LINAC2016 - Table of Session: TUOP (Oral Poster Session)

Paper	Title	Page
TUOP01	Applying Transverse Gradient Undulators to Suppression of Microbunching Instability	380
TUPLR001	use link to see paper's listing under its alternate paper code
	D. Huang, H.X. Deng, C. Feng, D. Gu, Q. Gu, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	Funding: Major State Basic Research Development Program of China (2011CB808300). National Natural Science Foundation of China (NSFC), grant No. 11275253. The microbunching instability developed during the beam compression process in the linear accelerator (LIN-AC) of a free-electron laser (FEL) facility has always been a problem that degrades the lasing performance, and even no FEL is able to be produced if the beam quality is destroyed too much by the instability. A common way to suppress the microbunching instability is to introduce extra uncorrelated energy spread by the laser heater that heats the beam through the interaction between the electron and laser beam, as what has been successfully implemented in the Linac Coherent Light Source and Fermi@Elettra. In this paper, a simple and effective scheme is proposed to suppress the microbunching instability by adding two transverse gradient undulators (TGU) before and after the magnetic bunch compressor. The additional uncorrelated energy spread and the density mixing from the transverse spread brought up by the first TGU results in significant suppression of the instability. Meanwhile, the extra slice energy spread and the transverse emittance can also be effectively recovered by the second TGU. The magnitude of the suppression can be easily controlled by varying the strength of the magnetic fields of the TGUs. Theoretical analysis and numerical simulations demonstrate the capability of the proposed technique in the LINAC of an x-ray free-electron laser facility.
	Slides TUOP01 [1.148 MB]
	Poster TUOP01 [0.447 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUOP01
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TUOP02	CBETA: The Cornell/BNL 4-Turn ERL with FFAG Return Arcs for eRHIC Prototyping	384
TUPLR002	use link to see paper's listing under its alternate paper code
	G.H. Hoffstaetter, J. Barley, A.C. Bartnik, I.V. Bazarov, J. Dobbins, B.M. Dunham, R.G. Eichhorn, R.E. Gallagher, C.M. Gulliford, Y. Li, M. Liepe, W. Lou, C.E. Mayes, J.R. Patterson, D.M. Sabol, E.N. Smith, K.W. Smolenski Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA I. Ben-Zvi, J.S. Berg, S.J. Brooks, G.J. Mahler, F. Méot, M.G. Minty, S. Peggs, V. Ptitsyn, T. Roser, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, H. Witte BNL, Upton, Long Island, New York, USA D. Douglas JLab, Newport News, Virginia, USA
	Cornell University has prototyped technology essential for any high brightness electron ERL. This includes a DC gun and an SRF injector Linac with world-record current and normalized brightness in a bunch train, a high-current CW cryomodule, a high-power beam stop, and several diagnostics tools for high-current and high-brightness beams, e.g. slid measurements for 6-D phase-space densities, a fast wire scanner for beam profiles, and beam loos diagnostics. All these are now available to equip a one-cryomodule ERL, and laboratory space has been cleared out and is radiation shielded to install this ERL at Cornell. BNL has designed a multi-turn ERL for eRHIC, where beam is transported more than 20 times around the RHIC tunnel. The number of transport lines is minimized by using two non-scaling (NS) FFAG arcs. A collaboration between BNL and Cornell has been formed to investigate the new NS-FFAG optics and the multi-turn eRHIC ERL design by building a 4-turn, one-cryomodule ERL at Cornell. It has a NS-FFAG return loop built with permanent magnets and is meant to accelerate 40mA beam to 200MeV.
	Slides TUOP02 [7.848 MB]
	Poster TUOP02 [13.981 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUOP02
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TUOP03	Developments on the 1.4 MeV/u Pulsed Gas Stripper Cell	387
SPWR028	use link to see paper's listing under its alternate paper code
TUPRC001	use link to see paper's listing under its alternate paper code
	P. Scharrer, W.A. Barth, Ch.E. Düllmann, J. Khuyagbaatar, A. Yakushev HIM, Mainz, Germany W.A. Barth, M. Bevcic, Ch.E. Düllmann, L. Groening, K.P. Horn, E. Jäger, J. Khuyagbaatar, J. Krier, P. Scharrer, A. Yakushev GSI, Darmstadt, Germany Ch.E. Düllmann, P. Scharrer Mainz University, Mainz, Germany
	The GSI UNILAC in combination with SIS18 will serve as a high-current, heavy-ion injector for the FAIR facility. It must meet high demands in terms of beam brilliance at a low duty factor. As part of an UNILAC upgrade program dedicated to FAIR, a new pulsed gas stripper cell was developed, aiming for increased beam intensities inside the post-stripper. The pulsed gas injection is synchronized with the beam pulse timing, enabling a highly-demanded, increased gas density. First tests using uranium beams on a hydrogen target showed a 60%-increased stripping efficiency into the desired 28+ charge state. In 2015, the setup was improved to be able to deliver increased target thicknesses and enhanced flexibility of the gas injection. In recent beam times, the pulsed gas cell was used with various ion-beam types, to test the capabilities for operation at the GSI UNILAC. The stripping of two ion beams in different gases at different gas densities was successfully tested in mixed-beam operation. Charge fractions, beam emittance, and energy-loss were systematically measured using uranium, bismuth, titanium, and argon beams on hydrogen, helium, and nitrogen targets. Selected results will be presented at the conference.
