IPAC2019 - List of Keywords (vacuum)

Paper	Title	Other Keywords	Page
MOPGW010	First Application of Online Particle Swarm Optimization at SOLEIL	injection, storage-ring, operation, controls	82
	A. Bence, L.S. Nadolski SOLEIL, Gif-sur-Yvette, France J. Li HZB, Berlin, Germany
	First attempts of online optimisation of SOLEIL using Particle Swarm Optimisation (PSO) is reported with two major applications. This technique proves to be particularly suitable in a control room and could become a standard operation tool for tuning the accelerators in complement of other techniques. The first optimisation of the injection in the storage ring will be presented using the injection septa and the vertical correctors of the booster to storage ring transfer line. The second work will summarise the results obtained from the optimisation of the transverse on- and off-momentum dynamics in presence of insertion devices. Main results, the implementation and improvements will be presented and discussed thoroughly.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW010
About •	paper received ※ 19 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPGW053	Residual Gas Lifetime In High Energy Photon Source (HEPS)	scattering, electron, dynamic-aperture, photon	210
	S.K. Tian, H.S. Xu IHEP, Beijing, People’s Republic of China
	High vacuum has always been mandatory in particle accelerators. This is especially true for circular machines, where the beam makes thousands or millions turns, and beam lifetime is heavily affected by the residual gas scattering. At the beginning of storage ring operation the lifetime was very short mostly dominated by residual gas scattering. The residual gas lifetime is comprised of the elastic and inelastic scattering on electrons and elastic and inelastic scattering on nuclei. One usually calculates only the elastic scattering on nuclei (single Coulomb scattering) and inelastic scattering on nuclei (bremsstrahlung) of the residual gas scattering lifetime component. The analytic calculation the residual gas scattering lifetime and simulations of the beam interaction with the residual gas with code will be shown in this presentation
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW053
About •	paper received ※ 15 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019
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MOPGW058	Towards a Sextupole-Free Electron Storage Ring	electron, impedance, storage-ring, feedback	217
	T.-Y. Lee, T. Ha PAL, Pohang, Kyungbuk, Republic of Korea
	This paper studies if it is possible to build an electron storage ring with no or a small number of sextupole mag-nets. If it is possible, the electron storage ring will be great-ly simplified. For the purpose, two methods are presented in the paper to handle head-tail instability: One is to use dielectric vacuum chamber made of such materials as ceramic or glass to reduce broadband impedance signifi-cantly. Then head-tail instability would be extremely weak. The other method is to install a bunch-by-bunch feedback system to suppress the already weak head-tail instability due to the dielectric vacuum chamber.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW058
About •	paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW061	Radiation from a Dielectrically Loaded Waveguide with Open End	GUI, radiation, embedded, acceleration	228
	S.N. Galyamin, A.A. Grigoreva, A.V. Tyukhtin, V.V. Vorobev Saint Petersburg State University, Saint Petersburg, Russia A. Aryshev KEK, Ibaraki, Japan
	Funding: Work supported by Russian Science Foundation (Grant No. 18-72-10137). Open-ended waveguide structures with dielectric loading excited by specially prepared electron bunches are considered as promising candidates for development of contemporary sources of Terahertz (THz) radiation. Despite of the fact that both ordinary vacuum THz devices (e.g., backward wave oscillator) are widely available and other mechanisms for THz generation are discussed, beam driven sources are still extremely attractive due to the extraordinary peak power of THz radiation. In this report, we study electromagnetic (EM) field produced by a charged particle bunch exiting an open-ended circular waveguide with dielectric filling placed inside collinear vacuum waveguide of a larger radius. Based on the previously developed theory, we mainly investigate Cherenkov radiation generated penetrated vacuum regions of the structure due to the diffraction mechanism. We pay attention to the case of a train of short bunches resulting in high-order Cherenkov modes excitation. We also develop analytical procedure allowing performing the limiting process to the case of infinite radius of the outer waveguide. B.D. O’Shea et al., Nature Communications, Vol. 7, P. 12763, (2016). ** S.N. Galyamin et al., J. Instrumentation, Vol. 13, P. C02012 (2018).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW061
About •	paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW066	Local Impedance Measurements Using the Orbit Bump Method at ALBA	impedance, storage-ring, betatron, simulation	240
	Z. Martí, G. Benedetti, T.F.G. Günzel, U. Iriso ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
	The orbit bump technique has been used at the ALBA Storage Ring to characterize with good precision the impedance of single machine elements, like the in-vacuum undulators or the CLIC stripline kicker. The results are compared with theoretical studies, as well as impedance measurements done at ALBA using other methods like the turn by turn betatron phase or from the analysis of the detuning slopes of the Transverse Mode Coupling Instability.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW066
About •	paper received ※ 14 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019
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MOPGW071	Resistive Wall Effects in the CLIC Beam Delivery System	luminosity, wakefield, collider, feedback	258
	D. Arominski, A. Latina, D. Schulte CERN, Meyrin, Switzerland
	Resistive wall wakefields are an important issue to study for future linear colliders. Wakefields in the Beam Delivery System (BDS) might cause severe multi-bunch effects, leading to beam quality and luminosity losses. The resistive wall effects depend on the beam pipe apertures and materials, which are optimised to limit the impact on the beam. This paper presents a study of this problem for the 380 GeV and 3 TeV beam parameters and optics of the Compact Linear Collider’s BDS. First, the optimisation of the beam pipe apertures to limit the impact of resistive wall effect on the beam quality is shown, then the luminosity and its quality are presented. Finally, the proposed design parameters are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW071
About •	paper received ※ 16 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW074	New Spiral Beam Screen Design for the FCC-hh Injection Kicker Magnet	kicker, impedance, injection, coupling	270
	A. Chmielinska, M.J. Barnes CERN, Geneva, Switzerland
	The injection kicker system for the Future Circular Collider (FCC-hh) must satisfy demanding requirements. To achieve low pulse ripple and fast field rise and fall times, the injection system will use ferrite loaded transmission line type magnets. The beam coupling impedance of the kicker magnets is crucial, as this can be a dominant contribution to beam instabilities. In addition, interaction of the high intensity beam with the real part of the longitudinal beam coupling impedance can result in high power deposition in the ferrite yoke. This gives a significant risk that the ferrite yoke will exceed its Curie temperature: hence, a suitable beam screen will be a critical feature. In this paper, we present a novel concept - a spiral beam screen. The fundamental advantage of the new design is a significant reduction of the maximum voltage induced on the screen conductors, thus decreased probability of electrical breakdown. In addition, the longitudinal beam coupling impedance is optimized to minimize power deposition in the magnet.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW074
About •	paper received ※ 26 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW122	Beam-based Measurement of Broadband Longitudinal Impedance at NSLS-II	impedance, simulation, diagnostics, storage-ring	400
	V.V. Smaluk, B. Bacha, G. Bassi, A. Blednykh BNL, Upton, Long Island, New York, USA
	Funding: Department of Energy Contract No. DE-SC0012704 Interaction of a particle beam with the vacuum chamber impedance is one of the main effects limiting the beam intensity in accelerators. Minimization of the impedance is an essential part of the vacuum chamber design for any new accelerator project. The impedance can be estimated experimentally by measuring beam dynamics effects caused by the beam-impedance interaction. Experience obtained at many accelerator facilities shows the beam-based measurements are often different from the pre-computed impedance budgets, the discrepancy of a factor of two or even more is not unusual. The measurements of broadband longitudinal impedance carried out at NSLS-II are discussed in comparison with the numerically simulated impedance budget.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW122
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPGW128	Simulation and Analysis of Wake Fields and Trapped RF Modes in Insertion Device Vacuum Chambers at the Canadian Light Source	simulation, undulator, insertion-device, insertion	414
	E.J. Ericson, D. Bertwistle, M.J. Boland CLS, Saskatoon, Saskatchewan, Canada M.J. Boland, M. Castillo Sosa University of Saskatchewan, Saskatoon, Canada D. Pelz RFS, Kilsyth, Australia
	Funding: CFI, NSERC, NRC, CIHR, the Province of Saskatchewan, WD, WESTGRID, Compute Canada, and the University of Saskatchewan The Canadian Light Source (CLS) synchrotron operates with four in-vacuum insertion devices, three in-vacuum undulators, and one in-vacuum wiggler. Presently, each of the devices occupies half of a straight section. The wiggler is unique in our ring as it is both in-vacuum and shares a straight section with an in-vacuum undulator. We have observed gap dependent beam instabilities in the undulator located in the straight section. In order to better understand the problem, the cause of the instabilities was investigated using 3D electromagnetic modelling. First, the ’trapped’ RF modes (natural resonances) for this undulator chamber, their Q value, and their peak frequencies were analysed using Eigenmode simulation. Secondly, beam excitation of the Eigenmodes was simulated with the Wakefield solver. Herein we present the results of this electromagnetic modelling.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW128
About •	paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPRB027	Progress of HEPS Accelerator System Design	storage-ring, cavity, booster, lattice	633
	P. He, J.S. Cao, F.S. Chen, J. Chen, H. Dong, D.Y. He, Y. Jiao, W. Kang, C.H. Li, J.Y. Li, F. Long, H.H. Lu, X. Qi, Q. Qin, H. Qu, J.Q. Wang, G. Xu, J.H. Yue, J. Zhang, J.R. Zhang, P. Zhang IHEP, Beijing, People’s Republic of China
	The 4th generation ring-based light sources, HEPS (High Energy Photon Source) 7BA lattice has been de-veloped at IHEP. This is 6Gev, 200mA machine which has horizontal emittance Ɛh around 60pm.rad to gain the high brilliance photon beam. this compact lattice design bring so many engineering challenges for accelerator magnets, vacuum components, beam diagnotice, etc. This paper will present the noval lattice design and subsystem design progress.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB027
About •	paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB036	Study on Beam-induced heating in injection section of Hefei Light Source	impedance, kicker, radiation, experiment	652
	D.R. Xu, W. Xu USTC/NSRL, Hefei, Anhui, People’s Republic of China
	Ceramic chambers distributed with metal belts on the inner surface are installed in the injection section at Hefei Light Source (HLS). Heating on the ceramics chambers has been observed during machine operation. An air compressor is used to cool these chambers due to concerns of overheating during top-up operation mode. To understand the sources of the heating, a series of experiments are performed with various beam currents and bunch filling patterns. The study shows that the heating is mainly caused by the narrow-band impedances of the ceramic chambers and their adjacent vacuum components.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB036
About •	paper received ※ 22 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB075	Radiation Limits on Permanent Magnets in CBETA	radiation, electron, permanent-magnet, focusing	745
	V.O. Kostroun, C.M. Gulliford Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	The Cornell Brookhaven Energy Recovery Linac Test Accelerator (CBETA), under construction at Cornell, uses Fixed Field Alternating Gradient (FFAG) Halbach magnets made from grade N35EH NdFeB. To reduce the 1% level magnetization errors in fabricated blocks to magnets with better than 0.001 field accuracy, iron wire shimming is necessary. This also limits magnetization changes by external influences to the ~1% level. The ambient radiation field present during CBETA operation can induce permanent magnet demagnetization. The radiation field arises from electrons in the beam halo hitting the vacuum chamber and from residual gas, Touschek and Intra-Beam scattering. The radiation dose rate due to electrons striking the vacuum chamber of a 4 cell straight section of CBETA FFAG magnets was calculated using the many particle Monte Carlo radiation code MCNP6.2. MCNP6.2 has a track-length heating tally for different particles and a collision heating tally that gives energy deposition/mass from all particles in the problem. Calculations show that electron loss has to be a fraction of a watt/m to keep the dose rate at an acceptable level during the accelerator lifetime.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB075
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPTS008	ESS RFQ: Construction Status and Power Couplers Qualification	rfq, cavity, coupling, pick-up	855
	O. Piquet, A.C. Chauveau, D. Chirpaz-Cerbat, M. Desmons, A.C. France, P. Hamel, B. Pottin CEA-IRFU, Gif-sur-Yvette, France A. Dubois, A. Gaget, Y. Le Noa, L. Napoly, M. Oublaid, G. Perreu CEA-DRF-IRFU, France
	The 352 MHz Radio Frequency Quadrupole (RFQ) for the European Spallation Source ERIC (ESS) will be de-livered during 2019. It is provided by CEA, IRFU, Sac-lay/France. It consists of five sections with a total length of 4.6 m and accelerates the proton beam from 75 keV up to 3.6 MeV. It will be feed with 1.6 MW peak power through two coaxial loop couplers. This paper will present the manufacturing status of the five sections and the qualification test of the RF power couplers.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS008
About •	paper received ※ 07 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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MOPTS022	Current Status of the MYRRHA Cavities	cavity, resonance, status, operation	892
	K. Kümpel, D. Bade, M. Busch, D. Koser, S. Lamprecht, N.F. Petry, H. Podlech, S. Zimmermann IAP, Frankfurt am Main, Germany
	The MYRRHA (Multi-purpose hYbrid Research Reac-tor for High-tech Applications) Project is a planned ac-celerator driven system (ADS) for the transmutation of long-living radioactive waste. In order test the reliability of the planned 17 MeV injector, a shortened injector with 5.9 MeV consisting of the ion source, a 4-Rod RFQ, 2 Quarter Wave Rebunchers (QWRs) and a total of 7 normal conducting CH structures is currently being installed in Louvein-la-Neuve (LLN, Belgium). Before the cavities can be tested with beam, they are subjected to so-called low power tests several times during the individual con-struction stages in order to be able to correct any devia-tions. This paper describes the status of the two Quarter Wave Rebunchers, which are currently in the process of copper plating and final acceptance, as well as the first two CH structures, the first of which is already being conditioned while CH 2 is still in preparation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS022
About •	paper received ※ 10 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS049	The First Replacement of the RF Window of the ACS Cavity	cavity, linac, operation, proton	971
	J. Tamura, Y. Kondo, T. Morishita JAEA/J-PARC, Tokai-mura, Japan F. Naito, M. Otani KEK, Tokai, Ibaraki, Japan Y. Nemoto Nippon Advanced Technology Co., Ltd., Tokai, Japan
	In 2013, the Annular-ring Coupled Structure (ACS) cavities were installed to the Japan Proton Accelerator Research Complex (J-PARC) linac. Since then, the ACS cavities have been stably running. Although any serious problem induced by the ACS RF window has not yet observed, we decided to replace the RF window of one ACS cavity, which is the eighteenth accelerating cavity in the order of beam energy (ACS18), by the newly manufactured one. The major motivations of the replacement are to check the surface condition of the RF window which have been under operation for nearly five years and to confirm the availability of the newly manufactured RF window. By making use of the summer maintenance period of 2018, we carried out the replacement. This was the first experience for us to replace the RF window installed to the ACS cavity in the linac accelerator tunnel. As for the removed RF window, there was no any abnormal warning found with the visual examination. At the starting up of the cavity’s operation after the maintenance period, we investigated how much time would be required for an RF conditioning. It took around fifty hours so that the peak RF power including the beam loading is stably input to the cavity through the new RF window. The ACS cavity with the new RF window is now stably operating.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS049
About •	paper received ※ 01 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS093	Ultra-High Vacuum Characterization of Molybdenum-Carbide Graphite for HL-LHC Collimators	collimation, site, proton, collider	1078
	F. Carra, C. Accettura, A. Bertarelli, G. Bregliozzi, G. Cattenoz, S. Redaelli, M. Taborelli CERN, Meyrin, Switzerland M. Beghi POLIMI, Milano, Italy J. Guardia Valenzuela Universidad de Zaragoza, Zaragoza, Spain
	Funding: This work has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No. 730871. Research supported by the HL-LHC project In view of the High-Luminosity upgrade of the Large Hadron Collider (LHC) collimation system, a family of novel molybdenum-carbide graphite (MoGr) composites was developed to meet the challenging requirements of HL-LHC beam-halo collimation, in particular the electrical conductivity and thermo-mechanical performances. The Ultra-High Vacuum (UHV) behaviour of this material was extensively characterized to assess its compatibility with the accelerator’s specifications. The results presented in this paper correlate the outgassing behaviour with the microscopic features of MoGr compared to other graphite-based materials. Residual gas analysis (RGA) was exploited to optimize post-production treatments.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS093
About •	paper received ※ 12 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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MOPTS094	Dust Analysis from LHC Vacuum System to Identify the Source of Macro-Particle-Beam-Interactions	beam-losses, operation, proton, dipole	1082
	L.K. Grob, A. Apollonio, C. Charvet, E. Garcia-Tabares Valdivieso, H. Kos, R. Schmidt CERN, Geneva, Switzerland C. Neves Hochschule Furtwangen, Furtwangen, Germany
	Since in 2010 the first sub-millisecond beam losses were observed at varying locations all along the LHC, it is well known that dust can interact with high-intensity proton beams and cause significant beam losses. Initially the sudden localized losses were enigmatic and coined the phrase ’unidentified falling objects’ (UFOs), which is still widely used. These very fast beam losses have resulted in hundreds of premature beam dumps and even magnet quenches since the start of LHC. So far, the only mitigation strategy involved an optimization of dump thresholds and the beneficial conditioning effect which leads to a reduction of the UFO rate over time. To understand the physics involved in these events and to allow an active diminution, it is essential to know the chemical composition and the size of the dust particulates interacting with the protons. The exchange of a dipole magnet offered the unique opportunity to collect dust samples from inside the LHC vacuum system. They were extracted from the various components and analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy to reveal size distribution and abundant elements. The results of this investigation will optimize the existing UFO models and the improved understanding of the phenomenon may help to prevent future performance limitations. This is also of relevance for future projects, in particular for the Future Circular Collider (FCC) under study.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS094
About •	paper received ※ 15 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019
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TUXXPLS3	The Design Optimization of the Dielectric Assist Accelerating Structure for Better Heat and Gas Transfer	cavity, multipactoring, embedded, lattice	1179
	S. Mori, M. Yoshida KEK, Ibaraki, Japan D. Sato AIST, Tsukuba, Ibaraki, Japan
	The dielectric-assist accelerating (DAA) structure is a dielectric-inserted normal-conducting cavity, which provides high Q value at room temperature. This accelerating structure is composed of dielectric disks and a dielectric cylindrical layer inserted in a copper cavity. For the realistic operation, the removal of heat from the dielectric cells and the vacuum evacuation of gas inside the cylindrical layers have not considered yet. In order to solve the problems, we propose the optimized design of the DAA structure, where the extended part of the dielectric disk is embedded in the copper cavity and the choke structure is applied. We show the result of the electromagnetic-field simulation of the extended DAA structure and the thermal simulation to clarify the relation between a duty factor and maximum temperature of the dielectric cells.
	Slides TUXXPLS3 [5.892 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUXXPLS3
About •	paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUYPLM3	Status of the MAX IV Accelerators	storage-ring, electron, sextupole, linac	1185
	P.F. Tavares, E. Al-Dmour, Å. Andersson, J. Breunlin, F.J. Cullinan, E. Mansten, S. Molloy, D.K. Olsson, D. Olsson, M. Sjöström, S. Thorin MAX IV Laboratory, Lund University, Lund, Sweden
	The MAX IV facility in Lund, Sweden, consists of three electron accelerators and their respective synchrotron radiation beamlines: a 3 GeV ring, which is the first implementation worldwide of a multi-bend achromat lattice, a 1.5 GeV ring optimized for soft X-Rays and UV radiation production and a 3 GeV linear accelerator that acts as a full-energy injector into both rings and provides electron pulses as short as 100 fs that produce X-rays by spontaneous emission in the undulators of the short-pulse facility (SPF). In this paper, we review the latest achieved accelerator performance and operational results.
	Slides TUYPLM3 [9.108 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUYPLM3
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPMP003	Development of Remote Handleable Axially Decoupled Radiation Resistant Vacuum Seal	target, interface, operation, electron	1233
	R.R. Nagimov, Y. Bylinskii, L. Egoriti, A. Gottberg, G.W. Hodgson, A.N. Koveshnikov, D. Yosifov TRIUMF, Vancouver, Canada
	Funding: ARIEL is funded by the Canada Foundation for Innovation (CFI), the Provinces of AB, BC, MA, ON, QC, and TRIUMF. TRIUMF receives federal funding via a contribution agreement with the NRC of Canada. Advanced Rare IsotopE Laboratory (ARIEL) facility is a major expansion of TRIUMF’s rare isotope research program. Aiming to triple the production of rare isotopes, ARIEL facility includes the new electron linac driver and two target stations for electron and proton beams. Particularities of ARIEL target stations design define the requirements for vacuum interfaces with both primary electron and proton beamlines and rare-isotope beamlines. None of the existing products fully met the requirements, driving the development of custom vacuum interfaces. The design of new vacuum seals is driven both by unique design specifications (limited amount of allowed axial forces, extreme radiation resistance, remote handleability and high repeatability) as well as limitations of the proposed design of beamline infrastructure in the target hall (limited available space and the choice of materials for certain components). This paper discusses preliminary results of the vacuum seal development and presents first results of prototype testing.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP003
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPMP004	Dynamic Pressure in the LHC - Influence of Ions Induced by Ionization of Residual Gas by Both the Proton Beam and the Electron Cloud	electron, proton, experiment, ECR	1236
	S. Bilgen, C. Bruni, B. Mercier, G. Sattonnay LAL, Orsay, France V. Baglin CERN, Geneva, Switzerland
	Funding: work supported by FCC project (CERN & LAL-CNRS-IN2P3) Ultra-High Vacuum is an essential requirement to reach design performances in high-energy particle colliders. For the future HL-LHC or FCC study, the understanding of the beam interactions with the vacuum chamber is fundamental to provide solutions to mitigate the pressure rises induced by electronic, photonic and ionic molecular desorption. Studies were performed on the ions, produced by molecular ionization generated by the proton beam and the electron cloud, and stimulating molecular desorption by the surface bombardment. In-situ measurements were carried out, on the LHC Vacuum Pilot Sector (VPS), to monitor the dynamic pressure, and to collect the electrical signals due to the electron cloud and to the ions interacting with the vacuum chamber walls. Experimental measurements of electrical signals recorded by copper electrodes were compared to calculations taking into account both the Secondary Electron Yield of copper and electron energy distribution. Finally, it seems that copper electrodes were not fully conditioned and an ion current could be estimated. THE LHC VACUUM PILOT-SECTOR PROJECT B. Henrist, V. Baglin, G. Bregliozzi, and P. Chiggiato, CERN, Geneva, Switzerland Proceedings of IPAC2014, Dresden, Germany.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP004
About •	paper received ※ 01 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPMP007	DYVACS (DYnamic VACuum Simulation) Code: Calculation of Gas Density Profiles in Presence of Electron Cloud	electron, proton, photon, experiment	1244
	G. Sattonnay, S. Bilgen, B. Mercier LAL, Orsay, France V. Baglin CERN, Meyrin, Switzerland
	The computation of residual gas density profiles in particle accelerators is an essential task to optimize beam pipes and vacuum system design. In a hadron collider such as the LHC, the beam induces dynamic effects due to ion, electron and photon-stimulated gas desorption. The well-known VASCO* code developed at CERN in 2004 (and then PyVASCO) is already used to estimate vacuum stability and density profiles in steady state conditions. Nevertheless, some phenomena are not taken into account such as the ionization of residual gas by the electron clouds. Therefore, we propose an upgrade of this code by introducing electron cloud maps* to estimate the electron density and the ionization of gas by electrons, leading to an increase of both electron- and ion-induced desorption. Results obtained with the new code (called DYVACS for DYnamic VACuum Simulation) will be compared to pressure measurements in the VPS sector**** of the LHC. * A. Rossi, Tech. Rep., LHC Proj. Note 341 I. Aichinger, et al arXiv:1707.07525 * T. Demma et al Phys. Rev. Acceler. and Beams 10, 114401 (2007) **** B. Henrist et al, Proc. IPAC2014, Dresden
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP007
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPMP013	New Design of Vacuum Chambers for Radiation Shield Installation at Beam Injection Area of J-PARC RCS	injection, radiation, damping, flattop	1255
	J. Kamiya, K. Kotoku, Y. Shobuda, T. Takayanagi, K. Yamamoto, T. Yanagibashi JAEA/J-PARC, Tokai-mura, Japan K. Horino, N. Miki Nippon Advanced Technology Co., Ltd., Tokai, Japan
	One of the issues in the J-PARC 3 GeV rapid cycling synchrotron is the high residual radiation dose around the beam injection point. A radiation shield is necessary to reduce radiation exposure of workers when maintenance is performed there. A space to install the radiation shield should be secured by newly designing a structure of the vacuum chamber at the injection point and the alumina ceramics beam pipes for the shift bump magnets. To make the space for the shield, the chamber is lengthened along the beam line and the cross-sectional shape is changed from circle to rectangle. The displacement and inner stress of the vacuum chamber due to atmospheric pressure was evaluated to be enough small by the calculation. For the ceramics beam pipe’s rf-shield, the damping resistor was effective to reduce the induced modulation voltages by the pulsed magnetic field.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP013
About •	paper received ※ 29 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPMP018	Feasibility Tests of a Vacuum System for SPring-8-II	photon, hardware, multipole, operation	1272
	K. Tamura, T. Bizen, M. Masaki, H. Ohkuma, M. Oishi, M. Shoji, S. Takahashi, Y. Taniuchi JASRI, Hyogo, Japan T. Bizen, M. Oishi, S. Takahashi RIKEN SPring-8 Center, Hyogo, Japan
	For SPring-8-II, the major upgrade of SPring-8, a test half-cell including permanent/electro magnets and a vacuum system was constructed, and hardware feasibility tests have been performed since 2017. Features of the SPring-8-II vacuum system are 1) introduction of the concept of a stainless steel 12 m-long integral chamber (LIC) with a welded structure, and 2) adoption of ex-situ baking of the chamber. The 12 m LIC with a narrow aperture, flangeless structure and a minimum number of bellows was designed so that the vacuum system could be installed without interference with the magnets of a narrow bore diameter aligned on girders with a severe packing factor. For replacement of the existing system with a new one in a short black-out period, the 12 m LIC is planned to be moved into the accelerator tunnel with keeping ultra-high vacuum (UHV) by closing thin gate valves at both ends, after evacuation to UHV by ex-situ baking and NEG activation. This presentation will overview the vacuum system, mainly the 12 m LIC, developed for the test half-cell, and describe the vacuum performance and the result of the assembly test conducted with the permanent/electro magnets.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP018
About •	paper received ※ 15 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019
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TUPMP019	Vacuum Performance of the NEG-coated Chamber for U#19 at PF-ring	photon, simulation, MMI, undulator	1276
	Y. Tanimoto, T. Honda, X.J. Jin, T. Nogami, R. Takai, M. Yamamoto KEK, Ibaraki, Japan
	At the Photon Factory storage ring (PF-ring) in KEK, a new APPLE-II type elliptically polarizing undulator (U#19) was installed in October 2018. The U#19 vacuum chamber is 4.1 meters in length, and the beam channel with a 15x90 elliptical profile and two cooling-water channels alongside were formed by extrusion of A6060-T6 aluminum alloy. The inner surface of the beam channel is coated with a Ti-Zr-V Non-Evaporable Getter (NEG) thin film, as it has a high effective pumping speed and a low Photon Stimulated Desorption (PSD) yield. After the installation of the U#19, the neighboring uncoated chambers and vacuum components were baked out at 200 °C for 44 hours, and then the NEG coating was activated at 160 °C for 48 hours. As a result, the pressures in the neighboring chambers reached as low as 10^-8 Pa. The conditioning of the vacuum chambers with irradiation of Synchrotron radiation evolved favorably as had been expected by a combined simulation of Synrad and Molflow, leading to a satisfactory recovery of the beam lifetime. Vacuum performance of the NEG-coated chamber was assessed especially by means of a residual gas analysis, and the properties of the NEG film were characterized by surface analyses including SEM, EDX, and XRD.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP019
About •	paper received ※ 16 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPMP021	Comparison of TiZrV Non-evaporable Getter Films Deposited by DC Magnetron Sputtering or Quantitative Deposition	site, target, interface, electron	1283
	X.Q. Ge, W. Li, J.Q. Shao, S. Wang, Y.G. Wang, Y. Wang, W. Wei, B. Zhang, Y.X. Zhang USTC/NSRL, Hefei, Anhui, People’s Republic of China
	Ti-Zr-V non-evaporable getter (NEG) films have been widely used in vacuum chambers of various accelerators since their discovery. Recently, we have used a new method called ’quantitative deposition’ to deposit Ti-Zr-V NEG films on nichrome substrates. The surface morphology and surface chemical bonding information were collected by scanning electron microscopy. Although the film deposited by DC magnetron sputtering has more uniform grain growth, smoother grain boundaries and higher porosity, the two films all have porous network structure and can be used as getter films.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP021
About •	paper received ※ 24 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPMP031	Research on Secondary Electron Emission Characteristics of Diamond-like Carbon Thin Films	electron, experiment, laser, gun	1306
	Y.X. Zhang, X.Q. Ge, W. Li, J.Q. Shao, S. Wang, Y.G. Wang, Y. Wang, W. Wei, B. Zhang, B.L. Zhu USTC/NSRL, Hefei, Anhui, People’s Republic of China
	In modern particle accelerators, the build-up of electron cloud is a main limiting factor for the achievement of high-quality beam. Among the techniques to mitigate it, coating the internal walls of the beam pipes with a thin film which has a low secondary electron yield (SEY) is considered to be one of the most effective means. From several earlier studies, it was found that diamond-like carbon (DLC) thin films are potential coatings. This paper is mainly about the research on secondary electron emission characteristics of DLC thin films. The secondary electron emission (SEE) tests were done at temperature of 298 K and vacuum pressure of 2×10^-9 Torr. Here, we obtained the characteristics of the SEE from DLC film coatings with different thickness under ultrahigh-vacuum (UHV) conditions. The maximum secondary electron yield (SEY), δmax, of the DLC thin films under different primary electron doses were also obtained, respectively.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP031
About •	paper received ※ 26 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPMP033	Design of the Neutron Imaging Differential Pumping Line at LLNL	neutron, target, shielding, simulation	1312
	J.A. Caggiano, D. Castronovo, P. Fitsos, D.J. Gibson, J. Hall, M.S. Johnson, R.A. Marsh, B. Rusnak LLNL, Livermore, California, USA
	Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. The neutron imaging system at LLNL is a radiographic capability for imaging objects with fast, quasi-monoenergetic neutrons at ≤1mm spatial resolution. The neutron production source is a deuteron beam (4 or 7 MeV) incident upon a rotating, high-pressure, windowless, pure-deuterium gas target. The windowless nature of the target combined with the high pressure leads to significant gas leakage upstream of the neutron production target. This leakage degrades the imaging quality by (1) increasing the depth-of-field blurring and (2) increasing the beam diameter and divergence in the transverse direction via angular straggling in the residual gas. To mitigate these effects, and guided by bench tests and simulations, we designed a differential pumping line (DPL) to ensure the highest quality imaging system. The system consists of three primary stages (chambers), each separated by carefully shaped apertures. These apertures can be long and thin with low-angle tapers due to the high quality of the beam optics (convergence at the target < 5mrad) and low emittance of the beam (~5 pi mm-mrad). The primary cascaded roots pumps are sized to remove >99% of the incoming mass flow in each stage, ensuring that by the third stage furthest from the target, turbomolecular pumps are able to operate in a nominal ~mTorr range. We anticipate full system testing with helium in mid 2019.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP033
About •	paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPMP035	Design of the Vacuum System of the FCC-ee Electron-Positron Collider	collider, photon, dipole, quadrupole	1319
	R. Kersevan, C. Garion CERN, Geneva, Switzerland
	The Future Circular Collider (FCC) Design Study includes the twin storage ring (FCC-ee) where electrons and positrons are stored and made to collide inside two detectors. The vacuum system of FCC-ee must be designed in order to deal with a lower-energy (45.6 GeV), high-current (1390 mA) Z-pole machine and at a later stage with a higher-energy (182.5 GeV) low-current (5.4 mA). The former machine is the most challenging one from the point of view of vacuum, since the photon-stimulated desorption (PSD) generated by the copious synchrotron radiation (SR) fans is quite large. While several concepts have been considered at the beginning, the design retained for the Conceptual Design Report (CDR) is one where the cross-section of the vacuum chamber (VC) in the arcs is a scaled-down version of the one implemented in the SUPERKEKB collider. Contrary to SUPERKEKB tough, the SR fans are absorbed by many short absorbers, with average spacing of 5.8 m. This allow a localization of the PSD gas load and to place lumped pumps in front of the SR absorbers, to maximize the pumping efficiency. The VC design is compatible with the design of the common-yoke dipoles and quadrupoles. The VC material is copper alloy. Optimization of the pressure profiles has been carried out by means of extensive coupled montecarlo simulations, for SR and molecular flow. For the higher energy versions of the machine, for which the SR spectra are characterized by critical energies well above the Compton edge, the localized absorbers facilitate also shielding the tunnel and any radiation-sensitive machine components from X-ray photon damage, by installing short high-Z material around the absorbers. The major features of the CDR relevant for vacuum will be highlighted in the paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP035
About •	paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPMP036	Results on the FCC-hh Beam Screen Sawtooth at the Kit Electron Storage Ring Kararesults on the Fcc-Hh Beam Screen Sawtooth at the Kit Electron Storage Ring Kara	photon, radiation, experiment, electron	1323
	L.A. Gonzalez, V. Baglin, I. Bellafont, P. Chiggiato, C. Garion, R. Kersevan CERN, Geneva, Switzerland I. Bellafont, F. Pérez ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain S. Casalbuoni, E. Huttel KIT, Eggenstein-Leopoldshafen, Germany
	Funding: * The European Circular Energy-Frontier Collider Study (EuroCirCol) project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant No 654305. In the framework of the EuroCirCol collaboration (work package 4 "Cryogenic Beam Vacuum System"), the fabrication of the FCC-hh beam screen (BS) prototype has been carried out with the aim of testing it at room temperature on the Karlsruhe Institute of Technology (KIT) 2.5 GeV electron storage ring KARA (KArlsruhe Research Accelerator) light source. The BS prototype was tested on a beamline installed by the collaboration, named as BEam Screen TEstbench EXperiment (BESTEX). KARA has been chosen because its synchrotron radiation (SR) spectrum, photon flux and power match quite well the one foreseen for the 50+50 TeV FCC-hh proton collider. The BS prototype (2 m in length) was manufactured according to the base line design (BD) of the FCC-hh BS. It implements a saw-tooth profile designed to absorb the SR generated at the bending magnets. Also, a laser-ablated anti-electron cloud surface texturing [2] was applied at the BS inner walls. We present here the results obtained at BESTEX and the comparison of the results obtained during irradiation of the saw-tooth profile at different geometric configurations. This activity has been carried out in the framework of the EuroCirCol collaboration (work package 4 "Cryogenic Beam Vacuum System").*
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP036
About •	paper received ※ 13 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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TUPMP037	Recent Developments of Monte-Carlo Codes Molflow+ and Synrad+	simulation, photon, synchrotron, synchrotron-radiation	1327
	R. Kersevan, M. Ady CERN, Geneva, Switzerland
	Molflow+ and Synrad+ are Monte Carlo simulation tools for ultra-high vacuum and synchrotron radiation, respectively. Over the years they have become a common tool for designing and analysing the vacuum system of particle accelerators. This contribution gives a short summary about new features added since IPAC-14. Some highlights: In traditional Monte Carlo simulations, one simulated ’virtual’ particle represents a given number of physical molecules or photons. This is a weakness where the pressure or flux of the simulated system spans across multiple orders of magnitude. Synrad now supports low flux mode, a weighed Monte Carlo technique where the represented number of photons is reduced at every reflection, providing significantly better statistics at low flux regions. As for Molflow+, angle maps allow recording the molecules, directional distribution at any point, and then desorb a reduced gas quantity according to the recording. In linear systems, this allows iterative simulations that have been proven to treat systems up to 7 orders of magnitude of pressure difference. Without the new technique the computing time would be prohibitively slow on desktop computers, which is what most users of the two codes use. Both codes now have a built-in geometry builder that allows creating simple models through a set of 3D operations, and modifying those imported from CAD tools. Molflow+ has recently become open source, and it has been made compatible with, and tested on different versions of Linux and macOS. Examples of application of Molflow+ to novel Beam Gas Curtain detector and the design of the FCC-ee vacuum system will be given, alongside with some benchmarking runs against data published in literature. M. Ady, R. Kersevan, "Introduction to the Latest Version of the Test-particle Monte Carlo Code Molflow+", Proc. IPAC’14, Dresden, Germany, June 2014, pp. 2348-2350.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP037
About •	paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPMP038	Summary of Modelling Studies on the Beam Induced Vacuum Effects in the FCC-hh	electron, photon, collider, synchrotron	1331
	I. Bellafont, R. Kersevan, L. Mether CERN, Geneva, Switzerland
	Funding: The European Circular Energy-Frontier Collider Study (EuroCirCol) project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant No 654305. EuroCirCol is a conceptual design study of a Future Circular Collider (FCC-hh) which aims to expand the current energy and luminosity frontiers that the LHC has established. The vacuum chamber of this 50 TeV, 100 km collider, will have to cope with unprecedented levels of synchrotron radiation power for proton colliders, dealing simultaneously with a tighter magnet aperture. Since the high radiation power and photon flux will release large amounts of gas into the system, the difficulty to keep a low level of residual gas density increases considerably compared with the LHC. This article presents a study of the beam induced vacuum effects for the FCC-hh novel conditions, the different phenomena which, owing to the presence of the beam, have an impact on the vacuum level of the accelerator. To achieve this, a novel beam screen has been proposed, featuring specific mitigating measures aimed at dealing with the beam induced effects. It is concluded that thanks to the new beam screen design, the vacuum level in the FCC-hh shall be adequate, allowing to reach the molecular density requirement of better than 10¹⁵ H₂/m3 with baseline beam parameters within the first months of conditioning.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP038
About •	paper received ※ 10 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPMP041	Preliminary Design of RF-Shielded Bellows	wakefield, interface, shielding, experiment	1341
	Y.T. Huang, C.K. Chan, C.-C. Chang, C.M. Cheng, P.J. Chou, Y.C. Yang NSRRC, Hsinchu, Taiwan
	A new design of RF-shielded bellows is proposed for the TPS to alleviate wake field effects and Joule heating resulting from contact resistance at the contact interface of sliding two dissimilar metals. Most efforts are put into controlling corrosion which is regarded as the main cause of electrical contact degradation. Rh-Au is chosen as a mating interface because they are stable under high temperature condition. Experimental tests are made to find an effective plating thickness of Rh and Au and to determine a suitable normal load applicable on the Rh-Au interface. A preliminary design of RF-shielded bellows that can sustain thousands of cycles during their lifetime is under testing.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP041
About •	paper received ※ 06 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPMP042	The Beam Cleaning Analysis for the TPS Vacuum System	MMI, radiation, operation, ECR	1344
	Y.C. Yang, C.K. Chan, C.-C. Chang, A.Y. Chen, J.-Y. Chuang, C.H. Huang NSRRC, Hsinchu, Taiwan
	Commissioning for the TPS, a low-emittance 3-GeV synchrotron ring, started in December 2014 and is now currently operating in top-up mode at 400mA for users. Until the last machine shut down in December 2018, a total beam dose of 4919 Ah was accumulated and the beam cleaning effect decreased the dynamic pressure to 1.5×10^-11 Pa/mA. During past years operation, several vacuum chambers were replaced to improve vacuum performance and avoid exposure to synchrotron radiation from insertion devices. In this paper, the beam cleaning evolution of new vacuum sections will be discussed and compared with experience in the rest of the storage ring. A particular cleaning evolution could be predicted and can be referenced for machine shutdown planning in the future.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP042
