IPAC2014 - List of Authors (De Santis, S.)

Paper	Title	Page
MOPME083	Fast Kicker Systems for ALS-U	564
	G.C. Pappas, S. De Santis, J.E. Galvin, L.R. Reginato, C. Steier, C. Sun, H. Tarawneh, W.L. Waldron 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 Fast kicker systems are required for the proposed upgrade of ALS to a diffraction-limited light source (ALS-U). The main approach is to have multiple stripline kicker magnets driven by inductive adders. The design details of the kicker structures and the inductive adder options will be discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME083
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MOPME084	Proposal for a Soft X-ray Diffraction Limited Upgrade of the ALS	567
	C. Steier, A. Anders, D. Arbelaez, K.M. Baptiste, W. Barry, J.M. Byrd, K. Chow, S. De Santis, R.M. Duarte, R.W. Falcone, J.-Y. Jung, S.D. Kevan, S. Kwiatkowski, T.H. Luo, A. Madur, H. Nishimura, J.R. Osborn, G.C. Pappas, L.R. Reginato, D. Robin, F. Sannibale, D. Schlueter, C. Sun, C.A. Swenson, H. Tarawneh, W.L. Waldron, 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 Berkeley Lab has been updated many times and remains as one of the brightest sources for soft x-rays worldwide. However, recent developments in technology, accelerator physics and simulation techniques open the door to much larger future brightness improvements. Similar to proposals at several other 3rd generation sources, this could be achieved by reducing the horizontal emittance with a new ring based on a multi-bend achromat lattice, reusing the existing tunnel, as well as much of the infrastructure and beamlines. After studying candidate lattice designs, development efforts in the last year have concentrated on technology and physics challenges in four main areas: Injection, Vacuum Systems, Magnets and Insertion Devices, as well as main and harmonic RF systems.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME084
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MOPRI054	Status of the APEX Project at LBNL	727
	F. Sannibale, K.M. Baptiste, C.W. Cork, J.N. Corlett, S. De Santis, L.R. Doolittle, J.A. Doyle, D. Filippetto, G.L. Harris, G. Huang, H. Huang, R. Huang, T.D. Kramasz, S. Kwiatkowski, R.E. Lellinger, V. Moroz, W.E. Norum, C. F. Papadopoulos, G.J. Portmann, H.J. Qian, J.W. Staples, M. Vinco, S.P. Virostek, R.P. Wells, M.S. Zolotorev LBNL, Berkeley, California, USA R. Huang USTC/NSRL, Hefei, Anhui, People's Republic of China
	Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231 The Advanced Photo-injector EXperiment (APEX) at the Lawrence Berkeley National Laboratory (LBNL), consists in the development of an injector designed to demonstrate the capability of the VHF gun, a normal conducting 186 MHz RF gun operating in CW mode, to deliver the brightness required by X-ray FEL applications at MHz repetition rate. APEX is organized in 3 main phases where different aspects of the required performance are gradually demonstrated. The status and future plans for the project are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI054
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MOPRI055	APEX Present Experimental Results	730
	D. Filippetto, C.W. Cork, S. De Santis, L.R. Doolittle, G. Huang, R. Huang, W.E. Norum, C. F. Papadopoulos, G.J. Portmann, H.J. Qian, F. Sannibale, J.W. Staples, R.P. Wells LBNL, Berkeley, California, USA J. Yang TUB, Beijing, People's Republic of China
	Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231 The APEX electron source at LBNL combines high-repetition-rate and high beam brightness typical of photo-guns, delivering low emittance electron pulses at MHz frequency. Proving the high beam quality of the beam is an essential step for the success of the experiment. It would enable high repetition rate operations for brightness-hungry applications such as X-Ray FELs, and MHz ultrafast electron diffraction. A full 6D characterization of the beam phase space at the gun beam energy (750 keV) is foreseen in the first phase of the project. Diagnostics for low and high current measurements have been installed and tested, measuring the performances of different cathode materials in a RF environment with mA average current. A double-slit system allows the characterization of beam emittance at high charge and full current (mA). An rf deflecting cavity and a high precision spectrometer allow the characterization of the longitudinal phase space. Here we present the latest results at low and high repetition rate, discussing the tools and techniques used.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI055