	Slides TUOP03 [1.131 MB]
	Poster TUOP03 [5.943 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUOP03
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TUOP04	On the Acceleration of Rare Isotope Beams in the Reaccelerator (ReA3) at the National Superconducting Cyclotron Laboratory at MSU	390
TUPLR076	use link to see paper's listing under its alternate paper code
	A.C.C. Villari, G. Bollen, M. Ikegami, S.M. Lidia, S. Nash, R. Shane, Q. Zhao FRIB, East Lansing, USA D.B. Crisp, A. Lapierre, D.J. Morrissey, R. Rencsok, R.J. Ringle, S. Schwarz, C. Sumithrarachchi, T. Summers NSCL, East Lansing, Michigan, USA
	The ReAccelerator ReA3 is a worldwide unique, state-of-the-art linear accelerator for rare isotope beams. Beams of rare isotopes are produced and separated in-flight at the NSCL Coupled Cyclotron Facility and subsequently stopped in a linear gas cell. The rare isotopes are then continuously extracted as 1+ ions and transported into a beam cooler and buncher. Ion pulses provided by this device are then transported to a charge breeder based on an Electron Beam Ion Trap (EBIT) where they are captured in flight. The 1+ ions are ionized to a charge state suitable for acceleration in the superconducting radiofrequency (SRF) ReA3 linac, extracted in a pulsed mode and mass analyzed. The extracted beam is pre-bunched before injection into the RFQ and SRF linac, both operating at frequency of 80.5 MHz, and then accelerated to energies from 300 keV/u up to 6 MeV/u, depending on the charge-to-mass ratio of the ion. Stable isotopes can alternatively also be injected into the linac from the EBIT in off-line mode (by ionization of residual gas) or from external off-line ion sources. This contribution will focus on the methodology, properties and techniques used to accelerate and control low intensity rare isotope beams. Results obtained during the preparation of various experiments using the ReA facility, including those with the rare ions 46Ar and 37,46,47K will also be presented.
	Slides TUOP04 [1.979 MB]
	Poster TUOP04 [2.602 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUOP04
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUOP05	First Experiments at the CW-Operated RFQ for Intense Proton Beams	394
SPWR014	use link to see paper's listing under its alternate paper code
TUPLR075	use link to see paper's listing under its alternate paper code
	P.P. Schneider, D. Born, M. Droba, C. Lorey, O. Meusel, D. Noll, H. Podlech, A. Schempp, B. Thomas, C. Wagner IAP, Frankfurt am Main, Germany
	This contribution describes the first experiments with the cw-operated RFQ, which is designed to accelerate protons from 120keV to 700keV for the FRANZ-Project. The commissioning is done using the RF and ion beam scrubbing technique. In the first phase, the acceptance of the RFQ is scanned and the performance of the RFQ without space-charge effects is evaluated with a 2mA proton beam. The second phase will increase the beam current up to 50mA and a third phase with a machine upgrade for a beam current of up to 200mA is planned. The configuration of a high-current RFQ, transporting beam current increasing from 2mA with no space-charge forces to a beam with high space-charge effects gives an unique insight in the beam optics of the space-charge effects. The measurements are done with a slit-grid emittance scanner for the transversal phase-space, a faraday cup for the transmitted current and a momentum spectrometer to measure the energy spread. The results set the basis for later experiments on variations of the beam current and the future coupling of the RFQ with an IH-structure*. Bechtold, A., et al., MOP001, LINAC08 Meusel, O., et al., MO3A03, LINAC12 * Vossberg, M., et al., WEPFI009, IPAC13 **** Heilmann, M., et al., THPWO017, IPAC13
	Slides TUOP05 [2.435 MB]
	Poster TUOP05 [4.550 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUOP05
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TUOP07	High Performance Next-Generation Nb3Sn Cavities for Future High Efficiency SRF Linacs	398
TUPRC031	use link to see paper's listing under its alternate paper code