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPMP044	Special Aluminum Gasket Sealing of Non-circular Profile Flanges for the Accelerator UHV Systems	impedance, photon, experiment, emittance	1347
	G.Y. Hsiung NSRRC, Hsinchu, Taiwan
	Most of the beam ducts for the accelerators are not regularly the circular profile. Unfortunately, the conflat (CF-) flanges and the gaskets with non-circular profile were not commercially available. Besides, additional RF-contact bridges between the flanges must be built in for mitigating the impedance from the flange-gaps. In this presentation, various types of the aluminum (Al-) gaskets designed for the non-circular profile Al-flanges for the accelerator ultrahigh vacuum (UHV) systems are introduced. The surface of the Al-flange is flat to accommodate the special Al-gasket with knife edges for the sealing. Both the flange and gasket are manufactured by the oil-free Ethanol-CNC-machining process that any non-circular profile, e.g. rectangular, race-track, key-hole, etc., flanges can be precisely produced. The inner diameters of the gasket just suits those of the flanges that the impedance from the gap is significantly reduced. The flanges and gaskets after oil-free machining can be assembled immediately without any chemical cleaning. The experimental results for the as-mentioned non-circular profile Al-flanges reveal the UHV quality at pressure < 20 nPa after vacuum baking.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP044
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPMP050	Conceptual Design of the Diamond-II Vacuum System	photon, storage-ring, target, controls	1362
	M.P. Cox, C. Burrows, A.G. Day, J.A. Dymoke-Bradshaw, R.K. Grant, N.P. Hammond, X. Liu, A.G. Miller, H.S. Shiers, N. Warner DLS, Oxfordshire, United Kingdom
	The conceptual design of the vacuum system for the Diamond-II storage ring upgrade is described. Due to the small vessel cross section, typically 20 mm inside diameter (ID), and the consequent conductance limitation, distributed pumping is provided by non-evaporable getter (NEG) coating supplemented by ion pumps at high gas load locations. In-situ bakeout is incorporated to allow rapid recovery from both planned vacuum interventions and unplanned vacuum events. The vacuum vessels are constructed mainly from copper alloy while stainless steel is used in regions of AC magnets requiring low electrical conductivity. The proposed layout, engineering and build sequence of the vacuum system are described along with gas flow simulations confirming the vacuum performance advantages of NEG-coated vessels compared with uncoated vessels.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP050
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPMP054	Investigations on Cryopanels in the Room Temperature Heavy Ion Synchrotron SIS18	cryogenics, heavy-ion, synchrotron, operation	1372
	L.H.J. Bozyk, S. Aumüller, P.J. Spiller GSI, Darmstadt, Germany
	The heavy ion synchrotron SIS18 at GSI will serve as injector ring for the FAIR-facility and provide high intensity heavy ion beams. The operation of such beams requires the usage of low charge states, which have high cross sections for ionization. To overcome this issue, many upgrade measure have been realized in the past decade, such as the installation of an ion catcher system with low desorption surfaces and coating 65% of the circumference of SIS18 with NEG to lower the static gas pressure. Since the vacuum dynamics during operation prevent the achievement of the intensity goals for FAIR, new concepts have to be developed, to increase the beam intensity. One idea is the installation of additional pumping speed in the form of cryogenic surfaces. Heavy residual gas components, which have the highest ionization cross sections can be cryopumped at moderate temperatures, i.e. already at 50-80 K. In fact, the only typical residual gas component which can not be pumped via cryosorption in this temperature regime is Hydrogen, which has a factor 50 lower ionization cross sections than Argon, the heaviest residual gas component. In this paper, we present a study of the integration of cryopanels into the vacuum chambers of SIS18.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP054
About •	paper received ※ 13 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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TUPMP056	LANSCE Vacuum System Improvements in the Last ~10 Years	operation, neutron, linac, status	1375
	T. Tajima, J.E. Bernal, M.J. Borden, J.P. Chamberlin, F.A. Martinez, J.F. O’Hara, A. Poudel, K.A. Stephens LANL, Los Alamos, New Mexico, USA
	Funding: DOE/NNSA The Los Alamos Neutron Science Center (LANSCE) accelerator started its operation in 1972. To mitigate the vulnerability due to old equipment and to restore the 120 Hz operation capability we lost a while ago, we have gone through a refurbishment / risk mitigation project since 2007. This paper summarizes the improvements in the vacuum systems in the last ~10 years and shows some data on the downtimes caused by vacuum failures. The refurbished equipment is significantly more maintainable and will contribute to extend the life of this old accelerator, but it has been a challenge to reduce the downtime. Some examples that caused a long downtime will be described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP056
About •	paper received ※ 24 May 2019 paper accepted ※ 26 May 2019 issue date ※ 21 June 2019
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TUPGW003	Sirius Status Update	storage-ring, booster, alignment, controls	1381
	A.R.D. Rodrigues, F.C. Arroyo, J.F. Citadini, R.H.A. Farias, J.G.R.S. Franco, R. Junqueira Leão, L. Liu, S.R. Marques, R.T. Neuenschwander, C. Rodrigues, F. Rodrigues, R.M. Seraphim, O.H.V. Silva, F.H. de Sá LNLS, Campinas, Brazil
	Sirius is a 4th generation 3 GeV low emittance electron storage ring that is in its final installation phase at the Brazilian Center for Research in Energy and Materials (CNPEM) campus in Campinas, Brazil. Presently the injector installation is complete, and the storage ring installation is being finalized. Most subsystems are under test and tuning in real working conditions. Six beamlines are also under construction. In this paper we report on the Sirius main subsystems installation status.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW003
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW009	THE ESRF FROM 1988 TO 2018, 30 YEARS OF INNOVATION AND OPERATION	operation, SRF, injection, emittance	1400
	J.-L. Revol, L. Farvacque, L. Hardy, P. Raimondi ESRF, Grenoble, France
	In 1988, eleven European countries joined forces to build the European Synchrotron Facility in Grenoble [France]. The ESRF was the first third-generation light source worldwide. After 30 years of innovation and user operation, the present storage ring was shut down to leave room for a new and brighter source. This paper describes the evolution of the facility from its origin to the Ex-tremely Bright Source (EBS). Firstly, the operational aspects including reliability and beam modes are consid-ered. This is followed by the presentation of the progress of lattice and the implementation of top-up. Finally, the development of the radio frequency and vacuum systems are discussed. To conclude, the lessons learned from 30 years operation are summarized, especially in view of EBS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW009
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW014	Characterization and Implementation of the Cryogenic Permanent Magnet Undulator CPMU17 at Bessy II	undulator, laser, feedback, operation	1415
	J. Bahrdt, W. Frentrup, S. Gottschlich, S. Grimmer, M. Huck, C. Kuhn, A. Meseck, C. Rethfeldt, M. Scheer, B. Schulz HZB, Berlin, Germany E.C.M. Rial DLS, Oxfordshire, United Kingdom
	In fall 2018, the cryogenic undulator CPMU17 was installed in BESSY II. Before installation, the undulator was characterized with an in-vacuum Hallprobe bench and an in-vacuum moving wire. Both systems were developed at HZB. The commissioning of the device included the orbit and tune corrections, optimization of the injection, characterization of the heat dissipation, tuning the Landau cavities for a reduction of the heat dissipation in the taper sections (temperatures below 60°C) and testing of the machine protection system. The undulator is ready to deliver light for beamline commissioning. Spectral tuning on a high undulator harmonic (longitudinal taper and alignment of e-beam orbit and undulator axis) will be done as soon as the DCM is operational.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW014
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW015	Petra III Operation and Studies 2018	operation, impedance, undulator, radiation	1419
	M. Bieler, I.V. Agapov, Y.-C. Chae, J. Keil, G.K. Sahoo, R. Wanzenberg DESY, Hamburg, Germany
	At DESY the Synchrotron Light Source PETRA III offers scientists outstanding opportunities for experiments with hard X-rays of exceptionally high brilliance since 2009. This paper describes the operational schedule, the operational statistics and the most important beam studies done at PETRA III in 2018.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW015
About •	paper received ※ 26 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPGW017	Superconducting Undulator Coils with Period Length Doubling	undulator, FEM, operation, storage-ring	1426
	S. Casalbuoni, N. Glamann, A.W. Grau, T. Holubek, D. Saez de Jauregui KIT, Eggenstein-Leopoldshafen, Germany
	Funding: Work supported by the German government in the BMBF-project Superconducting ’Insertion Device Technologies for Ultra-Low-Emittance Light Sources’ (05K12CK1) Only since few years it has been demonstrated experimentally that NbTi based superconducting undulators (SCUs) have a higher peak field on axis for the same gap and period length in operation with electron beam with respect to permanent magnet undulators (even the ones in vacuum and cooled to cryogenic temperatures). Another advantage of NbTi based SCUs with respect to permanent magnet devices is radiation hardness, widely demonstrated for NbTi magnets, which is and will become an increasingly important issue with the small gaps in the newest machines as round beam storage rings and FELs. Moreover, SCU technology allows switching of the period length by changing the current direction in one of separately powered subset of winding packages of the superconducting coils. This feature further broadens the energy range of the emitted photons, required by the different beamlines. To this end 0.5 m long superconducting undulator coils with switchable period length between 17 mm and 34 mm have been developed. In this contribution we describe the design and report on the quench tests, as well as on the magnetic field measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW017
About •	paper received ※ 25 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPGW019	Progress of the BESSY VSR Cold String Development and Testing	cavity, GUI, simulation, experiment	1434
	H.-W. Glock, V. Dürr, F. Glöckner, J. Knobloch, M. Tannert, A.V. Vélez, D. Wolk, N. Wunderer HZB, Berlin, Germany J. Guo, R.A. Rimmer, H. Wang JLab, Newport News, Virginia, USA
	The so-called VSR (Variable Storage Ring) upgrade of the 3rd gen. light source BESSY II will provide the capability to simultaneously store long (about 20 ps rms length) and short (1 ps or less) bunches in the ring. This will be accomplished by inserting a module with four superconducting cavities, two of them operating at 1.5 GHz as the third harmonic of the 500 MHz driving RF, two at 1.75 GHz. The "cold" string of those four cavities also includes supporting and connecting devices, as there will be: - three intermediate bellows, all shielded against leaking fundamental mode cavity fields, one additionally acting as a collimator for incident synchrotron light; - two tuneable bellows at the module ends; - two warm end groups outside the module, housing toroidal dielectric wake field absorbers, another bellow and a vacuum pump connection. The recent design progress of those components will be reported, including a description of a beam test planned for the central collimating shielded bellow.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW019
About •	paper received ※ 22 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPGW059	Studies of The Electron Beam Lifetime in Solaris Electron Storage Ring	electron, storage-ring, cavity, scattering	1541
	R. Panas, A.M. Marendziak, A.I. Wawrzyniak, M. Wisniowski Solaris National Synchrotron Radiation Centre, Jagiellonian University, Kraków, Poland
	Solaris storage ring is a recently constructed and commissioned machine operated in decay mode. With total accumulated beam dose near to 1000 A.h the measured total lifetime has reached 16 h for 270mA of a stored current. In this paper, the beam lifetime studies are presented using measured residual gas analysis and vertical scraper position for tuned and detuned Landau cavities. It shows that for stable beam the lifetime is dominated by the interaction of the electron with residual gas (vacuum lifetime) and between electrons interaction within a bunch (Touschek lifetime). The estimated vacuum, Touschek and total beam lifetimes from theoretical analysis are also compared with the measured beam lifetime.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW059
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW069	Insertion Devices for the Day-One Beamlines of ILSF	undulator, wiggler, storage-ring, polarization	1561
	M. Hadad Shahid Beheshti University, Tehran, Iran S. Dastan, M. Hadad, J. Rahighi, M. Razazian, F. Saeidi, S. Yousefnejad ILSF, Tehran, Iran
	The Iranian Light Source Facility (ILSF) is a new 3 GeV synchrotron radiation laboratory with ultralow emittance of 270 pm-rad, which is in the design stage. Seven beamlines are planned to start operation with several different insertion devices installed in the storage ring either from "day one" or within the first year of operation. The most operational undulator for polarized radiations -Apple II- has been deliberated for the solid state electron spectroscopy, the Spectromicroscopy and the ARPES beamlines. The hybrid wigglers for the XPD and the EXAFS beamlines and in-vacuum undulators for Macromolecular Crystallography and SCD beamlines have been chosen too. The emission of these IDs covers a wide spectral range extending from hard X-rays to UV. Pre-design of the IDs were already done in ILSF. The main parameters of magnetic design as well as radiation parameters for the first phase of ILSF insertion devices have been described in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW069
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW082	Impedance of the Flange Joints With the RF Contact Spring in NSLS-II	impedance, storage-ring, cavity, damping	1597
	A. Blednykh, B. Bacha, G. Bassi, C. Hetzel, B.N. Kosciuk, T.V. Shaftan, V.V. Smaluk, G.M. Wang BNL, Upton, Long Island, New York, USA
	Funding: This work was supported by Department of Energy Contract No. DE-SC0012704 Since the beginning of the NSLS-II commissioning, temperature of the vacuum components has been moni-tored by the Resistance Temperature Detectors located predominantly outside of the vacuum enclosure and at-tached to the chamber body. Temperature map helps us to control overheating of the vacuum components around the ring especially during the current ramp-up. The average current of 475mA has been achieved with two main 500MHz RF cavities and w/o harmonic cavities. Effect of the RF shielded flanges on local heat and on the longitu-dinal beam dynamics is discussed in details.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW082
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW088	Removal and Installation Planning for the Advanced Light Source - Upgrade Project	storage-ring, MMI, injection, shielding	1609
	D. Leitner, P.W. Casey, K. Chow, D.F. Fuller, M. Leitner, A.J. Lodge, M. Lopez, J. Niu, P. Novak, C. Steier, S.P. Virostek, W.L. Waldron LBNL, Berkeley, California, USA
	The ALS-U project is a proposed upgrade to the Advanced Light Source (ALS) at Berkeley Lab that aims to deliver diffraction limited performance in the soft x-ray range. By lowering the horizontal emittance to about 70 pm rad, the brightness for soft x-rays will increase two orders of magnitude compared to the current ALS. The design utilizes a nine-bend achromat lattice, with reverse bending magnets and on-axis swap-out injection utilizing an accumulator ring. This paper will describe the preliminary plans for the installation of the new three-bend achromat accumulator ring (AR) in the existing tunnel and for replacing the current storage ring with the new nine-bend achromat lattice. The AR will be installed during regular maintenance shutdowns while the ALS continues to operate. The SR will be replaced during a nine months installation period followed by three months of commissioning during the twelve darktime period.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW088
About •	paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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TUPGW097	Design Progress of ALS-U, the Soft X-ray Diffraction Limited Upgrade of the Advanced Light Source	emittance, lattice, cavity, storage-ring	1639
	C. Steier, Ph. Amstutz, K.M. Baptiste, P.A. Bong, E.S. Buice, P.W. Casey, K. Chow, S. De Santis, R.J. Donahue, M.P. Ehrlichman, J.P. Harkins, T. Hellert, M.J. Johnson, J.-Y. Jung, S.C. Leemann, R.M. Leftwich-Vann, D. Leitner, T.H. Luo, O. Omolayo, J.R. Osborn, G. Penn, G.J. Portmann, D. Robin, F. Sannibale, C. Sun, C.A. Swenson, M. Venturini, S.P. Virostek, W.L. Waldron, E.J. Wallén LBNL, Berkeley, California, USA
	Funding: This work was 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 project to upgrade the Advanced Light Source to a multi bend achromat lattice received CD-1 approval in 2018 marking the end of its conceptual design phase. The ALS-U design promises to deliver diffraction limited performance in the soft x-ray range by lowering the horizontal emittance to about 70 pm rad resulting in two orders of magnitude brightness increase for soft x-rays compared to the current ALS. The design utilizes a nine bend achromat lattice, with reverse bending magnets and on-axis swap-out injection utilizing an accumulator ring. This paper presents recent design progress of the accelerator, as well as new results of the mature R&D program.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW097
About •	paper received ※ 21 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPGW108	Characterization of NEG Coatings for SLS 2.0	GUI, impedance, resonance, coupling	1662
	M.M. Dehler, A. Citterio PSI, Villigen PSI, Switzerland S. Alberti, J.P. Hogge SPC-EPFL, Lausanne, Switzerland M. Hahn, H.P. Marques ESRF, Grenoble, France X.Y. Liu USTC/NSRL, Hefei, Anhui, People’s Republic of China
	To limit desorption and ameliorate pumping of the narrow 20 mm aperture vacuum chamber of SLS2.0, it is planned to fully coat it with nonevaporable getter (NEG) material. NEG coating can be produced with different structural characteristics, from dense films to columnar growth, with corresponding distinct electrical properties affecting the machine impedance and the instability threshold of the accelerator. In order to evaluate and characterize the coating process for geometries similar to the SLS chamber, we measured the resonance properties of coated and uncoated shorted waveguide pieces. First tests were done with standard X band waveguides at 12 and 7 GHz. Test setups using elliptical cross sections are in preparation, also for higher frequencies allowing the characterization of thin NEG layers. The final goal is to have a standardized process to test of samples coated by external producers. We describe the setups and first results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW108
About •	paper received ※ 10 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW109	Conceptual Design of Vacuum Chamber for SPS-II Storage Ring	storage-ring, photon, impedance, emittance	1666
	T. Phimsen, S. Chaichuay, N. Juntong, P. Klysubun, S. Prawanta, P. Sudmuang, P. Sunwong SLRI, Nakhon Ratchasima, Thailand R. Deepan, A. Khamkham Suranaree University of Technology, Nakhon Ratchasima, Thailand
	The SPS-II is a 3 GeV ultralow emittance light source which is now under studied and designed by Thailand Synchrotron Light Research Institute (SLRI). The SPS-II storage ring is based on Double-Triple Bend Achromat (DTBA) cell with a circumference of 321.3 m aiming for horizontal emittance of less than 1 nm-rad. The compact lattice leaves narrow space for vacuum components. The small gap between poles of the magnets requires narrow vacuum chambers and limits the conductance of the chambers. The chambers will be made by stainless steel with a thickness of 1.5 mm. the cross section of beam duct is 40 mm × 16 mm elliptical shape. The bending chamber is designed as a long triangular chamber such that photon absorber can be installed as far from the light source as possible to lower the power density of the heat load. The overview of designed vacuum system for the SPS-II is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW109
About •	paper received ※ 14 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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TUPRB004	Magnetic Measurements of Insertion Devices Using the Vibrating Wire Technique	experiment, simulation, insertion-device, hardware	1683
	C.K. Baribeau, D. Bertwistle, E.J. Ericson, J.T. Gilbert, T.M. Pedersen CLS, Saskatoon, Saskatchewan, Canada
	The commissioning of new in-vacuum insertion devices (ID) at the Canadian Light Source has motivated the assembly and development of a vibrating wire system. The advantage of the technique is that it is a sensitive magnetic measurement instrument at relatively low cost. Moreover, most hall probe systems require transverse access, which is often not available for in-vacuum or Delta-like devices. It is comparatively simple to string a taut wire through the gap of an in-vacuum ID. We describe the experimental challenges in mapping the field of an 80 mm period in-vacuum wiggler, IVW80, using the vibrating wire technique, and compare results against simulation and data obtained from Hall probe measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB004
About •	paper received ※ 08 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPRB006	Effect of Electrostatic Deflectors and Fringe Fields on Spin for Hadron Electric Dipole Moment Measurements on Storage Rings	storage-ring, dipole, polarization, controls	1691
	J. Michaud, J.-M. De Conto, Y. Gómez Martínez LPSC, Grenoble Cedex, France
	The observed matter-antimatter asymmetry in the universe cannot be explained by the Standard Model. An explanation is a non-vanishing Electric Dipole Moment of subatomic particles. The JEDI (Jülich Electric Dipole moment Investigations) collaboration is preparing a direct EDM measurement of protons and deuterons first at the storage ring COSY (COoler SYnchrotron) and later at a dedicated storage ring. To achieve this, one needs a stable polarization, i.e. around 1000 seconds for spin coherence time. One source of decoherence are the electrostatic deflectors, and this must be quantified. We developed an analytical model for cylindrical deflectors, including fringe fields, and the associated beam and spin transfer functions, integrated over the deflector. All boundaries (including ground) are considered, giving a realistic, accurate field map up to any order. We get universal formulas, the only adjustable parameter being the deflector gap/radius ratio, all other terms being numerical. This has been implemented in BMAD. We present the mathematical, physical and numerical developments, as well as results for a proton storage ring.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB006
About •	paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPRB015	Cryogenic, in-Vacuum Magnetic Measurement Setup for Superconducting Undulators	undulator, detector, GUI, synchrotron	1709
	A.W. Grau, S. Casalbuoni, N. Glamann, D. Saez de Jauregui KIT, Eggenstein-Leopoldshafen, Germany
	The magnetic field quality has a strong impact on the performance of insertion devices (IDs) when installed in synchrotron light sources. Superconducting IDs have the advantage to produce a higher magnetic peak field for a given gap and period length than IDs assembled with permanent magnets. Before installation of a superconducting ID in a synchrotron light source it is of fundamental importance to characterize the magnetic properties by accurate field and field integral measurements. We follow this aim within our R&D program for superconducting undulators (SCUs). In this contribution, we describe the equipment and the challenges of a cryogenic, in vacuum measurement setup to perform magnetic measurements of the local field, the field integrals and the multipole components of in vacuum SCUs assembled in the final cryostat.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB015
About •	paper received ※ 29 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPRB021	Undulator Radiation Dose Caused by Synchrotron Radiation at the European XFEL	undulator, radiation, FEL, simulation	1724
	S. Liu DESY, Hamburg, Germany Y. Li, F. Wolff-Fabris EuXFEL, Hamburg, Germany
	Radiation damage of the undulators is a big concern for the light sources. At the European XFEL (EuXFEL), dosimeters based on on-line Radfets are used for the un-dulator radiation dose measurements. However, since the Radfets are not only sensitive to the electrons and neu-trons but also to the photons, it can capture the synchro-tron radiation (SR) generated in the undulators, which is not considered to be the main source for undulator radia-tion damage. Therefore, it is important to estimate the contribution of synchrotron radiation to the radiation doses measured by the Radfets. For this purpose, we have first calculated the synchrotron radiation profile using SPECTRA, and then put the profile into the tracking code BDSIM to track it through the whole undulator beam line. The radiation doses from SR have been simulated and compared with the measured values. The differences in the radiation doses measured by the Radfets before and after Pb shielding will also be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB021
About •	paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPRB022	Triple Period Undulator	undulator, radiation, photon, operation	1728
	A. Meseck, J. Bahrdt, W. Frentrup, M. Huck, C. Kuhn, C. Rethfeldt, M. Scheer HZB, Berlin, Germany E.C.M. Rial DLS, Oxfordshire, United Kingdom
	Insertion devices are one of the key components of modern synchrotron radiation facilities. They allow for generation of radiation with superior properties enabling experiments in a variety of disciplines, such as chemistry, biology, crystallography and physics to name a few. For future cutting edge experiments in soft and tender x-rays users require high flux and variable Polarization over a wide photon energy range independent of other desired properties like variable pulse length, variable timing or Fourier transform limited pulses. In this paper, we propose a novel ID-structure, called Triple Period Undulator (TPU), which allow us to deliver a wide energy range from a few ten eV to a few keV at the same beamline with high flux and variable Polarization. The TPU are particularly interesting in context of BESSY III, the successor facility of BESSY II.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB022
About •	paper received ※ 15 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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TUPRB040	Development of Coherent Terahertz Wave Sources and Transport Systems at LEBRA Linac	FEL, linac, electron, radiation	1775
	T. Sakai, K. Hayakawa, Y. Hayakawa, K. Nogami, Y. Sumitomo, T. Tanaka LEBRA, Funabashi, Japan H. Ogawa, N. Sei AIST, Tsukuba, Ibaraki, Japan
	Funding: This work was supported by JSPS KAKENHI (Grant-in-Aid for Young Scientists (B)) Grant Number JP16K17539 and JP16H03912. Development of a 125 MeV S-band electron linac for the generation of Free Electron Laser (FEL), Parametric X-ray Radiation (PXR) and coherent terahertz waves (THz waves) has been underway at LEBRA of Nihon University as a joint research with KEK and National Institute of Advanced Industrial Science and Technology (AIST). The high power coherent transition radiation (CTR), coherent edge radiation (CER) and the coherent synchrotron radiation (CSR) wave sources development has been carried out since 2011 at LEBRA. The transport systems of the each THz wave were installed in the vacuum chamber on the downstream side of the 45 degrees bending magnet of the PXR and FEL beam-line. In particular, a CER of the generated the FEL beam line can also be guided without disturbing the FEL oscillations. Additionally, a part of the mirror of the transport optical system is constructed using Indium Tin Oxide (ITO) mirror with the optimized for the transport of the THz wave. In this report, construction of the THz transport beam lines and the property of the THz lights are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB040
About •	paper received ※ 19 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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TUPRB055	First Results of the IVU16 Prototype Undulator Measurements	FEL, undulator, MMI, SRF	1808
	C. Yu, Y.Z. He, X. Hu, Z. Jiang, M.F. Qian, Y.M. Wen, S. Xiang, L. Yin, J.D. Zhang, W. Zhang, Q.G. Zhou SINAP, Shanghai, People’s Republic of China H.X. Deng, B. Liu, D. Wang SARI-CAS, Pudong, Shanghai, People’s Republic of China H.F. Wang, Z.T. Zhao SSRF, Shanghai, People’s Republic of China
	The Shanghai Synchrotron Radiation Facility (SSRF) has developed a 16 mm period length, 4 mm gap, in-vacuum undulator (IVU) that is planned to be installed and tested in the 1.5 GeV SXFEL-SBP beam line. This paper will describe the main parameters of the undulator and the key design choices that have been made. The first undulator prototype was assembled and magnetically tested. First measurements with vacuum chamber will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB055
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPRB072	Compact APPLE X for Future SXL FEL and 3 GeV Ring at MAX IV Laboratory	undulator, polarization, photon, FEL	1833
	H. Tarawneh, P. N’gotta, L.K. Roslund, A. Thiel, K. Åhnberg MAX IV Laboratory, Lund University, Lund, Sweden
	An overview of the design of compact elliptically polarizing undulator with small round magnetic gap to provide full polarization control of synchrotron radiation in a more cost effective manner and consuming less built in space than the state of the art devices. This type of undulator is meant as source for the potential future Soft X-ray (SXL) FEL beamline using the linear accelerator at MAX IV. In addition, it offers new capabilities for future beamlines at the 3 GeV ring to use full polarization control to photon energies using the fundamental harmonic which are not attainable with today’s technology of the out-of-vacuum insertion devices at 3 GeV beam energy.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB072
About •	paper received ※ 30 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPRB081	Beam Motion and Photon Flux Dips during Injection at the Taiwan Photon Source	injection, kicker, photon, betatron	1848
	C.H. Huang, H.-P. Chang, C.H. Chen, Y.-S. Cheng, P.C. Chiu, C.-S. Fann, K.T. Hsu, K.H. Hu, C.Y. Liao, Y.-C. Liu, C.Y. Wu NSRRC, Hsinchu, Taiwan
	The Taiwan photon source (TPS) is a 3 GeV synchrotron light source now in routine operation at the NSRRC. At the beginning of beam commissioning, significant photon flux dips could be observed at injection due to a blow-up of the beam size. To eliminate this transient effect, all four kickers were rematched. The leakage field was shielded and the induced current loops at vacuum chambers in the injection area were also eliminated. These efforts reduced the horizontal betatron oscillations and orbit distortions to around one-tenth. In order to decrease the recovery time of photon dips during injection, the operational chromaticity was reduced to improve incoherent effects. After all those improvements, the photon flux dips during injection dropped to 30 % and the recovery time to less than 1 msec.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB081
About •	paper received ※ 17 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPRB083	Status of Clara Front End Commissioning and First User Experiments	laser, experiment, linac, diagnostics	1851
	D. Angal-Kalinin, A.D. Brynes, R.K. Buckley, S.R. Buckley, R.J. Cash, H.M. Castaneda Cortes, J.A. Clarke, P.A. Corlett, L.S. Cowie, K.D. Dumbell, D.J. Dunning, B.D. Fell, P. Goudket, A.R. Goulden, S.A. Griffiths, J. Henderson, F. Jackson, J.K. Jones, N.Y. Joshi, S.L. Mathisen, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, A.J. Moss, B.D. Muratori, T.C.Q. Noakes, T.H. Pacey, M.D. Roper, Y.M. Saveliev, D.J. Scott, B.J.A. Shepherd, R.J. Smith, E.W. Snedden, M. Surman, N. Thompson, C. Tollervey, R. Valizadeh, D.A. Walsh, T.M. Weston, A.E. Wheelhouse, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom A.D. Brynes, J.A. Clarke, K.D. Dumbell, D.J. Dunning, P. Goudket, F. Jackson, J.K. Jones, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, A.J. Moss, B.D. Muratori, T.C.Q. Noakes, Y.M. Saveliev, D.J. Scott, B.J.A. Shepherd, M. Surman, N. Thompson, R. Valizadeh, A.E. Wheelhouse, P.H. Williams Cockcroft Institute, Warrington, Cheshire, United Kingdom R.F. Clarke, G. Cox, M.D. Hancock, J.P. Hindley, C. Hodgkinson, A. Oates, W. Smith, J.T.G. Wilson STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom L.S. Cowie Cockcroft Institute, Lancaster University, Lancaster, United Kingdom N.Y. Joshi, T.H. Pacey UMAN, Manchester, United Kingdom
	CLARA (Compact Linear Accelerator for Research and Applications) is a test facility for Free Electron Laser (FEL) research and other applications at STFC’s Daresbury Laboratory. The first exploitation period using CLARA Front End (FE) provided a range of beam parameters to 12 user experiments. Beam line to Beam Area 1 (BA1) was commissioned and optimised for these experiments, some involving TW laser integration. In addition to the user exploitation programme, significant advances were made to progress on machine development. This paper summarises these developments and presents the near future plan for CLARA.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB083
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPRB094	New Superconducting Undulator Magnetic Measurement System for the Advanced Photon Source Upgrade	GUI, undulator, photon, storage-ring	1881
	M. Kasa, E.R. Anliker, Y. Ivanyushenkov, Y. Shiroyanagi ANL, Argonne, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. Magnetic measurements of existing superconducting undulators (SCUs) are performed under normal operating conditions after final assembly into the cryostat and before installation on the Advanced Photon Source (APS) storage ring. The SCU cryostat for the APS upgrade has been scaled in length from the current cryostat and will contain two SCUs. While some aspects of the current measurement system are desirable to retain, such as a room temperature measurement bore, scaling the current measurement techniques to the length required for the APS upgrade cryostat is not feasible. To address these challenges a unique system has been developed at the APS to allow measurements of the two SCU magnets in the long cryostat. The measurement system developed allows the magnets to be operated under normal operating conditions while maintaining the measurement equipment at room temperature and atmospheric pressure.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB094
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPRB095	Superconducting Undulators for the Advanced Photon Source Upgrade	undulator, photon, electron, operation	1884
	M. Kasa, E.R. Anliker, J.D. Fuerst, Q.B. Hasse, Y. Ivanyushenkov, I. Kesgin, Y. Shiroyanagi, E. Trakhtenberg ANL, Argonne, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. The magnetic devices group at the Advanced Photon Source (APS) is in the process of designing and developing superconducting undulators (SCUs) for the APS upgrade. While similar in some aspects to previous SCU systems currently in operation at the existing APS, the new SCU systems will include two undulators installed in one cryostat which occupies an entire straight section of the storage ring. Straight sections containing planar undulators will either be configured as ’in-line’, where the two undulators behave as one source, or canted, where the two undulators are operated independently. Also under development is a superconducting arbitrary polarizing emitter (SCAPE) which can produce planar, elliptical, and helical undulator fields.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB095
About •	paper received ※ 14 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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TUPRB101	Damping Trapped Modes in an in-Vacuum Undulator at a Synchrotron Radiation Light Source	simulation, damping, HOM, impedance	1895
	K. Tian, Z. Li, A. Ringwall, J.J. Sebek SLAC, Menlo Park, California, USA
	Funding: Work supported by US Department of Energy Contract DE-AC03-76SF00515. In this paper, we report the efforts in solving the problem of coupled-bunch instabilities caused by an in-vacuum undulator in the SPEAR3 storage ring. After exploring several approaches to reduce the strength of the trapped modes, we found that ferrite dampers were the most effective and simplest way for mode damping in our SPEAR3 in-vacuum undulator. The results of the first RF cold measurement on an in-vacuum undulator equipped with these ferrite dampers agree well with numerical simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB101
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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TUPRB108	Mechanical Design of a Dielectric Wakefield Dechirper System for CLARA	FEL, wakefield, electron, alignment	1912
	M. Colling, D.J. Dunning, B.D. Fell, T.H. Pacey, Y.M. Saveliev STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	STFC Daresbury Laboratory are developing a compact electron beam energy dechirper system, based on dielectric wakefield structure, for the on-site electron accelerator CLARA (Compact Linear Accelerator for Research and Applications). CLARA will be an experimental free electron laser (FEL) facility operating at 250MeV and will be a test bed for a variety of novel FEL schemes. The dechirper dielectric quartz plates will induce wakefields within the structure which can remove the beam chirp that is initially introduced to compress the electron bunch longitudinally. Removing or adjusting the amount of chirp enables researchers to reduce or adjust the bunch energy/momentum spread, expanding the FEL capabilities. The attachment and alignment of the quartz plates present numerous mechanical design challenges that require high precision manufacturing and quartz plate positioning via fiducialisation. This paper will review the dechirper specifications, the chosen design solutions, measured mechanical performance, and the expected effect of the dechirper on CLARA FEL operation.
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TUPTS011	Vacuum Lifetime and Surface Charge Limit Investigations Concerning High Intensity Spin-polarized Photoinjectors	cathode, electron, laser, experiment	1954
	S. Friederich, K. Aulenbacher, C. Matejcek IKP, Mainz, Germany K. Aulenbacher GSI, Darmstadt, Germany K. Aulenbacher HIM, Mainz, Germany
	Funding: DFG excellence initiative PRISMA+, Bundesministerium für Bildung und Forschung "Verbundforschung FKZ 05K16UMA" The Small Thermalized Electron Source at Mainz (STEAM) is a dc photoemission source. It is designed to operate at up to 200kV bias voltage with an accelerating field of up to 5 MV/m at the cathode surface. In several experiments, the properties of GaAs operating under the conditions of spin-polarized photoemission were investigated. Its performance, quantum efficiency lifetime and surface charge limit observations for bulk-GaAs will be discussed.
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TUPTS021	Basic Design of the RF Power System for IRANCYC-10 Accelerator	cyclotron, simulation, ISOL, operation	1972
	M. Dehghan, F. Abbasi Shahid Beheshti University, Tehran, Iran H. Azizi ILSF, Tehran, Iran F. Ghasemi NSTRI, Tehran, Iran A. Taghibi Khotbeh-Sara KNTU, Tehran, Iran
	In this paper the basic design of an RF system to produce the required power of IRANCYC-10 cyclotron accelerator is reported. The designed system can generate 15 kW power at the operating frequency of 71 MHz CW. The authors provide a step-by-step ex-planation of the process of the design. It is carried out in three sections; (1) RF design features of the acceler-ator is investigated and power value is calculated in accordance with the requirements of the cyclotron, (2) the choice of solid state amplifiers as the RF power source is presented with its available power and struc-ture, (3) design of insertion instruments is reported to transfer and combine the RF power. The purpose of the paper is to achieve the best performance of the RF system, as well as decreasing overall size by using modular devices.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS021
About •	paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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TUPTS026	Negative Electron Affinity GaAs Cathode Activation With CsKTe Thin Film	cathode, electron, photon, gun	1986
	M. Kuriki KEK, Ibaraki, Japan K. Masaki HU/AdSM, Higashi-Hiroshima, Japan
	Funding: This work is partly supported by Japan-US Cooperative grant for scientific studies, Grant aid for scientific study by MEXT Japan (KAKENHI). Negative Electron Affinity (NEA) GaAs cathode is an unique device which can generate a highly polarized electron beam with circularly polarized light. The NEA surface is conventionally made by Cs and \rm O/NF₃ adsorption on the cleaned p-doped GaAs crystal, but the robustness of the cathode is very limited, so that the electron emission is easily lost by residual gas adsorption, ion back-bombardment, etc. To improve the cathode robustness, NEA activation with a stable thin-film on GaAs surface according to Hetero junction hypothesis has been proposed by the author. An experiment of the NEA activation with CsKTe thin film was carried out at Hiroshima University and a significant electron emission with 1.43 eV photon was observed which strongly suggested NEA activation. The cathode showed 16 to 20 times improvement of lifetime comparing to GaAs activated with Cs and O.
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TUPTS032	Radiation Design of New 30 kW Beam Dump of J-PARC Main Ring	neutron, proton, radiation, site	2005
	M.J. Shirakata, H. Kuboki, J. Takano KEK, Ibaraki, Japan
	The J-PARC Main Ring (MR) has a beam dump for the beam study and beam abort. Its present capacity is 7.5 kW in one hour average which is limited by radiation condition for the environments. The number of protons in one MR cycle is 2.6·10⁺¹⁴ in recent days, which corresponds to the beam power of 500 kW. As the top energy of J-PARC MR is 30 GeV, the number of available beam shots is restricted to less than twenty in one hour with such an intense beam. It imposes a big limitation on high power beam tuning and study. The number of protons is expected to become 3.3·10⁺¹⁴ for MW operation. Hence, an upgrade of the beam dump from 7.5 kW to 30 kW is planned. The radiation dose rate should be less than 0.25μSv/h on the ground. The backscattered neutron flux should be examined in the accelerator tunnel. The new dump design on radiation matters is described in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS032
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TUPTS035	Vacuum Tube Operation Analysis for 1.2 MW Beam Acceleration in J-PARC RCS	acceleration, cavity, operation, power-supply	2017
	M. Yamamoto, M. Nomura, T. Shimada, F. Tamura JAEA/J-PARC, Tokai-mura, Japan M. Furusawa, K. Hara, K. Hasegawa, C. Ohmori, Y. Sugiyama, M. Yoshii KEK, Tokai, Ibaraki, Japan
	The J-PARC RCS has successfully accelerated 1 MW proton beam, matching the designed beam power. Therefore, we have considered acceleration beyond the designed beam power, with the next target being 1.2 MW. An issue for 1.2 MW beam acceleration is the rf system. The present anode power supply is limited by its output current, and the vacuum tube amplifier suffers from an unbalance of the anode voltage swing, arising from the combination of multi-harmonic rf driving and push-pull operation. We have investigated the mitigation of the maximum anode currents and unbalanced tubes by choosing appropriate circuit parameters of the rf cavity with the tube amplifier. We describe the analysis results of the vacuum tube operation for 1.2 MW beam acceleration in the RCS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS035
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TUPTS036	Operation Status of J-PARC Rapid Cycling Synchrotron	operation, proton, status, synchrotron	2020
	J. Kamiya, K. Yamamoto JAEA/J-PARC, Tokai-mura, Japan
	The 3 GeV rapid cycling synchrotron (RCS) at the Japan Proton Accelerator Research Complex (J-PARC) provides more than 500 kW beams to the Material and Life Science Facility (MLF) and Main Ring (MR). In such a high-intensity hadron accelerator, even losing less than 0.1% of the beam can cause many problems. Such lost protons can cause serious radio-activation and accelerator component malfunctions. Therefore, we have conducted a beam study to achieve high-power operation. In addition, we have also maintained the accelerator components to enable stable operation. This paper reports the status of the J-PARC RCS over the last year.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS036
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TUPTS065	RF Conditioning of the CLARA 400 Hz Photoinjector	cavity, GUI, controls, operation	2067