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TUPRI085	Development of a 4 GS/s Intra-bunch Instability Control System for the SPS - Next Steps	1766
	J.D. Fox, J.M. Cesaratto, J.E. Dusatko, K.M. Pollock, C.H. Rivetta, O. Turgut SLAC, Menlo Park, California, USA S. De Santis LBNL, Berkeley, California, USA W. Höfle, G. Kotzian, U. Wehrle CERN, Geneva, Switzerland
	Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP). We present the expanded system architecture in development for the control of intra-bunch instabilities in the SPS. Earlier efforts concentrated on validating the performance of a single-bunch demonstration processor. This minimal system was successfully commissioned at the SPS just prior to the LS1 shutdown. The architecture is now in expansion for more complex functionality, specifically multi-bunch control, control during energy ramps, and the expansion of the system front-end dynamic range with more sophisticated orbit offset techniques. Two designs of wideband kicker are being developed for installation and evaluation with the beam. With these GHz bandwidth devices and new RF amplifiers we anticipate being able to excite and control internal motion of the beam consistent with modes expected for Ecloud and TMCI effects. We highlight the expanded features, and present strategies for verifying the behavior of the beam-feedback system in the next series of machine measurements planned after the LS1 shutdown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI085
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TUPRI087	A Wideband Slotted Kicker Design for SPS Transverse Intra-bunch Feedback	1772
	J.M. Cesaratto, J.D. Fox, C.H. Rivetta SLAC, Menlo Park, California, USA D. Alesini, A. Gallo, M. Zobov INFN/LNF, Frascati (Roma), Italy S. De Santis LBNL, Berkeley, California, USA W. Höfle CERN, Geneva, Switzerland
	Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP) and by the EU FP7 HiLumi LHC - Grant Agreement 284404. In order for the SPS to meet the beam intensity demands for the HL-LHC upgrade, control and mitigation of transverse beam instabilities caused by electron cloud and TMCI will be essential. For this purpose a wideband intra-bunch feedback method has been proposed, based on a 4 GS/s front end data acquisition and processing, and on a back end frequency response extending to at least 1 GHz. A slotted type kicker, similar to those used for stochastic cooling, as well as an array of stripline kickers have been considered as the terminal elements of the feedback system. A slotted TEM type kicker has been designed fulfilling the bandwidth and kick strength requirements for the SPS application. In this paper we present an updated version of the design and electromagnetic characteristics, leading into the mechanical design and construction of the kicker occurring later this year.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI087
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WEPRO016	Injection/Extraction Kicker for the ALS-U Project	1977
	S. De Santis, W. Barry, S. Kwiatkowski, T.H. Luo, G.C. Pappas, L.R. Reginato, D. Robin, C. Steier, C. Sun, H. Tarawneh, W.L. Waldron LBNL, Berkeley, California, USA
	Funding: Work supported by the US Department of Energy under Contract no. DEAC02-05CH11231 The ALS-II proposal consists in the upgrade of the existing Advanced Light Source at LBNL to a new ultra-low emittance lattice for production of diffraction-limited soft x-rays. In order to compensate for the reduced beam lifetime we intend to operate the machine in continuous top-off mode, where one of several bunch trains is extracted every 30-60 seconds and swapped with a fresh train from the accumulator ring, which is injected on axis without perturbing the circulating beam. In this paper we present a possible design for the injection/extraction kicker based on matched stripline electrodes. The main parameters of such a kicker are discussed in reference to the minimum gap between trains, the storage ring lattice, and the characteristics of a suitable pulser. We also present results from 3D electromagnetic modeling of the proposed kicker performed to evaluate its rise and fall time and field uniformity characteristics.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO016
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Paper

