IPAC2019 - List of Keywords (radiation)

Paper	Title	Other Keywords	Page
MOPGW003	Collective Instability Studies for Sirius	simulation, impedance, storage-ring, coupling	61
	F.H. de Sá LNLS, Campinas, Brazil
	In this work we will present the estimates of single and multi-bunch instability thresholds and current-dependent effects, such as tune-shifts and potential-well distortion for the Sirius storage ring. The results were obtained by tracking simulations and semi-analytic methods using the updated and detailed impedance budget of the machine, which includes contributions from all the in-vacuum components and the coherent synchrotron radiation (CSR) impedance.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW003
About •	paper received ※ 15 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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MOPGW018	Perturbation of Synchrotron Motion in the Micro-Bunching Instability	electron, bunching, synchrotron, storage-ring	108
	T. Boltz, M. Brosi, E. Bründermann, B. Härer, A.-S. Müller, P. Schreiber, P. Schönfeldt, M. Yan KIT, Karlsruhe, Germany
	Short electron bunches in a storage ring are subject to complex longitudinal dynamics due to self-interaction with their own CSR. Above a particular threshold current, this leads to the formation of dynamically changing micro-structures within the bunch, generally known as the micro-bunching instability. The longitudinal dynamics of this phenomenon can be simulated by solving the Vlasov-Fokker-Planck equation, where the CSR self-interaction can be added as a perturbation to the Hamiltonian. This contribution particularly focuses on the comprehension of synchrotron motion in the micro-bunching instability and how it relates to the formation of the occurring micro-structures. Therefore, we adopt the perspective of a single particle and comment on its implications for collective motion. We explicitly show how the shape of the parallel plates CSR wake potential breaks homogeneity in longitudinal phase space and propose a quadrupole-like mode as potential seeding mechanism of the micro-bunching instability. The gained insights are verified using the passive particle tracking method of the Vlasov-Fokker-Planck solver Inovesa.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW018
About •	paper received ※ 15 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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MOPGW029	Preliminary Study of Bunch Compression in the Hefei Light Source	lattice, storage-ring, electron, synchrotron-radiation	151
	W. Li, Z.H. Bai, W. Li, J.G. Wang, D.R. Xu, Z. Zhao USTC/NSRL, Hefei, Anhui, People’s Republic of China
	Funding: This work was supported by the Fundamental Research Funds for the Central Universities (Grant No.WK2310000082 and WK2310000077), and the National Natural Science Foundation of China(GrantNo.11475167). Short electron bunch has interesting applications in the synchrotron radiation light sources, such as the production of powerful coherent THz radiation, time resolving spectrum analysis, etc. In this work, we are interested in acquiring the short bunch in the storage ring with a small circumference like Hefei Light Source. In this paper, we tried to approach the short bunch in two separate methods: by increasing the higher harmonic cavity voltage and by reducing the momentum compaction factor. The preliminary result and observations are shown and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW029
About •	paper received ※ 16 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW041	Transverse Profile Shaping of a Charged-Particle Beam using Multipole Magnets - Formation of Hollow Beams -	octupole, target, optics, multipole	184
	Y. Yuri, T. Yuyama QST/Takasaki, Takasaki, Japan M. Fukuda RCNP, Osaka, Japan
	The use of multipole magnets enables us to shape the transverse profile of a charged-particle beam into various ones that can never be realized through linear beam optics. To date, the formation of a large-area beam with a uniform transverse intensity distribution has been actually realized using octupole magnets in several accelerator facilities. In this presentation, we demonstrate the formation of different beam profiles using multipole magnets rather than existing rectangular uniform beams. Results of tracking simulations and beam-formation experiments will be shown on the formation of clear-cut beams with different cross-sectional shapes, depending on the order and strength of applied multipole magnets. The dynamic behavior of a beam focused with multipole magnets is also investigated theoretically to better understand the numerical and experimental results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW041
About •	paper received ※ 19 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW048	Design Study of an Electron Storage Ring for the Future Plan of Hiroshima Synchrotron Radiation Center.	storage-ring, synchrotron, emittance, synchrotron-radiation	200
	S. Matsuba, M. Katoh, K.S. Shimada HSRC, Higashi-Hiroshima, Japan K. Harada KEK, Ibaraki, Japan K. Kawase QST, Tokai, Japan