Paper

Title

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MOPGW010

First Application of Online Particle Swarm Optimization at SOLEIL

injection, storage-ring, operation, controls

82

A. Bence, L.S. Nadolski
SOLEIL, Gif-sur-Yvette, France
J. Li
HZB, Berlin, Germany

First attempts of online optimisation of SOLEIL using Particle Swarm Optimisation (PSO) is reported with two major applications. This technique proves to be particularly suitable in a control room and could become a standard operation tool for tuning the accelerators in complement of other techniques. The first optimisation of the injection in the storage ring will be presented using the injection septa and the vertical correctors of the booster to storage ring transfer line. The second work will summarise the results obtained from the optimisation of the transverse on- and off-momentum dynamics in presence of insertion devices. Main results, the implementation and improvements will be presented and discussed thoroughly.

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paper received ※ 19 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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MOPGW053

Residual Gas Lifetime In High Energy Photon Source (HEPS)

scattering, electron, dynamic-aperture, photon

210

S.K. Tian, H.S. Xu
IHEP, Beijing, People’s Republic of China

High vacuum has always been mandatory in particle accelerators. This is especially true for circular machines, where the beam makes thousands or millions turns, and beam lifetime is heavily affected by the residual gas scattering. At the beginning of storage ring operation the lifetime was very short mostly dominated by residual gas scattering. The residual gas lifetime is comprised of the elastic and inelastic scattering on electrons and elastic and inelastic scattering on nuclei. One usually calculates only the elastic scattering on nuclei (single Coulomb scattering) and inelastic scattering on nuclei (bremsstrahlung) of the residual gas scattering lifetime component. The analytic calculation the residual gas scattering lifetime and simulations of the beam interaction with the residual gas with code will be shown in this presentation

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MOPGW058

Towards a Sextupole-Free Electron Storage Ring

electron, impedance, storage-ring, feedback

217

T.-Y. Lee, T. Ha
PAL, Pohang, Kyungbuk, Republic of Korea

This paper studies if it is possible to build an electron storage ring with no or a small number of sextupole mag-nets. If it is possible, the electron storage ring will be great-ly simplified. For the purpose, two methods are presented in the paper to handle head-tail instability: One is to use dielectric vacuum chamber made of such materials as ceramic or glass to reduce broadband impedance signifi-cantly. Then head-tail instability would be extremely weak. The other method is to install a bunch-by-bunch feedback system to suppress the already weak head-tail instability due to the dielectric vacuum chamber.

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paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPGW061

Radiation from a Dielectrically Loaded Waveguide with Open End

GUI, radiation, embedded, acceleration

228

S.N. Galyamin, A.A. Grigoreva, A.V. Tyukhtin, V.V. Vorobev
Saint Petersburg State University, Saint Petersburg, Russia
A. Aryshev
KEK, Ibaraki, Japan

Funding: Work supported by Russian Science Foundation (Grant No. 18-72-10137).
Open-ended waveguide structures with dielectric loading excited by specially prepared electron bunches are considered as promising candidates for development of contemporary sources of Terahertz (THz) radiation. Despite of the fact that both ordinary vacuum THz devices (e.g., backward wave oscillator) are widely available and other mechanisms for THz generation are discussed, beam driven sources are still extremely attractive due to the extraordinary peak power of THz radiation*. In this report, we study electromagnetic (EM) field produced by a charged particle bunch exiting an open-ended circular waveguide with dielectric filling placed inside collinear vacuum waveguide of a larger radius. Based on the previously developed theory**, we mainly investigate Cherenkov radiation generated penetrated vacuum regions of the structure due to the diffraction mechanism. We pay attention to the case of a train of short bunches resulting in high-order Cherenkov modes excitation. We also develop analytical procedure allowing performing the limiting process to the case of infinite radius of the outer waveguide.
* B.D. O’Shea et al., Nature Communications, Vol. 7, P. 12763, (2016).
** S.N. Galyamin et al., J. Instrumentation, Vol. 13, P. C02012 (2018).

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MOPGW066

Local Impedance Measurements Using the Orbit Bump Method at ALBA

impedance, storage-ring, betatron, simulation

240

Z. Martí, G. Benedetti, T.F.G. Günzel, U. Iriso
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

The orbit bump technique has been used at the ALBA Storage Ring to characterize with good precision the impedance of single machine elements, like the in-vacuum undulators or the CLIC stripline kicker. The results are compared with theoretical studies, as well as impedance measurements done at ALBA using other methods like the turn by turn betatron phase or from the analysis of the detuning slopes of the Transverse Mode Coupling Instability.

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MOPGW071

Resistive Wall Effects in the CLIC Beam Delivery System

luminosity, wakefield, collider, feedback

258

D. Arominski, A. Latina, D. Schulte
CERN, Meyrin, Switzerland

Resistive wall wakefields are an important issue to study for future linear colliders. Wakefields in the Beam Delivery System (BDS) might cause severe multi-bunch effects, leading to beam quality and luminosity losses. The resistive wall effects depend on the beam pipe apertures and materials, which are optimised to limit the impact on the beam. This paper presents a study of this problem for the 380 GeV and 3 TeV beam parameters and optics of the Compact Linear Collider’s BDS. First, the optimisation of the beam pipe apertures to limit the impact of resistive wall effect on the beam quality is shown, then the luminosity and its quality are presented. Finally, the proposed design parameters are discussed.

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MOPGW074

New Spiral Beam Screen Design for the FCC-hh Injection Kicker Magnet

kicker, impedance, injection, coupling

270

A. Chmielinska, M.J. Barnes
CERN, Geneva, Switzerland

The injection kicker system for the Future Circular Collider (FCC-hh) must satisfy demanding requirements. To achieve low pulse ripple and fast field rise and fall times, the injection system will use ferrite loaded transmission line type magnets. The beam coupling impedance of the kicker magnets is crucial, as this can be a dominant contribution to beam instabilities. In addition, interaction of the high intensity beam with the real part of the longitudinal beam coupling impedance can result in high power deposition in the ferrite yoke. This gives a significant risk that the ferrite yoke will exceed its Curie temperature: hence, a suitable beam screen will be a critical feature. In this paper, we present a novel concept - a spiral beam screen. The fundamental advantage of the new design is a significant reduction of the maximum voltage induced on the screen conductors, thus decreased probability of electrical breakdown. In addition, the longitudinal beam coupling impedance is optimized to minimize power deposition in the magnet.

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MOPGW122

Beam-based Measurement of Broadband Longitudinal Impedance at NSLS-II

impedance, simulation, diagnostics, storage-ring

400

V.V. Smaluk, B. Bacha, G. Bassi, A. Blednykh
BNL, Upton, Long Island, New York, USA

Funding: Department of Energy Contract No. DE-SC0012704
Interaction of a particle beam with the vacuum chamber impedance is one of the main effects limiting the beam intensity in accelerators. Minimization of the impedance is an essential part of the vacuum chamber design for any new accelerator project. The impedance can be estimated experimentally by measuring beam dynamics effects caused by the beam-impedance interaction. Experience obtained at many accelerator facilities shows the beam-based measurements are often different from the pre-computed impedance budgets, the discrepancy of a factor of two or even more is not unusual. The measurements of broadband longitudinal impedance carried out at NSLS-II are discussed in comparison with the numerically simulated impedance budget.

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MOPGW128

Simulation and Analysis of Wake Fields and Trapped RF Modes in Insertion Device Vacuum Chambers at the Canadian Light Source

simulation, undulator, insertion-device, insertion

414

E.J. Ericson, D. Bertwistle, M.J. Boland
CLS, Saskatoon, Saskatchewan, Canada
M.J. Boland, M. Castillo Sosa
University of Saskatchewan, Saskatoon, Canada
D. Pelz
RFS, Kilsyth, Australia

Funding: CFI, NSERC, NRC, CIHR, the Province of Saskatchewan, WD, WESTGRID, Compute Canada, and the University of Saskatchewan
The Canadian Light Source (CLS) synchrotron operates with four in-vacuum insertion devices, three in-vacuum undulators, and one in-vacuum wiggler. Presently, each of the devices occupies half of a straight section. The wiggler is unique in our ring as it is both in-vacuum and shares a straight section with an in-vacuum undulator. We have observed gap dependent beam instabilities in the undulator located in the straight section. In order to better understand the problem, the cause of the instabilities was investigated using 3D electromagnetic modelling. First, the ’trapped’ RF modes (natural resonances) for this undulator chamber, their Q value, and their peak frequencies were analysed using Eigenmode simulation. Secondly, beam excitation of the Eigenmodes was simulated with the Wakefield solver. Herein we present the results of this electromagnetic modelling.

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MOPRB027

Progress of HEPS Accelerator System Design

storage-ring, cavity, booster, lattice

633

P. He, J.S. Cao, F.S. Chen, J. Chen, H. Dong, D.Y. He, Y. Jiao, W. Kang, C.H. Li, J.Y. Li, F. Long, H.H. Lu, X. Qi, Q. Qin, H. Qu, J.Q. Wang, G. Xu, J.H. Yue, J. Zhang, J.R. Zhang, P. Zhang
IHEP, Beijing, People’s Republic of China

The 4th generation ring-based light sources, HEPS (High Energy Photon Source) 7BA lattice has been de-veloped at IHEP. This is 6Gev, 200mA machine which has horizontal emittance Ɛh around 60pm.rad to gain the high brilliance photon beam. this compact lattice design bring so many engineering challenges for accelerator magnets, vacuum components, beam diagnotice, etc. This paper will present the noval lattice design and subsystem design progress.

