IPAC2019 - Classification: MC2: Photon Sources and Electron Accelerators / T12 Beam Injection/Extraction and Transport

Paper	Title	Page
WEPMP001	Proposed Nonlinear Injection Kicker for the Australian Synchrotron	2300
	R. Auchettl, Y.E. Tan AS - ANSTO, Clayton, Australia
	Future beamline development at the Australian Synchrotron requires free floor space within the straights for a short undulator and relocation of diagnostics. Our current injection method uses a four-dipole kicker configuration that perturbs the stored beam during injection while also taking up approximately 4 meters of valuable space. To free this valuable space and provide transparent injections to the beamlines, a single pulsed nonlinear magnetic field kicker (NLK) will be deployed. The NLK has a flat and zero field at the stored beam but maximum field where the injected beam is located off-axis. NLKs deflect only the injected beam, leaving the stored beam undisturbed. NLKs have been extensively prototyped by many facilities around the world already and can produce injection efficiencies of 99 % (see e.g. ). This paper presents the preliminary magnet design for installation of a NLK at the Australian Synchrotron. We discuss the beam dynamics and thermal transfer constraints on kicker placement, field-flatness and the magnet and ceramic chamber design for adaptation to our 3 GeV beam. Installation plans and other constraints for future deployment are also outlined. T. Pulampong and R. Bartolini, "A Non-linear Injection Kicker for Diamond Light Source", in: Proc. IPAC’13, pp. 2268-2270.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP001
About •	paper received ※ 15 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019
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WEPMP009	Renovation of Off-Axis Beam Injection Scheme for Next-Generation Photon Sources	2318
	S. Takano, K. Fukami, C. Kondo, M. Masaki, M. Oishi, M. Shoji, K. Tamura, T. Taniuchi, T. Watanabe, K. Yanagida JASRI, Hyogo, Japan H. Akikawa, K. Sato Nihon Koshuha Co. Ltd, Yokohama, Japan K. Fukami, T. Hara, T. Inagaki, C. Kondo, M. Oishi, S. Takano, H. Tanaka, T. Watanabe RIKEN SPring-8 Center, Hyogo, Japan K. Hamato, J. Kataoka, K. Kusano, K. Ogata, Y. Saito TOKIN, Sendai, Miyagi, Japan
	Funding: Work supported by Ministry of education, culture, sports, science and technology JAPAN (MEXT). Photon sources are looking for performance upgrades by pursuing higher photon brilliance and coherence these years. The trend is pushing the lattice design to lower the beam emittance, which naturally results in the narrower dynamic aperture. One bottleneck in the upgrades is a beam injection system capable of accumulating required beam intensity and keeping top-up operations with such narrow apertures. Beam injection with a nonlinear kicker and transverse/longitudinal on-axis injections are now in the limelight. However, these techniques still need time to be put into practical use. We take an alternative approach for the SPring-8 upgrade, SPring-8-II, renovating the off-axis beam injection scheme to address the following requirements for the coming diffraction-limited storage rings (DLSRs): minimizing of both injection beam amplitude and perturbation to stored beam, and topping-up functionality. This presentation will overview the renewed off-axis beam injection scheme and report the development status of the following three key components: 1) permanent magnet based DC septum magnet, 2) in-vacuum pulse septum magnet, and 3) twin kickers driven by a single solid state pulser.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP009
About •	paper received ※ 10 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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WEPMP015	Status of the R&D for HALS Injection System	2335
	L. Shang, W. Liu, Y. Lu, F.L. Shang, W.B. Song, Z.B. Sun USTC/NSRL, Hefei, Anhui, People’s Republic of China
	Hefei Advanced Light Source (HALS) is a diffraction-limited synchrotron radiation source proposed by the NSRL. A comprehensive R&D program funded by the local government was initiated in the end of 2017. The program focuses on the key technologies including the injection, magnets, vacuum, mechanics, RF, etc. The formal construction of HALS is estimated to begin in 2020. This paper presents the R&D of the injection system, including the fast kicker, nanosecond pulser, NLK (non-linear kicker) and the septum magnet. Test results of the prototype fast kicker, pulsed power and the NLK are given and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP015
About •	paper received ※ 16 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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WEPMP016	The Design and Preliminary Test of a Stripline Kicker for HALS	2338
	W. Liu, F.L. Shang, L. Shang, W.B. Song, Z.B. Sun USTC/NSRL, Hefei, Anhui, People’s Republic of China