	Hiroshima synchrotron radiation center equips a 700 MeV electron storage ring nicknamed HiSOR. It has been operated for more than 20 years. The emittance of HiSOR is 400 nm, which is larger by one or more orders of magnitude than typical modern synchrotron light sources. Therefore, as the future plan of the facility, a new low emittance storage ring is desired. Several designs have been examined. In the newest version, we have selected the lattice structure similar to ASTRID 2 compact light source in Aarhus University, Denmark. The design goal is the energy of around 500 MeV, the circumference shorter than 50 m and the emittance smaller than 10 nm with straight sections for undulators more than 4. In this conference, we report the latest result from the design study.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW048
About •	paper received ※ 01 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPGW051	Diffusion Map Analysis in High Energy Storage Ring Based e⁺/e⁻ Collider	dynamic-aperture, synchrotron-radiation, collider, synchrotron	203
	J. Wu, Q. Qin, Y. Zhang IHEP, Beijing, People’s Republic of China J. Wu, Y. Zhang University of Chinese Academy of Sciences, Beijing, People’s Republic of China
	Funding: Project 11775238 supported by NSFC In a very high energy e⁺/e⁻ storage ring collider, e.g. Circular Electron Positron Collider (CEPC), the dynamic aperture is limited by the strong synchrotron radiation especially in the vertical direction. Some tracking results also shows that the beam lifetime does not correspond well to the dynamic aperture. Here we develop a method called diffusion map analysis, aiming to describe the beam distribution diffusion in transverse amplitude space by tracking less turns. The diffusion may come from quantum fluctuation of SR, beamstrahlung effect and nonlinearity. Comparing cases with different configuration of sextupoles, the diffusion map analysis presents good consistency with beam lifetime that needs much more turns of tracking. Constraints based on the diffusion map is applied to our dynamic aperture optimization, which could help us achieve enough long beam lifetime.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW051
About •	paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW059	Dynamic Aperture Limitation in e⁺ e⁻ Colliders due to Synchrotron Radiation in Quadrupoles	quadrupole, synchrotron, betatron, synchrotron-radiation	221
	A.V. Bogomyagkov, S.A. Glukhov, E.B. Levichev, S.V. Sinyatkin BINP SB RAS, Novosibirsk, Russia
	In a lepton storage ring of very high energy (e.g. in the e⁺e^- Higgs factory) synchrotron radiation from quadrupoles constrains transverse dynamic aperture even in the absence of any magnetic nonlinearities. This was observed in tracking for LEP and the Future Circular e⁺e^- Collider (FCC-ee). Synchrotron radiation in the quadrupoles modulates the particle energy at the double betatron frequency. Energy modulation varies transverse focusing strength at the same frequency and creates a parametric resonance of the betatron oscillations with unusual properties. It occurs at arbitrary betatron frequency and the magnitude of the parameter modulation of the betatron oscillation depends on the oscillation amplitude. Equilibrium between the radiation damping and the resonant excitation gives the boundary of the stable motion. Here we continue comparison of tracking results with analytical calculations of the parametric resonance.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW059
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW060	Cherenkov Radiation at Off-Axis Bunch Passage Through Dielectric Concentrator	target, diagnostics, site, polarization	225
	S.N. Galyamin, A.V. Tyukhtin, V.V. Vorobev Saint Petersburg State University, Saint Petersburg, Russia
	Funding: Work supported by the Grant from Russian Foundation for Basic Research (No. 17-52-04107). Development of tunable systems for non-invasive bunch diagnostics is a modern trend in accelerator physics. Certain dielectric targets are considered in this context, for example, dielectric cones or prisms. Moreover, all-dielectric target which increase the radiated Cherenkov field near the predetermined focus up to several orders of magnitude has been described* and field near its focus and sensitivity of this target have been analyzed*. Here we consider a non-symmetrical case where charge trajectory has a shift with respect to structure axis. We develop analytical approach for description of Cherenkov radiation, perform three-dimensional simulations and compare the results. S.N. Galyamin and A.V. Tyukhtin, Phys. Rev. Lett., 113, 064802 (2014). ** S.N. Galyamin and A.V. Tyukhtin, Nucl. Instr. Meth. Phys. Res. B. 2017. V. 402. P.185-189.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW060
About •	paper received ※ 14 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, vacuum, 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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MOPGW062	Radiation of a Charge Moving in a Wire Structure	FEL, simulation, lattice, electron	231