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MOPRB036

Study on Beam-induced heating in injection section of Hefei Light Source

impedance, kicker, radiation, experiment

652

D.R. Xu, W. Xu
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Ceramic chambers distributed with metal belts on the inner surface are installed in the injection section at Hefei Light Source (HLS). Heating on the ceramics chambers has been observed during machine operation. An air compressor is used to cool these chambers due to concerns of overheating during top-up operation mode. To understand the sources of the heating, a series of experiments are performed with various beam currents and bunch filling patterns. The study shows that the heating is mainly caused by the narrow-band impedances of the ceramic chambers and their adjacent vacuum components.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB036

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paper received ※ 22 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPRB075

Radiation Limits on Permanent Magnets in CBETA

radiation, electron, permanent-magnet, focusing

745

V.O. Kostroun, C.M. Gulliford
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

The Cornell Brookhaven Energy Recovery Linac Test Accelerator (CBETA), under construction at Cornell, uses Fixed Field Alternating Gradient (FFAG) Halbach magnets made from grade N35EH NdFeB. To reduce the 1% level magnetization errors in fabricated blocks to magnets with better than 0.001 field accuracy, iron wire shimming is necessary. This also limits magnetization changes by external influences to the ~1% level. The ambient radiation field present during CBETA operation can induce permanent magnet demagnetization. The radiation field arises from electrons in the beam halo hitting the vacuum chamber and from residual gas, Touschek and Intra-Beam scattering. The radiation dose rate due to electrons striking the vacuum chamber of a 4 cell straight section of CBETA FFAG magnets was calculated using the many particle Monte Carlo radiation code MCNP6.2. MCNP6.2 has a track-length heating tally for different particles and a collision heating tally that gives energy deposition/mass from all particles in the problem. Calculations show that electron loss has to be a fraction of a watt/m to keep the dose rate at an acceptable level during the accelerator lifetime.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB075

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

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MOPTS008

ESS RFQ: Construction Status and Power Couplers Qualification

rfq, cavity, coupling, pick-up

855

O. Piquet, A.C. Chauveau, D. Chirpaz-Cerbat, M. Desmons, A.C. France, P. Hamel, B. Pottin
CEA-IRFU, Gif-sur-Yvette, France
A. Dubois, A. Gaget, Y. Le Noa, L. Napoly, M. Oublaid, G. Perreu
CEA-DRF-IRFU, France

The 352 MHz Radio Frequency Quadrupole (RFQ) for the European Spallation Source ERIC (ESS) will be de-livered during 2019. It is provided by CEA, IRFU, Sac-lay/France. It consists of five sections with a total length of 4.6 m and accelerates the proton beam from 75 keV up to 3.6 MeV. It will be feed with 1.6 MW peak power through two coaxial loop couplers. This paper will present the manufacturing status of the five sections and the qualification test of the RF power couplers.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS008

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

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MOPTS022

Current Status of the MYRRHA Cavities

cavity, resonance, status, operation

892

K. Kümpel, D. Bade, M. Busch, D. Koser, S. Lamprecht, N.F. Petry, H. Podlech, S. Zimmermann
IAP, Frankfurt am Main, Germany

The MYRRHA (Multi-purpose hYbrid Research Reac-tor for High-tech Applications) Project is a planned ac-celerator driven system (ADS) for the transmutation of long-living radioactive waste. In order test the reliability of the planned 17 MeV injector, a shortened injector with 5.9 MeV consisting of the ion source, a 4-Rod RFQ, 2 Quarter Wave Rebunchers (QWRs) and a total of 7 normal conducting CH structures is currently being installed in Louvein-la-Neuve (LLN, Belgium). Before the cavities can be tested with beam, they are subjected to so-called low power tests several times during the individual con-struction stages in order to be able to correct any devia-tions. This paper describes the status of the two Quarter Wave Rebunchers, which are currently in the process of copper plating and final acceptance, as well as the first two CH structures, the first of which is already being conditioned while CH 2 is still in preparation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS022

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paper received ※ 10 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS049

The First Replacement of the RF Window of the ACS Cavity

cavity, linac, operation, proton

971

J. Tamura, Y. Kondo, T. Morishita
JAEA/J-PARC, Tokai-mura, Japan
F. Naito, M. Otani
KEK, Tokai, Ibaraki, Japan
Y. Nemoto
Nippon Advanced Technology Co., Ltd., Tokai, Japan

In 2013, the Annular-ring Coupled Structure (ACS) cavities were installed to the Japan Proton Accelerator Research Complex (J-PARC) linac. Since then, the ACS cavities have been stably running. Although any serious problem induced by the ACS RF window has not yet observed, we decided to replace the RF window of one ACS cavity, which is the eighteenth accelerating cavity in the order of beam energy (ACS18), by the newly manufactured one. The major motivations of the replacement are to check the surface condition of the RF window which have been under operation for nearly five years and to confirm the availability of the newly manufactured RF window. By making use of the summer maintenance period of 2018, we carried out the replacement. This was the first experience for us to replace the RF window installed to the ACS cavity in the linac accelerator tunnel. As for the removed RF window, there was no any abnormal warning found with the visual examination. At the starting up of the cavity’s operation after the maintenance period, we investigated how much time would be required for an RF conditioning. It took around fifty hours so that the peak RF power including the beam loading is stably input to the cavity through the new RF window. The ACS cavity with the new RF window is now stably operating.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS049

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paper received ※ 01 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS093

Ultra-High Vacuum Characterization of Molybdenum-Carbide Graphite for HL-LHC Collimators

collimation, site, proton, collider

1078

F. Carra, C. Accettura, A. Bertarelli, G. Bregliozzi, G. Cattenoz, S. Redaelli, M. Taborelli
CERN, Meyrin, Switzerland
M. Beghi
POLIMI, Milano, Italy
J. Guardia Valenzuela
Universidad de Zaragoza, Zaragoza, Spain

Funding: This work has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No. 730871. Research supported by the HL-LHC project
In view of the High-Luminosity upgrade of the Large Hadron Collider (LHC) collimation system, a family of novel molybdenum-carbide graphite (MoGr) composites was developed to meet the challenging requirements of HL-LHC beam-halo collimation, in particular the electrical conductivity and thermo-mechanical performances. The Ultra-High Vacuum (UHV) behaviour of this material was extensively characterized to assess its compatibility with the accelerator’s specifications. The results presented in this paper correlate the outgassing behaviour with the microscopic features of MoGr compared to other graphite-based materials. Residual gas analysis (RGA) was exploited to optimize post-production treatments.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS093

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paper received ※ 12 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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MOPTS094

Dust Analysis from LHC Vacuum System to Identify the Source of Macro-Particle-Beam-Interactions

beam-losses, operation, proton, dipole

1082

L.K. Grob, A. Apollonio, C. Charvet, E. Garcia-Tabares Valdivieso, H. Kos, R. Schmidt
CERN, Geneva, Switzerland
C. Neves
Hochschule Furtwangen, Furtwangen, Germany

Since in 2010 the first sub-millisecond beam losses were observed at varying locations all along the LHC, it is well known that dust can interact with high-intensity proton beams and cause significant beam losses. Initially the sudden localized losses were enigmatic and coined the phrase ’unidentified falling objects’ (UFOs), which is still widely used. These very fast beam losses have resulted in hundreds of premature beam dumps and even magnet quenches since the start of LHC. So far, the only mitigation strategy involved an optimization of dump thresholds and the beneficial conditioning effect which leads to a reduction of the UFO rate over time. To understand the physics involved in these events and to allow an active diminution, it is essential to know the chemical composition and the size of the dust particulates interacting with the protons. The exchange of a dipole magnet offered the unique opportunity to collect dust samples from inside the LHC vacuum system. They were extracted from the various components and analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy to reveal size distribution and abundant elements. The results of this investigation will optimize the existing UFO models and the improved understanding of the phenomenon may help to prevent future performance limitations. This is also of relevance for future projects, in particular for the Future Circular Collider (FCC) under study.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS094

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

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TUXXPLS3

The Design Optimization of the Dielectric Assist Accelerating Structure for Better Heat and Gas Transfer

cavity, multipactoring, embedded, lattice

1179

S. Mori, M. Yoshida
KEK, Ibaraki, Japan
D. Sato
AIST, Tsukuba, Ibaraki, Japan

The dielectric-assist accelerating (DAA) structure is a dielectric-inserted normal-conducting cavity, which provides high Q value at room temperature. This accelerating structure is composed of dielectric disks and a dielectric cylindrical layer inserted in a copper cavity. For the realistic operation, the removal of heat from the dielectric cells and the vacuum evacuation of gas inside the cylindrical layers have not considered yet. In order to solve the problems, we propose the optimized design of the DAA structure, where the extended part of the dielectric disk is embedded in the copper cavity and the choke structure is applied. We show the result of the electromagnetic-field simulation of the extended DAA structure and the thermal simulation to clarify the relation between a duty factor and maximum temperature of the dielectric cells.

Slides TUXXPLS3 [5.892 MB]

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

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TUYPLM3

Status of the MAX IV Accelerators

storage-ring, electron, sextupole, linac

1185

P.F. Tavares, E. Al-Dmour, Å. Andersson, J. Breunlin, F.J. Cullinan, E. Mansten, S. Molloy, D.K. Olsson, D. Olsson, M. Sjöström, S. Thorin
MAX IV Laboratory, Lund University, Lund, Sweden

The MAX IV facility in Lund, Sweden, consists of three electron accelerators and their respective synchrotron radiation beamlines: a 3 GeV ring, which is the first implementation worldwide of a multi-bend achromat lattice, a 1.5 GeV ring optimized for soft X-Rays and UV radiation production and a 3 GeV linear accelerator that acts as a full-energy injector into both rings and provides electron pulses as short as 100 fs that produce X-rays by spontaneous emission in the undulators of the short-pulse facility (SPF). In this paper, we review the latest achieved accelerator performance and operational results.

Slides TUYPLM3 [9.108 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUYPLM3

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPMP003

Development of Remote Handleable Axially Decoupled Radiation Resistant Vacuum Seal

target, interface, operation, electron

1233

R.R. Nagimov, Y. Bylinskii, L. Egoriti, A. Gottberg, G.W. Hodgson, A.N. Koveshnikov, D. Yosifov
TRIUMF, Vancouver, Canada

Funding: ARIEL is funded by the Canada Foundation for Innovation (CFI), the Provinces of AB, BC, MA, ON, QC, and TRIUMF. TRIUMF receives federal funding via a contribution agreement with the NRC of Canada.
Advanced Rare IsotopE Laboratory (ARIEL) facility is a major expansion of TRIUMF’s rare isotope research program. Aiming to triple the production of rare isotopes, ARIEL facility includes the new electron linac driver and two target stations for electron and proton beams. Particularities of ARIEL target stations design define the requirements for vacuum interfaces with both primary electron and proton beamlines and rare-isotope beamlines. None of the existing products fully met the requirements, driving the development of custom vacuum interfaces. The design of new vacuum seals is driven both by unique design specifications (limited amount of allowed axial forces, extreme radiation resistance, remote handleability and high repeatability) as well as limitations of the proposed design of beamline infrastructure in the target hall (limited available space and the choice of materials for certain components). This paper discusses preliminary results of the vacuum seal development and presents first results of prototype testing.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP003

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

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TUPMP004

Dynamic Pressure in the LHC - Influence of Ions Induced by Ionization of Residual Gas by Both the Proton Beam and the Electron Cloud

electron, proton, experiment, ECR

1236

S. Bilgen, C. Bruni, B. Mercier, G. Sattonnay
LAL, Orsay, France
V. Baglin
CERN, Geneva, Switzerland

Funding: work supported by FCC project (CERN & LAL-CNRS-IN2P3)
Ultra-High Vacuum is an essential requirement to reach design performances in high-energy particle colliders. For the future HL-LHC or FCC study, the understanding of the beam interactions with the vacuum chamber is fundamental to provide solutions to mitigate the pressure rises induced by electronic, photonic and ionic molecular desorption. Studies were performed on the ions, produced by molecular ionization generated by the proton beam and the electron cloud, and stimulating molecular desorption by the surface bombardment. In-situ measurements were carried out, on the LHC Vacuum Pilot Sector (VPS)*, to monitor the dynamic pressure, and to collect the electrical signals due to the electron cloud and to the ions interacting with the vacuum chamber walls. Experimental measurements of electrical signals recorded by copper electrodes were compared to calculations taking into account both the Secondary Electron Yield of copper and electron energy distribution. Finally, it seems that copper electrodes were not fully conditioned and an ion current could be estimated.
* THE LHC VACUUM PILOT-SECTOR PROJECT
B. Henrist, V. Baglin, G. Bregliozzi, and P. Chiggiato, CERN, Geneva, Switzerland
Proceedings of IPAC2014, Dresden, Germany.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP004

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paper received ※ 01 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPMP007

DYVACS (DYnamic VACuum Simulation) Code: Calculation of Gas Density Profiles in Presence of Electron Cloud

electron, proton, photon, experiment

1244

G. Sattonnay, S. Bilgen, B. Mercier
LAL, Orsay, France
V. Baglin
CERN, Meyrin, Switzerland

The computation of residual gas density profiles in particle accelerators is an essential task to optimize beam pipes and vacuum system design. In a hadron collider such as the LHC, the beam induces dynamic effects due to ion, electron and photon-stimulated gas desorption. The well-known VASCO* code developed at CERN in 2004 (and then PyVASCO**) is already used to estimate vacuum stability and density profiles in steady state conditions. Nevertheless, some phenomena are not taken into account such as the ionization of residual gas by the electron clouds. Therefore, we propose an upgrade of this code by introducing electron cloud maps*** to estimate the electron density and the ionization of gas by electrons, leading to an increase of both electron- and ion-induced desorption. Results obtained with the new code (called DYVACS for DYnamic VACuum Simulation) will be compared to pressure measurements in the VPS sector**** of the LHC.
* A. Rossi, Tech. Rep., LHC Proj. Note 341
** I. Aichinger, et al arXiv:1707.07525
*** T. Demma et al Phys. Rev. Acceler. and Beams 10, 114401 (2007)
**** B. Henrist et al, Proc. IPAC2014, Dresden

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

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TUPMP013

New Design of Vacuum Chambers for Radiation Shield Installation at Beam Injection Area of J-PARC RCS

injection, radiation, damping, flattop

1255

J. Kamiya, K. Kotoku, Y. Shobuda, T. Takayanagi, K. Yamamoto, T. Yanagibashi
JAEA/J-PARC, Tokai-mura, Japan
K. Horino, N. Miki
Nippon Advanced Technology Co., Ltd., Tokai, Japan

One of the issues in the J-PARC 3 GeV rapid cycling synchrotron is the high residual radiation dose around the beam injection point. A radiation shield is necessary to reduce radiation exposure of workers when maintenance is performed there. A space to install the radiation shield should be secured by newly designing a structure of the vacuum chamber at the injection point and the alumina ceramics beam pipes for the shift bump magnets. To make the space for the shield, the chamber is lengthened along the beam line and the cross-sectional shape is changed from circle to rectangle. The displacement and inner stress of the vacuum chamber due to atmospheric pressure was evaluated to be enough small by the calculation. For the ceramics beam pipe’s rf-shield, the damping resistor was effective to reduce the induced modulation voltages by the pulsed magnetic field.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP013

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paper received ※ 29 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPMP018

Feasibility Tests of a Vacuum System for SPring-8-II

photon, hardware, multipole, operation

1272

K. Tamura, T. Bizen, M. Masaki, H. Ohkuma, M. Oishi, M. Shoji, S. Takahashi, Y. Taniuchi
JASRI, Hyogo, Japan
T. Bizen, M. Oishi, S. Takahashi
RIKEN SPring-8 Center, Hyogo, Japan

For SPring-8-II, the major upgrade of SPring-8, a test half-cell including permanent/electro magnets and a vacuum system was constructed, and hardware feasibility tests have been performed since 2017. Features of the SPring-8-II vacuum system are 1) introduction of the concept of a stainless steel 12 m-long integral chamber (LIC) with a welded structure, and 2) adoption of ex-situ baking of the chamber. The 12 m LIC with a narrow aperture, flangeless structure and a minimum number of bellows was designed so that the vacuum system could be installed without interference with the magnets of a narrow bore diameter aligned on girders with a severe packing factor. For replacement of the existing system with a new one in a short black-out period, the 12 m LIC is planned to be moved into the accelerator tunnel with keeping ultra-high vacuum (UHV) by closing thin gate valves at both ends, after evacuation to UHV by ex-situ baking and NEG activation. This presentation will overview the vacuum system, mainly the 12 m LIC, developed for the test half-cell, and describe the vacuum performance and the result of the assembly test conducted with the permanent/electro magnets.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP018

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paper received ※ 15 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019

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TUPMP019

Vacuum Performance of the NEG-coated Chamber for U#19 at PF-ring

photon, simulation, MMI, undulator

1276

Y. Tanimoto, T. Honda, X.J. Jin, T. Nogami, R. Takai, M. Yamamoto
KEK, Ibaraki, Japan

At the Photon Factory storage ring (PF-ring) in KEK, a new APPLE-II type elliptically polarizing undulator (U#19) was installed in October 2018. The U#19 vacuum chamber is 4.1 meters in length, and the beam channel with a 15x90 elliptical profile and two cooling-water channels alongside were formed by extrusion of A6060-T6 aluminum alloy. The inner surface of the beam channel is coated with a Ti-Zr-V Non-Evaporable Getter (NEG) thin film, as it has a high effective pumping speed and a low Photon Stimulated Desorption (PSD) yield. After the installation of the U#19, the neighboring uncoated chambers and vacuum components were baked out at 200 °C for 44 hours, and then the NEG coating was activated at 160 °C for 48 hours. As a result, the pressures in the neighboring chambers reached as low as 10^-8 Pa. The conditioning of the vacuum chambers with irradiation of Synchrotron radiation evolved favorably as had been expected by a combined simulation of Synrad and Molflow, leading to a satisfactory recovery of the beam lifetime. Vacuum performance of the NEG-coated chamber was assessed especially by means of a residual gas analysis, and the properties of the NEG film were characterized by surface analyses including SEM, EDX, and XRD.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP019

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paper received ※ 16 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPMP021

Comparison of TiZrV Non-evaporable Getter Films Deposited by DC Magnetron Sputtering or Quantitative Deposition

site, target, interface, electron

1283

X.Q. Ge, W. Li, J.Q. Shao, S. Wang, Y.G. Wang, Y. Wang, W. Wei, B. Zhang, Y.X. Zhang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Ti-Zr-V non-evaporable getter (NEG) films have been widely used in vacuum chambers of various accelerators since their discovery. Recently, we have used a new method called ’quantitative deposition’ to deposit Ti-Zr-V NEG films on nichrome substrates. The surface morphology and surface chemical bonding information were collected by scanning electron microscopy. Although the film deposited by DC magnetron sputtering has more uniform grain growth, smoother grain boundaries and higher porosity, the two films all have porous network structure and can be used as getter films.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP021

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paper received ※ 24 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPMP031

Research on Secondary Electron Emission Characteristics of Diamond-like Carbon Thin Films

electron, experiment, laser, gun

1306

Y.X. Zhang, X.Q. Ge, W. Li, J.Q. Shao, S. Wang, Y.G. Wang, Y. Wang, W. Wei, B. Zhang, B.L. Zhu
USTC/NSRL, Hefei, Anhui, People’s Republic of China

In modern particle accelerators, the build-up of electron cloud is a main limiting factor for the achievement of high-quality beam. Among the techniques to mitigate it, coating the internal walls of the beam pipes with a thin film which has a low secondary electron yield (SEY) is considered to be one of the most effective means. From several earlier studies, it was found that diamond-like carbon (DLC) thin films are potential coatings. This paper is mainly about the research on secondary electron emission characteristics of DLC thin films. The secondary electron emission (SEE) tests were done at temperature of 298 K and vacuum pressure of 2×10^-9 Torr. Here, we obtained the characteristics of the SEE from DLC film coatings with different thickness under ultrahigh-vacuum (UHV) conditions. The maximum secondary electron yield (SEY), δmax, of the DLC thin films under different primary electron doses were also obtained, respectively.

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paper received ※ 26 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPMP033

Design of the Neutron Imaging Differential Pumping Line at LLNL

neutron, target, shielding, simulation

1312

J.A. Caggiano, D. Castronovo, P. Fitsos, D.J. Gibson, J. Hall, M.S. Johnson, R.A. Marsh, B. Rusnak
LLNL, Livermore, California, USA

Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
The neutron imaging system at LLNL is a radiographic capability for imaging objects with fast, quasi-monoenergetic neutrons at ≤1mm spatial resolution. The neutron production source is a deuteron beam (4 or 7 MeV) incident upon a rotating, high-pressure, windowless, pure-deuterium gas target. The windowless nature of the target combined with the high pressure leads to significant gas leakage upstream of the neutron production target. This leakage degrades the imaging quality by (1) increasing the depth-of-field blurring and (2) increasing the beam diameter and divergence in the transverse direction via angular straggling in the residual gas. To mitigate these effects, and guided by bench tests and simulations, we designed a differential pumping line (DPL) to ensure the highest quality imaging system. The system consists of three primary stages (chambers), each separated by carefully shaped apertures. These apertures can be long and thin with low-angle tapers due to the high quality of the beam optics (convergence at the target < 5mrad) and low emittance of the beam (~5 pi mm-mrad). The primary cascaded roots pumps are sized to remove >99% of the incoming mass flow in each stage, ensuring that by the third stage furthest from the target, turbomolecular pumps are able to operate in a nominal ~mTorr range. We anticipate full system testing with helium in mid 2019.

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

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TUPMP035

Design of the Vacuum System of the FCC-ee Electron-Positron Collider

collider, photon, dipole, quadrupole

1319

R. Kersevan, C. Garion
CERN, Geneva, Switzerland

The Future Circular Collider (FCC) Design Study includes the twin storage ring (FCC-ee) where electrons and positrons are stored and made to collide inside two detectors. The vacuum system of FCC-ee must be designed in order to deal with a lower-energy (45.6 GeV), high-current (1390 mA) Z-pole machine and at a later stage with a higher-energy (182.5 GeV) low-current (5.4 mA). The former machine is the most challenging one from the point of view of vacuum, since the photon-stimulated desorption (PSD) generated by the copious synchrotron radiation (SR) fans is quite large. While several concepts have been considered at the beginning, the design retained for the Conceptual Design Report (CDR) is one where the cross-section of the vacuum chamber (VC) in the arcs is a scaled-down version of the one implemented in the SUPERKEKB collider. Contrary to SUPERKEKB tough, the SR fans are absorbed by many short absorbers, with average spacing of 5.8 m. This allow a localization of the PSD gas load and to place lumped pumps in front of the SR absorbers, to maximize the pumping efficiency. The VC design is compatible with the design of the common-yoke dipoles and quadrupoles. The VC material is copper alloy. Optimization of the pressure profiles has been carried out by means of extensive coupled montecarlo simulations, for SR and molecular flow. For the higher energy versions of the machine, for which the SR spectra are characterized by critical energies well above the Compton edge, the localized absorbers facilitate also shielding the tunnel and any radiation-sensitive machine components from X-ray photon damage, by installing short high-Z material around the absorbers. The major features of the CDR relevant for vacuum will be highlighted in the paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP035

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paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPMP036

Results on the FCC-hh Beam Screen Sawtooth at the Kit Electron Storage Ring Kararesults on the Fcc-Hh Beam Screen Sawtooth at the Kit Electron Storage Ring Kara

photon, radiation, experiment, electron

1323

L.A. Gonzalez, V. Baglin, I. Bellafont, P. Chiggiato, C. Garion, R. Kersevan
CERN, Geneva, Switzerland
I. Bellafont, F. Pérez
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
S. Casalbuoni, E. Huttel
KIT, Eggenstein-Leopoldshafen, Germany

Funding: * The European Circular Energy-Frontier Collider Study (EuroCirCol) project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant No 654305.
In the framework of the EuroCirCol collaboration (work package 4 "Cryogenic Beam Vacuum System"), the fabrication of the FCC-hh beam screen (BS) prototype has been carried out with the aim of testing it at room temperature on the Karlsruhe Institute of Technology (KIT) 2.5 GeV electron storage ring KARA (KArlsruhe Research Accelerator) light source. The BS prototype was tested on a beamline installed by the collaboration, named as BEam Screen TEstbench EXperiment (BESTEX). KARA has been chosen because its synchrotron radiation (SR) spectrum, photon flux and power match quite well the one foreseen for the 50+50 TeV FCC-hh proton collider. The BS prototype (2 m in length) was manufactured according to the base line design (BD) of the FCC-hh BS. It implements a saw-tooth profile designed to absorb the SR generated at the bending magnets. Also, a laser-ablated anti-electron cloud surface texturing [2] was applied at the BS inner walls. We present here the results obtained at BESTEX and the comparison of the results obtained during irradiation of the saw-tooth profile at different geometric configurations.
This activity has been carried out in the framework of the EuroCirCol* collaboration (work package 4 "Cryogenic Beam Vacuum System").

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP036

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paper received ※ 13 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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TUPMP037

Recent Developments of Monte-Carlo Codes Molflow+ and Synrad+

simulation, photon, synchrotron, synchrotron-radiation

1327

R. Kersevan, M. Ady
CERN, Geneva, Switzerland

Molflow+ and Synrad+ are Monte Carlo simulation tools for ultra-high vacuum and synchrotron radiation, respectively. Over the years they have become a common tool for designing and analysing the vacuum system of particle accelerators. This contribution gives a short summary about new features added since IPAC-14*. Some highlights: In traditional Monte Carlo simulations, one simulated ’virtual’ particle represents a given number of physical molecules or photons. This is a weakness where the pressure or flux of the simulated system spans across multiple orders of magnitude. Synrad now supports low flux mode, a weighed Monte Carlo technique where the represented number of photons is reduced at every reflection, providing significantly better statistics at low flux regions. As for Molflow+, angle maps allow recording the molecules, directional distribution at any point, and then desorb a reduced gas quantity according to the recording. In linear systems, this allows iterative simulations that have been proven to treat systems up to 7 orders of magnitude of pressure difference. Without the new technique the computing time would be prohibitively slow on desktop computers, which is what most users of the two codes use. Both codes now have a built-in geometry builder that allows creating simple models through a set of 3D operations, and modifying those imported from CAD tools. Molflow+ has recently become open source, and it has been made compatible with, and tested on different versions of Linux and macOS. Examples of application of Molflow+ to novel Beam Gas Curtain detector and the design of the FCC-ee vacuum system will be given, alongside with some benchmarking runs against data published in literature.
* M. Ady, R. Kersevan, "Introduction to the Latest Version of the Test-particle Monte Carlo Code Molflow+", Proc. IPAC’14, Dresden, Germany, June 2014, pp. 2348-2350.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP037

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paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPMP038

Summary of Modelling Studies on the Beam Induced Vacuum Effects in the FCC-hh

electron, photon, collider, synchrotron

1331

I. Bellafont, R. Kersevan, L. Mether
CERN, Geneva, Switzerland

Funding: The European Circular Energy-Frontier Collider Study (EuroCirCol) project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant No 654305.
EuroCirCol is a conceptual design study of a Future Circular Collider (FCC-hh) which aims to expand the current energy and luminosity frontiers that the LHC has established. The vacuum chamber of this 50 TeV, 100 km collider, will have to cope with unprecedented levels of synchrotron radiation power for proton colliders, dealing simultaneously with a tighter magnet aperture. Since the high radiation power and photon flux will release large amounts of gas into the system, the difficulty to keep a low level of residual gas density increases considerably compared with the LHC. This article presents a study of the beam induced vacuum effects for the FCC-hh novel conditions, the different phenomena which, owing to the presence of the beam, have an impact on the vacuum level of the accelerator. To achieve this, a novel beam screen has been proposed, featuring specific mitigating measures aimed at dealing with the beam induced effects. It is concluded that thanks to the new beam screen design, the vacuum level in the FCC-hh shall be adequate, allowing to reach the molecular density requirement of better than 10¹⁵ H₂/m3 with baseline beam parameters within the first months of conditioning.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP038

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paper received ※ 10 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPMP041

Preliminary Design of RF-Shielded Bellows

wakefield, interface, shielding, experiment

1341

Y.T. Huang, C.K. Chan, C.-C. Chang, C.M. Cheng, P.J. Chou, Y.C. Yang
NSRRC, Hsinchu, Taiwan

A new design of RF-shielded bellows is proposed for the TPS to alleviate wake field effects and Joule heating resulting from contact resistance at the contact interface of sliding two dissimilar metals. Most efforts are put into controlling corrosion which is regarded as the main cause of electrical contact degradation. Rh-Au is chosen as a mating interface because they are stable under high temperature condition. Experimental tests are made to find an effective plating thickness of Rh and Au and to determine a suitable normal load applicable on the Rh-Au interface. A preliminary design of RF-shielded bellows that can sustain thousands of cycles during their lifetime is under testing.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP041

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paper received ※ 06 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPMP042

The Beam Cleaning Analysis for the TPS Vacuum System

MMI, radiation, operation, ECR

1344

Y.C. Yang, C.K. Chan, C.-C. Chang, A.Y. Chen, J.-Y. Chuang, C.H. Huang
NSRRC, Hsinchu, Taiwan

Commissioning for the TPS, a low-emittance 3-GeV synchrotron ring, started in December 2014 and is now currently operating in top-up mode at 400mA for users. Until the last machine shut down in December 2018, a total beam dose of 4919 Ah was accumulated and the beam cleaning effect decreased the dynamic pressure to 1.5×10^-11 Pa/mA. During past years operation, several vacuum chambers were replaced to improve vacuum performance and avoid exposure to synchrotron radiation from insertion devices. In this paper, the beam cleaning evolution of new vacuum sections will be discussed and compared with experience in the rest of the storage ring. A particular cleaning evolution could be predicted and can be referenced for machine shutdown planning in the future.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP042

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

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TUPMP044

Special Aluminum Gasket Sealing of Non-circular Profile Flanges for the Accelerator UHV Systems

impedance, photon, experiment, emittance

1347

G.Y. Hsiung
NSRRC, Hsinchu, Taiwan

Most of the beam ducts for the accelerators are not regularly the circular profile. Unfortunately, the conflat (CF-) flanges and the gaskets with non-circular profile were not commercially available. Besides, additional RF-contact bridges between the flanges must be built in for mitigating the impedance from the flange-gaps. In this presentation, various types of the aluminum (Al-) gaskets designed for the non-circular profile Al-flanges for the accelerator ultrahigh vacuum (UHV) systems are introduced. The surface of the Al-flange is flat to accommodate the special Al-gasket with knife edges for the sealing. Both the flange and gasket are manufactured by the oil-free Ethanol-CNC-machining process that any non-circular profile, e.g. rectangular, race-track, key-hole, etc., flanges can be precisely produced. The inner diameters of the gasket just suits those of the flanges that the impedance from the gap is significantly reduced. The flanges and gaskets after oil-free machining can be assembled immediately without any chemical cleaning. The experimental results for the as-mentioned non-circular profile Al-flanges reveal the UHV quality at pressure < 20 nPa after vacuum baking.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP044

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPMP050

Conceptual Design of the Diamond-II Vacuum System

photon, storage-ring, target, controls

1362

M.P. Cox, C. Burrows, A.G. Day, J.A. Dymoke-Bradshaw, R.K. Grant, N.P. Hammond, X. Liu, A.G. Miller, H.S. Shiers, N. Warner
DLS, Oxfordshire, United Kingdom

The conceptual design of the vacuum system for the Diamond-II storage ring upgrade is described. Due to the small vessel cross section, typically 20 mm inside diameter (ID), and the consequent conductance limitation, distributed pumping is provided by non-evaporable getter (NEG) coating supplemented by ion pumps at high gas load locations. In-situ bakeout is incorporated to allow rapid recovery from both planned vacuum interventions and unplanned vacuum events. The vacuum vessels are constructed mainly from copper alloy while stainless steel is used in regions of AC magnets requiring low electrical conductivity. The proposed layout, engineering and build sequence of the vacuum system are described along with gas flow simulations confirming the vacuum performance advantages of NEG-coated vessels compared with uncoated vessels.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP050

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

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TUPMP054

Investigations on Cryopanels in the Room Temperature Heavy Ion Synchrotron SIS18

cryogenics, heavy-ion, synchrotron, operation

1372

L.H.J. Bozyk, S. Aumüller, P.J. Spiller
GSI, Darmstadt, Germany

The heavy ion synchrotron SIS18 at GSI will serve as injector ring for the FAIR-facility and provide high intensity heavy ion beams. The operation of such beams requires the usage of low charge states, which have high cross sections for ionization. To overcome this issue, many upgrade measure have been realized in the past decade, such as the installation of an ion catcher system with low desorption surfaces and coating 65% of the circumference of SIS18 with NEG to lower the static gas pressure. Since the vacuum dynamics during operation prevent the achievement of the intensity goals for FAIR, new concepts have to be developed, to increase the beam intensity. One idea is the installation of additional pumping speed in the form of cryogenic surfaces. Heavy residual gas components, which have the highest ionization cross sections can be cryopumped at moderate temperatures, i.e. already at 50-80 K. In fact, the only typical residual gas component which can not be pumped via cryosorption in this temperature regime is Hydrogen, which has a factor 50 lower ionization cross sections than Argon, the heaviest residual gas component. In this paper, we present a study of the integration of cryopanels into the vacuum chambers of SIS18.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP054

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paper received ※ 13 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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TUPMP056

LANSCE Vacuum System Improvements in the Last ~10 Years

operation, neutron, linac, status

1375

T. Tajima, J.E. Bernal, M.J. Borden, J.P. Chamberlin, F.A. Martinez, J.F. O’Hara, A. Poudel, K.A. Stephens
LANL, Los Alamos, New Mexico, USA

Funding: DOE/NNSA
The Los Alamos Neutron Science Center (LANSCE) accelerator started its operation in 1972. To mitigate the vulnerability due to old equipment and to restore the 120 Hz operation capability we lost a while ago, we have gone through a refurbishment / risk mitigation project since 2007. This paper summarizes the improvements in the vacuum systems in the last ~10 years and shows some data on the downtimes caused by vacuum failures. The refurbished equipment is significantly more maintainable and will contribute to extend the life of this old accelerator, but it has been a challenge to reduce the downtime. Some examples that caused a long downtime will be described.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP056

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paper received ※ 24 May 2019 paper accepted ※ 26 May 2019 issue date ※ 21 June 2019

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TUPGW003

Sirius Status Update

storage-ring, booster, alignment, controls

1381

A.R.D. Rodrigues, F.C. Arroyo, J.F. Citadini, R.H.A. Farias, J.G.R.S. Franco, R. Junqueira Leão, L. Liu, S.R. Marques, R.T. Neuenschwander, C. Rodrigues, F. Rodrigues, R.M. Seraphim, O.H.V. Silva, F.H. de Sá
LNLS, Campinas, Brazil

Sirius is a 4th generation 3 GeV low emittance electron storage ring that is in its final installation phase at the Brazilian Center for Research in Energy and Materials (CNPEM) campus in Campinas, Brazil. Presently the injector installation is complete, and the storage ring installation is being finalized. Most subsystems are under test and tuning in real working conditions. Six beamlines are also under construction. In this paper we report on the Sirius main subsystems installation status.

