocities and gap numbers. In addition to reaching the resonance frequency of 216.816 MHz and the influence of the bellow tuners on the frequency, the mechanical stability of the bellow tuners, the thermal effects on the cavity and the measures to mitigate secondary electron emission are investigated.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP005

About •

paper received ※ 19 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP007

Electromagnetic Design of the Prototype Spoke Cavity for the JAEA-ADS Linac

399

J. Tamura, K. Hasegawa, Y. Kondo, F.M. Maekawa, S.I. Meigo, B. Yee-Rendón
JAEA/J-PARC, Tokai-mura, Japan
E. Kako, T. Konomi, H. Sakai, K. Umemori
KEK, Ibaraki, Japan

The Japan Atomic Energy Agency (JAEA) is proposing an accelerator-driven subcritical system (ADS) as a future project to transmute long-lived nuclides to short-lived or stable ones. In the JAEA-ADS, a high-power proton beam of 30 MW with a final beam energy of 1.5 GeV is required with a high reliability. Furthermore, the accelerator needs to be operated in a continuous wave mode in order to be compatible with the reactor operation. As the first step toward the detailed design of the JAEA-ADS linac, we are planning to demonstrate a high-field measurement by prototyping a low-beta single spoke resonator (SSR1). We performed the electromagnetic design, and confirmed that the cavity performances of the SSR1 model with and without dimensional constraint.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP007

About •

paper received ※ 02 July 2019 paper accepted ※ 04 July 2019 issue date ※ 14 August 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP008

HOMs Extraction Structure Design for HEPS 166.6 MHz Cavities

403

X.R. Hao
IHEP, Beijing, People’s Republic of China

Higher order modes (HOMs) may af{}fect beam stability and refrigeration requirements of superconducting cavity such as the 166.6~MHz superconducting(SC) cavity, which is studied at IHEP. Under certain conditions beam-induced HOMs can accumulate suf{}f{}icient energy to destabilize the beam or quench the SC cavities. In order to limit these ef{}fects, we considers the use of coaxial HOM couplers on the cut-of{}f tubes of the SC cavity. However, HOMs cannot be ef{}fectively extracted by HOM couplers. Therefore, it is necessary to design a HOMs extraction structure to introduce the dangerous modes from the cavity into the bundle tube, which are designed to couple to potentially dangerous modes while suf{}ficiently rejecting the fundamental mode. The HOMs extraction structure consists of an enlarged tubes, a coaxial structure, and the petal. The extraction of the dangerous modes and the suppression of the fundamental mode are realized by the petal structure and the coaxial structure. In order to verify the designs, a rapid prototype for the favored structure was fabricated and characterized on a low-power test-stand.

Poster TUP008 [1.665 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP008

About •

paper received ※ 22 June 2019 paper accepted ※ 01 July 2019 issue date ※ 14 August 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP010

Mechanical Design and Horizontal Tests of a Dressed 166.6 MHz Quarter-wave β=1 SRF Cavity System

408

X.Y. Zhang, X.R. Hao, D.B. Li, Z.Q. Li, H.Y. Lin, Q. Ma, Z.H. Mi, Q.Y. Wang, P. Zhang
IHEP, Beijing, People’s Republic of China

Funding: This work has been supported by HEPS-TF project.
A 166.6 MHz quarter-wave β=1 superconducting proof-of-principle cavity has been designed and recently been dressed with a helium jacket, fundamental power coupler and tuner. The cavity was subsequently installed in a modified cryomodule and tested in a horizontal manner at both 4.2 K and 2 K. The helium jacket was successfully developed with a focus on minimizing frequency shift due to helium pressure fluctuation while retaining a reasonable tuning range. The Lorentz force detuning (LFD) and microphonics were also optimized during the design. The df/dp and LFD coefficient were measured to be -3.1 Hz/mbar and -0.8 Hz/(MV/m)². These are in good agreement with simulations. Future work is mainly to reduce the stiffness of the cavity and further suppress the vibration mode of the inner conductor.

