IPAC2017 - List of Authors (Sannibale, F.)

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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TUPAB138	LCLS-II Injector Physics Design and Beam Tuning	1655
	F. Zhou, D. Dowell, P. Emma, J.F. Schmerge SLAC, Menlo Park, California, USA C.E. Mitchell, F. Sannibale LBNL, Berkeley, California, USA
	Funding: US DOE under grant No. DE-AC02-76SF00515. LCLS-II is a proposed high-repetition rate (up to 1 MHz) Free Electron Laser X-ray light source, based on a CW normal conducting (NC) RF gun injector and a CW 4-GeV superconducting (SC) linac, under construction at SLAC. LCLS-II CW injector consists of a 186 MHz NC RF gun, two solenoids, two BPMs, 1.3 GHz NC RF buncher, and 1.3 GHz SC standard 8-cavity cryomodule to boost the beam energy >95 MeV, and 5 pairs of steering correctors. In this paper, we describe the injector physics design including the beam optimization and low level RF requirement, and also present the studies of beam performance with any one SC cavity failure. The beam tuning procedure is developed with the correctors and two BPMs. The simulations of the phase/amplitude calibration for the gun and buncher and beam based alignment for cathode, two solenoids, and RF buncher with the limited diagnostics, will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB138
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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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WEPAB105	Design of the ALS-U Storage Ring Lattice	2827
	C. Sun, J.-Y. Jung, H. Nishimura, D. Robin, F. Sannibale, C. Steier, C.A. Swenson, M. Venturini, W. Wan LBNL, Berkeley, California, USA
	Funding: The Advanced Light Source 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 Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory is proposing the upgrade of its synchrotron light source to reach soft x-ray diffraction limits within the present ALS footprint. The storage ring lattice design and optimization of this light source is one of the challenging aspects for this proposed upgrade. The candidate upgrade lattice needs not only to fulfill the physics design requirements such as brightness, injection efficiency and beam lifetime, but also to meet engineering constraints such as space limitations, maximum magnet strength as well as beamline port locations. In this paper, we will present the lattice design goals and choices and discuss the optimization approaches for the proposed ALS upgrade.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB105
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THPIK120	The RF and Mechanical Design of a Compact, 2.5 kW, 1.3 GHz Resonant Loop Coupler for the APEX Buncher Cavity	4380
	S.P. Virostek, F. Sannibale, J.W. Staples LBNL, Berkeley, California, USA H.J. Qian DESY Zeuthen, Zeuthen, Germany
	Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231. The Advanced Photo-injector Experiment (APEX) at the Lawrence Berkeley National Laboratory (LBNL) is an injector system designed to demonstrate the capability of a normal conducting 186 MHz RF gun operating in CW mode to deliver the brightness required by X-ray FEL applications operating at MHz repetition rate, such as LCLS-II. A 240 kV, 1.3 GHz CW buncher cavity design was developed as part of the APEX experiment. The two-cell cavity profile has been optimized to minimize the RF power requirements and to remove multipacting resonances over the full range of operation. In order to excite the cavity stably at pi-mode and remove the dipole-like coupler kick, the two cells are to be independently driven by four, 2.5 kW, coaxial resonant loop couplers with integrated ceramic windows and a matching section in the body of the coupler. The coupler's inner conductor has a single diameter change at a specified distance from the ceramic insulator in order to cancel the wave reflected from the ceramic window, thus comprising the matching section. The details of the RF analysis, mechanical design, fabrication and testing of the coupler are presented here.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK120
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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)

TUPAB138

LCLS-II Injector Physics Design and Beam Tuning

1655

F. Zhou, D. Dowell, P. Emma, J.F. Schmerge
SLAC, Menlo Park, California, USA
C.E. Mitchell, F. Sannibale
LBNL, Berkeley, California, USA

Funding: US DOE under grant No. DE-AC02-76SF00515.
LCLS-II is a proposed high-repetition rate (up to 1 MHz) Free Electron Laser X-ray light source, based on a CW normal conducting (NC) RF gun injector and a CW 4-GeV superconducting (SC) linac, under construction at SLAC. LCLS-II CW injector consists of a 186 MHz NC RF gun, two solenoids, two BPMs, 1.3 GHz NC RF buncher, and 1.3 GHz SC standard 8-cavity cryomodule to boost the beam energy >95 MeV, and 5 pairs of steering correctors. In this paper, we describe the injector physics design including the beam optimization and low level RF requirement, and also present the studies of beam performance with any one SC cavity failure. The beam tuning procedure is developed with the correctors and two BPMs. The simulations of the phase/amplitude calibration for the gun and buncher and beam based alignment for cathode, two solenoids, and RF buncher with the limited diagnostics, will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB138

Export •

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

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

Export •

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

WEPAB105

Design of the ALS-U Storage Ring Lattice

2827

C. Sun, J.-Y. Jung, H. Nishimura, D. Robin, F. Sannibale, C. Steier, C.A. Swenson, M. Venturini, W. Wan
LBNL, Berkeley, California, USA

Funding: The Advanced Light Source 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 Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory is proposing the upgrade of its synchrotron light source to reach soft x-ray diffraction limits within the present ALS footprint. The storage ring lattice design and optimization of this light source is one of the challenging aspects for this proposed upgrade. The candidate upgrade lattice needs not only to fulfill the physics design requirements such as brightness, injection efficiency and beam lifetime, but also to meet engineering constraints such as space limitations, maximum magnet strength as well as beamline port locations. In this paper, we will present the lattice design goals and choices and discuss the optimization approaches for the proposed ALS upgrade.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB105

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

THPIK120

The RF and Mechanical Design of a Compact, 2.5 kW, 1.3 GHz Resonant Loop Coupler for the APEX Buncher Cavity

4380

S.P. Virostek, F. Sannibale, J.W. Staples
LBNL, Berkeley, California, USA
H.J. Qian
DESY Zeuthen, Zeuthen, Germany

Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231.
The Advanced Photo-injector Experiment (APEX) at the Lawrence Berkeley National Laboratory (LBNL) is an injector system designed to demonstrate the capability of a normal conducting 186 MHz RF gun operating in CW mode to deliver the brightness required by X-ray FEL applications operating at MHz repetition rate, such as LCLS-II. A 240 kV, 1.3 GHz CW buncher cavity design was developed as part of the APEX experiment. The two-cell cavity profile has been optimized to minimize the RF power requirements and to remove multipacting resonances over the full range of operation. In order to excite the cavity stably at pi-mode and remove the dipole-like coupler kick, the two cells are to be independently driven by four, 2.5 kW, coaxial resonant loop couplers with integrated ceramic windows and a matching section in the body of the coupler. The coupler's inner conductor has a single diameter change at a specified distance from the ceramic insulator in order to cancel the wave reflected from the ceramic window, thus comprising the matching section. The details of the RF analysis, mechanical design, fabrication and testing of the coupler are presented here.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK120

Export •

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