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW009

THE ESRF FROM 1988 TO 2018, 30 YEARS OF INNOVATION AND OPERATION

operation, SRF, injection, emittance

1400

J.-L. Revol, L. Farvacque, L. Hardy, P. Raimondi
ESRF, Grenoble, France

In 1988, eleven European countries joined forces to build the European Synchrotron Facility in Grenoble [France]. The ESRF was the first third-generation light source worldwide. After 30 years of innovation and user operation, the present storage ring was shut down to leave room for a new and brighter source. This paper describes the evolution of the facility from its origin to the Ex-tremely Bright Source (EBS). Firstly, the operational aspects including reliability and beam modes are consid-ered. This is followed by the presentation of the progress of lattice and the implementation of top-up. Finally, the development of the radio frequency and vacuum systems are discussed. To conclude, the lessons learned from 30 years operation are summarized, especially in view of EBS.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW009

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

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TUPGW014

Characterization and Implementation of the Cryogenic Permanent Magnet Undulator CPMU17 at Bessy II

undulator, laser, feedback, operation

1415

J. Bahrdt, W. Frentrup, S. Gottschlich, S. Grimmer, M. Huck, C. Kuhn, A. Meseck, C. Rethfeldt, M. Scheer, B. Schulz
HZB, Berlin, Germany
E.C.M. Rial
DLS, Oxfordshire, United Kingdom

In fall 2018, the cryogenic undulator CPMU17 was installed in BESSY II. Before installation, the undulator was characterized with an in-vacuum Hallprobe bench and an in-vacuum moving wire. Both systems were developed at HZB. The commissioning of the device included the orbit and tune corrections, optimization of the injection, characterization of the heat dissipation, tuning the Landau cavities for a reduction of the heat dissipation in the taper sections (temperatures below 60°C) and testing of the machine protection system. The undulator is ready to deliver light for beamline commissioning. Spectral tuning on a high undulator harmonic (longitudinal taper and alignment of e-beam orbit and undulator axis) will be done as soon as the DCM is operational.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW014

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

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TUPGW015

Petra III Operation and Studies 2018

operation, impedance, undulator, radiation

1419

M. Bieler, I.V. Agapov, Y.-C. Chae, J. Keil, G.K. Sahoo, R. Wanzenberg
DESY, Hamburg, Germany

At DESY the Synchrotron Light Source PETRA III offers scientists outstanding opportunities for experiments with hard X-rays of exceptionally high brilliance since 2009. This paper describes the operational schedule, the operational statistics and the most important beam studies done at PETRA III in 2018.

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

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TUPGW017

Superconducting Undulator Coils with Period Length Doubling

undulator, FEM, operation, storage-ring

1426

S. Casalbuoni, N. Glamann, A.W. Grau, T. Holubek, D. Saez de Jauregui
KIT, Eggenstein-Leopoldshafen, Germany

Funding: Work supported by the German government in the BMBF-project Superconducting ’Insertion Device Technologies for Ultra-Low-Emittance Light Sources’ (05K12CK1)
Only since few years it has been demonstrated experimentally that NbTi based superconducting undulators (SCUs) have a higher peak field on axis for the same gap and period length in operation with electron beam with respect to permanent magnet undulators (even the ones in vacuum and cooled to cryogenic temperatures). Another advantage of NbTi based SCUs with respect to permanent magnet devices is radiation hardness, widely demonstrated for NbTi magnets, which is and will become an increasingly important issue with the small gaps in the newest machines as round beam storage rings and FELs. Moreover, SCU technology allows switching of the period length by changing the current direction in one of separately powered subset of winding packages of the superconducting coils. This feature further broadens the energy range of the emitted photons, required by the different beamlines. To this end 0.5 m long superconducting undulator coils with switchable period length between 17 mm and 34 mm have been developed. In this contribution we describe the design and report on the quench tests, as well as on the magnetic field measurements.

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paper received ※ 25 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPGW019

Progress of the BESSY VSR Cold String Development and Testing

cavity, GUI, simulation, experiment

1434

H.-W. Glock, V. Dürr, F. Glöckner, J. Knobloch, M. Tannert, A.V. Vélez, D. Wolk, N. Wunderer
HZB, Berlin, Germany
J. Guo, R.A. Rimmer, H. Wang
JLab, Newport News, Virginia, USA

The so-called VSR (Variable Storage Ring) upgrade of the 3rd gen. light source BESSY II will provide the capability to simultaneously store long (about 20 ps rms length) and short (1 ps or less) bunches in the ring. This will be accomplished by inserting a module with four superconducting cavities, two of them operating at 1.5 GHz as the third harmonic of the 500 MHz driving RF, two at 1.75 GHz. The "cold" string of those four cavities also includes supporting and connecting devices, as there will be: - three intermediate bellows, all shielded against leaking fundamental mode cavity fields, one additionally acting as a collimator for incident synchrotron light; - two tuneable bellows at the module ends; - two warm end groups outside the module, housing toroidal dielectric wake field absorbers, another bellow and a vacuum pump connection. The recent design progress of those components will be reported, including a description of a beam test planned for the central collimating shielded bellow.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW019

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paper received ※ 22 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPGW059

Studies of The Electron Beam Lifetime in Solaris Electron Storage Ring

electron, storage-ring, cavity, scattering

1541

R. Panas, A.M. Marendziak, A.I. Wawrzyniak, M. Wisniowski
Solaris National Synchrotron Radiation Centre, Jagiellonian University, Kraków, Poland

Solaris storage ring is a recently constructed and commissioned machine operated in decay mode. With total accumulated beam dose near to 1000 A.h the measured total lifetime has reached 16 h for 270mA of a stored current. In this paper, the beam lifetime studies are presented using measured residual gas analysis and vertical scraper position for tuned and detuned Landau cavities. It shows that for stable beam the lifetime is dominated by the interaction of the electron with residual gas (vacuum lifetime) and between electrons interaction within a bunch (Touschek lifetime). The estimated vacuum, Touschek and total beam lifetimes from theoretical analysis are also compared with the measured beam lifetime.

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW069

Insertion Devices for the Day-One Beamlines of ILSF

undulator, wiggler, storage-ring, polarization

1561

M. Hadad
Shahid Beheshti University, Tehran, Iran
S. Dastan, M. Hadad, J. Rahighi, M. Razazian, F. Saeidi, S. Yousefnejad
ILSF, Tehran, Iran

The Iranian Light Source Facility (ILSF) is a new 3 GeV synchrotron radiation laboratory with ultralow emittance of 270 pm-rad, which is in the design stage. Seven beamlines are planned to start operation with several different insertion devices installed in the storage ring either from "day one" or within the first year of operation. The most operational undulator for polarized radiations -Apple II- has been deliberated for the solid state electron spectroscopy, the Spectromicroscopy and the ARPES beamlines. The hybrid wigglers for the XPD and the EXAFS beamlines and in-vacuum undulators for Macromolecular Crystallography and SCD beamlines have been chosen too. The emission of these IDs covers a wide spectral range extending from hard X-rays to UV. Pre-design of the IDs were already done in ILSF. The main parameters of magnetic design as well as radiation parameters for the first phase of ILSF insertion devices have been described in this paper.

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW082

Impedance of the Flange Joints With the RF Contact Spring in NSLS-II

impedance, storage-ring, cavity, damping

1597

A. Blednykh, B. Bacha, G. Bassi, C. Hetzel, B.N. Kosciuk, T.V. Shaftan, V.V. Smaluk, G.M. Wang
BNL, Upton, Long Island, New York, USA

Funding: This work was supported by Department of Energy Contract No. DE-SC0012704
Since the beginning of the NSLS-II commissioning, temperature of the vacuum components has been moni-tored by the Resistance Temperature Detectors located predominantly outside of the vacuum enclosure and at-tached to the chamber body. Temperature map helps us to control overheating of the vacuum components around the ring especially during the current ramp-up. The average current of 475mA has been achieved with two main 500MHz RF cavities and w/o harmonic cavities. Effect of the RF shielded flanges on local heat and on the longitu-dinal beam dynamics is discussed in details.

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW088

Removal and Installation Planning for the Advanced Light Source - Upgrade Project

storage-ring, MMI, injection, shielding

1609

D. Leitner, P.W. Casey, K. Chow, D.F. Fuller, M. Leitner, A.J. Lodge, M. Lopez, J. Niu, P. Novak, C. Steier, S.P. Virostek, W.L. Waldron
LBNL, Berkeley, California, USA

The ALS-U project is a proposed upgrade to the Advanced Light Source (ALS) at Berkeley Lab that aims to deliver diffraction limited performance in the soft x-ray range. By lowering the horizontal emittance to about 70 pm rad, the brightness for soft x-rays will increase two orders of magnitude compared to the current ALS. The design utilizes a nine-bend achromat lattice, with reverse bending magnets and on-axis swap-out injection utilizing an accumulator ring. This paper will describe the preliminary plans for the installation of the new three-bend achromat accumulator ring (AR) in the existing tunnel and for replacing the current storage ring with the new nine-bend achromat lattice. The AR will be installed during regular maintenance shutdowns while the ALS continues to operate. The SR will be replaced during a nine months installation period followed by three months of commissioning during the twelve darktime period.

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

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TUPGW097

Design Progress of ALS-U, the Soft X-ray Diffraction Limited Upgrade of the Advanced Light Source

emittance, lattice, cavity, storage-ring

1639

C. Steier, Ph. Amstutz, K.M. Baptiste, P.A. Bong, E.S. Buice, P.W. Casey, K. Chow, S. De Santis, R.J. Donahue, M.P. Ehrlichman, J.P. Harkins, T. Hellert, M.J. Johnson, J.-Y. Jung, S.C. Leemann, R.M. Leftwich-Vann, D. Leitner, T.H. Luo, O. Omolayo, J.R. Osborn, G. Penn, G.J. Portmann, D. Robin, F. Sannibale, C. Sun, C.A. Swenson, M. Venturini, S.P. Virostek, W.L. Waldron, E.J. Wallén
LBNL, Berkeley, California, USA

Funding: This work was 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 project to upgrade the Advanced Light Source to a multi bend achromat lattice received CD-1 approval in 2018 marking the end of its conceptual design phase. The ALS-U design promises to deliver diffraction limited performance in the soft x-ray range by lowering the horizontal emittance to about 70 pm rad resulting in two orders of magnitude brightness increase for soft x-rays compared to the current ALS. The design utilizes a nine bend achromat lattice, with reverse bending magnets and on-axis swap-out injection utilizing an accumulator ring. This paper presents recent design progress of the accelerator, as well as new results of the mature R&D program.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW097

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

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TUPGW108

Characterization of NEG Coatings for SLS 2.0

GUI, impedance, resonance, coupling

1662

M.M. Dehler, A. Citterio
PSI, Villigen PSI, Switzerland
S. Alberti, J.P. Hogge
SPC-EPFL, Lausanne, Switzerland
M. Hahn, H.P. Marques
ESRF, Grenoble, France
X.Y. Liu
USTC/NSRL, Hefei, Anhui, People’s Republic of China

To limit desorption and ameliorate pumping of the narrow 20 mm aperture vacuum chamber of SLS2.0, it is planned to fully coat it with nonevaporable getter (NEG) material. NEG coating can be produced with different structural characteristics, from dense films to columnar growth, with corresponding distinct electrical properties affecting the machine impedance and the instability threshold of the accelerator. In order to evaluate and characterize the coating process for geometries similar to the SLS chamber, we measured the resonance properties of coated and uncoated shorted waveguide pieces. First tests were done with standard X band waveguides at 12 and 7 GHz. Test setups using elliptical cross sections are in preparation, also for higher frequencies allowing the characterization of thin NEG layers. The final goal is to have a standardized process to test of samples coated by external producers. We describe the setups and first results.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW108

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

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TUPGW109

Conceptual Design of Vacuum Chamber for SPS-II Storage Ring

storage-ring, photon, impedance, emittance

1666

T. Phimsen, S. Chaichuay, N. Juntong, P. Klysubun, S. Prawanta, P. Sudmuang, P. Sunwong
SLRI, Nakhon Ratchasima, Thailand
R. Deepan, A. Khamkham
Suranaree University of Technology, Nakhon Ratchasima, Thailand

The SPS-II is a 3 GeV ultralow emittance light source which is now under studied and designed by Thailand Synchrotron Light Research Institute (SLRI). The SPS-II storage ring is based on Double-Triple Bend Achromat (DTBA) cell with a circumference of 321.3 m aiming for horizontal emittance of less than 1 nm-rad. The compact lattice leaves narrow space for vacuum components. The small gap between poles of the magnets requires narrow vacuum chambers and limits the conductance of the chambers. The chambers will be made by stainless steel with a thickness of 1.5 mm. the cross section of beam duct is 40 mm × 16 mm elliptical shape. The bending chamber is designed as a long triangular chamber such that photon absorber can be installed as far from the light source as possible to lower the power density of the heat load. The overview of designed vacuum system for the SPS-II is presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW109

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paper received ※ 14 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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TUPRB004

Magnetic Measurements of Insertion Devices Using the Vibrating Wire Technique

experiment, simulation, insertion-device, hardware

1683

C.K. Baribeau, D. Bertwistle, E.J. Ericson, J.T. Gilbert, T.M. Pedersen
CLS, Saskatoon, Saskatchewan, Canada

The commissioning of new in-vacuum insertion devices (ID) at the Canadian Light Source has motivated the assembly and development of a vibrating wire system. The advantage of the technique is that it is a sensitive magnetic measurement instrument at relatively low cost. Moreover, most hall probe systems require transverse access, which is often not available for in-vacuum or Delta-like devices. It is comparatively simple to string a taut wire through the gap of an in-vacuum ID. We describe the experimental challenges in mapping the field of an 80 mm period in-vacuum wiggler, IVW80, using the vibrating wire technique, and compare results against simulation and data obtained from Hall probe measurements.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB004

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paper received ※ 08 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPRB006

Effect of Electrostatic Deflectors and Fringe Fields on Spin for Hadron Electric Dipole Moment Measurements on Storage Rings

storage-ring, dipole, polarization, controls

1691

J. Michaud, J.-M. De Conto, Y. Gómez Martínez
LPSC, Grenoble Cedex, France

The observed matter-antimatter asymmetry in the universe cannot be explained by the Standard Model. An explanation is a non-vanishing Electric Dipole Moment of subatomic particles. The JEDI (Jülich Electric Dipole moment Investigations) collaboration is preparing a direct EDM measurement of protons and deuterons first at the storage ring COSY (COoler SYnchrotron) and later at a dedicated storage ring. To achieve this, one needs a stable polarization, i.e. around 1000 seconds for spin coherence time. One source of decoherence are the electrostatic deflectors, and this must be quantified. We developed an analytical model for cylindrical deflectors, including fringe fields, and the associated beam and spin transfer functions, integrated over the deflector. All boundaries (including ground) are considered, giving a realistic, accurate field map up to any order. We get universal formulas, the only adjustable parameter being the deflector gap/radius ratio, all other terms being numerical. This has been implemented in BMAD. We present the mathematical, physical and numerical developments, as well as results for a proton storage ring.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB006

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paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPRB015

Cryogenic, in-Vacuum Magnetic Measurement Setup for Superconducting Undulators

undulator, detector, GUI, synchrotron

1709

A.W. Grau, S. Casalbuoni, N. Glamann, D. Saez de Jauregui
KIT, Eggenstein-Leopoldshafen, Germany

The magnetic field quality has a strong impact on the performance of insertion devices (IDs) when installed in synchrotron light sources. Superconducting IDs have the advantage to produce a higher magnetic peak field for a given gap and period length than IDs assembled with permanent magnets. Before installation of a superconducting ID in a synchrotron light source it is of fundamental importance to characterize the magnetic properties by accurate field and field integral measurements. We follow this aim within our R&D program for superconducting undulators (SCUs). In this contribution, we describe the equipment and the challenges of a cryogenic, in vacuum measurement setup to perform magnetic measurements of the local field, the field integrals and the multipole components of in vacuum SCUs assembled in the final cryostat.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB015

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paper received ※ 29 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPRB021

Undulator Radiation Dose Caused by Synchrotron Radiation at the European XFEL

undulator, radiation, FEL, simulation

1724

S. Liu
DESY, Hamburg, Germany
Y. Li, F. Wolff-Fabris
EuXFEL, Hamburg, Germany

Radiation damage of the undulators is a big concern for the light sources. At the European XFEL (EuXFEL), dosimeters based on on-line Radfets are used for the un-dulator radiation dose measurements. However, since the Radfets are not only sensitive to the electrons and neu-trons but also to the photons, it can capture the synchro-tron radiation (SR) generated in the undulators, which is not considered to be the main source for undulator radia-tion damage. Therefore, it is important to estimate the contribution of synchrotron radiation to the radiation doses measured by the Radfets. For this purpose, we have first calculated the synchrotron radiation profile using SPECTRA, and then put the profile into the tracking code BDSIM to track it through the whole undulator beam line. The radiation doses from SR have been simulated and compared with the measured values. The differences in the radiation doses measured by the Radfets before and after Pb shielding will also be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB021

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

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TUPRB022

Triple Period Undulator

undulator, radiation, photon, operation

1728

A. Meseck, J. Bahrdt, W. Frentrup, M. Huck, C. Kuhn, C. Rethfeldt, M. Scheer
HZB, Berlin, Germany
E.C.M. Rial
DLS, Oxfordshire, United Kingdom

Insertion devices are one of the key components of modern synchrotron radiation facilities. They allow for generation of radiation with superior properties enabling experiments in a variety of disciplines, such as chemistry, biology, crystallography and physics to name a few. For future cutting edge experiments in soft and tender x-rays users require high flux and variable Polarization over a wide photon energy range independent of other desired properties like variable pulse length, variable timing or Fourier transform limited pulses. In this paper, we propose a novel ID-structure, called Triple Period Undulator (TPU), which allow us to deliver a wide energy range from a few ten eV to a few keV at the same beamline with high flux and variable Polarization. The TPU are particularly interesting in context of BESSY III, the successor facility of BESSY II.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB022

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paper received ※ 15 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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TUPRB040

Development of Coherent Terahertz Wave Sources and Transport Systems at LEBRA Linac

FEL, linac, electron, radiation

1775

T. Sakai, K. Hayakawa, Y. Hayakawa, K. Nogami, Y. Sumitomo, T. Tanaka
LEBRA, Funabashi, Japan
H. Ogawa, N. Sei
AIST, Tsukuba, Ibaraki, Japan

Funding: This work was supported by JSPS KAKENHI (Grant-in-Aid for Young Scientists (B)) Grant Number JP16K17539 and JP16H03912.
Development of a 125 MeV S-band electron linac for the generation of Free Electron Laser (FEL), Parametric X-ray Radiation (PXR) and coherent terahertz waves (THz waves) has been underway at LEBRA of Nihon University as a joint research with KEK and National Institute of Advanced Industrial Science and Technology (AIST). The high power coherent transition radiation (CTR), coherent edge radiation (CER) and the coherent synchrotron radiation (CSR) wave sources development has been carried out since 2011 at LEBRA. The transport systems of the each THz wave were installed in the vacuum chamber on the downstream side of the 45 degrees bending magnet of the PXR and FEL beam-line. In particular, a CER of the generated the FEL beam line can also be guided without disturbing the FEL oscillations. Additionally, a part of the mirror of the transport optical system is constructed using Indium Tin Oxide (ITO) mirror with the optimized for the transport of the THz wave. In this report, construction of the THz transport beam lines and the property of the THz lights are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB040

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paper received ※ 19 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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TUPRB055

First Results of the IVU16 Prototype Undulator Measurements

FEL, undulator, MMI, SRF

1808

C. Yu, Y.Z. He, X. Hu, Z. Jiang, M.F. Qian, Y.M. Wen, S. Xiang, L. Yin, J.D. Zhang, W. Zhang, Q.G. Zhou
SINAP, Shanghai, People’s Republic of China
H.X. Deng, B. Liu, D. Wang
SARI-CAS, Pudong, Shanghai, People’s Republic of China
H.F. Wang, Z.T. Zhao
SSRF, Shanghai, People’s Republic of China

The Shanghai Synchrotron Radiation Facility (SSRF) has developed a 16 mm period length, 4 mm gap, in-vacuum undulator (IVU) that is planned to be installed and tested in the 1.5 GeV SXFEL-SBP beam line. This paper will describe the main parameters of the undulator and the key design choices that have been made. The first undulator prototype was assembled and magnetically tested. First measurements with vacuum chamber will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB055

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPRB072

Compact APPLE X for Future SXL FEL and 3 GeV Ring at MAX IV Laboratory

undulator, polarization, photon, FEL

1833

H. Tarawneh, P. N’gotta, L.K. Roslund, A. Thiel, K. Åhnberg
MAX IV Laboratory, Lund University, Lund, Sweden

An overview of the design of compact elliptically polarizing undulator with small round magnetic gap to provide full polarization control of synchrotron radiation in a more cost effective manner and consuming less built in space than the state of the art devices. This type of undulator is meant as source for the potential future Soft X-ray (SXL) FEL beamline using the linear accelerator at MAX IV. In addition, it offers new capabilities for future beamlines at the 3 GeV ring to use full polarization control to photon energies using the fundamental harmonic which are not attainable with today’s technology of the out-of-vacuum insertion devices at 3 GeV beam energy.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB072

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paper received ※ 30 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPRB081

Beam Motion and Photon Flux Dips during Injection at the Taiwan Photon Source

injection, kicker, photon, betatron

1848

C.H. Huang, H.-P. Chang, C.H. Chen, Y.-S. Cheng, P.C. Chiu, C.-S. Fann, K.T. Hsu, K.H. Hu, C.Y. Liao, Y.-C. Liu, C.Y. Wu
NSRRC, Hsinchu, Taiwan

The Taiwan photon source (TPS) is a 3 GeV synchrotron light source now in routine operation at the NSRRC. At the beginning of beam commissioning, significant photon flux dips could be observed at injection due to a blow-up of the beam size. To eliminate this transient effect, all four kickers were rematched. The leakage field was shielded and the induced current loops at vacuum chambers in the injection area were also eliminated. These efforts reduced the horizontal betatron oscillations and orbit distortions to around one-tenth. In order to decrease the recovery time of photon dips during injection, the operational chromaticity was reduced to improve incoherent effects. After all those improvements, the photon flux dips during injection dropped to 30 % and the recovery time to less than 1 msec.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB081

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paper received ※ 17 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPRB083

Status of Clara Front End Commissioning and First User Experiments

laser, experiment, linac, diagnostics

1851

D. Angal-Kalinin, A.D. Brynes, R.K. Buckley, S.R. Buckley, R.J. Cash, H.M. Castaneda Cortes, J.A. Clarke, P.A. Corlett, L.S. Cowie, K.D. Dumbell, D.J. Dunning, B.D. Fell, P. Goudket, A.R. Goulden, S.A. Griffiths, J. Henderson, F. Jackson, J.K. Jones, N.Y. Joshi, S.L. Mathisen, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, A.J. Moss, B.D. Muratori, T.C.Q. Noakes, T.H. Pacey, M.D. Roper, Y.M. Saveliev, D.J. Scott, B.J.A. Shepherd, R.J. Smith, E.W. Snedden, M. Surman, N. Thompson, C. Tollervey, R. Valizadeh, D.A. Walsh, T.M. Weston, A.E. Wheelhouse, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
A.D. Brynes, J.A. Clarke, K.D. Dumbell, D.J. Dunning, P. Goudket, F. Jackson, J.K. Jones, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, A.J. Moss, B.D. Muratori, T.C.Q. Noakes, Y.M. Saveliev, D.J. Scott, B.J.A. Shepherd, M. Surman, N. Thompson, R. Valizadeh, A.E. Wheelhouse, P.H. Williams
Cockcroft Institute, Warrington, Cheshire, United Kingdom
R.F. Clarke, G. Cox, M.D. Hancock, J.P. Hindley, C. Hodgkinson, A. Oates, W. Smith, J.T.G. Wilson
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
L.S. Cowie
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
N.Y. Joshi, T.H. Pacey
UMAN, Manchester, United Kingdom

CLARA (Compact Linear Accelerator for Research and Applications) is a test facility for Free Electron Laser (FEL) research and other applications at STFC’s Daresbury Laboratory. The first exploitation period using CLARA Front End (FE) provided a range of beam parameters to 12 user experiments. Beam line to Beam Area 1 (BA1) was commissioned and optimised for these experiments, some involving TW laser integration. In addition to the user exploitation programme, significant advances were made to progress on machine development. This paper summarises these developments and presents the near future plan for CLARA.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB083

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

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TUPRB094

New Superconducting Undulator Magnetic Measurement System for the Advanced Photon Source Upgrade

GUI, undulator, photon, storage-ring

1881

M. Kasa, E.R. Anliker, Y. Ivanyushenkov, Y. Shiroyanagi
ANL, Argonne, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
Magnetic measurements of existing superconducting undulators (SCUs) are performed under normal operating conditions after final assembly into the cryostat and before installation on the Advanced Photon Source (APS) storage ring. The SCU cryostat for the APS upgrade has been scaled in length from the current cryostat and will contain two SCUs. While some aspects of the current measurement system are desirable to retain, such as a room temperature measurement bore, scaling the current measurement techniques to the length required for the APS upgrade cryostat is not feasible. To address these challenges a unique system has been developed at the APS to allow measurements of the two SCU magnets in the long cryostat. The measurement system developed allows the magnets to be operated under normal operating conditions while maintaining the measurement equipment at room temperature and atmospheric pressure.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB094

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

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TUPRB095

Superconducting Undulators for the Advanced Photon Source Upgrade

undulator, photon, electron, operation

1884

M. Kasa, E.R. Anliker, J.D. Fuerst, Q.B. Hasse, Y. Ivanyushenkov, I. Kesgin, Y. Shiroyanagi, E. Trakhtenberg
ANL, Argonne, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
The magnetic devices group at the Advanced Photon Source (APS) is in the process of designing and developing superconducting undulators (SCUs) for the APS upgrade. While similar in some aspects to previous SCU systems currently in operation at the existing APS, the new SCU systems will include two undulators installed in one cryostat which occupies an entire straight section of the storage ring. Straight sections containing planar undulators will either be configured as ’in-line’, where the two undulators behave as one source, or canted, where the two undulators are operated independently. Also under development is a superconducting arbitrary polarizing emitter (SCAPE) which can produce planar, elliptical, and helical undulator fields.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB095

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paper received ※ 14 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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TUPRB101

Damping Trapped Modes in an in-Vacuum Undulator at a Synchrotron Radiation Light Source

simulation, damping, HOM, impedance

1895

K. Tian, Z. Li, A. Ringwall, J.J. Sebek
SLAC, Menlo Park, California, USA

Funding: Work supported by US Department of Energy Contract DE-AC03-76SF00515.
In this paper, we report the efforts in solving the problem of coupled-bunch instabilities caused by an in-vacuum undulator in the SPEAR3 storage ring. After exploring several approaches to reduce the strength of the trapped modes, we found that ferrite dampers were the most effective and simplest way for mode damping in our SPEAR3 in-vacuum undulator. The results of the first RF cold measurement on an in-vacuum undulator equipped with these ferrite dampers agree well with numerical simulations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB101

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paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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TUPRB108

Mechanical Design of a Dielectric Wakefield Dechirper System for CLARA

FEL, wakefield, electron, alignment

1912

M. Colling, D.J. Dunning, B.D. Fell, T.H. Pacey, Y.M. Saveliev
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

STFC Daresbury Laboratory are developing a compact electron beam energy dechirper system, based on dielectric wakefield structure, for the on-site electron accelerator CLARA (Compact Linear Accelerator for Research and Applications). CLARA will be an experimental free electron laser (FEL) facility operating at 250MeV and will be a test bed for a variety of novel FEL schemes. The dechirper dielectric quartz plates will induce wakefields within the structure which can remove the beam chirp that is initially introduced to compress the electron bunch longitudinally. Removing or adjusting the amount of chirp enables researchers to reduce or adjust the bunch energy/momentum spread, expanding the FEL capabilities. The attachment and alignment of the quartz plates present numerous mechanical design challenges that require high precision manufacturing and quartz plate positioning via fiducialisation. This paper will review the dechirper specifications, the chosen design solutions, measured mechanical performance, and the expected effect of the dechirper on CLARA FEL operation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB108

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paper received ※ 13 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPTS011

Vacuum Lifetime and Surface Charge Limit Investigations Concerning High Intensity Spin-polarized Photoinjectors

cathode, electron, laser, experiment

1954

S. Friederich, K. Aulenbacher, C. Matejcek
IKP, Mainz, Germany
K. Aulenbacher
GSI, Darmstadt, Germany
K. Aulenbacher
HIM, Mainz, Germany

Funding: DFG excellence initiative PRISMA+, Bundesministerium für Bildung und Forschung "Verbundforschung FKZ 05K16UMA"
The Small Thermalized Electron Source at Mainz (STEAM) is a dc photoemission source. It is designed to operate at up to 200kV bias voltage with an accelerating field of up to 5 MV/m at the cathode surface. In several experiments, the properties of GaAs operating under the conditions of spin-polarized photoemission were investigated. Its performance, quantum efficiency lifetime and surface charge limit observations for bulk-GaAs will be discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS011

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paper received ※ 29 April 2019 paper accepted ※ 28 May 2019 issue date ※ 21 June 2019

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TUPTS021

Basic Design of the RF Power System for IRANCYC-10 Accelerator

cyclotron, simulation, ISOL, operation

1972

M. Dehghan, F. Abbasi
Shahid Beheshti University, Tehran, Iran
H. Azizi
ILSF, Tehran, Iran
F. Ghasemi
NSTRI, Tehran, Iran
A. Taghibi Khotbeh-Sara
KNTU, Tehran, Iran

In this paper the basic design of an RF system to produce the required power of IRANCYC-10 cyclotron accelerator is reported. The designed system can generate 15 kW power at the operating frequency of 71 MHz CW. The authors provide a step-by-step ex-planation of the process of the design. It is carried out in three sections; (1) RF design features of the acceler-ator is investigated and power value is calculated in accordance with the requirements of the cyclotron, (2) the choice of solid state amplifiers as the RF power source is presented with its available power and struc-ture, (3) design of insertion instruments is reported to transfer and combine the RF power. The purpose of the paper is to achieve the best performance of the RF system, as well as decreasing overall size by using modular devices.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS021

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paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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TUPTS026

Negative Electron Affinity GaAs Cathode Activation With CsKTe Thin Film

cathode, electron, photon, gun

1986

M. Kuriki
KEK, Ibaraki, Japan
K. Masaki
HU/AdSM, Higashi-Hiroshima, Japan

Funding: This work is partly supported by Japan-US Cooperative grant for scientific studies, Grant aid for scientific study by MEXT Japan (KAKENHI).
Negative Electron Affinity (NEA) GaAs cathode is an unique device which can generate a highly polarized electron beam with circularly polarized light. The NEA surface is conventionally made by Cs and \rm O/NF₃ adsorption on the cleaned p-doped GaAs crystal, but the robustness of the cathode is very limited, so that the electron emission is easily lost by residual gas adsorption, ion back-bombardment, etc. To improve the cathode robustness, NEA activation with a stable thin-film on GaAs surface according to Hetero junction hypothesis has been proposed by the author. An experiment of the NEA activation with CsKTe thin film was carried out at Hiroshima University and a significant electron emission with 1.43 eV photon was observed which strongly suggested NEA activation. The cathode showed 16 to 20 times improvement of lifetime comparing to GaAs activated with Cs and O.