Title

Page

Fast Kicker Systems for ALS-U

564

G.C. Pappas, S. De Santis, J.E. Galvin, L.R. Reginato, C. Steier, C. Sun, H. Tarawneh, W.L. Waldron
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
Fast kicker systems are required for the proposed upgrade of ALS to a diffraction-limited light source (ALS-U). The main approach is to have multiple stripline kicker magnets driven by inductive adders. The design details of the kicker structures and the inductive adder options will be discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME083

Export •

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

MOPME084

Proposal for a Soft X-ray Diffraction Limited Upgrade of the ALS

567

C. Steier, A. Anders, D. Arbelaez, K.M. Baptiste, W. Barry, J.M. Byrd, K. Chow, S. De Santis, R.M. Duarte, R.W. Falcone, J.-Y. Jung, S.D. Kevan, S. Kwiatkowski, T.H. Luo, A. Madur, H. Nishimura, J.R. Osborn, G.C. Pappas, L.R. Reginato, D. Robin, F. Sannibale, D. Schlueter, C. Sun, C.A. Swenson, H. Tarawneh, W.L. Waldron, 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 Berkeley Lab has been updated many times and remains as one of the brightest sources for soft x-rays worldwide. However, recent developments in technology, accelerator physics and simulation techniques open the door to much larger future brightness improvements. Similar to proposals at several other 3rd generation sources, this could be achieved by reducing the horizontal emittance with a new ring based on a multi-bend achromat lattice, reusing the existing tunnel, as well as much of the infrastructure and beamlines. After studying candidate lattice designs, development efforts in the last year have concentrated on technology and physics challenges in four main areas: Injection, Vacuum Systems, Magnets and Insertion Devices, as well as main and harmonic RF systems.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME084

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MOPRI054

Status of the APEX Project at LBNL

727

F. Sannibale, K.M. Baptiste, C.W. Cork, J.N. Corlett, S. De Santis, L.R. Doolittle, J.A. Doyle, D. Filippetto, G.L. Harris, G. Huang, H. Huang, R. Huang, T.D. Kramasz, S. Kwiatkowski, R.E. Lellinger, V. Moroz, W.E. Norum, C. F. Papadopoulos, G.J. Portmann, H.J. Qian, J.W. Staples, M. Vinco, S.P. Virostek, R.P. Wells, M.S. Zolotorev
LBNL, Berkeley, California, USA
R. Huang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231
The Advanced Photo-injector EXperiment (APEX) at the Lawrence Berkeley National Laboratory (LBNL), consists in the development of an injector designed to demonstrate the capability of the VHF gun, a normal conducting 186 MHz RF gun operating in CW mode, to deliver the brightness required by X-ray FEL applications at MHz repetition rate. APEX is organized in 3 main phases where different aspects of the required performance are gradually demonstrated. The status and future plans for the project are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI054

Export •

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

MOPRI055

APEX Present Experimental Results

730

D. Filippetto, C.W. Cork, S. De Santis, L.R. Doolittle, G. Huang, R. Huang, W.E. Norum, C. F. Papadopoulos, G.J. Portmann, H.J. Qian, F. Sannibale, J.W. Staples, R.P. Wells
LBNL, Berkeley, California, USA
J. Yang
TUB, Beijing, People's Republic of China

Funding: Work supported by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231
The APEX electron source at LBNL combines high-repetition-rate and high beam brightness typical of photo-guns, delivering low emittance electron pulses at MHz frequency. Proving the high beam quality of the beam is an essential step for the success of the experiment. It would enable high repetition rate operations for brightness-hungry applications such as X-Ray FELs, and MHz ultrafast electron diffraction. A full 6D characterization of the beam phase space at the gun beam energy (750 keV) is foreseen in the first phase of the project. Diagnostics for low and high current measurements have been installed and tested, measuring the performances of different cathode materials in a RF environment with mA average current. A double-slit system allows the characterization of beam emittance at high charge and full current (mA). An rf deflecting cavity and a high precision spectrometer allow the characterization of the longitudinal phase space. Here we present the latest results at low and high repetition rate, discussing the tools and techniques used.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI055