	D.L. Hall, J.J. Kaufman, M. Liepe, J.T. Maniscalco, R.D. Porterpresenter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: DOE A 1.3 GHz ILC-shape single-cell Nb3Sn cavity fabricated at Cornell has shown record performance, exceeding the cryogenic efficiency of niobium cavities at the gradients and quality factors demanded by some contemporary accelerator designs. An optimisation of the coating process has resulted in more cavities of the same design that achieve similar performance, proving the reproducibility of the method. In this paper, we discuss the current limitations on the peak accelerating gradients achieved by these cavities. In particular, high-pulsed-power RF testing, and thermometry mapping of the cavity during CW operation, are used to draw conclusions regarding the nature of the quench limitation. In light of these promising results, the feasibility and utility of applying the current state of the technology to a real-life application is discussed.
	Slides TUOP07 [1.506 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUOP07
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TUOP08	On Magnetic Flux Trapping in Superconductors	402
TUPRC030	use link to see paper's listing under its alternate paper code
	R.G. Eichhorn, J. Hoke, Z. Mayle Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Magnetic flux trapped on the cool-down has become an important factor in the performance in superconducting cavities. We have conducted flux trapping experiments on samples that reveal a very interesting feature of the mechanism on flux trapping which might impact magnetic shielding concepts of future cryomodules.
	Slides TUOP08 [1.787 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUOP08
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TUOP09	State of the Art Advanced Magnetron for Accelerator RF Power Source	405
TUPLR006	use link to see paper's listing under its alternate paper code
	H. Obata, K. Furumoto, H. Miyamoto New Japan Radio Co., Ltd., Fujimino Saitama, Japan
	X ray sources for linear accelerators continue to be a necessary requirement for industries such as medical, inspection, and nondestructive test equipment. Future requirements for such sources are; low cost, compact packaging and high performance of the RF source for electron acceleration. The magnetron has proven to be a perfect source over other RF sources for linear accelerator use. Because of its simple design, low cost per output, small size and proven performance it meets all required characteristics. New Japan Radio Co., Ltd. has improved and modified its linac magnetrons' performance and characteristics enabling easy matching to the linac modulator, long life and maximum output power. This paper will provide a detailed explanation on the improved magnetron design methodology and its effects on the performance of these magnetrons installed in linac systems. These technologies have been utilized successfully on a commercial level worldwide over the last few years. The technology has been deployed into linac systems operating in S and X band and soon C band, at various output power levels.
	Slides TUOP09 [1.127 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUOP09
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TUOP11	Methods for Bunch Shape Monitor Phase Resolution Improvement	408
TUPRC027	use link to see paper's listing under its alternate paper code
	A. Feschenko, S.A. Gavrilovpresenter RAS/INR, Moscow, Russia
	Bunch shape monitors, based on secondary electrons emission, are widely used for measurements of longitudinal bunch profiles during a linac commissioning and initial optimization of beam dynamics. A typical phase resolution of these devices is about 1°. However it becomes insufficient for new modern linacs, which require a better resolution. Some developed methods for a phase resolution improvement are discussed.
	Slides TUOP11 [21.248 MB]
	Poster TUOP11 [1.888 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUOP11
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TUOP12	Latest Cryogenic Testing of the 2.1 GHz Five-Cell Superconducting RF Cavity with a Photonic Band Gap Coupler Cell
TUPLR049	use link to see paper's listing under its alternate paper code
	S. Arsenyev, R.J. Temkin MIT/PSFC, Cambridge, Massachusetts, USA C.H. Boulware, T.L. Grimm, A. Rogacki Niowave, Inc., Lansing, Michigan, USA W.B. Haynes, D.Y. Shchegolkov, E.I. Simakovpresenter, T. Tajima LANL, Los Alamos, New Mexico, USA
	We present results from the latest of the two cryogenic tests with the first multi-cell superconducting radio frequency (SRF) cavity with a photonic band gap (PBG) coupler cell. Achieving higher average beam currents is particularly desirable for future light sources and particle colliders based on SRF energy-recovery-linacs (ERLs). Beam current in ERLs is limited by the beam break-up instability, caused by parasitic HOMs interacting with the beam in accelerating cavities. A PBG cell incorporated in an accelerating cavity can reduce the negative effect of HOMs by providing a frequency selective damping mechanism, thus allowing significantly higher beam currents. The multi-cell cavity was designed and fabricated of niobium. After an unsuccessful first cryogenic test, modifications were wade to waveguide coupler joints. In the second test, the high cavity Q-factor was demonstrated at the temperature of 4.2 K at accelerating gradients up to 3 MV/m. The measured value of the cavity Q-factor was 1.55*10⁸, in agreement with prediction.
	Slides TUOP12 [1.046 MB]
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Paper