Poster TUP010 [1.245 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP010

About •

paper received ※ 23 June 2019 paper accepted ※ 29 June 2019 issue date ※ 14 August 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP011

QWR085 Design for Bisol Post Accelerator SCL2

413

M. Chen, S. Chen, A.Q. Cheng, J.K. Hao, K.X. Liu, Y.Q. Liu, D.M. Ouyang, S.W. Quan, F. Zhu
PKU, Beijing, People’s Republic of China
Z. Peng
CIAE, Beijing, People’s Republic of China

BISOL(Beijing Isotope-Separation-On-Line Neutron-Rich Beam Facility) is a new generation radioactive ion beam(RIB) facility[1]. It consists a CARR nuclear reactor, a high intensity deuteron accelerator and a post accelera-tor. QWR085 cavity is supposed to be used in SCL2 of post accelerator. This paper mainly talks about the elec-tromagnetic design, mechanical design and vibration damper design of QWR085.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP011

About •

paper received ※ 23 June 2019 paper accepted ※ 29 June 2019 issue date ※ 14 August 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP014

Mechanical Design and Fabrication Aspects of Prototype SSR2 Jacketed Cavities

424

M. Parise, D. Passarelli, F. Ruiu
Fermilab, Batavia, Illinois, USA
P. Duchesne, D. Longuevergne, D. Reynet
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France

A total of 35 Superconducting SSR2 spoke cavities will be installed in the PIP II SRF linac at Fermilab and a total of 8 prototype SSR2 cavities will be manufactured for the prototype cryomodule. In this paper, the mechanical design and fabrication aspects of the prototype jacketed SSR2 cavity will be presented. RF and mechanical design activities were conducted in parallel directly on the jacketed cavity in order to minimize the number of design iterations. Also, the lessons learned from other spoke cavities experiences (i.e. SSR1 at Fermilab and ESS double spoke at IPNO) were considered since the early stage of the design.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP014

About •

paper received ※ 23 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP016

Quarter-wave Resonator with the Optimized Shape for Quantum Information Systems

430

S.V. Kutsaev, R.B. Agustsson, P.R. Carriere, A. Moro, A.Yu. Smirnov, K.V. Taletski
RadiaBeam, Santa Monica, California, USA
A.N. Cleland, É. Dumur
The University of Chicago, Chicago, Illinois, USA
Z.A. Conway
ANL, Lemont, Illinois, USA
K.V. Taletski
MEPhI, Moscow, Russia

Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics, under SBIR grant DE-SC0018753
Quantum computers (QC), if realized, could disrupt many computationally intense fields of science. The building block element of a QC is a quantum bit (qubit). Qubits enable the use of quantum superposition and multi-state entanglement in QC calculations, allowing a QC to simultaneously calculate millions of computations at once. However, quantum states stored in a qubit degrade with decreased quality factors and interactions with the environment. One technical solution to improve qubit lifetimes and network interactions is a circuit comprised of a Josephson junction located inside of a high Q-factor superconducting 3D cavity. RadiaBeam, in collaboration with Argonne National Laboratory and The University of Chicago, has developed a superconducting radio-frequency quarter-wave resonant cavity (QWR) for quantum computation. Here a 6 GHz QWR was optimized to include tapering of the inner and outer conductors, a toroidal shape for the resonator shorting plane, and the inner conductor to reduce parasitic capacitance. In this paper, we present the results of the qubit cavity design optimization, fabrication, processing and testing in a single-photon regime at mK temperatures.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP016

About •

paper received ※ 23 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP032

Modal Analysis and Vibration Test for Quarter Wave Resonator for RAON

485

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

Funding: This paper was supported by the Rare Isotope Science Project (RISP), which is funded by the Ministry of Science and ICT (MSIT) and National Research Foundation (NRF) of the Republic of Korea.
The Rare Isotope Science Project (RISP) in the Institute of Basic Science (IBS), Korea, is developing and con-structing the multi-purpose linear accelerator at the north side of Daejeon, South Korea. RISP accelerator (RAON) is composed with low-energy region (SCL3) and high-energy region (SCL2), and low-energy region is made with quarter-wave resonator (QWR) and half-wave resonator (HWR) when high-energy region is made with single spoke resonator type-1 (SSR1) and type-2 (SSR2). This paper shows about the initial resonance issues of QWR superconducting (SC) cavity during cold test and SRF disturbance measurement. Afterwards, this paper shows the modal analysis and vibration test of QWR SC cavity.