	Stripline kicker is an important components of both on-axis longitudinal accumulation and on-axis swap out injection schemes in HALS (Hefei Advanced Light Source). After more than one year of R&D, construction of the first prototype is completed. The kicker performance is simulated by CST. The results show that in the range of 0~1GHz, on differential mode, S11 is less than - 23.7dB. In order to facilitate installation, the extension part and PTFE bracket were designed. The assembly of kicker and feedthrough has been tested with pulse generator and network analyser.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP016
About •	paper received ※ 25 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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WEPMP017	A New Nonlinear Kicker Design and Measurement	2342
	W.B. Song, W. Liu, Y. Lu, F.L. Shang, L. Shang, Z.B. Sun USTC/NSRL, Hefei, Anhui, People’s Republic of China
	Funding: Work supported by The National Key Research and Development Program of China(2016YFA0402000) and Pre-research Project of Hefei Advanced Light Source For the beam injection of HALS, a feasible injection scheme is proposed and a single-pulse nonlinear kicker has been designed for off-axis injection. The kicker has been improved on the basis of the previous designed one, and the structure of the kicker was simulated by OPERA, and the prototype has been processed and measured. The results showed that the kicker designed in this paper has less influence on stored beam and lower difficulty in location.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP017
About •	paper received ※ 26 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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WEPMP018	A Novel Non-Linear Strip-Line Kicker Driven by Fast Pulser in Common Mode	2345
	J. Chen, Z. Duan, L. Huo, Y. Li, H. Shi, G. Wang, L. Wang, N. Wang IHEP, Beijing, People’s Republic of China
	The next generation storage ring-based light sources adopt multi-bend achromat lattices to achieve a low emittance. The dynamic apertures of these machines are usually less than 10 mm so that the traditional pulsed local bump injection is difficult to achieve. Off-axis injection with a pulsed multipole or a non-linear kicker could be a viable solution which requires a moderate dynamic aperture of a few mm. In this paper, a novel non-linear kicker design is presented. Unlike pulsed sextupole or nonlinear kicker magnet, the nonlinear kicker we proposed is a traveling wave kicker with 2 strip-line electrodes driven by a nanosecond-level fast pulser in common mode. The disturbance to the stored beam is minimal since the perturbation is limited to the target bunch alone. Work support by NSFC(11475200 and 11675194).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP018
About •	paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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WEPMP019	Physical Design of HEPS Low Energy Transport Line	2349
	Y.M. Peng, C. Meng, H.S. Xu IHEP, Beijing, People’s Republic of China
	he High Energy Photon Source (HEPS), a kilometre-scale storage ring based light source, with emittance less than 60 pm.rad, will be constructed in Beijing, China. It con-sists of a 500 MeV linac, a 500 MeV low energy transport line, a full energy booster synchrotron, two 6- GeV transport lines, a 6 GeV ultra-low emittance storage ring, and the beam line experimental stations. The low energy transport line connecting the linac and the booster. Based on the construction layout restrictions, the beam enve-lopes of the linac and the booster should be matched, and the beam produced by the linac is high efficiently trans-mitted to the booster injection point. HEPS low energy transport line has three functional sections, the achromat injection matching section, the optics matching section and the output matching section. In order to correct the error effects on the beam, 8 BPM are set in the low energy transport line. There are also 6 horizontal correctors and 6vertical correctors for beam trajectory correction. This paper will show the detailed design of HEPS low energy transport line.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP019
About •	paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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WEPMP029	Systematic Optics Studies for the Commissioning of the AWAKE Beamline	2383
	C. Bracco, B. Goddard, I. Gorgisyan, M. Turner, F.M. Velotti, L. Verra CERN, Geneva, Switzerland M. Aiba PSI, Villigen PSI, Switzerland