Export •

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

TUPRI085

Development of a 4 GS/s Intra-bunch Instability Control System for the SPS - Next Steps

1766

J.D. Fox, J.M. Cesaratto, J.E. Dusatko, K.M. Pollock, C.H. Rivetta, O. Turgut
SLAC, Menlo Park, California, USA
S. De Santis
LBNL, Berkeley, California, USA
W. Höfle, G. Kotzian, U. Wehrle
CERN, Geneva, Switzerland

Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP).
We present the expanded system architecture in development for the control of intra-bunch instabilities in the SPS. Earlier efforts concentrated on validating the performance of a single-bunch demonstration processor. This minimal system was successfully commissioned at the SPS just prior to the LS1 shutdown. The architecture is now in expansion for more complex functionality, specifically multi-bunch control, control during energy ramps, and the expansion of the system front-end dynamic range with more sophisticated orbit offset techniques. Two designs of wideband kicker are being developed for installation and evaluation with the beam. With these GHz bandwidth devices and new RF amplifiers we anticipate being able to excite and control internal motion of the beam consistent with modes expected for Ecloud and TMCI effects. We highlight the expanded features, and present strategies for verifying the behavior of the beam-feedback system in the next series of machine measurements planned after the LS1 shutdown.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI085

Export •

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

TUPRI087

A Wideband Slotted Kicker Design for SPS Transverse Intra-bunch Feedback

1772

J.M. Cesaratto, J.D. Fox, C.H. Rivetta
SLAC, Menlo Park, California, USA
D. Alesini, A. Gallo, M. Zobov
INFN/LNF, Frascati (Roma), Italy
S. De Santis
LBNL, Berkeley, California, USA
W. Höfle
CERN, Geneva, Switzerland

Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research Program (LARP) and by the EU FP7 HiLumi LHC - Grant Agreement 284404.
In order for the SPS to meet the beam intensity demands for the HL-LHC upgrade, control and mitigation of transverse beam instabilities caused by electron cloud and TMCI will be essential. For this purpose a wideband intra-bunch feedback method has been proposed, based on a 4 GS/s front end data acquisition and processing, and on a back end frequency response extending to at least 1 GHz. A slotted type kicker, similar to those used for stochastic cooling, as well as an array of stripline kickers have been considered as the terminal elements of the feedback system. A slotted TEM type kicker has been designed fulfilling the bandwidth and kick strength requirements for the SPS application. In this paper we present an updated version of the design and electromagnetic characteristics, leading into the mechanical design and construction of the kicker occurring later this year.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI087

Export •

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

WEPRO016

Injection/Extraction Kicker for the ALS-U Project

1977

S. De Santis, W. Barry, S. Kwiatkowski, T.H. Luo, G.C. Pappas, L.R. Reginato, D. Robin, C. Steier, C. Sun, H. Tarawneh, W.L. Waldron
LBNL, Berkeley, California, USA

Funding: Work supported by the US Department of Energy under Contract no. DEAC02-05CH11231
The ALS-II proposal consists in the upgrade of the existing Advanced Light Source at LBNL to a new ultra-low emittance lattice for production of diffraction-limited soft x-rays. In order to compensate for the reduced beam lifetime we intend to operate the machine in continuous top-off mode, where one of several bunch trains is extracted every 30-60 seconds and swapped with a fresh train from the accumulator ring, which is injected on axis without perturbing the circulating beam. In this paper we present a possible design for the injection/extraction kicker based on matched stripline electrodes. The main parameters of such a kicker are discussed in reference to the minimum gap between trains, the storage ring lattice, and the characteristics of a suitable pulser. We also present results from 3D electromagnetic modeling of the proposed kicker performed to evaluate its rise and fall time and field uniformity characteristics.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO016

Export •

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