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

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TUPTS032

Radiation Design of New 30 kW Beam Dump of J-PARC Main Ring

neutron, proton, radiation, site

2005

M.J. Shirakata, H. Kuboki, J. Takano
KEK, Ibaraki, Japan

The J-PARC Main Ring (MR) has a beam dump for the beam study and beam abort. Its present capacity is 7.5 kW in one hour average which is limited by radiation condition for the environments. The number of protons in one MR cycle is 2.6·10⁺¹⁴ in recent days, which corresponds to the beam power of 500 kW. As the top energy of J-PARC MR is 30 GeV, the number of available beam shots is restricted to less than twenty in one hour with such an intense beam. It imposes a big limitation on high power beam tuning and study. The number of protons is expected to become 3.3·10⁺¹⁴ for MW operation. Hence, an upgrade of the beam dump from 7.5 kW to 30 kW is planned. The radiation dose rate should be less than 0.25μSv/h on the ground. The backscattered neutron flux should be examined in the accelerator tunnel. The new dump design on radiation matters is described in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS032

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

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TUPTS035

Vacuum Tube Operation Analysis for 1.2 MW Beam Acceleration in J-PARC RCS

acceleration, cavity, operation, power-supply

2017

M. Yamamoto, M. Nomura, T. Shimada, F. Tamura
JAEA/J-PARC, Tokai-mura, Japan
M. Furusawa, K. Hara, K. Hasegawa, C. Ohmori, Y. Sugiyama, M. Yoshii
KEK, Tokai, Ibaraki, Japan

The J-PARC RCS has successfully accelerated 1 MW proton beam, matching the designed beam power. Therefore, we have considered acceleration beyond the designed beam power, with the next target being 1.2 MW. An issue for 1.2 MW beam acceleration is the rf system. The present anode power supply is limited by its output current, and the vacuum tube amplifier suffers from an unbalance of the anode voltage swing, arising from the combination of multi-harmonic rf driving and push-pull operation. We have investigated the mitigation of the maximum anode currents and unbalanced tubes by choosing appropriate circuit parameters of the rf cavity with the tube amplifier. We describe the analysis results of the vacuum tube operation for 1.2 MW beam acceleration in the RCS.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS035

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

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TUPTS036

Operation Status of J-PARC Rapid Cycling Synchrotron

operation, proton, status, synchrotron

2020

J. Kamiya, K. Yamamoto
JAEA/J-PARC, Tokai-mura, Japan

The 3 GeV rapid cycling synchrotron (RCS) at the Japan Proton Accelerator Research Complex (J-PARC) provides more than 500 kW beams to the Material and Life Science Facility (MLF) and Main Ring (MR). In such a high-intensity hadron accelerator, even losing less than 0.1% of the beam can cause many problems. Such lost protons can cause serious radio-activation and accelerator component malfunctions. Therefore, we have conducted a beam study to achieve high-power operation. In addition, we have also maintained the accelerator components to enable stable operation. This paper reports the status of the J-PARC RCS over the last year.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS036

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

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TUPTS065

RF Conditioning of the CLARA 400 Hz Photoinjector

cavity, GUI, controls, operation

2067

L.S. Cowie, D.J. Scott
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Automated conditioning of the 400 Hz photoinjector for CLARA was begun and the conditioning program refined. The conditioning was performed at 100 Hz. Masks were used to detect breakdowns in the reflected power and phase, and the breakdown rate was limited to 5x106 breakdowns per pulse. The cavity gradient and breakdown rate evolution over the conditioning time is presented. Post-pulse multipactor and other evidence of electron effects were detected. Possible mechanisms for this are discussed. The conditioning was interrupted by breakdown in the waveguide after reaching 2.5 MW, and will be resumed after the planned 6 month shutdown of CLARA.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS065

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

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TUPTS084

Performances of Silicon-Based Field-Emission Cathodes Coated with UltraNano Crystalline Diamond

cathode, electron, experiment, simulation

2117

O. Mohsen, V. Korampally, A. Lueangaramwong, P. Piot, V. Valluri
Northern Illinois University, DeKalb, Illinois, USA
R. Divan, A.V. Sumant
Argonne National Laboratory, Argonne, Illinois, USA
P. Piot
Fermilab, Batavia, Illinois, USA

Funding: Work supported by NSF grant PHY-1535401 and DOE award DE-SC0018367 with NIU
Field-emission electron sources have been considered as possible candidates for the production of bright or high-current electron bunches. In this paper, we report on the experimental characterization of silicon-based field-emitter arrays (FEA) in a DC high voltage gap. The silicon cathodes are produced via a simple self-assembling process. The measurement reported in this paper especially compares the field-emission properties of a nanostructured and planar diamond-coated Si-based cathode.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS084

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paper received ※ 17 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPTS101

Bi-Alkali Antimonide Photocathodes for LEReC DC Gun

cathode, electron, gun, laser

2154

E. Wang, A.V. Fedotov, M. Gaowei, D. Kayran, D. Lehn, C.J. Liaw, T. Rao, J.E. Tuozzolo, J. Walsh
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Low Energy RHIC electron cooling (LEReC) is a bunched electron cooler at RHIC. The Bi-alkali photocathodes are chosen as electron source due to its long lifetime and high QE at visible wavelength. Because the DC gun needs to produce 24/7 beams over several months, cathode production system and multiple cathodes transferring systems are designed, commissioned and in operation. In this report, we will describe our photocathodes production and discuss the cathode’s performance from cathode growth system to the DC gun.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS101

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPTS103

The Progress of High Current High Bunch Charge Polarized Electron HVDC Gun

cathode, gun, electron, high-voltage

2160

E. Wang, I. Ben-Zvi, R.F. Lambiase, W. Liu, O.H. Rahman, J. Skaritka, F.J. Willeke
BNL, Upton, Long Island, New York, USA
I. Ben-Zvi
Stony Brook University, Stony Brook, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The high current and high bunch charge polarized electron source is essential for cost reduction of eRHIC. It aims to deliver electron beam with 10 mA average current and 5.3 nC bunch charge. We analyzed the mechanism of cathode degradation and proposed using a large strain superlattice GaAs photocathode in a high voltage DC gun to increase the charge lifetime above kilo Coulomb. The gun has been designed and fabricated and expected to start commissioning by the mid of this year. In this paper, we will present the modeling of ion back bombardment and cathode degrading. We proposed an anode offset scheme to increase cathode lifetime. Also, we will describe the details of gun design and the strategies to demonstrate high current high charge polarized electron beam from this source.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS103

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

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TUPTS106

First Commissioning of LCLS-II CW Injector Source

gun, cavity, operation, electron

2171

F. Zhou, C. Adolphsen, A.L. Benwell, G.W. Brown, W.S. Colocho, Y. Ding, M.P. Dunning, K. Grouev, B.T. Jacobson, X. Liu, T.J. Maxwell, J.F. Schmerge, T.J. Smith, T. Vecchione, F.Y. Wang, C.M. Zimmer
SLAC, Menlo Park, California, USA
G. Huang, F. Sannibale
LBNL, Berkeley, California, USA

Funding: The work is supported by DOE under grant No. DE-AC02-76SF00515
The LCLS-II injector source includes a 186MHz CW rf-gun, a 1.3 GHz CW rf-buncher, a loadlock system for photocathode change, two main solenoids, and a few essential diagnostics. The electron beam is designed to operate at a high repetition rate, up to 1-MHz. Since summer of 2018 we started LCLS-II injector source commissioning immediately after the major installation was completed. Initial commissioning showed the rf-gun was severely contaminated with hydrocarbons and very limited power <600W could be fed into the gun cavity. After a few significant processes, we eventually removed the hydrocarbons and successfully delivered desired rf power of 80 kW to the gun. This paper reports first com-missioning results including gun bakeout and vacuum processing, CW RF-gun and buncher operation with nom-inal power, and measurements of rf stability and dark current.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS106

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

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TUPTS109

Status of AC Dipole Project at Rhic Injectors for Polarized 3He, Update

dipole, booster, resonance, proton

2177

K. Hock, C.W. Dawson, H. Huang, J.P. Jamilkowski, F. Méot, P. Oddo, M.C. Paniccia, Y. Tan, N. Tsoupas, J.E. Tuozzolo, K. Zeno
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
An ac dipole will be used for the efficient transport of polarized 3He in the AGS Booster as it is accelerated to |Gγ|=10.5. The ac dipole introduces a coherent vertical beam oscillation which allows preservation of polarization through the two intrinsic resonances Gγ=12-νy and Gγ=6+νy resonances, by full spin flipping. The AGS Booster ac dipole will be tested with protons crossing the Gγ=0+νy intrinsic resonance, which has ac dipole requirements similar to polarized 3He crossing the Gγ=12-νy resonance, providing a convenient proof of principle. This paper gives a status of the project.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS109

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paper received ※ 13 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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TUPTS111

Study on Improving Durability of Cs-Te Photocathode for an RF-gun

cathode, gun, electron, brightness

2182

T. Tamba, J. Miyamatsu, K. Sakaue, M. Washio
Waseda University, Tokyo, Japan

At Waseda University, we have been studying for high quality electron beam generation using 1.6 cell Cs-Te photocathode rf-gun. We use photocathode as the electron source, which can generate high- quality electron beam such as low emittance, and short bunch. The performance of photocathode is evaluated mainly in terms of quantum efficiency (Q.E.) and lifetime. Cs-Te photocathode used in the rf-gun is known for high Q.E. about 10% with UV light and relatively longer lifetime among semiconductor photocathodes. Since it is a hard environment for photocathode inside the gun, it is necessary to replace the photocathode every several months. In other words, in order to achieve long-term operation of rf-gun, it is necessary to find highly durable photocathode recipe. It has been reported that the Cs-Te photocathode by co-evaporation can produce a photocathode having a longer lifetime as compared with the sequential evaporation. Moreover, we have done studies to improve lifetime and durability of Cs-Te photocathode by coating the cathode surface with CsBr thin film. In this conference, we report the evaluation results of Cs-Te photocathode by co-evaporation, CsBr coating and future prospects.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS111

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paper received ※ 12 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPTS112

Stand-alone Accelerator System Based on SRF Quarter-wave Resonators

cryomodule, SRF, operation, cavity

2185

S.V. Kutsaev, R.B. Agustsson, R.D. Berry, D. Chao
RadiaBeam, Santa Monica, California, USA
Z.A. Conway
ANL, Argonne, Illinois, USA

Funding: This material is based upon work supported by the U.S. Department of Energy under contracts DE-SC0017101 and DE-AC02-06CH11357. This research used resources of DOE ANL’s ATLAS facility.
Superconducting accelerators are large and complex systems requiring a central refrigerator and distributed transfer systems to supply 2-4 K liquid helium. Stand-alone, cryocooler-based systems are of interest both to scientific facilities and industrial applications, as they do not require large cryogenic infrastructure and trained specialists for operation. Here we present our approach to the challenge of using low-power commercially available cryocoolers to operate niobium superconducting resonators at 4.4 K with high accelerating voltages and several watts of heating. Engineering and design results from RadiaBeam Systems, collaborating with Argonne National Laboratory, for a stand-alone liquid-cooled cryomodule with 10 Watts of 4.4 K cooling capacity housing a 72.75 MHz quarter-wave resonator operating at 2 MV for synchronous ions travelling at 7.7% of speed of light will be discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS112

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

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TUPTS114

Electron Stimulated Desorption from Cryogenic NEG-Coated Surfaces

electron, cryogenics, experiment, site

2193

R. Sirvinskaite, M.D. Cropper
Loughborough University, Loughborough, Leicestershire, United Kingdom
A.N. Hannah, O.B. Malyshev, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
S. Wang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Non-Evaporable Getter (NEG) coating has been used for years in many particle accelerators due to its advantages like evenly distributed pumping speed, low thermal outgassing, and low photon, electron and ion stimulated desorption yields. Although NEG coating has been tested at room temperatures intensively, there is little data on its behaviour at cryogenic temperatures. Tests in this environment are important for the Future Circular Collider (FCC) study and other accelerator facilities where the operational conditions of the beam screen are restricted to cryogenic temperatures. This work will provide some preliminary results on NEG properties at low temperatures, e.g. pumping speed and capacity, as well as its behaviour under electron bombardment, where electron stimulated desorption (ESD) yields will be calculated. The ternary Ti-Zr-V coating, deposited with dense and columnar structure, will be the first material to be tested at cryogenic temperatures in ASTeC Daresbury laboratory. The results were compared with the ones obtained at room temperature, offering an insight into the behaviour of NEG-coated cryogenic chambers when beam-induced effects are present.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS114

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

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TUPTS115

The Progress in Physical Start-Up of the NSC KIPT Subcritical Neutron Source Facility Driven by an Electron Linear Accelerator

neutron, target, electron, detector

2197

P. Gladkikh, O.V. Bykhun, I.M. Karnaukhov, A. Mytsykov, V. Stomin, I. Ushakov, A.Y. Zelinsky
NSC/KIPT, Kharkov, Ukraine

National Science Center ’Kharkov Institute of Physics &Technology’ (NSC KIPT), Kharkov, Ukraine and Argonne National Laboratory (ANL), Chicago, USA are jointly constructing and commissioning the Ukraine Neutron Source facility. The facility consists of a subcritical assembly driven by a 100MeV/100kW electron linear accelerator. The electron beam will be used for generating the neutrons for operating the subcritical assembly using tungsten or natural uranium target. The facility is planned to support the Ukraine nuclear industry, and provide a capability for performing reactor physics, material research, and basic science experiments, to produce medical isotopes, train young nuclear professionals. The integrating facility tests were completed at the end of 2018, and physical start-up operation began in 2019. The facility commissioning and current start-up results are presented and discussed in the paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS115

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

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WEXXPLS2

Accelerator Vacuum Windows: A Review of Past Research and a Strategy for the Development of a New Design for Improved Safety and Longevity for Particle Accelerators

Windows, radiation, experiment, scattering

2237

C.R. Ader, M.L. Alvarez, J.S. Batko, R. Campos, M.W. McGee, A.C. Watts
Fermilab, Batavia, Illinois, USA

Funding: Fermi National Accelerator Laboratory
Vacuum window research continues at Fermilab and this paper will examine cost effective, consistent designs which can have a significant impact on accelerator laboratories in terms of safety and cost. Issues such as the design, materials, analysis, testing and fabrication are addressed, including beam scattering and materials cost-benefit analysis and examining potential material substitutes for beryllium. A previous research paper has examined current fabrication and design techniques and also failure modes at Fermi, and this paper focuses on emerging and novel technologies for vacuum window fabrication. Many different paths have been taken by High Energy Physics (HEP) Laboratories throughout the world with varying success. The history of vacuum window development is extensive and not well defined, and a matrix of the research already completed on materials and joint design for vacuum windows will be shown. This report finally includes a treatise for vacuum window technology and a view towards emerging designs and materials and discusses future advances of research such as fabrication techniques including additive manufacturing and ultrasonic welding. Further exploration into these would prove beneficial to developing vacuum windows that are safer and stronger while being more transparent to the beam.

Slides WEXXPLS2 [3.139 MB]

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

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WEXXPLS3

Is it Possible to Use Additive Manufacturing for Accelerator UHV Beam Pipes?

electron, laser, ECR, experiment

2240

G. Sattonnay, M. Alves, S. Bilgen, B.J. Bonnis, A. Gonnin, D. Grasset, S. Jenzer, F. Letellier-Cohen, B. Mercier, E. Mistretta
LAL, Orsay, France
F. Brisset
ICMMO, Orsay, France

Funding: Work supported by a grant from IN2P3/CNRS, program I3D metal
Recently, additive manufacturing (AM) has revolutionized mechanical engineering by allowing the quick production of mechanical components with complex shapes. AM by selective laser melting (SLM) is an advanced manufacturing process which uses lasers to melt metal powders one layer at a time to produce final 3D components. This technology could be also used to make Ultra High Vacuum components. Therefore, we investigated in this work the reproducibility of AM 316L stainless steel properties for different specimen supplied by several manufacturers with the same SLM process. Clearly, the microstructure and therefore the mechanical properties of the investigated AM samples are different as a function of manufacturers: indeed, they are largely influenced by processing parameters, which produces heterogeneous and anisotropic microstructures that differ from traditional wrought counterparts. Samples were also submitted to bake cycles at high temperature, in order to check the structural stability of material properties after heat treatments. The outgassing rates and the secondary emission yield of vacuum components constructed from AM 316L were also measured. Finally, the possibility to use AM for accelerator beam pipes will be discussed.

Slides WEXXPLS3 [9.009 MB]

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paper received ※ 01 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEYYPLS3

Development of Methods for Calculation of Bunch Radiation in Presence of Dielectric Objects

radiation, target, simulation, focusing

2274

A.V. Tyukhtin, E.S. Belonogaya, S.N. Galyamin, V.V. Vorobev
Saint Petersburg State University, Saint Petersburg, Russia

Funding: This work was supported by the Russian Science Foundation (Grant # 18-72-10137).
Radiation of charged particles moving in presence of dielectric targets is of interests for various applications in accelerator and beam physics*. Typically, the size of the target is much larger than the wavelengths under consideration. This fact gives us an obvious small parameter of the problem and allows developing approximate methods of analysis. We develop two methods: "ray-optical method" and "aperture method"**. These methods can be very effective for all situations where we can find the tangential field components on the "aperture" which is an object boundary illuminated by Cherenkov radiation. We apply the aperture method to different dielectric objects including a prism, a cone, and a ball. Electromagnetic field is analyzed on different distances from the objects. The special attention is given to investigation of the field in the far-field (Fraunhofer) area having large importance for various applications. We obtain analytical results for different objects, demonstrate typical radiation patterns and discuss new physical effects, in particular, the phenomenon of concentration of radiation and effect of "Cherenkov spotlight". Prospects of use of aperture method and ray-optical one for other objects are discussed as well.
* R.Kieffer et al, PRL, 121, 054802 (2018).
** E.S.Belonogaya et al, JOSA B, 32, 649 (2015); S.N.Galyamin, A.V.Tyukhtin, PRL, 113, 064802 (2014); A.V.Tyukhtin et al, J. Instrum., 13, C02033 (2018).

Slides WEYYPLS3 [4.063 MB]

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

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WEZPLM1

The LATINO Project - An Italian Perspective on Connecting SMEs with Research Infrastructures

laser, instrumentation, radio-frequency, operation

2277

L. Sabbatini, D. Alesini, A. Falone, A. Gallo
INFN/LNF, Frascati, Italy
V. Pettinacci
INFN-Roma, Roma, Italy

Funding: The LATINO project is co-funded by the Regione Lazio within POR-FESR 2014-2020 European activities (public call ’Open Research Infrastructures’).
The National Laboratories of Frascati (LNF) are the first Italian research facility for the study of nuclear and subnuclear physics with accelerators and are the largest laboratories of the Italian National Institute for Nuclear Physics (INFN), the public body whose mission is theoretical, experimental and technological research in subnuclear, nuclear and astroparticle physics. LNF have an extensive experience in designing, installation, testing and operation of particle accelerators and the related technologies. The competences range over almost all the technologies related to particle accelerators, including radio frequency, vacuum, magnets and mechanics. LNF have always had a close relationship with the regional and national industries, stimulating the development and growth of the industrial background by means of close collaboration with partners. The LATINO (a Laboratory in Advanced Technologies for INnOvation) project is an initiative that fits into this path and aims to strengthen this relationship, allowing access to the technologies, instruments and competences not otherwise available to the enterprises. A modern vision of advanced economies recommends the Technology Transfer from the research world to the productive activities through the creation of research infrastructures as the most efficient system for generating innovation and economic development [1-3]. The Regione Lazio, despite hosting centres of excellence, has a delay in the establishment of this kind of infrastructures.

Slides WEZPLM1 [4.103 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEZPLM1

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

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WEPMP001

Proposed Nonlinear Injection Kicker for the Australian Synchrotron

kicker, injection, synchrotron, storage-ring

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.

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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

septum, injection, kicker, photon

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.

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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

kicker, injection, septum, storage-ring

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

kicker, impedance, simulation, high-voltage

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.

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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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WEPMP022

Design and Construction of the CERN SPS Extraction Protection Elements for LIU

extraction, simulation, quadrupole, brightness

2359

B. Balhan, C. Baud, J.C.C.M. Borburgh, M.A. Fraser, M. Hourican, L.O. Jorat, F.-X. Nuiry, S. Pianese
CERN, Geneva, Switzerland

At CERN, the SPS synchrotron is equipped with two fast extraction channels towards the LHC. As a part of the LHC injector upgrade project (LIU), the protection devices upstream of the septa in both extraction channels will be upgraded. Various failure scenarios have been studied and presented in the past, but the definitive approach for the equipment protection upgrade for each channel has now been determined. This paper describes the consequences of the most significant failure scenarios and the impact of the heat deposition in the diluter. The resulting material stresses are evaluated. The detailed layout for the extraction protection equipment for each extraction channel is outlined. The final layout consists of a extended diluter in Long Straight Section (LSS) 6 (TPSG6) and the installation of an additional movable absorber (TPSC4) upstream of the quadrupole in front of the existing protection equipment in LSS 4. The detailed mechanical design of the TPSC4 and the construction status of both TPSC4 and TPSG6 are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP022

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paper received ※ 10 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPMP024

Alternative Material Choices to Reduce Activation of Extraction Equipment

extraction, shielding, radiation, proton

2363

D. Björkman, B. Balhan, J.C.C.M. Borburgh, L.S. Esposito, M.A. Fraser, B. Goddard, L.S. Stoel, H. Vincke
CERN, Geneva, Switzerland

At CERN, the Super Proton Synchrotron (SPS) is equipped with a resonant slow extraction system in Long Straight Section 2 (LSS2) towards the fixed target (FT) beam lines in the North Area. The extraction region provides the physics experiments with a quasi-DC flux of high-energy protons over a few seconds, which corresponds to tens of thousands of turns. The resonant slow extraction process provokes beam losses and is therefore the origin of radiation damage and the production of induced radioactivity in this region of the machine. This induced radioactivity imposed high constraints on the equipment design to be reliable to minimise the radiation exposure to personnel during machine maintenance. A detailed FLUKA model was developed in order to better understand the beam loss patterns, activation of the machine and to identify equipment components that could be optimised to reduce the residual dose related hazards. Simulations identified multiple alternative materials for extraction equipment components as well as shielding locations, which implementation could reduce residual activation hazards.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP024

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paper received ※ 26 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPMP040

Machine Protection Aspects of High-Voltage Flashovers of the LHC Beam Dump Dilution Kickers

kicker, operation, simulation, high-voltage

2418

C. Wiesner, W. Bartmann, C. Bracco, M. Calviani, E. Carlier, L. Ducimetière, M.I. Frankl, M.A. Fraser, S.S. Gilardoni, B. Goddard, V. Gomes Namora, T. Kramer, A. Lechner, N. Magnin, M. Meddahi, A. Perillo-Marcone, T. Polzin, L.C. Richtmann, V. Rizzoglio, V. Senaj, J.A.F. Somoza, D. Wollmann
CERN, Geneva, Switzerland

The LHC Beam Dump System is required to safely dispose of the energy of the stored beam. In order to reduce the energy density deposited in the beam dump, a dedicated dilution system is installed. On July 14, 2018, during a regular beam dump at 6.5 TeV beam energy, a high-voltage flashover of two vertical dilution kickers was observed, leading to a voltage breakdown and reduced dilution in the vertical plane. It was the first incident of this type since the start of LHC beam operation. In this paper, the flashover event is described and the implications analysed. Circuit simulations of the current in the magnet coil as well as simulations of the resulting beam sweep pattern are presented and compared with the measurements. The criticality of the event is assessed and implications for future failure scenarios are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP040

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paper received ※ 14 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

impedance, septum, simulation, storage-ring

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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WEPGW004

Wire Scanner for High Intensity Ion Beam*

quadrupole, focusing, electron, LEBT

2466

A. Beller, D. Bondoux, F. Bouly
LPSC, Grenoble Cedex, France

Funding: Part of this work supported by the European Atomic Energy Community (EURATOM) H₂020 Program under grant agreement n°662186 (MYRTE project).
The goal of the project is to develop a Wire-Scanner compatible with low energy - high intensity ion beams and adaptable to various beam chamber diameters. The purpose is to obtain the 2D beam profile by passing measurement wires through the beam. Thanks to a high speed passage of measurement wires, it allows to avoid "disrupting" the beam passage, and can be considered as a non-destructive diagnosis. Wires heating and measuring issues have been solved by using tungsten wires kept in tension by a mechanical system. All driving and signal measurements are performed by a PXI based system. The synchronization of the measurements is guaranteed by an analog input board recovering the wires current and the translator position, the latter being carried out by a laser sensor. Besides this technological aspect, an optimization algorithm for beam profile reconstruction from measured data under Gaussian hypothesis has been developed. The standalone system and first experimental results are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW004

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paper received ※ 13 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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WEPGW033

Development of the Bunch Shape Monitor Using the Carbon-Nano Tube Wire

electron, high-voltage, operation, DTL

2543

R. Kitamura, N. Hayashi, K. Hirano, Y. Kondo, K. Moriya, H. Oguri
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
K. Futatsukawa, T. Miyao, M. Otani
KEK, Ibaraki, Japan
S. Kosaka, Y. Nemoto
Nippon Advanced Technology Co., Ltd., Tokai, Japan

A bunch shape monitor (BSM) is one of the important instruments to measure the longitudinal phase space distribution. The information of the bunch length measured by the BSM is useful to tune phases of the accelerating cavities in the linear accelerator. For example, in the J-PARC linac, three BSM’s using the tungsten wire are installed and tested at the ACS section to measure the bunch shapes between the accelerating cavities. However, this conventional BSM is hard to measure the bunch shape of H⁻ beam with 3 MeV at the beam transport between the RFQ and DTL sections, because the wire is broken around the center region of the beam. The new BSM using the carbon-nano-tube (CNT) wire is being developed to be able to measure the bunch shape of the H⁻ beam with 3 MeV. One challenge to introduce the CNT wire for the BSM is the measure to the discharge. The careful attention should be paid to apply the high voltage of 10 kV to the CNT wire. The several measures are taken to suppress the discharge from the wire and operate the CNT-BSM. This presentation reports the current status of the development and future prospective for the CNT-BSM.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW033

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPGW037

Development of a Dense Gas Sheet Target for a 2D Beam Profile Monitor

electron, experiment, simulation, target

2554

N. Ogiwara, Y. Hori
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
Y. Hikichi, J. Kamiya, M. Kinsho
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
I. Yamada
Doshisha University, Graduate School of Engineering, Kyoto, Japan

We have been developing a dense gas sheet target to realize a non-destructive and fast-response beam profile monitor for the accelerators in J-PARC. The beaming effect in vacuum science and technology has been employed for making a gas sheet. The gas sheet with a thickness of ~ 1 mm and the density of 2 x 10^-4 Pa was successfully obtained. Then, we have successfully measured the profiles of the 400 MeV H⁻ ion beam in J-PARC linac by detecting the ions generated through the collision of this gas sheet to the H⁻ beam. This time, we have developed the gas sheet with the density of more than 10-3 Pa using a circular slit. The details of the new gas sheet generator will be shown.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW037

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paper received ※ 20 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEPGW046

Key Technologies for Remote Detection of CSNS Radiation Environment

controls, radiation, operation, target

2584

L. Kang, R.H. Liu, X.J. Nie, A.X. Wang, G.Y. Wang, D.H. Zhu
IHEP, Beijing, People’s Republic of China
J.X. Chen, H.Y. He, L. Liu, C.J. Ning, J.B. Yu, Y.J. Yu, J.S. Zhang
IHEP CSNS, Guangdong Province, People’s Republic of China

Funding: Work supported by National Nature Science Foundation of China (11375217)
China Spallation Neutron Source (CSNS) has been continuously operating in September 2018. As the operating time increases the radiation dose will also increase, some equipment maintenance and testing must take special tools and equipment. This article mainly introduced the studies on radiation environment of several detection technologies, such as: remote vacuum leak detection methods and equipment, strong magnetic field environment vibration measuring technology, using Qr code tracing machine walking vehicle inspection system and remote image vision measurement technology, etc., these advanced technology also has a guiding significance to other related fields.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW046

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paper received ※ 23 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPGW080

Design of Resonant Stripline BPM for an IR-FEL Project at NSRL

FEL, dipole, electron, emittance

2665

X.Y. Liu, B.G. Sun
USTC/NSRL, Hefei, Anhui, People’s Republic of China
M. Bopp, M.M. Dehler, X.Y. Liu, A. Scherer
PSI, Villigen PSI, Switzerland

Funding: Work supported by the National Science Foundation of China (11575181, 21327901, 11705203); X. Y. Liu was supported by the China Scholarship Council for a 2-year study at PSI (Grant No. 201706340057).
This paper presents the design of a 476MHz resonant stripline beam position monitor (BPM) for an IR-FEL machine at NSRL. This type of BPM was developed based on stripline BPM by moving the coupling feedthrough closer to the short end downstream. This modification introduces a resonance that gives this BPM a better capability to detect lower beam currents compared to broadband devices like button and stripline BPM. Meanwhile, the change is small enough to use the same type of electronics [1-3]. In the following sections, the basic principle, nonlinear effect, sensitivity, the filtered sum and difference signals, and the mechanical design of this BPM will be mainly discussed.
Email address: xiaoyu.liu@psi.ch

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW080

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paper received ※ 10 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPGW085

Development of Operating Alarm System at TPS

operation, controls, storage-ring, EPICS

2684

C.S. Huang, B.Y. Chen, C.K. Kuan, C.H. Kuo, T.Y. Lee, W.Y. Lin, S.Y. Perng, T.C. Tseng, H.S. Wang
NSRRC, Hsinchu, Taiwan

The Taiwan Photon Source (TPS) has many subsystems which includes magnet, power supply, vacuum, RF system, insertion device, control system, etc. Therefore, the operational and system check procedures are complex. In this paper, we summarize the routine operational procedures and propose an integrated operational alarm system that gathers machine information and sets high/low warning and fault limits for various signals which can help operators to quickly identify abnormal subsystems, thereby reducing machinery down time. The alarm system also has a wide range of applications, such as the event recording that helps the analysis after event. This new alarm system interface clearly indicates the machine status and improves operational efficiency.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW085

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

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WEPRB007

RF Commissioning of the SPIRAL2 RFQ in CW Mode and Beyond Nominal Field

cavity, LLRF, rfq, controls

2804

M. Di Giacomo, R. Ferdinand, H. Franberg, J.-M. Lagniel, G. Normand
GANIL, Caen, France
M. Desmons, P. Galdemard, Y. Lussignol, O. Piquet, S. Sube
CEA-DRF-IRFU, France