	The commissioning of the AWAKE electron beam line was successfully completed in 2018. Despite a modest length of about 15 m, this low-energy line is quite complex and several iterations were needed before finding satisfactory agreement between the model and the measurements. The work allowed to precisely predict the size and positioning of the electron beam at the merging point with the protons inside the plasma cell, where no direct measurement is possible. All the key aspects and corrections which had to be included in the model, precautions and systematic checks to apply for the correct setup of the line are presented. The sensitivity of the ~18 MeV electron beam to various perturbations, like different initial optics parameters and beam conditions, energy jitter and drifts, earth’s magnetic field etc., is described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP029
About •	paper received ※ 10 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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WEPMP042	Reduction of Stored Beam Oscillations During Injection at Diamond Light Source	2426
	R.T. Fielder, M. Apollonio, R. Bartolini, C. Bloomer, I.P.S. Martin DLS, Oxfordshire, United Kingdom
	At Diamond injection is performed by means a of a four kicker off-axis system, relying on a perfect timing and amplitude setting to produce a closed bump. Ageing of some of the kicker vessel components has progressively spoiled the performance of the system, causing oscillations in the stored beam. Various schemes to control these oscillations have been considered including introducing an additional compensating kicker, and installing a non-linear injection kicker. Results of simulations analysing these schemes are presented, along with measurements taken in the storage ring using an existing pinger magnet. The effects of the reduction on the quality of beam seen by beamlines is also considered.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP042
About •	paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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WEPMP043	Injection Studies for the Proposed Diamond-II Storage Ring	2430
	I.P.S. Martin, R. Bartolini, H. Ghasem, J.P. Kennedy, B. Singh DLS, Oxfordshire, United Kingdom
	The baseline design for the Diamond-II storage ring consists of a Modified-Hybrid 6-Bend Achromat, combining the ESRF-EBS low-emittance cell design with the DDBA mid-straight concept,. This cell design provides sufficient dynamic aperture to permit an off-axis injection scheme, provided the emittance of the injected beam is sufficiently low. In this paper we present simulations of an injection scheme using the anti-septum concept*, along with the design of an upgrade to the existing booster synchrotron. Alternate injection strategies are also discussed. ESRF Technical Design Study, ’The Orange Book’, (2014) R. Bartolini et al., PRAB 21, 050701, (2018) *C. Gough, M. Aiba, Proc. IPAC 2017, Copenhagen, Denmark, paper MOPIK104, (2017)
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP043
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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WEPMP049	Simulations of Beam Shaping for Dark Matter Experiments at LCLS-II	2443
	Y.M. Nosochkov, C. Hast, T.W. Markiewicz, L.Y. Nicolas, T.O. Raubenheimer, M. Santana-Leitner SLAC, Menlo Park, California, USA
	Funding: * Work supported by the U.S. DOE Contract DE-AC02-76SF00515. A new transfer beamline, called S30XL, and an experimental facility are proposed to be built at SLAC, taking advantage of the LCLS-II free electron laser (FEL) under construction. The S30XL will operate parasitically to the FEL by extracting the unused low intensity 4-GeV LCLS-II bunches into the existing A-line and the End Station-A (ESA). This provides a unique capability of multi-GeV nearly continuous electron beam for a variety of HEP experiments, in particular the dark matter search experiments. The latter require a very low beam current ranging from pA to micro-A, as well as a large beam spot at the detector. The necessary beam shaping will be performed using spoilers and collimators in the A-line, and by optimizing the optics. FLUKA and elegant codes are used to generate and track the beam into the ESA.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP049
About •	paper received ※ 16 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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WEPMP051	Impedance Study of a New Septum Chamber of SPEAR3	2447
	K. Tian, J. Langton, J.J. Sebek SLAC, Menlo Park, California, USA
	Funding: Work supported by US Department of Energy Contract DE-AC03-76SF00515. A new Septum magnet and chamber has been designed for the storage ring as a part of the accelerator improvement plan for operating a lower emittance lattice in SPEAR3. Therefore it is necessary to analyze the impedance effects on the beam from the new Septum chamber. Due to the complex design at the downstream transition of the Septum chamber, the longitudinal impedance is particular of concern. In this paper, we will present numerical simulation results for this particular component as well as the general analysis for the impedance effects of the whole chamber.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP051