	S.N. Galyamin, A.V. Tyukhtin, V.V. Vorobev Saint Petersburg State University, Saint Petersburg, Russia A.I. Benediktovitch EuXFEL, Hamburg, Germany A.I. Benediktovitch BSU, Minsk, Belarus, Belarus
	Funding: This work is supported by the grant from Russian Foundation for Basic Research (No. 17-52-04107). In the X-ray frequency region, interaction of relativistic electrons with crystals results in parametric X-ray radiation (PXR), with its frequency being determined by distance between crystallographic planes and direction of electron motion. If instead of crystal one considers an artificial periodic structure with periods of the order of mm, one can expect emission of radiation of a similar nature at terahertz (THz) frequencies. This frequency range is of significant interest during last decade due to its prospective applications. Moreover, artificial wire-like structures are considered as a promising alternative to conventional dielectric structures for wakefield acceleration. Here we consider electromagnetic (EM) field produced by a charged particle bunch moving through a lattice of parallel conducting wires. We present several approaches for analysis of EM field in the described wire structure. First, conventional two-wave approximation for describing the "short-wave response" is developed. Second, we use the effective medium approach and describe the "long-wave" part of the spectrum. Third, we develop a method based on vibrator antenna theory which can be useful for finite length wire structure. P.D. Hoang, et al., Phys. Rev. Lett., V. 120, P. 164801 (2018).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW062
About •	paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW064	On Wakefield in Dielectric Waveguide with Shallow Corrugation of Metallic Wall	GUI, ECR, wakefield, impedance	237
	A.V. Tyukhtin, E.R. Akhmatova, T.Yu. Alekhina, 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). Bunch radiation in periodical waveguides was mainly analyzed for situations when wavelengths are comparable to the structure period (Smith-Purcell emission). However, it is also of interest to study the "long-wave radiation" with wavelengths which are much larger than the structure period,. In such situation, the exact boundary conditions on the complicated periodic surface can be replaced with the equivalent boundary conditions (EBC) which must be fulfilled on the smooth surface. Earlier we considered with this approach radiation of the bunch moving along the axis of circular vacuum corrugated waveguide. Comparison of analytical results with COMSOL simulations showed high accuracy of the EBC method. Here we analyze an analogous problem for the waveguide with corrugated wall and dielectric filling under condition that Cherenkov effect takes place in the dielectric. Due to this fact the radiation differs radically from that in the vacuum waveguide. At the same time, the radiation has essential differences from the one in the usual dielectric waveguide. The radiation properties in the waveguide under consideration and its differences from the radiation in the waveguide with smooth wall are analyzed. G. Stupakov, K. Bane, Phys. Rev. ST-AB, 15 (2012) 124401. ** A.V. Tyukhtin et al, J. of Instrumentation, 13 (2018) C04009.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW064
About •	paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPGW100	Bypass Design for Testing Optical Stochastic Cooling at the Cornell Electron Storage Ring (CESR)	optics, sextupole, wiggler, damping	360
	W.F. Bergan, M.B. Andorf, M.P. Ehrlichman, V. Khachatryan, D.L. Rubin, S. Wang Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: NSF-1734189 DGE-1650441 Optical Stochastic Cooling (OSC) is a promising method for cooling very dense stored particle beams through the interference of radiation created in an upstream ’pickup’ wiggler and a downstream ’kicker’ wiggler. By correlating a particle’s path length via a bypass between the two wigglers with its betatron coordinates in the pickup, the particle will receive a kick in energy which, through coupling introduced by non-zero horizontal dispersion in the kicker, can reduce its betatron amplitude, thus cooling the beam. A proof-of-principle test of this technique is being planned at the Cornell Electron Storage Ring (CESR). In addition to maintaining standard requirements such as a large dynamic aperture and acceptable lattice functions throughout the ring, the design of the bypass is guided by the mutually competing goals of maximizing the cooling rate while maintaining a sufficiently large cooling acceptance with properly-corrected nonlinearities. We present a design of such a bypass and ring optics so as to best achieve these objectives.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW100
About •	paper received ※ 14 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019
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MOPGW116	Validation of a Novel Method for the Calculation of Near-Field Synchrotron Radiation	electron, acceleration, cyclotron, synchrotron	397
	F.Y. Li, B.E. Carlsten, R. Garimella, C. Huang, T.J. Kwan LANL, Los Alamos, New Mexico, USA