The SPIRAL2 RFQ was recently successfully commissioned at nominal voltage of 114 kV, corresponding to 1.65 Kilpatrick factor. The paper describes limitations of the RFQ main subsystems, cavity conditioning difficulties, as well as changes implemented in the LLRF and automatic procedures to simplify turn on and operation of the whole system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB007

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paper received ※ 26 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPRB008

Design Study of High Gradient Compact S-band TW Accelerating Structure for the ThomX LINAC Upgrade

linac, HOM, electron, emittance

2807

M. El Khaldi, M. Alkadi, C. Bruni, L. Garolfi, A. Gonnin, H. Monard
LAL, Orsay, France

ThomX is a Compton source project in the range of the hard X rays (45/90 keV). The machine is composed of a 50/70 MeV injector Linac and a storage ring where an electron bunch collides with a laser pulse accumulated in a Fabry-Perot resonator. The final goal is to provide an X-rays average flux of 10¹²-10¹³ ph/s. A demonstrator was funded and is being built on the Orsay university campus. The S-band injector Linac consists of 2.5 cell photocathode RF gun and a TW accelerating section. During the commissioning phase, a standard LIL S-band accelerating section is able to achieve around 50 MeV corresponding to around 45 keV X-rays energy. Since the maximum targeted X-ray energy is 90 keV, the development of a new S-band accelerating section, intended to replace the LIL structure, will provide an electron beam energy of 70 MeV. This requires essentially the development of more reliable high gradient compact S band accelerating section. Such design is tailored for high gradient operation, low breakdown rates. We present here the RF design of the LINAC upgrade and the performances obtained in terms of beam dynamics.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB008

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paper received ※ 02 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEPRB009

Validation of the Series Power Couplers of the LIPAc SRF Linac

operation, SRF, cryomodule, linac

2811

H. Jenhani, N. Bazin, C. Boulch, S. Chel, G. Devanz, G. Disset, C. Servouin
CEA-IRFU, Gif-sur-Yvette, France
I. Kirpitchev, J. Mollá, P. Méndez, D. Regidor, C. de la Morena
CIEMAT, Madrid, Spain

In the framework of the IFMIF/EVEDA project, the cryomodule of the Linear IFMIF Prototype Accelerator (LIPAc) will be assembled then tested at Rokkasho in 2019. Eight Series Power Couplers (PC) operating at 175 MHz were manufactured under a CEA contract, in order to equip this Cryomodule. They were all successfully RF conditioned up to 100 kW CW in TW and SW configurations. All the high RF power tests were performed under CIEMAT responsibility in BTESA Company premises, according to the CEA requirements. In order to fix difficulties encountered during the fab process, manufacturing and quality control have been analyzed in depth. Thanks to the corrective actions implemented, every PC reached the performances targeted for qualification. This paper will give details about this manufacturing phase and provide an overview of the obtained RF test results.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB009

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paper received ※ 09 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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WEPRB015

Cleanroom Installations for SRF Cavities at the Helmholtz-Institut Mainz

cavity, operation, heavy-ion, SRF

2830

T. Kürzeder, K. Aulenbacher, W.A. Barth, C. Burandt, F.D. Dziuba, V. Gettmann, R.G. Heine, S. Lauber, J. List, M. Miski-Oglu
HIM, Mainz, Germany
K. Aulenbacher, F.D. Dziuba
IKP, Mainz, Germany
W.A. Barth, C. Burandt, V. Gettmann, M. Miski-Oglu, S. Yaramyshev
GSI, Darmstadt, Germany
J. Conrad
TU Darmstadt, Darmstadt, Germany
R.G. Heine, F. Hug, T. Stengler
KPH, Mainz, Germany

At the Helmholtz-Institut Mainz (HIM) a cleanroom has been equipped with new tools and installations for the planned treatment of different superconducting RF-cavities. At first TESLA/XFEL type 9-cell cavities for the Mainz Energy-Recovering Superconducting Accelerator (MESA) project or 217 MHz multigap Crossbar H-mode cavities for the HElmholtz LInear ACcelerator (HELIAC) under development by HIM and GSI will be treated. The cleanroom installations, including the greyroom, cover an area of about 155 sqm. In its ISO-class 6 area a large ultrasonic and a conductance rinsing bath has been installed recently. A high pressure rinsing cabinet (HPR) has been implemented between the ISO-class 6 and 4 cleanroom. A RF-cavity can be loaded and unloaded from both sides. HPR treatments are possible for cavities of up to 1.4 m length and about 0.7 m diameter. For drying the ISO-class 4 clean room is equipped with a 160 C vacuum oven. New cleanroom lifters allow the handling of up to 200 kg heavy objects. A rail system in the cleanroom floor is installed to move out the entire cold string of the cleanroom after assembly and leak testing. First operational experiences with this facility will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB015

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paper received ※ 29 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPRB023

Vertical Test of ESS Medium Beta Cavities

cavity, HOM, cryomodule, linac

2852

A. Bosotti, M. Bertucci, A. Bignami, P. Michelato, L. Monaco, R. Paparella, D. Sertore
INFN/LASA, Segrate (MI), Italy
D. Reschke, A. Sulimov, M. Wiencek
DESY, Hamburg, Germany

The Medium beta (β=0.67) section of the European Spallation Source (ESS) Linac is composed of 36 six-cell elliptical superconducting (SC) cavities. As a part to the in kind contribution of Italy to the ESS project, INFN-LASA is in charge of the development and of the industrial production of the whole set of 36 resonators plus two spares. The production activity is now ongoing at ZANON. To qualify the cavities power tests in vertical cryostat has been committed to DESY. During the qualification tests, where the cavities provided with He tanks are pushed to their electromagnetic limits, recording their main electromagnetics parameters such as quality factor Q₀ vs E_acc. In this paper we report about the qualification tests performed on the first part of the quality production.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB023

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

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WEPRB026

Simulations of Beam Loading Compensation in a Wideband Accelerating Cavity Using a Circuit Simulator Including a LLRF Feedback Control

controls, cavity, feedback, simulation

2863

F. Tamura, M. Nomura, T. Shimada, M. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
M. Furusawa, K. Hara, K. Hasegawa, C. Ohmori, Y. Sugiyama, M. Yoshii
KEK, Tokai, Ibaraki, Japan

Magnetic alloy cavities are employed in the J-PARC RCS to generate high accelerating voltages. The cavity, which is driven by a vacuum tube amplifier, has a wideband frequency response and the beam loading in the cavity is multiharmonic. Therefore, the tube must generate a multiharmonic output current. An LTspice circuit model is developed to analyze the vacuum tube operation and the compensation of the multiharmonic beam loading. The model includes the cavity, tube amplifier, beam current, and LLRF feedback control. The feedback control consists of the I/Q demodulator including low pass filters, PI control, and I/Q modulator. In this presentation, we present the implementation of the LLRF functions in the LTspice simulations. The preliminary simulation results are also presented. The simulations fairly agree with the beam test results.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB026

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paper received ※ 23 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPRB046

Development of Flexible Waveguide for High Power High Vacuum Applications in S-band

GUI, simulation, factory, linac

2909

X. He, B. Deng, J. Lei, C. Meng, S. Pei
IHEP, Beijing, People’s Republic of China

A novel flexible waveguide is developed for S band 2856 MHz, which is a standard WR284 waveguide. The surface of the flexible waveguide is plated with Oxygen-free High Conductivity (OFHC) copper for the purpose of welding with the stainless steel flange in the vacuum furnace, for the flexible waveguide itself is made of brass. The prototype has got a certain amount of deformation which will be much more convenient for the connection between two hard waveguides. It also has a good measurement results of the lower power microwave test, and the 72 hours vacuum leakage test shows a satisfactory vacuum performance, no obvious surface collapse is observed. The high power test will be conducted after our high power test facility is available, which will tell us the maximal power level of the flexible waveguide prototype.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB046

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paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEPRB047

High-Power Test of a 12 Cell Accelerating Structure Build in Halves

klystron, shielding, GUI, ECR

2912

M.M. Peng, Y.L. Jiang, J.Y. Liu, Z.N. Liu, X.C. Meng, J. Shi, H. Zha
TUB, Beijing, People’s Republic of China

An X-band 12 cell travelling-wave accelerating structure has been developed and high-power tested at Tsinghua University in China. This structure works at 2⁄3 π at the frequency of 11.424 GHz. It is a 12-cell constant-impedance structure build in halves and was silver-brazed as a vacuum tight structure. The high power test was conducted at Tsinghua X-band high power test facility [1] with a 50-MW X-band klystron at a repetition rate to 40 Hz. The final input power was 51.23 MW with a 200 ns pulse width, which means an accelerating gradient of 88.58 MV/m was reached. This paper presents the high power test results including the gradient and breakdown history.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB047

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paper received ※ 10 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEPRB061

The Integration and RF Conditioning of the ESS Double-Spoke Prototype Cryomodule at FREIA

cavity, software, proton, cryomodule

2952

H. Li, K. Fransson, K.J. Gajewski, L. Hermansson, A. Miyazaki, R.J.M.Y. Ruber, R. Santiago Kern
Uppsala University, Uppsala, Sweden

ESS, the European Spallation Source, will adopt a single family of double-spoke cavities for accelerating the proton beam from the normal conducting section to the first family of the elliptical superconducting cavities. They will be the first double-spoke cavities in the world to be commissioned for a high power proton accelerator. The first double-spoke cavity cryomodule for the ESS project is under high power test at Uppsala University. This paper presents the integration, RF conditioning and experience of this prototype cryomodule.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB061

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

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WEPRB075

Optimizing Room Temperature RF Structures for Accelerator Driven System Operations

cavity, operation, RF-structure, DTL

2993

D.L. Brown, M.T. Crofford
ORNL, Oak Ridge, Tennessee, USA
C.C. Peters
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy.
Minimizing beam trip rates is one of the key operational goals at the Spallation Neutron Source (SNS). Trip rates are closely monitored, and real-time statistics are kept during beam operations for immediate analysis. Beam trips are automatically binned by the length of the trip along with the cause for each trip. The shortest beam trips occur with the highest frequency and those trip rates are dominated by the room temperature RF structures. There can be many causes for the RF structure malfunctions, but one area that has had a major impact on trip rates is improvement in how RF processing is done on structures after extended maintenance periods. Details about the improvement in RF conditioning will be discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB075

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paper received ※ 13 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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WEPRB084

Mechanical Design and Analysis of the Proposed APEX2 VHF CW Electron Gun

cavity, gun, electron, cathode

3014

A.R. Lambert, H.Q. Feng, D. Filippetto, M.J. Johnson, D. Li, T.H. Luo, C.E. Mitchell, F. Sannibale, J.W. Staples, S.P. Virostek, R.P. Wells
LBNL, Berkeley, California, USA

Funding: Work supported by the Office of Science, U.S. Department of Energy under DOE contract number DEAC02-05CH11231
Normal conducting radio-frequency (RF) guns resonating in the very high frequency (VHF) range (30-300 MHz) and operating in continuous wave (CW) mode have successfully achieved the targeted brightness and reliability necessary for upgrading the performance of current lower repetition rate accelerator-based instruments such as X-ray free electron lasers (FELs), and ultra-fast electron diffraction (UED) and microscopy (UEM). The APEX2 (Advanced Photo-injector Experiment 2) electron gun is a proposed upgrade for the current LCLS-II injector, which was based on the original APEX design. In contrast, APEX2 is designed as a two-cell cavity operating at 162.5 MHz with a launching field at the cathode equal to 34 MV/m, producing a beam energy of 1.5 to 2 MeV, more than double APEX. Operation of the gun in this condition will require upwards of 200 kW of RF power, thus proper thermal management is crucial to achieve target performance. This paper describes the current design, thermal performance and tuning methods.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB084

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paper received ※ 13 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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WEPRB087

High-gradient SRF Cavity R&D at Cornell University

cavity, SRF, collider, linear-collider

3017

M. Ge, T. Gruber, J.J. Kaufman, P.N. Koufalis, G. Kulina, M. Liepe, J.T. Maniscalco
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Achieving high accelerating field is a critical R&D topic for superconducting RF cavities for future accelerators including the International Linear collider (ILC). The ILC requires an average accelerating field of 35MV/m with a Q₀ of at least 8.9·10⁹ at 2K. In this paper, we report the latest results from high-gradient research at Cornell, which focusses on 75C vacuum baking to improve maximum (quench) fields. We demonstrate that such low temperature bakes can significantly improve quench fields in certain cases by mitigating localized defects. We further report on high-pulsed power results of these cavities before and after baking.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB087

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paper received ※ 23 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019

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WEPRB097

Understanding and Mitigation of Field Emission in CEBAF SRF Linacs

cavity, cryomodule, linac, operation

3039

R.L. Geng, A. Freyberger, R.A. Rimmer
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
We will present current understanding of field emission in two 1.1 GeV CW SRF linacs at CEBAF and its mitigation for improved CEBAF energy reach and operation reliability. This contribution will provide a review of CEBAF gradient evolution since 2014, the impact of field emission, the effort in understanding the root cause of field emission in operational SRF cavities including the recently installed C100 cavities. We will evaluate the effect of initial mitigations implemented since 2016, aimed at reducing generation and transportation of new field emitting particulates. Effects of cavity thermal cycling aimed at abating activation of settled field emitting particulates will be evaluated as well. Remaining issues toward predictable control of field emission in operational SRF cavities will be discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB097

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paper received ※ 19 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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WEPRB107

The New 1-18 MHz Wideband RF System for the CERN PS Booster

cavity, electronics, electron, impedance

3063

M.M. Paoluzzi, L. Arnaudon, V. Bretin, Y. Cuvet, J. Daricou, S. Energico, M. Haase, A.J. Jones, D. Landré, C. Rossi
CERN, Meyrin, Switzerland
C. Ohmori
KEK/JAEA, Ibaraki-Ken, Japan

The LHC Injector Upgrade (LIU) project at CERN prepares the injectors to meet the requirements of the High Luminosity LHC. For protons, it includes the new Linac4, PS Booster (PSB), PS and SPS. Among the major changes concerning the PSB, the extraction energy increase from 1.4 GeV to 2 GeV and the higher beam intensity, made possible by the Linac4 together with the new charge exchange injection system into the PSB (2·10¹³ protons) strongly affect the RF system requirements. To deal with this more demanding beam operation, a new RF system was designed. It is based on modern magnetic alloy loaded cavities driven by solid-state amplifiers. Its wideband frequency response (1 MHz to 18 MHz) covers all the required frequency schemes. This new RF system has been produced in 2017 and 2018; installation is planned during 2019, the first year of Long Shutdown 2 (LS2) and commissioning foreseen in 2020. Most of the production and testing was outsourced to industry; parts acceptance, cavities assembly and pre-testing was done in-house. A quality assurance plan was established to achieve the required high reliability. This paper describes the procurement, production and testing strategies and methodologies. It also reports the achieved results, system performances and relevant statistics.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB107

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

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WEPTS014

Coherent vs Incoherent Effects and Debye Length

space-charge, plasma, focusing, lattice

3116

G. Franchetti
GSI, Darmstadt, Germany

In this proceeding it is discussed the effect of coherent vs. incoherent effect and discussing the validity of frozen models of space charge according to the Debye length and beam radius. This in view of discussing the relation of IBS and space charge

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS014

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paper received ※ 15 April 2019 paper accepted ※ 28 May 2019 issue date ※ 21 June 2019

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WEPTS052

Electron Cloud Build-Up Simulations in the Two-Beam Common Chamber of the HL-LHC TDIS With Nonuniform Surface Properties

electron, simulation, injection, operation

3236

G. Skripka, C. Bracco, G. Iadarola, A. Perillo-Marcone
CERN, Meyrin, Switzerland

The segmented injection protection absorber (TDIS) foreseen for the High-Luminosity Large Hadron Collider (HL-LHC) project is designed to protect the machine in case of injection kicker malfunctioning. Since the current LHC injection protection absorber has suffered from vacuum issues possibly induced by electron multipacting, numerical studies were done to estimate the electron flux expected on the internal surfaces of the TDIS. This device will consist of three pairs of movable absorbing blocks above and below one beam and a beam screen surrounding the second circulating beam. The build-up of electron cloud in the TDIS was simulated accounting for the presence of two counter-rotating beams, for the configuration of the jaws and for the different materials used for the different surfaces in the device. The simulation studies have also investigated the possibility of coating the most critical surfaces with amorphous carbon in order to mitigate the multipacting.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS052

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paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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WEPTS101

A General Comparison on Impedance Theory and CST Simulation of Discontinuities

impedance, simulation, coupling, storage-ring

3352

N. Khosravi, E. Ahmadi, M. Akhyani, S. Dastan, A.M. Mash’al
ILSF, Tehran, Iran
H. Karimi
Isfahan University of Technology, Isfahan, Iran

Inhomogeneity of vacuum chamber components is the main source of coupling impedance. Nowadays, wake potential is mostly predictable by 3D codes. Analytical prediction of impedance theories can be helpful as a side solution. On the other hand, some asymmetries in the geometry of components might make troubles and lead to imprecise numerical results in 3D simulations. Analytical approximation of discontinuities, holes, and grooves can give us an estimation of expected results and can be used as a benchmark in the case that we do not have any experimental data. To clarify the validity of theoretical expressions, general discontinuities are simulated in CST. The comparison of final results is presented here. At last, resistive wall impedance and some general discontinuities of components at ILSF storage ring are compared from the theoretical and simulation point of view.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS101

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paper received ※ 01 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019

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WEPTS118

Results of CEA Tests of SARAF Couplers Prototypes

cavity, EPICS, linac, controls

3382

G. Ferrand, Y. Baron, S. Bouaziz, D. Chirpaz-Cerbat, R. Cubizolles, F. Gohier, S. Ladegaillerie, A. Lotode, C. Madec, G. Monnereau, N. Pichoff, O. Piquet
CEA-IRFU, Gif-sur-Yvette, France
C. Boulch, E. Fayette, P. Guiho, Y. Lussignol, C. Servouin
CEA-DRF-IRFU, France

CEA is committed to delivering a Medium Energy Beam Transfer line and a superconducting linac (SCL) for SARAF accelerator in order to accelerate 5 mA beam of either protons from 1.3 MeV to 35 MeV or deuterons from 2.6 MeV to 40 MeV. The SCL consists in 4 cryomodules. The first two cryomodules host 6 and 7 half-wave resonator (HWR) low beta cavities (β = 0.09) at 176 MHz. The last two identical cryomodule will host 7 HWR high-beta cavities (β = 0.18) at 176 MHz. The maximal required power to be transmitted to the beam is 11.4 kW for high-beta cavity couplers. This document presents the results of the coupler tests and conditioning.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS118

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paper received ※ 23 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPMP009

LATINO: A Laboratory in Advanced Technologies for Innovation

laser, controls, radio-frequency, operation

3466

L. Sabbatini, D. Alesini, A. Falone, A. Gallo
INFN/LNF, Frascati (Roma), Italy
V. Pettinacci
INFN-Roma, Roma, Italy

Funding: The LATINO project is co-funded by the Regione Lazio within POR-FESR 2014-2020 European activities (public call ’Open Research Infrastructures’).
LATINO (a Laboratory in Advanced Technologies for INnOvation) is an open Research Infrastructure that will be hosted at the Frascati National Laboratories (LNF) of the Italian National Institute for Nuclear Physics (INFN). LATINO will allow the scientific community and the SMEs to get access to the technologies and competences developed for particle accelerators. The Infrastructure will be organized in four Laboratories: Radio Frequency, Vacuum and Thermal Treatments, Magnetic Measurements, Mechanical Integration. The list of the available instruments will include, besides others, a high power X-Band station to test cavities up to 50 Hz repetition rate and 200 MW input power, a network analyser to characterize microwave devices up to 100 GHz, a ultra high vacuum oven for thermal treatments and brazing, an outgassing measurement system to characterize vacuum materials, a stretched wire bench and a rotating coil for the magnetic field measurements of multipoles, environment and laser scanners. The regional and national industrial background comprises a remarkable number of highly qualified small and medium enterprises that could take advantage of the technologies offered by LATINO infrastructure to develop novel products within the Key Enabling Technologies and to get the access to new market segments. The Infrastructure will be fully operational at the beginning of 2020. For further information please visit www.latino.lnf.infn.it.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP009

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPMP012

New Industrial Application Beamline for the cERL in KEK

target, radiation, electron, linac

3475

Y. Morikawa, K. Haga, M. Hagiwara, K. Harada, N. Higashi, T. Honda, Y. Honda, M. Hosumi, Y. Kamiya, R. Kato, H. Kawata, Y. Kobayashi, H. Matsumura, C. Mitsuda, T. Miura, T. Miyajima, S. Nagahashi, N. Nakamura, K.N. Nigorikawa, T. Nogami, T. Obina, H. Sagehashi, H. Sakai, M. Shimada, M. Tadano, R. Takai, H. Takaki, O.A. Tanaka, Y. Tanimoto, A. Toyoda, T. Uchiyama, A. Ueda, K. Umemori, M. Yamamoto
KEK, Ibaraki, Japan

The new beam line for the industrial applications is constructed at the cERL (compact Energy Recovery LINAC) in KEK. In these applications, only north straight sections of cERL consisting of injector and main LINAC will be used. The test for the radio isotope production and electron beam irradiation for the materials are firstly planned with very small beam current without energy recovery.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP012

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paper received ※ 11 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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THPMP038

Collaborative Strategies for Meeting the Global Need for Cancer Radiation Therapy Treatment Systems

linac, electron, radiation, permanent-magnet

3526

M. Dosanjh, P. Collier, I. Syratchev, W. Wuensch
CERN, Meyrin, Switzerland
A. Aggarwal
KCL, London, United Kingdom
D. Angal-Kalinin, P.A. McIntosh, B.L. Militsyn
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
R. Apsimon
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
S.T. Boogert
Royal Holloway, University of London, Surrey, United Kingdom
G. Burt
Lancaster University, Lancaster, United Kingdom
N. Coleman, D.A. Pistenmaa
ICEC, Washington, DC, USA
A.W. Cross
USTRAT/SUPA, Glasgow, United Kingdom
I.V. Konoplev, S.L. Sheehy
JAI, Oxford, United Kingdom

The idea of designing affordable equipment and developing sustainable infrastructures for delivering radiation treatment for patients with cancer in countries that lack resources and expertise stimulated a first International Cancer Expert Corps (ICEC) championed, CERN-hosted workshop in Geneva in November 2016. Which has since been followed by three additional workshops involving the sponsorship and support from UK Science and Technology Facilities Council (STFC). One of the major challenges in meeting this need to deliver radiotherapy in low- and middle-income countries (LMIC) is to design a linear accelerator and associated instrumentation system which can be operated in locations where general infrastructures and qualified human resources are poor or lacking, power outages and water supply fluctuations can occur frequently and where climatic conditions might be harsh and challenging. In parallel it is essential to address education, training and mentoring requirements for current, as well as future novel radiation therapy treatment (RTT) systems.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP038

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paper received ※ 11 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPMP039

How Robust Are Existing Medical Linacs in Challenging Environments? A Study of Down Time and Failure Causes.

linac, controls, electron, gun

3530

S.L. Sheehy, L. Wroe
JAI, Oxford, United Kingdom
A.J. Egerton
Egerton Consulting Ltd, Minety, Malmesbury, Wiltshire, United Kingdom
A. Steinberg
Oxford University, Physics Department, Oxford, Oxon, United Kingdom

There is a severe lack of radiotherapy linear accelerators (LINACs) in Low- and Middle-Income countries (LMICs), limiting capacity for cancer care in these regions. Anecdotally, operating high tech accelerators in environments with power fluctuations, harsh climatic conditions and geographic isolation leads to large failure rates and downtime. To guide future developments, this study presents a data-driven approach to collect statistical data on LINAC downtime and failure modes, comparing to a simple availability model.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP039

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPGW039

Moderation of Positive Muons by Helium Gas

proton, experiment, simulation, scattering

3667

Y. Li, Y. Bao, R. Fan, X. Li, X. Tong
IHEP, Beijing, People’s Republic of China
C.J. Ning, P.C. Wang
IHEP CSNS, Guangdong Province, People’s Republic of China

Funding: This work is supported by CAS, National Natural Science Foundation of China (Grant No. 11875281), and China Postdoctoral Science Foundation (Grant No. 2019M650845)
Efficiently creating beams of spin-polarized positive muons with energies between eV and keV (so-called slow muon beams) is important for further development and application of muon spin rotation, relaxation, and resonance techniques. One existing moderation method involves the use of wide-band-gap materials as moderators such as rare gas solids and solid nitrogen thin films (band-gap energy between 11 eV and 22 eV). Based on this moderation method, we have studied the use of helium gas as a moderator, with the goal of producing the slow muon beam more efficiently. Because of helium’s high (24.6 eV) ionization energy and because the cross section for muonium formation is suppressed in helium gas, we expect the production of slow muons using helium gas to be highly efficient.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW039

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paper received ※ 01 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPGW050

Electromagnetic Field of a Charge Moving Through a Channel in Magnetized Plasma

plasma, proton, wakefield, electromagnetic-fields

3700

A.A. Grigoreva, T.Yu. Alekhina, S.N. Galyamin, A.V. Tyukhtin, V.V. Vorobev
Saint Petersburg State University, Saint Petersburg, Russia

Funding: Work supported by Russian Science Foundation (Grant No. 18-72-10137).
Recent success in beam-driven plasma wakefiled acceleration scheme with two proton bunches propagating through a hollow plasma channel* stimulates the research activity in this area. In this report, we investigate possibilities for additional tuning the structure of the accelerating field by the external magnetic field applied. The structure of surface waves at the channel boundary is of interest, and special attention is paid to the field characteristics that are essential for the wakefield acceleration method (amplitude of the accelerating field, the structure of the deflecting field) and the possibilities of controlling these characteristics by means of the external field.
* Gessner S.J. et al. Proc. IPAC2016. THPPA01.

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

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THPGW057

HL-LHC Full Remote Alignment Study

alignment, operation, MMI, luminosity

3716

A. Herty, R. De Maria, P. Fessia, D. Gamba, M. Giovannozzi, J. Hansen, I. Lamas Garcia, H. Mainaud Durand, S. Redaelli
CERN, Meyrin, Switzerland

Funding: Research supported by the HL-LHC project.
This study explores the benefits of extending the monitoring and remote alignment concept, proposed in the HL-LHC baseline, to additional components of the matching sections of the HL-LHC. The objective was to evaluate the benefits in terms of equipment performance and new opportunities for system simplification. In collaboration with the HL-LHC Working Group on Alignment, critical input parameters such as ground motion, manufacturing, assembly, and alignment tolerances, have been quantified. Solutions for the selected, manually aligned compo-nents have been investigated with the particular focus on vacuum design, mechanical design and the new alignment concept compatible with reliability and maintainability requirements. In this context, collimators and masks are key elements to be included in the extended alignment system. Their supporting systems will integrate the concept of on-line monitoring sensors and an actuator based, remote alignment platform. The full remote alignment of components will provide a positive impact to the machine operation reducing the need of human intervention in the tunnel and providing enhanced flexibility to perform the required alignment adjustment as part of an operational tool for the HL-LHC.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW057

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paper received ※ 09 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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THPGW080

Initial Results of High-Gradient Breakdown Tests for W-Band Accelerating Structures

cavity, experiment, electron, laser

3769

M.A.K. Othman, V.A. Dolgashev, A.A. Haase, E.A. Nanni, J. Neilson, S.G. Tantawi
SLAC, Menlo Park, California, USA
S. Jawla, J.F. Picard, R.J. Temkin
MIT/PSFC, Cambridge, Massachusetts, USA
S.C. Schaub
MIT, Cambridge, Massachusetts, USA
B. Spataro
INFN/LNF, Frascati, Italy

Funding: This work was supported by Department of Energy contract DE-AC02-76SF00515 (SLAC) and grant DE-SC0015566 (MIT). This work was also supported by NSF grants PHY-1734015.
Emerging accelerator technology at mm-wave and THz frequencies has recently shown notable progress. Indeed, metallic and dielectric accelerating structures at THz frequencies are plausible candidates toward miniaturization of accelerators. RF breakdown in such structures is a major factor limiting their performance. Therefore, comprehensive analysis of RF breakdown physics in mm-wave accelerating structures is needed, which includes understanding of dependencies of the breakdown rate on geometric, electromagnetic and material properties. In this work we report on high power tests of a 110 GHz single-cell standing wave accelerating structure powered by a 1 MW gyrotron. The RF power is coupled from the gyrotron into the accelerating structure with a Gaussian to TM01 mode converter through a quasi-optical setup. We demonstrate coupling of 10 ns, 100s of kilowatt pulses into the structure using a fast switch and achieving ~150 MV/m accelerating gradients. Measurements of RF signals and field-emitted currents allow for complete comprehensive of the high-gradient behavior of W-band structures, including breakdown probability.

