IPAC2017 - List of Authors (Byrd, J.M.)

Paper	Title	Page
MOPIK019	Upgrade Options Towards Higher Fields and Beam Energies for Continuous-Wave Room-Temperature VHF RF Guns	542
	F. Sannibale, J.M. Byrd, D. Filippetto, M.J. Johnson, D. Li, T.H. Luo, C.E. Mitchell, J.W. Staples, S.P. Virostek LBNL, Berkeley, California, USA
	Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231 Science demand for MHz-class repetition rate electron beam applications such as free electron lasers (FELs), inverse Compton scattering sources, and ultrafast electron diffraction and microscopy (UED/UEM), pushed the development of new gun schemes that could generate high brightness beams at such high rates. At the Lawrence Berkeley Lab (LBNL), we proposed a new concept room-temperature RF gun resonating in the VHF frequency range (30-300 MHz) capable of operating in continuous wave mode at the fields required for high-brightness performance. A first VHF-Gun was constructed and tested in the APEX facility at LBNL, which successfully demonstrated all design parameters and the generation of high brightness electron beams. A second version of the APEX VHF-Gun is being built at LBNL for the LCLS-II, the new SLAC X-ray FEL. Recent studies showed that a proposed LCLS-II upgrade and UED/UEM applications would greatly benefit from an increased gun brightness obtained by raising the electric field at the cathode and the beam energy at the gun exit. In this paper, we present and discuss possible upgrade options that would allow extension of the VHF-Gun performance towards these new goals.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK019
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MOPVA031	Low Energy Compact Storage Ring Design for Compton Gamma-Ray Light Source	921
	Z. Pan, J.M. Byrd, C. Sun LBNL, Berkeley, California, USA H. Hao, Y.K. Wu FEL/Duke University, Durham, North Carolina, USA W.-H. Huang, C.-X. Tang TUB, Beijing, People's Republic of China
	Gamma-ray sources with high flux and spectral densities are highly demanded by many nuclear experiments. We design a low energy compact storage ring to produce gamma-ray with energy in the range of 4-20 MeV based on Compton backscattering technique. The storage ring energy is 500-800 MeV with the circumference of about 59 m and natural emittance of about 3 nmrad at 500 MeV. In this paper, we present the storage ring lattice design and propose two collision configurations for Compton gamma-ray generation. Intrabeam scattering has been investigated which can increase emittance from 3 nmrad to 6 nmrad horizontally for 500 MeV ring. We also discuss how Compton scattering affects longitudinal and transverse beam dynamics by tracking macro particles using our parallel simulation code. Based on this study, we can further optimize our storage ring lattice design for the higher gamma-ray flux production.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA031
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TUPAB121	Bench Measurements and Beam Tests of a Prototype Stripline Kicker for Swap-Out Injection in the ALS-U	1599
	S. De Santis, J.M. Byrd, T.H. Luo, G.C. Pappas, C. Steier, C.A. Swenson, W.L. Waldron LBNL, Berkeley, California, USA
	Funding: Work supported by the the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The ALS upgrade to a diffraction-limited light source (ALS-U Project) relies on a swap-out injection scheme, where the circulating current is maintained constant by injecting on-axis fresh bunch trains, replacing old trains, which are simultaneously extracted. The realization of a stripline kicker to perform such an operation presents several challenges in terms of optimal matching to the pulser, contributions to the beam coupling impedance, and dissipation of the power deposited by the stored beam. To test our design choices for the ALS-U kicker, we have built and installed on the ALS a kicker with characteristics similar to the design for the ALS-U, as the more challenging aspects of the project are concerned. In particular, while the small distance between stripline electrodes reduces the required pulser voltage, the extreme proximity of the circulating beam requires a careful evaluation of the interaction between beam and kicker. In this paper we present the first measurements with beam, after the test kicker installation, together with the results of bench measurements performed on a cold model and computer simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB121
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WEPAB104	Status of the Conceptual Design of ALS-U	2824
	C. Steier, A.P. Allézy, A. Anders, K.M. Baptiste, J.M. Byrd, K. Chow, G.D. Cutler, S. De Santis, R.J. Donahue, R.M. Duarte, J.-Y. Jung, S.C. Leemann, M. Leitner, T.H. Luo, H. Nishimura, T. Oliver, O. Omolayo, J.R. Osborn, G.C. Pappas, S. Persichelli, M. Placidi, G.J. Portmann, S. Reyes, D. Robin, F. Sannibale, C. Sun, C.A. Swenson, M. Venturini, W.L. Waldron, E.J. Wallén, W. Wan LBNL, Berkeley, California, USA
	Funding: This work is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The ALS-U upgrade promises to deliver diffraction limited performance throughout the soft x-ray range by lowering the horizontal emittance to about 50~pm resulting in 2-3 orders of brightness increase for soft x-rays compared to the current ALS. The design utilizes a multi bend achromat lattice with on-axis swap-out injection and an accumulator ring. One central design goal is to install and commission ALS-U within a short dark period. This paper summarizes the status of the conceptual design of the accelerator, as well as some results of the R&D program that has been ongoing for the last 3 years.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB104
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WEPIK106	Impedance and Collective Effects for the Advanced Light Source Upgrade at LBNL	3192
	S. Persichelli, J.M. Byrd, S. De Santis, D. Li, T.H. Luo, C. Steier, M. Venturini LBNL, Berkeley, California, USA
	Funding: Work supported by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 The upgrade of the Advanced Light Source (ALS-U) consists of a multiband achromat ultralow emittance lattice for the production of diffraction-limited soft x-rays. A very important issue for ALS-U is represented by instabilities induced by wakefields, that may limit the peak current of individual bunches and the total beam current. In addition, vacuum chamber apertures of few millimeters, that are a key feature of low-emittance machines, can result in a significant increase in the Resistive Wall (RW) impedance. In this paper we present progress on establishing short range wakefield model for ALS-U and evaluating the impact on the longitudinal and transverse single-bunch dynamics.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK106
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THPVA055	The Preliminary Performance of the Timing and Synchronization System at Tsinghua University	4565
SUSPSIK113	use link to see paper's listing under its alternate paper code
	Z.Y. Lin, Y.-C. Du, W.-H. Huang, W.-H. Huang, C.-X. Tang, C.-X. Tang, J. Yang TUB, Beijing, People's Republic of China J.M. Byrd, L.R. Doolittle, G. Huang, Q. Qiang, R.B. Wilcox, Y.L. Xu LBNL, Berkeley, California, USA
	A precise timing and synchronization system is developed in Tsinghua University(THU). The whole system scheme includes fiber-based CW carrier phase reference distribution system (PRDS) for delivering stabilized RF phase reference to multiple receiver clients, Low Level RF (LLRF) control system to stabilized the accelerating mi-crowave field and laser-RF synchronization system for high precise synchronization of optical and RF signals. The system test and the demonstration experiment of each subsystem are carried on to evaluate the system and the phase error jitter resources are analysed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA055
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Paper