Title

Page

TUOP01

Applying Transverse Gradient Undulators to Suppression of Microbunching Instability

380

TUPLR001

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

D. Huang, H.X. Deng, C. Feng, D. Gu, Q. Gu, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

Funding: Major State Basic Research Development Program of China (2011CB808300). National Natural Science Foundation of China (NSFC), grant No. 11275253.
The microbunching instability developed during the beam compression process in the linear accelerator (LIN-AC) of a free-electron laser (FEL) facility has always been a problem that degrades the lasing performance, and even no FEL is able to be produced if the beam quality is destroyed too much by the instability. A common way to suppress the microbunching instability is to introduce extra uncorrelated energy spread by the laser heater that heats the beam through the interaction between the electron and laser beam, as what has been successfully implemented in the Linac Coherent Light Source and Fermi@Elettra. In this paper, a simple and effective scheme is proposed to suppress the microbunching instability by adding two transverse gradient undulators (TGU) before and after the magnetic bunch compressor. The additional uncorrelated energy spread and the density mixing from the transverse spread brought up by the first TGU results in significant suppression of the instability. Meanwhile, the extra slice energy spread and the transverse emittance can also be effectively recovered by the second TGU. The magnitude of the suppression can be easily controlled by varying the strength of the magnetic fields of the TGUs. Theoretical analysis and numerical simulations demonstrate the capability of the proposed technique in the LINAC of an x-ray free-electron laser facility.