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

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THPGW089

Mechanical Design of a Diamond Crystal Hard X-Ray Self-Seeding Monochromator for PAL-XFEL

FEL, controls, alignment, electron

3782

D. Shu, J.W.J. Anton, S.P. Kearney, K. Kim, Yu. Shvyd’ko
ANL, Argonne, Illinois, USA
H.-S. Kang, C.-K. Min, B.G. Oh, S.Y. Rah
PAL, Pohang, Kyungbuk, Republic of Korea

Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357
As a part of the Argonne Strategic Partnership Project (SPP) 85H21, a collaboration between Advanced Photon Source (APS), Argonne National Laboratory (ANL) and Pohang Accelerator Laboratory (PAL), we have designed, constructed, and tested a thin-film-diamond monochromator for the PAL X-ray Free-Electron-Laser (PAL-XFEL) hard x-ray self-seeding project*. The mechanical design of the PAL-XFEL diamond crystal hard x-ray self-seeding monochromator is based on the APS design of a diamond-crystal monochromator for the LCLS hard x-ray self-seeding project** with enhanced diamond crystal holder for two thin-film-diamond crystals with thicknesses of 30 microns and 100 microns***. The customized high quality thin-film-diamonds and special graphite holder were provided by the Technological Institute for Super-hard and Novel Carbon Materials of Russia (TISNCM)****, and tested at the APS***. An in-vacuum multi-axis precision positioning mechanism is designed to manipulate the duo-thin-film diamonds holder with resolutions and stabilities required by the hard x-ray self-seeding physics. Mechanical specifications, designs, and preliminary test results of the diamond monochromator are presented in this paper.
*Chang-Ki Min, et al, sub. J. Sync. Rad., 2018
**D. Shu, et al, J. Phys.: Conf. Ser. 425 (2013) 052004
***Y. Shvyd’ko, et al, FEL2017, Santa Fe
****Polyakov S, et. al, 2011 Diam. Rel. Mat. 20 726

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

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THPRB026

A 300 mm Long Prototype Strip-Line Kicker for the Heps Injection System

kicker, injection, impedance, simulation

3864

L. Wang, J. Chen, L. Huo, P. Liu, H. Shi, X.L. Shi, G. Wang, N. Wang
IHEP, Beijing, People’s Republic of China

In the High Energy Photon Source (HEPS), the dynamic aperture of machine is not large enough for off-axis injec-tion for its baseline 7BA lattice design. So, a group of superfast kickers with about 12 ns pulse bottom width are needed for on-axis swap out injection scheme. The design about a couple sets of 300 mm long strip-line kickers is presented. Five kickers as a module are placed in a stain-less steel vacuum vessel to solve the problem of longitu-dinal space restriction in injection area. So far, the proto-type development of strip-line kicker was completed. The results of time-domain reflectometer (TDR) test and high voltage pulse test show that the strip-line kicker can meet the requirement of the HEPS.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB026

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paper received ※ 06 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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THPRB035

Development of Beam Window Protection System for J-PARC Linac

linac, operation, PLC, site

3886

H. Takahashi, S. Hatakeyama, Y. Sawabe
JAEA/J-PARC, Tokai-mura, Japan
T. Ishiyama, T. Suzuki
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
T. Miyao
KEK, Ibaraki, Japan

In J-PARC Linac, beam study (including beam conditioning) is mainly performed using beam dump. A beam window is installed in the beam line to each beam dump. It is considered that the parameters of acceptable beam　to able to be injected the beam window are the 50 mA current, the 100 micro-sec width and the 2.5 Hz repetition. On the other hand, at beam study of Linac, the beam with higher power than these parameters are not used. Therefore, the beam study was started and performed only after the operator checked that the beam parameters are within the acceptable values. However, at the beam study of 2018, a beam windows of 0-degree dump was cracked because the beam that exceeds acceptable parameters was injected due to human error. Then, beam study using 0-degree dump was impossible at all. And, in order not to cause such accident again, we began to develop the beam window protection system. Moreover, as soon as possible, implementation of the system was required. Therefore, we designed and developed this system by improving it based on the particle management system which can measure all 25 Hz beam. We have developed a beam window protection system that monitors the beam current for each shot and accumulated beam current for a prescribed time and inhibits the beam by MPS when either value exceeds the threshold. Moreover, we succeeded in developing and implementing this system in a short time. This paper is described about development and function test of beam window protection system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB035

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

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THPRB072

Operational Experience of a Prototype LHC Injection Kicker Magnet with a Low SEY Coating and Redistributed Power Deposition

kicker, injection, operation, electron

3974

M.J. Barnes, C. Bracco, G. Bregliozzi, A. Chmielinska, L. Ducimetière, B. Goddard, G. Iadarola, T. Kramer, V. Vlachodimitropoulos, W.J.M. Weterings
CERN, Geneva, Switzerland
A. Chmielinska
EPFL, Lausanne, Switzerland
L. Vega Cid
ETSII UPM, Madrid, Spain

Funding: This research was supported by the HL-LHC project
In the event that it is necessary to exchange an LHC injection kicker magnet (MKI), the newly installed kicker magnet would limit HL-LHC operation for a few hundred hours due to dynamic vacuum activity. A surface coating with a low secondary electron yield, applied to the inner surface of an alumina tube to reduce dynamic vacuum activity without increasing the probability of UFOs, and which is compatible with the high voltage environment, was included in a prototype MKI installed in the LHC during the 2017-18 Year End Technical Stop. In addition, this MKI included an upgrade to relocate a significant portion of beam induced power from the yoke to a ’damping element’: this element is not at pulsed high voltage. The effectiveness of the upgrades has been demonstrated during LHC operation, hence a future version will include water cooling of this ’damping element’. This paper reviews dynamic vacuum around the MKIs and summarizes operational experience of the upgraded MKI.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB072

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paper received ※ 08 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPRB074

Studies Towards the New Beam Screen System of the LHC Injection Kicker Magnet for HL-LHC Operation

kicker, injection, operation, simulation

3982

V. Vlachodimitropoulos, M.J. Barnes, A. Chmielinska, L. Ducimetière, L. Vega Cid, W.J.M. Weterings
CERN, Geneva, Switzerland
A. Chmielinska
EPFL, Lausanne, Switzerland
L. Vega Cid
ETSII UPM, Madrid, Spain

Although no heating issues were observed in the Large Hadron Collider’s (LHC) injection kicker magnets (MKIs) during Run 2, simulations suggest that for operation with the high intensity beams of the High Luminosity LHC (HL-LHC) project, the magnet’s ferrite yokes will reach their Curie temperature, thus leading to long turnaround times before a new beam can be safely injected into the machine. To safely enter the HL-LHC era, a campaign to redesign the kicker’s beam screen was launched. An improved beam-screen has already been implemented in an upgraded MKI, that was installed in the LHC tunnel in the Year End Technical Stop (YETS) 17/18, and has been successfully tested during 2018 operation. However, the improved design alone is not expected to be enough for HL-LHC operation, and further modifications are required. In this work, the approach to the design from an electromagnetic point of view is presented and different considered options are reported, emphasising the final design of the new beam screen system that is currently being implemented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB074

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

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THPRB112

Commission of the Transverse Bunch-by-Bunch Feedback at SPEAR3

feedback, kicker, injection, GUI

4081

K. Tian, W.J. Corbett, X. Huang, N. Kurita, D.J. Martin, J.A. Safranek, J.J. Sebek
SLAC, Menlo Park, California, USA
D. Teytelman
Dimtel, San Jose, USA

Funding: Work supported by US Department of Energy Contract DE-AC03-76SF00515.
Driven by the demand of suppressing transverse beam instabilities and developing novel short pulse operation modes in SPEAR3 storage ring, a wide-band transverse bunch-by-bunch feedback system has been recently commissioned for SPEAR3 storage ring. The system was demonstrated to be sufficient to suppress the transverse coupled bunch instabilities caused by trapped RF modes in one of the in vacuum insertion devices. A new function of beam instability interlock has been developed and is part of machine protection system for the in vacuum insertion device. In addition, the bunch-by-bunch feedback system serves as a indispensable diagnostic tool that enables us to measure machine parameters, beam impedance, and characteristics of the beam instability modes. In this paper, we describe the scheme and performance of the bunch-by-bunch feedback system at SPEAR3.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB112

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

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THPTS001

Development of Cryogenic Suspension in the ANU 8t Superconducting Solenoid With Iron Yoke

solenoid, experiment, cryogenics, EPICS

4103

S.T. Battisson, N.R. Lobanov, D. Tsifakis, T.B. Tunningley
Research School of Physics and Engineering, Australian National University, Canberra, Australian Capitol Territory, Australia
J.F. Smith
University of Surrey, Department of Physics, Guildford, United Kingdom

Funding: The Australian Federal Government Superscience/EIF funding under the NCRIS mechanism.
An 8 Tesla superconducting solenoid was commissioned at The Australian National University to make precision measurements of fusion cross-sections. Forces between the solenoid and the iron yoke that houses it must always be maintained within safe limits and precision location of the solenoid coil is necessary to achieve this. Thermal contraction of components can impact the locating structure of the solenoid coil, leading to unsafe forces. Improvements to this structure allowed successful completion of the first fusion measurements with the 8T solenoidal separator, and demonstrated that it is now ready for a program of fusion measurements.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS001

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

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THPTS004

The Sirius Heating System for the In-situ NEG Activation

controls, power-supply, storage-ring, software

4109

P.H. Nallin, M. Bacchetti, F.G.R. Carrera, D.R. Cavalcante, R.O. Ferraz, P.P.S. Freitas, G.R. Gomes, J.G. Hidalgo, R.T. Neuenschwander, F.A.M. Pinto, A.R.D. Rodrigues, R.M. Seraphim
LNLS, Campinas, Brazil

Sirius is a 3 GeV fourth-generation synchrotron light source under commissioning in Brazil, with 518 m circumference and a bare lattice emittance of 0.25 nm.rad. This ultra-low emittance machine is based on approximately 700 magnets with 28 mm typical gap. The standard vacuum chamber, that makes up around 80% of the circumference, is a 26 mm external diameter copper tube. Due to the small conductance of the chambers and the limited space between the magnets, the vacuum pumping will be based on distributed concept and then non-evaporable getter (NEG) coating will be extensively used. To activate the NEG coating, the chambers must be heated at 200°C for about 24 hours. The solution for Sirius was the development of an ultra-thin heating tape, 0.4 mm thick, which allows an in-situ bake-out. The developed tapes are able to operate continuously at 220°C and have in their design a thermal shield that reduces the radiation heat loss to the magnets. This paper describes the development of the heating tape, its power supply, the control software and the operation of the system during the NEG activation at Sirius.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS004

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS007

MYRRHA 80 kW CW RF Coupler Design

cavity, multipactoring, electron, simulation

4115

Y. Gómez Martínez, M.A. Baylac, D. Bondoux, F. Bouly, P.-O. Dumont
LPSC, Grenoble Cedex, France
S. Blivet, C. Joly, J. Lesrel, H. Saugnac
IPN, Orsay, France
W. Kaabi
LAL, Orsay, France

MYRRHA [1] (Multi Purpose Hybrid Reactor for High Tech Applications) is an Accelerator Driven System (ADS) project. Its superconducting linac will provide a 600 MeV - 4 mA proton beam. The first project phase based on a 100 MeV linac is launched. The Radio-Frequency (RF) couplers have been designed to handle 80 kW CW at 352.2 MHz. This paper describes the thermal, mechanical and RF studies leading to the final design of the RF coupler.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS007

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paper received ※ 10 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPTS008

Prospects of Additive Manufacturing for Accelerators

cavity, niobium, detector, GUI

4118

N. Delerue, S. Jenzer
LAL, Orsay, France
H.C. Carduner
SUBATECH, Nantes, France
R.L. Gerard
CERN, Meyrin, Switzerland
P.M. Manil
CEA-DRF-IRFU, France
P.R. Repain
LPNHE, Paris, France
A. Simar
UCL, Louvain-la-Neuve, Belgium

Funding: Université Paris-SAclay, Labex P2IO and P2I departement
Additive manufacturing allows the production of mechanical components often much faster than traditional manufacturing. Several accelerators components built using additive manufacturing have already been qualified for use in accelerator. A workshop was held in Orsay in December 2018 to discuss the prospects of using additive manufacturing for particle accelerators and particle detectors. We report here on the prospects as far as accelerators are concerned.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS008

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paper received ※ 20 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS014

Visual Inspection of Curved Particle Accelerator Beam Pipes with a Modular Robot

controls, dipole, experiment, simulation

4135

N. Schweizer
RMR, TU Darmstadt, Darmstadt, Germany
I. Pongrac
GSI, Darmstadt, Germany

Inspecting ultra-high vacuum pipe systems of particle accelerators without disassembling the beam pipes is a complex challenge. In particular, curved sections of particle accelerators require a unique approach for the examination of the interior. For the planned heavy ion synchrotron SIS100 at FAIR, an inspection robot is currently under development, featuring an optical imaging system with which the robot can be navigated through the beam pipe. We present the current prototype, which is based on a modular snake-like robot with active wheels and joints. Due to the stipulated low movement velocity, it can be shown that a kinematic model is sufficient to control the robot whereas dynamical effects can be neglected. This concept is proven in experiments with the prototype. At the current development status, the robot is controlled manually by setting the velocity of the first module and its desired turning angle. In simulations we include a CAD model of a dipole chamber of the SIS100 and let an operator successfully navigate the robot through the beam pipe while only observing the camera image.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS014

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

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THPTS015

Design and Manufacturing of the First Multiplet for the Super-FRS at FAIR

quadrupole, sextupole, status, alignment

4138

E.J. Cho, H. Müller, C. Roux, K. Sugita, M. Winkler
GSI, Darmstadt, Germany
A. Borceto, G. Drago, G. Valesi, D. Ventura
ASG, Genova, Italy

The Super-FRS (Superconducting FRagment Separator) at FAIR is a two-stage in flight separator, which aims to produce rare isotopes of all elements up to Uranium and separate them spatially within a few hundred nanoseconds so that a study of very short lived nuclei can be performed efficiently. In total, it is required to construct 24 dipoles and 170 multipole magnets (quadrupole, sextupole, octupole and steering dipole). Due to the limit of space, the multipole magnets will be arranged as a group (2 ~ 9 magnets) in a common cryostat and they are called as a multiplet. The design challenge of the multiplet lies in a strong iron saturation of the quadrupole leading to disturb the field quality and high design pressure of the He vessel (20 bars). The first multiplet for the Super-FRS is constructed. The magnet column consisting of one quadrupole and one sextupole is cooled in a He vessel filled with up-to 800 liters of liquid He. The both magnets are superferric type and have a large warm bore radius of 190 mm. This paper presents the design overview and the manufacturing status of the first multiplet.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS015

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paper received ※ 12 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS020

ESS Magnets at Elettra Sincrotrone Trieste

quadrupole, ion-source, MMI, framework

4148

D. Castronovo, D. Caiazza, A. Fabris, R. Fabris, A. Gubertini, G. Loda
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

Elettra Sincrotrone Trieste Research Center (Elettra) is one the Italian Institutions committed to the realization of the Italian in-kind contributions for the European Spallation Source. One of these consists in the supply of several conventional iron dominated electro-magnets to be installed in the superconducting part of the linac and in the transfer lines. The total number of magnets amounts to 2 dipoles, 139 quadrupoles, of four different families, and 72 correctors, of three different types. This document reports all related magnetic design and optimisations carried out to meet the required specifications and on the status of production and testing.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS020

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

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THPTS026

Effect of Nitric Hydrofluoric Acid Treatment on Brazing of Alumina Ceramics and Pure Titanium

electron, controls, experiment, gun

4161

M. Kinsho, J. Kamiya
JAEA/J-PARC, Tokai-mura, Japan
K. Abe
Hitachi Power Semiconductor Device, Ltd., Hitachishi, Ibaraki, Japan
T. Nakamura
Asahi Kinzoku Co., Ltd., Gifu, Japan

Alumina ceramics vacuum chamber which is used for the 3GeV rapid-cycling synchrotron (RCS) in J-PARC is composed of alumina duct, titanium (Ti) flanges and Ti sleeves. Before brazing the alumina duct and the Ti sleeves, the Ti sleeves were treated with nitric hydrofluoric acid. The purpose of this study is to clear the effect of this treatment for titanium material. It was cleared by SEM observation that the roughness of the titanium material after the nitric hydrofluoric acid treatment becomes big. It was also measured that the thickness of oxide film on surface of the titanium material was 12.7 nm before treatment and 6.0 nm after treatment. As a result of measuring the wettability of the brazing material which was silver brazing filler metal (Ag: 72%, Cu: 28%) on the Ti surface and the diffusion of the Ti material into the brazing material, it became clear that both the clearing of oxide layer on the alumina ceramics and the vacuum condition of the vacuum heating furnace were important for brazing between alumina ceramics and pure titanium.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS026

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

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THPTS027

Accelerator Implementing Development of Ceramics Chamber with Integrated Pulsed Magnet for Beam Test

kicker, dipole, power-supply, injection

4164

C. Mitsuda, Y. Kobayashi, S. Nagahashi, T. Nogami, T. Obina, R. Takai, H. Takaki, T. Uchiyama, A. Ueda
KEK, Ibaraki, Japan
T. Honiden, T. Nakanishi
SES, Hyogo-pref., Japan
A. Sasagawa, A. Yokoyama, T. Yokoyama
KYOCERA Corporation, Higashiomi-city, Shiga, Japan

We advance the development of Ceramics Chamber Integrated Pulsed Magnet (CCIPM) of air-core type as the application to low emittance ring with a narrow bore of light source accelerator in the future. The CCIPM is composed of ceramics cylinder of 60 mm diameter and four copper coils, which are implanted in the groove penetrated on the ceramic thickness along 30 cm length by silver brazing*. In addition to this structure, we succeeded in the implementations of cable connecting base that mechanically connect the coils and power supply with feeder lines and the pattern shape coating inside the ceramic cylinder. Improved brazing technique made it possible to braze the coil and the base on the coil at the same time that the coils are implanted in the ceramic thickness. Newly developed functional coating can reduce the eddy current caused by main magnetic field and pass the alternate component of beam wall current by capacitance structure. We report the details about the performance from the viewpoint of vacuum, magnetic field, insulation on the accelerator implementation with the approach to new technical development, and the preparation progress of beam test in beam-transport line.
* C. Mitsuda, et al., in Proc. IPAC2015, Richmond, VA, USA, p. 2879

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS027

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paper received ※ 12 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS041

Progress and TDR Plans of the Mechanical System of CEPC

detector, alignment, collider, dipole

4200

H. Wang, S. Bai, M.X. Li, Y.D. Liu, C. Meng, H. Qu, J.L. Wang, P. Zhang, N. Zhou
IHEP, Beijing, People’s Republic of China

The TDR of CEPC is aimed at the key science and technology problems and makes preparations for the real project. This paper will describe the progress of mechanical system including the regular supports and transport vehicle design, the mockup plan, the installation scenario of machine detector interface (MDI) and the movable collimator, as well as the TDR plans of mechanical system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS041

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paper received ※ 28 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS045

Preparation of Titanum-Zirconium-Vanadium Films by Quantitative Deposition

experiment, electron, ECR, operation

4210

J.Q. Shao, C. Chen, X.Q. Ge, W. Li, S. Wang, Y. Wang, W. Wei, B. Zhang, Y.X. Zhang, B.L. Zhu
USTC/NSRL, Hefei, Anhui, People’s Republic of China

TiZrV has been used in vacuum technology and electric vacuum devices due to its high pumping speed and low activation temperature in recent years. At the same time, many preparation methods have been developed. Different from the current coating method of magnetron sputtering, this paper discusses the preparation of thin film coating from the viewpoint of vacuum sintering, which is flexible in design and more suitable for operation. Based on the analysis of the surface morphology of the sintered film, the feasibility and operability of the experimental method were explored from the surface compactness of the getter.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS045

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paper received ※ 25 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS056

New Undulator and Front End for XAIRA Beamline at ALBA

undulator, photon, storage-ring, synchrotron

4231

J. Campmany, J. Marcos, V. Massana
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

A new microfocus beamline for macromolecular crystallography, XAIRA, is being built at ALBA synchrotron light source. The light source for this new beamline is an in-vacuum undulator that can reach the spectrum range from 4 keV up to 20 keV. The in-vacuum undulator was terndered in 2018 and awarded to Kyma-RI consortium, and will be delivered to ALBA in November 2019. The Front End has been designed accordingly. It was tendered in 2018 and awarded to FMB. It will be delivered along second semester of 2019. In this paper we present the ID and FE designs.

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paper received ※ 11 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPTS062

Alternative Proposal for FCC-hh Extraction Septa

septum, extraction, quadrupole, simulation

4248

A. Sanz Ull, M.G. Atanasov, B. Balhan, J.C.C.M. Borburgh
CERN, Geneva, Switzerland

Challenging requirements are set for the FCC extraction septa magnets, notably for the magnetic field level, the septum thickness and the leak field. An alternative to the baseline FCC extraction layout with normal conducting Lambertson septa is proposed, consisting of a Superconducting Shield (SuShi) stage and a Truncated Cosine theta septa stage with the aim of reducing the necessary number of septa and installed length. The principal parameters of the septa are described and the feasibility discussed. Areas for study improvement are identified.
This paper is intended for publication in the PRAB special edition.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS062

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paper received ※ 13 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS071

Performance of TPS Cryogenic Permanent Magnet Undulators at NSRRC

undulator, permanent-magnet, cryogenics, controls

4278

J.C. Huang, C.S. Yang, C.K. Yang
NSRRC, Hsinchu, Taiwan
H. Kitamura
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
T. Kohda
NEOMAX Engineering Co., Ltd., Tokyo, Japan

Development of cryogenic permanent magnet un-dulators (CPMUs) is the most recent activity for Phase-II beamlines at the Taiwan Photon Source. A hybrid-type CPMU with a period length of 15 mm, based on PrFeB permanent-magnet materials, is under construc-tion. A maximum effective magnetic field of 1.33 T at a gap of 4 mm is obtained at 80 K.

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS072

Field Measurements for a Superconducting Magnet at Room Temperature

multipole, wiggler, superconducting-magnet, simulation

4281

J.C. Jan, C.-C. Chang, Y.L. Chu, J.C. Huang, C.-S. Hwang, C.Y. Kuo, F.-Y. Lin
NSRRC, Hsinchu, Taiwan

A superconducting multipole wiggler (SMPW) was fabricated at the National Synchrotron Radiation Research Center (NSRRC) and was installed in the Synchrotron Light Research Institute (SLRI). A 3.5 T field strength could be generated by the NbTi coils and the magnetic arrays are immersed in a liquid helium (LHe) bath. A removable mapping chamber, made from thin stainless steel sheets, was developed to allow field mapping in the narrow aperture of the SMPW. The mapping chamber provides a room temperature environment for the magnetic field mapping and enables an easier field scan in the cryostat. The design for the mapping chamber includes a blockage of heat transfer from room temperature to the LHe bath and is strong enough to resist deformations during evacuation. The mechanical design, strain simulation, thermal simulation, dummy test and measurement results with the mapping chamber will be discussed in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS072

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paper received ※ 10 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPTS080

Novel Technique Ion Assisted In-Situ Coating of Long, Small Diameter, Accelerator Beam Pipes with Compacted Thick Crystalline Copper Film

cathode, lattice, cryogenics, plasma

4301

A. Hershcovitch, M. Blaskiewicz, J.M. Brennan, W. Fischer, G.T. McIntyre, S. Verdú-Andrés
BNL, Upton, Long Island, New York, USA
A.X. Custer, M.Y. Erickson, H.J. Poole
PVI, Oxnard, California, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
Although great progress was made with in-situ copper coating, by magnetron sputtering, to address the high room temperature resistivity, literature indicates that conventionally deposited thick copper films do not retain the same RF conductivity at cryogenic temperatures, since straightforward deposition tends to result in films with columnar structure and other lattice defects, which cause significant conductivity degradation at cryogenic temperatures. We utilize energetic ions for ion assisted deposition (IAD) to reduce lattice imperfections, for coating. IAD that can in-situ coat long small diameter tubes with compacted crystalline structure thick copper films has been developed. Moreover, development of techniques and devices can resurrect IAD for other applications, which have been impractical and/or not viable economically. Comparison of conductivity at cryogenic temperatures between straight magnetron physical vapor deposition and IAD will be presented.

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS081

Novel Apparatus and Technique for Measuring RR Resistivity of Tube Coatings at Cryogenic Temperatures

cryogenics, lattice, cavity, experiment

4304

A. Hershcovitch, J.M. Brennan, R. Than, S. Verdú-Andrés, Q. Wu
BNL, Upton, Long Island, New York, USA
A.X. Custer, M.Y. Erickson, H.J. Poole
PVI, Oxnard, California, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
A unique apparatus for measuring RF resistivity of tubes and coated tubes at cryogenic temperatures is operational at BNL, which to our knowledge is the first of its kind. A folded quarter wave resonator structure of 300 mm length accesses a wide range of frequencies. The structure is cooled in liquid He bath at 4 K. All internal resonator components (except for test samples) were fabricated out of superconducting materials. Consequently, when the resonator is cooled, the bulk of the losses are due to the copper coating. The RF resistivity is determined from Q measurements, since for a fixed geometry the quality factor of a resonant cavity is proportional to the square root of the conductivity. The RF input loop and the output signal antenna are adjustable when cold via bellows to control matching to each cavity mode. The Q values of 10 resonant modes between 180 and 2500 MHz are deduced from the bandwidth of the S21 response Network Analyzer measurements. CST MicroWave Studio is used to extract the resistivity of the samples from the Q measurements. Resistivity results of solid Cu tube, 2, 5, & 10 μm Cu coated 316LN stainless steel RHIC beam tubes will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS081

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS086

Design of a CCD-based Laser Alignment Detection System

laser, alignment, detector, controls

4311

J.X. Chen
IHEP CSNS, Guangdong Province, People’s Republic of China
X.Y. He, W. Wang, H.T. Zhang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Funding: Work supported by National Natural Science Foundation of China (11705199)
Accelerator online alignment technology is an important means for accelerator stability detecting. A CCD-based laser alignment detection system is designed for the linear accelerator, and the detection distance of the system could reach 100m. The reference comparison method is used to detect the laser imaging position acquired by the reference detector at different times, and to obtain the relative positional deviation of the measurement reference or the tested objects. Through the measurement error analysis, the precision of the system is expected to reach ±10μm.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS086

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paper received ※ 11 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS091

Phase and Frequency Locked 350 MHz Magnetron

cathode, operation, injection, status

4325

M.L. Neubauer, A. Dudas, R.P. Johnson, S.A. Kahn, G.M. Kazakevich, M. Popovic
Muons, Inc, Illinois, USA

The 120kW 350 MHz magnetron is being developed for a number of RF systems, chiefly among them, Niowave’s 10 MeV accelerator. Industri-al applications of the magnetron have also been explored. The CW magnetron can be operated in the pulse mode by a novel injection locking system. We report on the status of the program and progress to date

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS091

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

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THPTS093

Synchrotron Radiation Heating of the Helical Superconducting Undulator

photon, synchrotron, radiation, synchrotron-radiation

4328

J.C. Dooling, R.J. Dejus, V. Sajaev
ANL, Argonne, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02- 06CH11357.
A helical superconducting undulator (HSCU) was installed in the Advanced Photon Source (APS) Storage Ring (SR) during the January 2018 maintenance period. Shortly after the reintroduction of beam into the SR in late January, higher than expected heating was observed in the cryogenic cooling system. Steering the electron beam orbit in the upstream dipole provided reduction of the amount of synchrotron radiation reaching into the HSCU and allowed the device to properly cool and operate. Modeling the HSCU geometry with MARS shows the importance of Compton Scattering in transferring synchrotron photons with energies in the range of 10-100 keV through the vacuum chamber into the HSCU magnet pole and winding regions. Simulations carried out using MARS with EGS5 enabled indicate a rapid increase in transfer efficiency from the chamber wall to the HSCU with photon energy. Realistic spectral distributions of synchrotron photons are employed as input to MARS for several bending magnet field strengths.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS093

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paper received ※ 12 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS094

High Gradient Quadrupoles for Low Emittance Synchrtrons

quadrupole, dipole, focusing, lattice

4332

S.K. Sharma, T.V. Shaftan, V.V. Smaluk, C.J. Spataro, T. Tanabe, G.M. Wang
BNL, Upton, Long Island, New York, USA
N.A. Mezentsev
BINP SB RAS, Novosibirsk, Russia

A new lattice design has been proposed recently based on a Complex-Bend concept [1,2] for low emittance syn-chrotrons. The dipoles of a standard DBA lattice are replaced in the Complex Bend by high-gradient (~ 450 T/m) quadrupoles interleaved between discrete dipoles. In another version of the Complex Bend [3] the high gradient quadrupoles are displaced transversely along the beam trajectory to generate the required dipole field. In the latter version the quadrupole strength is reduced to ~ 250 T/m for a lattice that will conform to the layout of the existing NSLS-II 3-GeV storage ring. In this paper we present conceptual designs of a Halbach permanent-magnet (PM) quadrupole, a hybrid PM quadrupole, and a superconducting quadrupole, that can produce the de-sired quadrupole strengths for the Complex Bend appli-cation. REFERENCES [1] T. Shaftan, V. Smaluk and G. Wang, ’The Concept of Com-plex Bend’, NSLS-II Tech note No. 276, Jan 2018. [2] G. Wang et al., ’Complex Bend: Strong-focusing magnet for low emittance synchrotrons’, Physical Review Accelerators and Beams, 21, 100703 (2018). [3] G. Wang et al., ’Complex Bend II’, paper submitted to Physi-cal Review Accelerators and Beams.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS094

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS103

First Results of the Analytical Method Used to Reduce Downtime Risk at an Accelerator Facility

target, linac, operation, DTL

4349

W.C. Barkley, M.J. Borden, R.W. Garnett, M.S. Gulley, E.L. Kerstiens, M. Pieck, D. Rees, F.E. Shelley, B.G. Smith
LANL, Los Alamos, New Mexico, USA

Funding: DOE
The Los Alamos Neutron Science Center (LANSCE), like many other accelerator facilities, was built decades ago and has been repurposed when new missions were adopted. With an ongoing beam availability expectation of at least 80% delivered to the Experimental Areas (EAs), a balance between cost of spare equipment and budget has always been a challenge. Beam availability data has been meticulously captured and binned over the years to completely characterize the Structures, Systems and Components (SSCs) and other factors that have caused or contributed to accelerator downtime. Over these years, a critical spares list prioritized the spare equipment purchases that were deemed most critical by the management team. In the span of the years 2013 ’ 2015, significant accelerator upgrades and equipment replacements were performed in a set of activities known as LANSCE-RM. Last year, a new risk-based approach was developed by the management team that included an analytical assessment and a quantitative evaluation of probability and consequence. The resulting risk register (risk-based equipment list) is being used to guide decisions on funding requests and provide justification to mitigate operational risks. A paper by the same authors was published at LINAC 2018 describing this risk-based approach that serves to reformulate the critical spares list. This paper, in the sections that follow, expands on the approach by detailing the specific results of the analyses that led to the first risk register. Additionally, it evaluates the historical beam downtime at LANSCE compared to the current funding allocation choices made to increase the reliability.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS103

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paper received ※ 10 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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FRXXPLM2

Magnet Design for Siam Photon Source II

photon, quadrupole, sextupole, multipole

4361

P. Sunwong, P. Klysubun, T. Phimsen, S. Prawanta, P. Sudmuang
SLRI, Nakhon Ratchasima, Thailand

Siam Photon Source II project has been approved and detailed technical design of the accelerator system is currently in progress. The Double Triple Bend Achromat (DTBA) lattice is implemented in the storage ring design for low emittance and more space for insertion devices. Magnets with moderate to high field requirements have been designed, including combined function magnet with the field gradient of 27.1 T/m, quadrupole magnets with the field gradient up to 60 T/m and multifunction sextupole magnets. This work presents the magnet requirement and specification, design concept, recent simulation results and analysis of the magnetic field quality. A plan for prototype development is also discussed.

Slides FRXXPLM2 [1.475 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-FRXXPLM2

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

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FRXXPLS1

Tests of a 3D Printed BPM with a Stretched Wire and with a Particle Beam

pick-up, experiment, electron, instrumentation

4368

N. Delerue, D. Auguste, J. Bonis, F. Gauthier, S. Jenzer, A.M. Moutardier
LAL, Orsay, France

Funding: CNRS/IN2P3
We have successfully printed a beam position monitor using 3D printing. After ultra-high vacuum testing and initial measurements with a network analyser we now reports on tests of this BPM using the stretched wire method. The BPM has been installed on a test stand with a wire going through it and electrical pulses have been sent. The signal measured on the pick-ups was compared to that of two conventional BPMs and shows no anomaly specific to the 3D printed BPMs. Following the success of these tests we have also installed this BPM in a beam line at the PhotoInjector at LAL (PHIL). We show that it can give position measurements with an accuracy comparable to that of other BPMs.

Slides FRXXPLS1 [29.118 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-FRXXPLS1

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paper received ※ 19 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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