Title

Page

Upgrade Options Towards Higher Fields and Beam Energies for Continuous-Wave Room-Temperature VHF RF Guns

542

F. Sannibale, J.M. Byrd, D. Filippetto, M.J. Johnson, D. Li, T.H. Luo, C.E. Mitchell, J.W. Staples, S.P. Virostek
LBNL, Berkeley, California, USA

Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231
Science demand for MHz-class repetition rate electron beam applications such as free electron lasers (FELs), inverse Compton scattering sources, and ultrafast electron diffraction and microscopy (UED/UEM), pushed the development of new gun schemes that could generate high brightness beams at such high rates. At the Lawrence Berkeley Lab (LBNL), we proposed a new concept room-temperature RF gun resonating in the VHF frequency range (30-300 MHz) capable of operating in continuous wave mode at the fields required for high-brightness performance. A first VHF-Gun was constructed and tested in the APEX facility at LBNL, which successfully demonstrated all design parameters and the generation of high brightness electron beams. A second version of the APEX VHF-Gun is being built at LBNL for the LCLS-II, the new SLAC X-ray FEL. Recent studies showed that a proposed LCLS-II upgrade and UED/UEM applications would greatly benefit from an increased gun brightness obtained by raising the electric field at the cathode and the beam energy at the gun exit. In this paper, we present and discuss possible upgrade options that would allow extension of the VHF-Gun performance towards these new goals.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK019

Export •

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

MOPVA031

Low Energy Compact Storage Ring Design for Compton Gamma-Ray Light Source

921

Z. Pan, J.M. Byrd, C. Sun
LBNL, Berkeley, California, USA
H. Hao, Y.K. Wu
FEL/Duke University, Durham, North Carolina, USA
W.-H. Huang, C.-X. Tang
TUB, Beijing, People's Republic of China

Gamma-ray sources with high flux and spectral densities are highly demanded by many nuclear experiments. We design a low energy compact storage ring to produce gamma-ray with energy in the range of 4-20 MeV based on Compton backscattering technique. The storage ring energy is 500-800 MeV with the circumference of about 59 m and natural emittance of about 3 nmrad at 500 MeV. In this paper, we present the storage ring lattice design and propose two collision configurations for Compton gamma-ray generation. Intrabeam scattering has been investigated which can increase emittance from 3 nmrad to 6 nmrad horizontally for 500 MeV ring. We also discuss how Compton scattering affects longitudinal and transverse beam dynamics by tracking macro particles using our parallel simulation code. Based on this study, we can further optimize our storage ring lattice design for the higher gamma-ray flux production.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA031