About •	paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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WEPMP053	Operational Results of Simultaneous Four-Beam Delivery at Jefferson Lab	2454
	R. Kazimi, A. Freyberger, J.M. Grames, J. Hansknecht, A.S. Hofler, T.E. Plawski, M. Poelker, M.F. Spata, Y.W. Wang JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. A concept for simultaneous beam delivery to all four CEBAF experimental halls from a single injector and a single main accelerator for the 12 GeV era was proposed in 2012. The original 12 GeV beam delivery plan was for a maximum of three experimental halls at a time as in the 6 GeV era. Therefore, the new concept increases the po-tential beam time for the experiments up to 33%. This change, although a major improvement in operational capabilities, required only limited modifications to the existing machine. The modifications were mainly timing and pattern changes to the beams in the injector, adding a fourth laser to the photo-cathode gun, and the addition of new RF separators to the highest pass of CEBAF. These changes are now complete and, for the first time, the full system is operating, producing four simultaneous beams through the accelerator to four different destinations. In this paper, in addition to presenting the results of the full system commissioning, we will discuss important details about the new configuration plus some of our operational challenges.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP053
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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WEPGW111	Design of Booster-to-Accumulator Transfer Line for Advanced Light Source Upgrade	2756
	C. Sun, Ph. Amstutz, T. Hellert, J.-Y. Jung, S.C. Leemann, J.R. Osborn, M. Placidi, C. Steier, C.A. Swenson, M. Venturini, W. Wan 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. For the Advanced Light Source Upgrade, an on-axis swap-out injection is applied to exchange bunch trains between the storage ring and the accumulator ring. To replenish the accumulator ring before the swap-out injection, an electron beam from Linac is first injected into the ALS booster to ramp up the energy, and then transported to the accumulator through the Booster-to-Accumulator (BTA) transfer line. The design of the BTA transfer line is a challenging task as it has to fit within a tight space while accommodating the booster and accumulator rings at different elevations. Moreover, the BTA design needs to meet the optics boundary conditions and ideally minimize the size requirements of vacuum-chamber apertures. In this paper, we will present a design option of the BTA transfer line, which meets both space limitations and beam physics requirements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW111
About •	paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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WEPTS089	Microbunching Instability Mitigation via Multi-Stage Cancellation	3321
	J. Qiang, B. Li LBNL, Berkeley, California, USA
	Funding: This work was supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 and used computer resources at the National Energy Research Scientific Computing Center. The microbunching instability driven by beam collective effects in the linear accelerator of a free electron laser (FEL) facility can significantly degrade electron beam quality and FEL performance. Understanding and control of the instability is a priority for the design of modern high-brightness electron accelerators. In this paper, we study an instability cancellation phenomenon due to 180 degree phase slippage of the current modulations between different amplification stages. A case study of using a nonisochronous dogleg section in a double compression scheme to cancel the current modulation is illustrated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS089
About •	paper received ※ 07 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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WEPTS090	Suppression of Microbunching Instability Through Dispersive Lattice	3325
	J. Qiang, B. Li LBNL, Berkeley, California, USA
	Funding: This work was supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 and used computer resources at the National Energy Research Scientific Computing Center. The microbunching instability from the initial small modulation such as shot-noise can be amplified by longitudinal space-charge force and causes significant electron beam quality degradation at the exit of accelerator for the next generation x-ray free electron laser. In the paper, we present analytical and numerical simulation studies of a novel method using dispersion leakage from some quadrupoles inside a chicane.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS090
About •	paper received ※ 26 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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Paper