	Funding: Work supported by the LDRD program at LANL. The phenomenon of synchrotron radiation (SR) from electrons is at the core of modern accelerator based light sources. While SR in the far field has been well characterized, the near-field SR and its impacts on self-consistent electron beam dynamics remain an ongoing topic. Since it is difficult to experimentally characterize the near fields, it is desirable to develop accurate and efficient numerical methods for the design of these light sources. Here, we investigate a novel method, originally proposed by Shintake and which potentially has both high efficiency and accuracy. We focus on the field calculation of this method and show that the original idea has missed the important terms of fields due to electron acceleration and therefore only applies to a linear motion. To correct this limitation we developed a modified algorithm that gives consistent fields with direct calculations using the Liénard-Wiechert equation. Some basic signatures of the near-field SR fields are also drawn for a cyclotron motion by using this modified approach.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW116
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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MOPGW124	Coherent Synchrotron Radiation Simulation for CBETA	simulation, linac, lattice, shielding	406
	W. Lou, C.M. Gulliford, G.H. Hoffstaetter, D. Sagan Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA C.E. Mayes SLAC, Menlo Park, California, USA N. Tsoupas BNL, Upton, Long Island, New York, USA
	CBETA is an energy recovery linac accelerating from 6 MeV to 150 MeV in four linac passes, using a single return beamline accepting all energies from 42 to 150 MeV. While CBETA gives promise to deliver unprecedentedly high beam current with simultaneously small emittance, Coherent Synchrotron Radiation (CSR) can pose detrimental effect on the beam at high bunch charges and short bunch lengths. To investigate the CSR effects on CBETA, we used the established simulation code Bmad to track a bunch with different parameters. We found that CSR causes phase space dilution, and the effect becomes more significant as the bunch charge and recirculation pass increase. Potential ways to mitigate the effect involving vacuum chamber shielding and increasing bunch length are being investigated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW124
About •	paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPMP013	New Nuclotron Beam Lines and Stations for Applied Researches	target, dipole, heavy-ion, diagnostics	449
	E. Syresin, A.A. Baldin, A.V. Butenko, G.A. Filatov, A.A. Slivin, G.N. Timoshenko, G.V. Trubnikov, A. Tuzikov JINR, Dubna, Moscow Region, Russia D.V. Bobrovskiy, A.I. Chumakov MEPhI, Moscow, Russia M.M. Kats, T. Kulevoy, D.A. Liakin, Y.E. Titarenko ITEP, Moscow, Russia
	New beamlines for applied researches on the Nuclotron are under development within the framework of implementation of the NICA accelerator facility. Ion beams with energies of 150-800 MeV/n extracted from the Nuclotron will be used for radiobiological researches and modeling of cosmic rays interactions with microchips. Equipment of two experimental stations is under development by the JINR-ITEP-MEPhi collaboration for these applied researches. Ion beams with the energy of 3.2 MeV/n extracted from the heavy ion linac HILAc will also be used for irradiation and testing of microchips. The specialized channel will be reconstructed for investigations in the field of relativistic nuclear power at light ion energies of 0.3-4.5 GeV/n. Three new experimental areas are organized for applied physics researches within the framework of implementation of the NICA accelerator facility.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP013
About •	paper received ※ 29 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPMP035	Effect of Emittance Constraints on Monochromatization at the Future Circular e⁺e⁻ Collider	emittance, luminosity, collider, photon	516
	M.A. Valdivia García, F. Zimmermann CERN, Meyrin, Switzerland
	Direct s-channel Higgs production in e+e− collisions is of interest if the collision energy spread can be comparable to the natural width of the standard model Higgs boson. At the Future Circular e⁺e⁻ Collider (FCC-ee), a monochromatization scheme could be employed in order to reduce the collision energy spread to the target value. This may be achieved by introducing a non-zero horizontal dispersion of opposite sign for the two colliding beams at the interaction point. In this case, the beamstrahlung increases the horizontal emittance in addition to energy spread and bunch length. The vertical emittance could either be tuned to a certain minimum value, possibly limited by the diagnostics resolution, or it could scale linearly with the horizontal emittance. For the FCC-ee at 62.5 GeV beam energy, we optimize the IP optics and beam parameters, considering these two different assumptions for the vertical emittance. We derive the maximum achievable luminosity as a function of collision energy spread for either case.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP035