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

TUPAB121

Bench Measurements and Beam Tests of a Prototype Stripline Kicker for Swap-Out Injection in the ALS-U

1599

S. De Santis, J.M. Byrd, T.H. Luo, G.C. Pappas, C. Steier, C.A. Swenson, W.L. Waldron
LBNL, Berkeley, California, USA

Funding: Work supported by the the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The ALS upgrade to a diffraction-limited light source (ALS-U Project) relies on a swap-out injection scheme, where the circulating current is maintained constant by injecting on-axis fresh bunch trains, replacing old trains, which are simultaneously extracted. The realization of a stripline kicker to perform such an operation presents several challenges in terms of optimal matching to the pulser, contributions to the beam coupling impedance, and dissipation of the power deposited by the stored beam. To test our design choices for the ALS-U kicker, we have built and installed on the ALS a kicker with characteristics similar to the design for the ALS-U, as the more challenging aspects of the project are concerned. In particular, while the small distance between stripline electrodes reduces the required pulser voltage, the extreme proximity of the circulating beam requires a careful evaluation of the interaction between beam and kicker. In this paper we present the first measurements with beam, after the test kicker installation, together with the results of bench measurements performed on a cold model and computer simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB121

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WEPAB104

Status of the Conceptual Design of ALS-U

2824

C. Steier, A.P. Allézy, A. Anders, K.M. Baptiste, J.M. Byrd, K. Chow, G.D. Cutler, S. De Santis, R.J. Donahue, R.M. Duarte, J.-Y. Jung, S.C. Leemann, M. Leitner, T.H. Luo, H. Nishimura, T. Oliver, O. Omolayo, J.R. Osborn, G.C. Pappas, S. Persichelli, M. Placidi, G.J. Portmann, S. Reyes, D. Robin, F. Sannibale, C. Sun, C.A. Swenson, M. Venturini, W.L. Waldron, E.J. Wallén, W. Wan
LBNL, Berkeley, California, USA

Funding: This work is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The ALS-U upgrade promises to deliver diffraction limited performance throughout the soft x-ray range by lowering the horizontal emittance to about 50~pm resulting in 2-3 orders of brightness increase for soft x-rays compared to the current ALS. The design utilizes a multi bend achromat lattice with on-axis swap-out injection and an accumulator ring. One central design goal is to install and commission ALS-U within a short dark period. This paper summarizes the status of the conceptual design of the accelerator, as well as some results of the R&D program that has been ongoing for the last 3 years.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB104

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WEPIK106

Impedance and Collective Effects for the Advanced Light Source Upgrade at LBNL

3192

S. Persichelli, J.M. Byrd, S. De Santis, D. Li, T.H. Luo, C. Steier, M. Venturini
LBNL, Berkeley, California, USA

Funding: Work supported by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231
The upgrade of the Advanced Light Source (ALS-U) consists of a multiband achromat ultralow emittance lattice for the production of diffraction-limited soft x-rays. A very important issue for ALS-U is represented by instabilities induced by wakefields, that may limit the peak current of individual bunches and the total beam current. In addition, vacuum chamber apertures of few millimeters, that are a key feature of low-emittance machines, can result in a significant increase in the Resistive Wall (RW) impedance. In this paper we present progress on establishing short range wakefield model for ALS-U and evaluating the impact on the longitudinal and transverse single-bunch dynamics.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK106

Export •

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THPVA055

The Preliminary Performance of the Timing and Synchronization System at Tsinghua University

4565

SUSPSIK113

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

Z.Y. Lin, Y.-C. Du, W.-H. Huang, W.-H. Huang, C.-X. Tang, C.-X. Tang, J. Yang
TUB, Beijing, People's Republic of China
J.M. Byrd, L.R. Doolittle, G. Huang, Q. Qiang, R.B. Wilcox, Y.L. Xu
LBNL, Berkeley, California, USA

A precise timing and synchronization system is developed in Tsinghua University(THU). The whole system scheme includes fiber-based CW carrier phase reference distribution system (PRDS) for delivering stabilized RF phase reference to multiple receiver clients, Low Level RF (LLRF) control system to stabilized the accelerating mi-crowave field and laser-RF synchronization system for high precise synchronization of optical and RF signals. The system test and the demonstration experiment of each subsystem are carried on to evaluate the system and the phase error jitter resources are analysed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPVA055

Export •

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