Title

Page

Proposed Nonlinear Injection Kicker for the Australian Synchrotron

2300

R. Auchettl, Y.E. Tan
AS - ANSTO, Clayton, Australia

Future beamline development at the Australian Synchrotron requires free floor space within the straights for a short undulator and relocation of diagnostics. Our current injection method uses a four-dipole kicker configuration that perturbs the stored beam during injection while also taking up approximately 4 meters of valuable space. To free this valuable space and provide transparent injections to the beamlines, a single pulsed nonlinear magnetic field kicker (NLK) will be deployed. The NLK has a flat and zero field at the stored beam but maximum field where the injected beam is located off-axis. NLKs deflect only the injected beam, leaving the stored beam undisturbed. NLKs have been extensively prototyped by many facilities around the world already and can produce injection efficiencies of 99 % (see e.g. *). This paper presents the preliminary magnet design for installation of a NLK at the Australian Synchrotron. We discuss the beam dynamics and thermal transfer constraints on kicker placement, field-flatness and the magnet and ceramic chamber design for adaptation to our 3 GeV beam. Installation plans and other constraints for future deployment are also outlined.
* T. Pulampong and R. Bartolini, "A Non-linear Injection Kicker for Diamond Light Source", in: Proc. IPAC’13, pp. 2268-2270.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP001

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paper received ※ 15 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019

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WEPMP009

Renovation of Off-Axis Beam Injection Scheme for Next-Generation Photon Sources

2318

S. Takano, K. Fukami, C. Kondo, M. Masaki, M. Oishi, M. Shoji, K. Tamura, T. Taniuchi, T. Watanabe, K. Yanagida
JASRI, Hyogo, Japan
H. Akikawa, K. Sato
Nihon Koshuha Co. Ltd, Yokohama, Japan
K. Fukami, T. Hara, T. Inagaki, C. Kondo, M. Oishi, S. Takano, H. Tanaka, T. Watanabe
RIKEN SPring-8 Center, Hyogo, Japan
K. Hamato, J. Kataoka, K. Kusano, K. Ogata, Y. Saito
TOKIN, Sendai, Miyagi, Japan

Funding: Work supported by Ministry of education, culture, sports, science and technology JAPAN (MEXT).
Photon sources are looking for performance upgrades by pursuing higher photon brilliance and coherence these years. The trend is pushing the lattice design to lower the beam emittance, which naturally results in the narrower dynamic aperture. One bottleneck in the upgrades is a beam injection system capable of accumulating required beam intensity and keeping top-up operations with such narrow apertures. Beam injection with a nonlinear kicker and transverse/longitudinal on-axis injections are now in the limelight. However, these techniques still need time to be put into practical use. We take an alternative approach for the SPring-8 upgrade, SPring-8-II, renovating the off-axis beam injection scheme to address the following requirements for the coming diffraction-limited storage rings (DLSRs): minimizing of both injection beam amplitude and perturbation to stored beam, and topping-up functionality. This presentation will overview the renewed off-axis beam injection scheme and report the development status of the following three key components: 1) permanent magnet based DC septum magnet, 2) in-vacuum pulse septum magnet, and 3) twin kickers driven by a single solid state pulser.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP009

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paper received ※ 10 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPMP015

Status of the R&D for HALS Injection System

2335

L. Shang, W. Liu, Y. Lu, F.L. Shang, W.B. Song, Z.B. Sun
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Hefei Advanced Light Source (HALS) is a diffraction-limited synchrotron radiation source proposed by the NSRL. A comprehensive R&D program funded by the local government was initiated in the end of 2017. The program focuses on the key technologies including the injection, magnets, vacuum, mechanics, RF, etc. The formal construction of HALS is estimated to begin in 2020. This paper presents the R&D of the injection system, including the fast kicker, nanosecond pulser, NLK (non-linear kicker) and the septum magnet. Test results of the prototype fast kicker, pulsed power and the NLK are given and discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP015