Slides TUOP01 [1.148 MB]

Poster TUOP01 [0.447 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUOP01

Export •

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

TUOP02

CBETA: The Cornell/BNL 4-Turn ERL with FFAG Return Arcs for eRHIC Prototyping

384

TUPLR002

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

G.H. Hoffstaetter, J. Barley, A.C. Bartnik, I.V. Bazarov, J. Dobbins, B.M. Dunham, R.G. Eichhorn, R.E. Gallagher, C.M. Gulliford, Y. Li, M. Liepe, W. Lou, C.E. Mayes, J.R. Patterson, D.M. Sabol, E.N. Smith, K.W. Smolenski
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
I. Ben-Zvi, J.S. Berg, S.J. Brooks, G.J. Mahler, F. Méot, M.G. Minty, S. Peggs, V. Ptitsyn, T. Roser, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, H. Witte
BNL, Upton, Long Island, New York, USA
D. Douglas
JLab, Newport News, Virginia, USA

Cornell University has prototyped technology essential for any high brightness electron ERL. This includes a DC gun and an SRF injector Linac with world-record current and normalized brightness in a bunch train, a high-current CW cryomodule, a high-power beam stop, and several diagnostics tools for high-current and high-brightness beams, e.g. slid measurements for 6-D phase-space densities, a fast wire scanner for beam profiles, and beam loos diagnostics. All these are now available to equip a one-cryomodule ERL, and laboratory space has been cleared out and is radiation shielded to install this ERL at Cornell. BNL has designed a multi-turn ERL for eRHIC, where beam is transported more than 20 times around the RHIC tunnel. The number of transport lines is minimized by using two non-scaling (NS) FFAG arcs. A collaboration between BNL and Cornell has been formed to investigate the new NS-FFAG optics and the multi-turn eRHIC ERL design by building a 4-turn, one-cryomodule ERL at Cornell. It has a NS-FFAG return loop built with permanent magnets and is meant to accelerate 40mA beam to 200MeV.

Slides TUOP02 [7.848 MB]

Poster TUOP02 [13.981 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUOP02

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

TUOP03

Developments on the 1.4 MeV/u Pulsed Gas Stripper Cell

387

SPWR028

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

TUPRC001

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

P. Scharrer, W.A. Barth, Ch.E. Düllmann, J. Khuyagbaatar, A. Yakushev
HIM, Mainz, Germany
W.A. Barth, M. Bevcic, Ch.E. Düllmann, L. Groening, K.P. Horn, E. Jäger, J. Khuyagbaatar, J. Krier, P. Scharrer, A. Yakushev
GSI, Darmstadt, Germany
Ch.E. Düllmann, P. Scharrer
Mainz University, Mainz, Germany

The GSI UNILAC in combination with SIS18 will serve as a high-current, heavy-ion injector for the FAIR facility. It must meet high demands in terms of beam brilliance at a low duty factor. As part of an UNILAC upgrade program dedicated to FAIR, a new pulsed gas stripper cell was developed, aiming for increased beam intensities inside the post-stripper. The pulsed gas injection is synchronized with the beam pulse timing, enabling a highly-demanded, increased gas density. First tests using uranium beams on a hydrogen target showed a 60%-increased stripping efficiency into the desired 28+ charge state. In 2015, the setup was improved to be able to deliver increased target thicknesses and enhanced flexibility of the gas injection. In recent beam times, the pulsed gas cell was used with various ion-beam types, to test the capabilities for operation at the GSI UNILAC. The stripping of two ion beams in different gases at different gas densities was successfully tested in mixed-beam operation. Charge fractions, beam emittance, and energy-loss were systematically measured using uranium, bismuth, titanium, and argon beams on hydrogen, helium, and nitrogen targets. Selected results will be presented at the conference.