About •	paper received ※ 16 May 2019 paper accepted ※ 22 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, vacuum, kicker, 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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MOPRB061	Simulations and Measurements of Coherent Synchrotron Radiation at the MAX-IV Short Pulse Facility	detector, simulation, electron, dipole	712
	B.S. Kyle University of Manchester, Manchester, United Kingdom R.B. Appleby UMAN, Manchester, United Kingdom M. Brandin, E. Mansten, S. Thorin MAX IV Laboratory, Lund University, Lund, Sweden T.H. Pacey STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom P.H. Williams Cockcroft Institute, Warrington, Cheshire, United Kingdom J. Wolfenden The University of Liverpool, Liverpool, United Kingdom
	The Coherent Synchrotron Radiation (CSR) interaction is a source of unwanted correlated energy spread in short-bunch Free-Electron Lasers (FEL), diluting the desired FEL spectrum and reducing the total brightness of the light source. Many accelerator codes make use of 1-dimensional approximations in the calculation of the CSR-wake, which breaks down for bunch dimensions typical within bunch compressor dipoles in FELs. General Particle Tracer simulations of the CSR interaction make use of the 3-dimensional bunch distribution, making it advantageous in modelling the short-bunch, high aspect ratio regimes typical of modern 4th-generation light sources. Measurements of THz CSR emitted from the final bunch compressor dipole of the SP02 beamline at the MAX-IV Short Pulse Facility (SPF) were used, alongside start-to-end GPT and Elegant simulations, to characterize coherent radiation emission across a broad range of bunch lengths.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB061
About •	paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB075	Radiation Limits on Permanent Magnets in CBETA	electron, vacuum, 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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MOPRB088	Study of Fluctuations in Undulator Radiation in the IOTA Ring at Fermilab	experiment, undulator, electron, photon	777
	I. Lobach University of Chicago, Chicago, Illinois, USA A. Halavanau, Z. Huang, V. Yakimenko SLAC, Menlo Park, California, USA K. Kim ANL, Argonne, Illinois, USA V.A. Lebedev, S. Nagaitsev, A.L. Romanov, G. Stancari, A. Valishev Fermilab, Batavia, Illinois, USA A.Y. Murokh RadiaBeam, Los Angeles, California, USA T.V. Shaftan BNL, Upton, Long Island, New York, USA
	We study turn-by-turn fluctuations in the number of emitted photons in an undulator, installed in the IOTA electron storage ring at Fermilab with an InGaAs PIN photodiode and an integrating circuit. Our study was motivated by the previous experiment . We propose a theoretical model for the experimental data from and in our own experiment we attempted to verify the model in an independent and more systematic way. Moreover, these fluctuations are an interesting subject for a study by itself, since they act as a seed for SASE in FELs. We improve the precision of the measurements from * by subtracting the average signal amplitude using a comb filter with a one-turn IOTA delay, and by using a special algorithm for noise subtraction. We obtain a reasonable agreement between our theoretical model and experiment. Along with repeating the experiment from , which was performed at a constant beam current, we also collect data for fluctuations in undulator light at different beam current values. Lastly, in our experiment we were able to see the transition from Poisson statistics to Super-Poisson statistics for undulator light, whereas in only the latter statistics was observed. * M. Teich et al., PRL, vol. 65, no. 27, p. 3393 (1990).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB088
About •	paper received ※ 14 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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MOPRB089	Experimental Study of a Single Electron in a Storage Ring via Undulator Radiation	photon, electron, undulator, experiment	781
	S. Nagaitsev, A.L. Romanov, G. Stancari Fermilab, Batavia, Illinois, USA A. Arodzero, A.Y. Murokh, M. Ruelas RadiaBeam, Santa Monica, California, USA I. Lobach University of Chicago, Chicago, Illinois, USA T.V. Shaftan BNL, Upton, Long Island, New York, USA
	A single electron orbiting around a ring and emitting single quanta at the rate of about one event per hundred turns could produce a wealth of information about physical processes in large traps (i.e. storage rings) for charged particles. It should be noted that Paul and Penning traps in the 1980s led to the Nobel prize for studying state and motion of single quantum particles, and just recently the Penning trap technique has enabled the measurement of a single proton magnetic moment with an unprecedented precision of 10 decimal places. The information from the storage ring traps could also be used for characterization of a quantum system as well as the "trap" itself, i.e. measuring properties of the storage ring lattice and electron interaction with the laser fields. Although, the interest in single electron quantum processes today is mostly academic in nature, the diagnostics and methodology developed for single electron radiation studies could find subsequent applications in a variety of applied disciplines in quantum technology, including quantum communications and quantum computing.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB089