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paper received ※ 16 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPMP016

The Design and Preliminary Test of a Stripline Kicker for HALS

2338

W. Liu, F.L. Shang, L. Shang, W.B. Song, Z.B. Sun
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Stripline kicker is an important components of both on-axis longitudinal accumulation and on-axis swap out injection schemes in HALS (Hefei Advanced Light Source). After more than one year of R&D, construction of the first prototype is completed. The kicker performance is simulated by CST. The results show that in the range of 0~1GHz, on differential mode, S11 is less than - 23.7dB. In order to facilitate installation, the extension part and PTFE bracket were designed. The assembly of kicker and feedthrough has been tested with pulse generator and network analyser.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP016

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paper received ※ 25 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPMP017

A New Nonlinear Kicker Design and Measurement

2342

W.B. Song, W. Liu, Y. Lu, F.L. Shang, L. Shang, Z.B. Sun
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Funding: Work supported by The National Key Research and Development Program of China(2016YFA0402000) and Pre-research Project of Hefei Advanced Light Source
For the beam injection of HALS, a feasible injection scheme is proposed and a single-pulse nonlinear kicker has been designed for off-axis injection. The kicker has been improved on the basis of the previous designed one, and the structure of the kicker was simulated by OPERA, and the prototype has been processed and measured. The results showed that the kicker designed in this paper has less influence on stored beam and lower difficulty in location.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP017

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paper received ※ 26 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPMP018

A Novel Non-Linear Strip-Line Kicker Driven by Fast Pulser in Common Mode

2345

J. Chen, Z. Duan, L. Huo, Y. Li, H. Shi, G. Wang, L. Wang, N. Wang
IHEP, Beijing, People’s Republic of China

The next generation storage ring-based light sources adopt multi-bend achromat lattices to achieve a low emittance. The dynamic apertures of these machines are usually less than 10 mm so that the traditional pulsed local bump injection is difficult to achieve. Off-axis injection with a pulsed multipole or a non-linear kicker could be a viable solution which requires a moderate dynamic aperture of a few mm. In this paper, a novel non-linear kicker design is presented. Unlike pulsed sextupole or nonlinear kicker magnet, the nonlinear kicker we proposed is a traveling wave kicker with 2 strip-line electrodes driven by a nanosecond-level fast pulser in common mode. The disturbance to the stored beam is minimal since the perturbation is limited to the target bunch alone.
Work support by NSFC(11475200 and 11675194).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP018

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paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPMP019

Physical Design of HEPS Low Energy Transport Line

2349

Y.M. Peng, C. Meng, H.S. Xu
IHEP, Beijing, People’s Republic of China

he High Energy Photon Source (HEPS), a kilometre-scale storage ring based light source, with emittance less than 60 pm.rad, will be constructed in Beijing, China. It con-sists of a 500 MeV linac, a 500 MeV low energy transport line, a full energy booster synchrotron, two 6- GeV transport lines, a 6 GeV ultra-low emittance storage ring, and the beam line experimental stations. The low energy transport line connecting the linac and the booster. Based on the construction layout restrictions, the beam enve-lopes of the linac and the booster should be matched, and the beam produced by the linac is high efficiently trans-mitted to the booster injection point. HEPS low energy transport line has three functional sections, the achromat injection matching section, the optics matching section and the output matching section. In order to correct the error effects on the beam, 8 BPM are set in the low energy transport line. There are also 6 horizontal correctors and 6vertical correctors for beam trajectory correction. This paper will show the detailed design of HEPS low energy transport line.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP019

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paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPMP029

Systematic Optics Studies for the Commissioning of the AWAKE Beamline

2383

C. Bracco, B. Goddard, I. Gorgisyan, M. Turner, F.M. Velotti, L. Verra
CERN, Geneva, Switzerland
M. Aiba
PSI, Villigen PSI, Switzerland