Poster TUP032 [0.584 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP032

About •

paper received ※ 23 June 2019 paper accepted ※ 01 July 2019 issue date ※ 14 August 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP066

New Design of SSR2 Spoke Cavity for PIP II SRF Linac

600

P. Berrutti, I.V. Gonin, T.N. Khabiboulline, M. Parise, D. Passarelli, G.V. Romanov, F. Ruiu, A.I. Sukhanov, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Funding: US Department of Energy
Superconducting SSR2 spoke cavities provide acceleration of the H⁻ in PIP II SRF linac from 35 to 185 MeV. The RF and mechanical design of the SSR2 cavities has been completed and satisfies the technical requirements. However, our resent results of the high RF power tests of fully dressed SSR1 cavities show considerably strong multipacting (MP), which took significant time to process. On the other hand, the new results of the tests of balloon cavity showed significant mitigation of MP. In this paper we present the results of the improved design of the SSR2 cavity, based on the balloon cavity concept. The electromagnetic design is presented, including RF parameter optimization, MP simulations, field asymmetry analysis, High Order Mode (HOM) calculations. Mechanical analysis of the dressed cavity is presented also, which includes Lorentz Force Detuning optimization, and reduction of the cavity resonance frequency sensitivity versus He pressure fluctuations. The design completely satisfies the PIP II technical requirements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP066

About •

paper received ※ 21 June 2019 paper accepted ※ 01 July 2019 issue date ※ 14 August 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRCAA2

Balloon Single Spoke Resonator - A New Variant for Reduced Multipacting

Z.Y. Yao, R.E. Laxdal
TRIUMF, Vancouver, Canada

Spoke resonators have been widely proposed and optimized for various applications. Good performance has been demonstrated by many cavity tests. Accompanying the great progress, the adverse impact of strong multipacting (MP) is also noted, consistent with modern 3D simulations. This paper will discuss MP behaviors in the single spoke resonator (SSR). In particular a phenomenological theory is developed to highlight the details of the geometry that affect MP. The analysis leads to an optimized geometry of a single spoke resonator defined here as the ’balloon’ geometry. TRIUMF has designed, fabricated and tested the first balloon SSR at 325 MHz and β=0.3. Cold tests proved the principle of the balloon concept, the elimination of MP barriers around the operational gradient. This paper will also report the details of the mechanical and RF design, the fabrication steps and recent cold test results.

Slides FRCAA2 [19.831 MB]

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRCAA4

Progress in SRF CH-Cavities for the HELIAC CW Linac at GSI

1206

M. Miski-Oglu, K. Aulenbacher, W.A. Barth, C. Burandt, F.D. Dziuba, V. Gettmann, T. Kürzeder, S. Lauber, J. List, S. Yaramyshev
HIM, Mainz, Germany
K. Aulenbacher, W.A. Barth, C. Burandt, F.D. Dziuba, V. Gettmann, M. Heilmann, T. Kürzeder, S. Lauber, J. List, A. Rubin, A. Schnase, S. Yaramyshev
GSI, Darmstadt, Germany
K. Aulenbacher, F.D. Dziuba, J. List
KPH, Mainz, Germany
M. Basten, M. Busch, T. Conrad, H. Podlech, M. Schwarz
IAP, Frankfurt am Main, Germany
S. Lauber
IKP, Mainz, Germany

The machine beam commissioning is a major milestone of the R&D for the superconducting heavy ion continuous wave linear accelerator HELIAC of Helmholtz Institute Mainz (HIM) and GSI developed in collaboration with IAP Goethe-University Frankfurt. During successful beam commissioning of the superconducting 15-gap Crossbar H-mode cavity at GSI Helmholtzzentrum für Schwerionenforschung heavy ions up to the design beam energy have been accelerated. The design acceleration gain of 3.5 MeV has been reached with full transmission for heavy ion beams of up to 1.5 particle mueA. We present fabrication experience and results of off-line and on-line cavity performance. The next step is the procurement and commissioning of so called ’Advanced Demonstrator’ - the first of series cryomodule for the entire accelerator HELIAC. Results of further Demonstrator beam tests, as well as the status of the Advanced demonstrator project will be reported.

Slides FRCAA4 [9.864 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-FRCAA4

About •

paper received ※ 23 June 2019 paper accepted ※ 02 July 2019 issue date ※ 14 August 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)