Slides TUOP03 [1.131 MB]

Poster TUOP03 [5.943 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUOP03

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

TUOP04

On the Acceleration of Rare Isotope Beams in the Reaccelerator (ReA3) at the National Superconducting Cyclotron Laboratory at MSU

390

TUPLR076

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

A.C.C. Villari, G. Bollen, M. Ikegami, S.M. Lidia, S. Nash, R. Shane, Q. Zhao
FRIB, East Lansing, USA
D.B. Crisp, A. Lapierre, D.J. Morrissey, R. Rencsok, R.J. Ringle, S. Schwarz, C. Sumithrarachchi, T. Summers
NSCL, East Lansing, Michigan, USA

The ReAccelerator ReA3 is a worldwide unique, state-of-the-art linear accelerator for rare isotope beams. Beams of rare isotopes are produced and separated in-flight at the NSCL Coupled Cyclotron Facility and subsequently stopped in a linear gas cell. The rare isotopes are then continuously extracted as 1+ ions and transported into a beam cooler and buncher. Ion pulses provided by this device are then transported to a charge breeder based on an Electron Beam Ion Trap (EBIT) where they are captured in flight. The 1+ ions are ionized to a charge state suitable for acceleration in the superconducting radiofrequency (SRF) ReA3 linac, extracted in a pulsed mode and mass analyzed. The extracted beam is pre-bunched before injection into the RFQ and SRF linac, both operating at frequency of 80.5 MHz, and then accelerated to energies from 300 keV/u up to 6 MeV/u, depending on the charge-to-mass ratio of the ion. Stable isotopes can alternatively also be injected into the linac from the EBIT in off-line mode (by ionization of residual gas) or from external off-line ion sources. This contribution will focus on the methodology, properties and techniques used to accelerate and control low intensity rare isotope beams. Results obtained during the preparation of various experiments using the ReA facility, including those with the rare ions 46Ar and 37,46,47K will also be presented.

Slides TUOP04 [1.979 MB]

Poster TUOP04 [2.602 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUOP04

Export •

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

TUOP05

First Experiments at the CW-Operated RFQ for Intense Proton Beams

394

SPWR014

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

TUPLR075

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

P.P. Schneider, D. Born, M. Droba, C. Lorey, O. Meusel, D. Noll, H. Podlech, A. Schempp, B. Thomas, C. Wagner
IAP, Frankfurt am Main, Germany

This contribution describes the first experiments with the cw-operated RFQ*, which is designed to accelerate protons from 120keV to 700keV for the FRANZ-Project**. The commissioning is done using the RF and ion beam scrubbing technique. In the first phase, the acceptance of the RFQ is scanned and the performance of the RFQ without space-charge effects is evaluated with a 2mA proton beam. The second phase will increase the beam current up to 50mA and a third phase with a machine upgrade for a beam current of up to 200mA is planned. The configuration of a high-current RFQ***, transporting beam current increasing from 2mA with no space-charge forces to a beam with high space-charge effects gives an unique insight in the beam optics of the space-charge effects. The measurements are done with a slit-grid emittance scanner for the transversal phase-space, a faraday cup for the transmitted current and a momentum spectrometer to measure the energy spread. The results set the basis for later experiments on variations of the beam current and the future coupling of the RFQ with an IH-structure****.
* Bechtold, A., et al., MOP001, LINAC08
** Meusel, O., et al., MO3A03, LINAC12
*** Vossberg, M., et al., WEPFI009, IPAC13
**** Heilmann, M., et al., THPWO017, IPAC13

Slides TUOP05 [2.435 MB]

Poster TUOP05 [4.550 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUOP05

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TUOP07

High Performance Next-Generation Nb3Sn Cavities for Future High Efficiency SRF Linacs

398

TUPRC031

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

D.L. Hall, J.J. Kaufman, M. Liepe, J.T. Maniscalco, R.D. Porterpresenter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: DOE
A 1.3 GHz ILC-shape single-cell Nb3Sn cavity fabricated at Cornell has shown record performance, exceeding the cryogenic efficiency of niobium cavities at the gradients and quality factors demanded by some contemporary accelerator designs. An optimisation of the coating process has resulted in more cavities of the same design that achieve similar performance, proving the reproducibility of the method. In this paper, we discuss the current limitations on the peak accelerating gradients achieved by these cavities. In particular, high-pulsed-power RF testing, and thermometry mapping of the cavity during CW operation, are used to draw conclusions regarding the nature of the quench limitation. In light of these promising results, the feasibility and utility of applying the current state of the technology to a real-life application is discussed.