The commissioning of the AWAKE electron beam line was successfully completed in 2018. Despite a modest length of about 15 m, this low-energy line is quite complex and several iterations were needed before finding satisfactory agreement between the model and the measurements. The work allowed to precisely predict the size and positioning of the electron beam at the merging point with the protons inside the plasma cell, where no direct measurement is possible. All the key aspects and corrections which had to be included in the model, precautions and systematic checks to apply for the correct setup of the line are presented. The sensitivity of the ~18 MeV electron beam to various perturbations, like different initial optics parameters and beam conditions, energy jitter and drifts, earth’s magnetic field etc., is described.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP029

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paper received ※ 10 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPMP042

Reduction of Stored Beam Oscillations During Injection at Diamond Light Source

2426

R.T. Fielder, M. Apollonio, R. Bartolini, C. Bloomer, I.P.S. Martin
DLS, Oxfordshire, United Kingdom

At Diamond injection is performed by means a of a four kicker off-axis system, relying on a perfect timing and amplitude setting to produce a closed bump. Ageing of some of the kicker vessel components has progressively spoiled the performance of the system, causing oscillations in the stored beam. Various schemes to control these oscillations have been considered including introducing an additional compensating kicker, and installing a non-linear injection kicker. Results of simulations analysing these schemes are presented, along with measurements taken in the storage ring using an existing pinger magnet. The effects of the reduction on the quality of beam seen by beamlines is also considered.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP042

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paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEPMP043

Injection Studies for the Proposed Diamond-II Storage Ring

2430

I.P.S. Martin, R. Bartolini, H. Ghasem, J.P. Kennedy, B. Singh
DLS, Oxfordshire, United Kingdom

The baseline design for the Diamond-II storage ring consists of a Modified-Hybrid 6-Bend Achromat, combining the ESRF-EBS low-emittance cell design with the DDBA mid-straight concept*,**. This cell design provides sufficient dynamic aperture to permit an off-axis injection scheme, provided the emittance of the injected beam is sufficiently low. In this paper we present simulations of an injection scheme using the anti-septum concept***, along with the design of an upgrade to the existing booster synchrotron. Alternate injection strategies are also discussed.
*ESRF Technical Design Study, ’The Orange Book’, (2014)
**R. Bartolini et al., PRAB 21, 050701, (2018)
***C. Gough, M. Aiba, Proc. IPAC 2017, Copenhagen, Denmark, paper MOPIK104, (2017)

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP043

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEPMP049

Simulations of Beam Shaping for Dark Matter Experiments at LCLS-II

2443

Y.M. Nosochkov, C. Hast, T.W. Markiewicz, L.Y. Nicolas, T.O. Raubenheimer, M. Santana-Leitner
SLAC, Menlo Park, California, USA

Funding: * Work supported by the U.S. DOE Contract DE-AC02-76SF00515.
A new transfer beamline, called S30XL, and an experimental facility are proposed to be built at SLAC, taking advantage of the LCLS-II free electron laser (FEL) under construction. The S30XL will operate parasitically to the FEL by extracting the unused low intensity 4-GeV LCLS-II bunches into the existing A-line and the End Station-A (ESA). This provides a unique capability of multi-GeV nearly continuous electron beam for a variety of HEP experiments, in particular the dark matter search experiments. The latter require a very low beam current ranging from pA to micro-A, as well as a large beam spot at the detector. The necessary beam shaping will be performed using spoilers and collimators in the A-line, and by optimizing the optics. FLUKA and elegant codes are used to generate and track the beam into the ESA.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP049

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paper received ※ 16 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPMP051