Slides TUOP07 [1.506 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUOP07

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TUOP08

On Magnetic Flux Trapping in Superconductors

402

TUPRC030

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

R.G. Eichhorn, J. Hoke, Z. Mayle
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Magnetic flux trapped on the cool-down has become an important factor in the performance in superconducting cavities. We have conducted flux trapping experiments on samples that reveal a very interesting feature of the mechanism on flux trapping which might impact magnetic shielding concepts of future cryomodules.

Slides TUOP08 [1.787 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUOP08

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TUOP09

State of the Art Advanced Magnetron for Accelerator RF Power Source

405

TUPLR006

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

H. Obata, K. Furumoto, H. Miyamoto
New Japan Radio Co., Ltd., Fujimino Saitama, Japan

X ray sources for linear accelerators continue to be a necessary requirement for industries such as medical, inspection, and nondestructive test equipment. Future requirements for such sources are; low cost, compact packaging and high performance of the RF source for electron acceleration. The magnetron has proven to be a perfect source over other RF sources for linear accelerator use. Because of its simple design, low cost per output, small size and proven performance it meets all required characteristics. New Japan Radio Co., Ltd. has improved and modified its linac magnetrons' performance and characteristics enabling easy matching to the linac modulator, long life and maximum output power. This paper will provide a detailed explanation on the improved magnetron design methodology and its effects on the performance of these magnetrons installed in linac systems. These technologies have been utilized successfully on a commercial level worldwide over the last few years. The technology has been deployed into linac systems operating in S and X band and soon C band, at various output power levels.

Slides TUOP09 [1.127 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUOP09

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TUOP11

Methods for Bunch Shape Monitor Phase Resolution Improvement

408

TUPRC027

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A. Feschenko, S.A. Gavrilovpresenter
RAS/INR, Moscow, Russia

Bunch shape monitors, based on secondary electrons emission, are widely used for measurements of longitudinal bunch profiles during a linac commissioning and initial optimization of beam dynamics. A typical phase resolution of these devices is about 1°. However it becomes insufficient for new modern linacs, which require a better resolution. Some developed methods for a phase resolution improvement are discussed.

Slides TUOP11 [21.248 MB]

Poster TUOP11 [1.888 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-TUOP11

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TUOP12

Latest Cryogenic Testing of the 2.1 GHz Five-Cell Superconducting RF Cavity with a Photonic Band Gap Coupler Cell

TUPLR049

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S. Arsenyev, R.J. Temkin
MIT/PSFC, Cambridge, Massachusetts, USA
C.H. Boulware, T.L. Grimm, A. Rogacki
Niowave, Inc., Lansing, Michigan, USA
W.B. Haynes, D.Y. Shchegolkov, E.I. Simakovpresenter, T. Tajima
LANL, Los Alamos, New Mexico, USA

We present results from the latest of the two cryogenic tests with the first multi-cell superconducting radio frequency (SRF) cavity with a photonic band gap (PBG) coupler cell. Achieving higher average beam currents is particularly desirable for future light sources and particle colliders based on SRF energy-recovery-linacs (ERLs). Beam current in ERLs is limited by the beam break-up instability, caused by parasitic HOMs interacting with the beam in accelerating cavities. A PBG cell incorporated in an accelerating cavity can reduce the negative effect of HOMs by providing a frequency selective damping mechanism, thus allowing significantly higher beam currents. The multi-cell cavity was designed and fabricated of niobium. After an unsuccessful first cryogenic test, modifications were wade to waveguide coupler joints. In the second test, the high cavity Q-factor was demonstrated at the temperature of 4.2 K at accelerating gradients up to 3 MV/m. The measured value of the cavity Q-factor was 1.55*10⁸, in agreement with prediction.

Slides TUOP12 [1.046 MB]

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