Impedance Study of a New Septum Chamber of SPEAR3

2447

K. Tian, J. Langton, J.J. Sebek
SLAC, Menlo Park, California, USA

Funding: Work supported by US Department of Energy Contract DE-AC03-76SF00515.
A new Septum magnet and chamber has been designed for the storage ring as a part of the accelerator improvement plan for operating a lower emittance lattice in SPEAR3. Therefore it is necessary to analyze the impedance effects on the beam from the new Septum chamber. Due to the complex design at the downstream transition of the Septum chamber, the longitudinal impedance is particular of concern. In this paper, we will present numerical simulation results for this particular component as well as the general analysis for the impedance effects of the whole chamber.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP051

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paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPMP053

Operational Results of Simultaneous Four-Beam Delivery at Jefferson Lab

2454

R. Kazimi, A. Freyberger, J.M. Grames, J. Hansknecht, A.S. Hofler, T.E. Plawski, M. Poelker, M.F. Spata, Y.W. Wang
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
A concept for simultaneous beam delivery to all four CEBAF experimental halls from a single injector and a single main accelerator for the 12 GeV era was proposed in 2012. The original 12 GeV beam delivery plan was for a maximum of three experimental halls at a time as in the 6 GeV era. Therefore, the new concept increases the po-tential beam time for the experiments up to 33%. This change, although a major improvement in operational capabilities, required only limited modifications to the existing machine. The modifications were mainly timing and pattern changes to the beams in the injector, adding a fourth laser to the photo-cathode gun, and the addition of new RF separators to the highest pass of CEBAF. These changes are now complete and, for the first time, the full system is operating, producing four simultaneous beams through the accelerator to four different destinations. In this paper, in addition to presenting the results of the full system commissioning, we will discuss important details about the new configuration plus some of our operational challenges.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP053

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paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPGW111

Design of Booster-to-Accumulator Transfer Line for Advanced Light Source Upgrade

2756

C. Sun, Ph. Amstutz, T. Hellert, J.-Y. Jung, S.C. Leemann, J.R. Osborn, M. Placidi, C. Steier, C.A. Swenson, M. Venturini, W. Wan
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.
For the Advanced Light Source Upgrade, an on-axis swap-out injection is applied to exchange bunch trains between the storage ring and the accumulator ring. To replenish the accumulator ring before the swap-out injection, an electron beam from Linac is first injected into the ALS booster to ramp up the energy, and then transported to the accumulator through the Booster-to-Accumulator (BTA) transfer line. The design of the BTA transfer line is a challenging task as it has to fit within a tight space while accommodating the booster and accumulator rings at different elevations. Moreover, the BTA design needs to meet the optics boundary conditions and ideally minimize the size requirements of vacuum-chamber apertures. In this paper, we will present a design option of the BTA transfer line, which meets both space limitations and beam physics requirements.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW111

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paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPTS089

Microbunching Instability Mitigation via Multi-Stage Cancellation

3321

J. Qiang, B. Li
LBNL, Berkeley, California, USA

Funding: This work was supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 and used computer resources at the National Energy Research Scientific Computing Center.
The microbunching instability driven by beam collective effects in the linear accelerator of a free electron laser (FEL) facility can significantly degrade electron beam quality and FEL performance. Understanding and control of the instability is a priority for the design of modern high-brightness electron accelerators. In this paper, we study an instability cancellation phenomenon due to 180 degree phase slippage of the current modulations between different amplification stages. A case study of using a nonisochronous dogleg section in a double compression scheme to cancel the current modulation is illustrated.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS089

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paper received ※ 07 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEPTS090

Suppression of Microbunching Instability Through Dispersive Lattice

3325

J. Qiang, B. Li
LBNL, Berkeley, California, USA

Funding: This work was supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 and used computer resources at the National Energy Research Scientific Computing Center.
The microbunching instability from the initial small modulation such as shot-noise can be amplified by longitudinal space-charge force and causes significant electron beam quality degradation at the exit of accelerator for the next generation x-ray free electron laser. In the paper, we present analytical and numerical simulation studies of a novel method using dispersion leakage from some quadrupoles inside a chicane.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS090

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paper received ※ 26 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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