About •	paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPRB093	eRHIC Electron Ring Design Status	polarization, electron, storage-ring, solenoid	794
	C. Montag, M. Blaskiewicz, C. Hetzel, D. Holmes, Y. Li, H. Lovelace III, V. Ptitsyn, K.S. Smith, S. Tepikian, F.J. Willeke, H. Witte, W. Xu BNL, Upton, Long Island, New York, USA E. Gianfelice-Wendt Fermilab, Batavia, Illinois, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. For the proposed electron-ion collider eRHIC, an electron storage ring will be installed in the existing RHIC tunnel. To reach the high luminosity of up to 10³⁴ cm^-2 sec^-1, beam currents up to 2.5A have to be stored. Besides high luminosity the physics program requires spin polarization levels of 70 percent, with both spin "up" and spin "down" orientations present in the fill. This is only feasible by using a full-energy spin polarized injector that replaces bunches faster than the depolarization rate. To limit the repetition rate of that injector to about one hertz, the polarization lifetime in the storage ring has to be maximized by proper spin matching and countermeasures for the machine misalignments. We will give an overview of the electron storage ring design.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB093
About •	paper received ※ 13 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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MOPTS047	Radiation Measurement in the 1st Beam Commissioning Campaign of the LIPAc RFQ	rfq, neutron, proton, MMI	964
	K. Kondo, S. Kwon, K. Sakamoto, T. Shinya, M. Sugimoto QST, Aomori, Japan L. Bellan, F. Grespan, F. Scantamburlo INFN/LNL, Legnaro (PD), Italy P. Cara IFMIF/EVEDA, Rokkasho, Japan H. Dzitko F4E, Germany R. Heidinger Fusion for Energy, Garching, Germany I. Podadera CIEMAT, Madrid, Spain
	The 1st proton beam acceleration of the Linear IFMIF Prototype Accelerator (LIPAc) through its novel RFQ was succeeded on 13th June 2018. Addition to plenty of beam diagnostics equipped in the beam line, we prepared some radiation detectors placed around the accelerator in order to acquire supplemental information of the beam, as an indirect measurement. In the first day of the beam injec-tion to the RFQ, the gamma-rays corresponding to certain excited states of Al of the low power beam dump were successfully detected by a LaBr3(Ce) scintillation detec-tor. Some neutrons, which would originate from the inter-action of protons with Cu somewhere, were also ob-served. These results proved that the beam was certainly accelerated up to about 2.5 MeV, and provided us a defin-itive confidence that the RFQ was working appropriately from the very beginning of the commissioning. Also, the comparison of the radiation yields with the RFQ trans-mission provided additional information on the beam energy distribution.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS047
About •	paper received ※ 23 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019
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MOPTS054	Status of the CLEAR Electron Beam User Facility at CERN	experiment, electron, plasma, operation	983
	K.N. Sjobak, E. Adli, C.A. Lindstrøm University of Oslo, Oslo, Norway M. Bergamaschi, S. Burger, R. Corsini, A. Curcio, S. Curt, S. Döbert, W. Farabolini, D. Gamba, L. Garolfi, A. Gilardi, I. Gorgisyan, E. Granados, H. Guerin, R. Kieffer, M. Krupa, T. Lefèvre, S. Mazzoni, G. McMonagle, N. Nadenau, H. Panuganti, S. Pitman, V. Rude, A. Schlogelhofer, P.K. Skowroński, M. Wendt, A.P. Zemanek CERN, Geneva, Switzerland A. Lyapin UCL, London, United Kingdom
	The CERN Linear Electron Accelerator for Research (CLEAR) has now finished its second year of operation, providing a testbed for new accelerator technologies and a versatile radiation source. Hosting a varied experimental program, this beamline provides a flexible test facility for users both internal and external to CERN, as well as being an excellent accelerator physics training ground. The energy can be varied between 60 and 220 MeV, bunch length between 1 and 4 ps, bunch charge in the range 10 pC to 2 nC, and number of bunches in the range 1 to 200, at a repetition rate of 0.8 to 10 Hz. The status of the facility with an overview of the recent experimental results is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS054
About •	paper received ※ 12 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS091	Mechanical Robustness of HL-LHC Collimator Designs	experiment, site, proton, interface	1070
	F. Carra, A. Bertarelli, G. Gobbi, J. Guardia, M. Guinchard, F.J. Harden, M. Pasquali, S. Redaelli, E. Skordis CERN, Meyrin, Switzerland
	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. Two new absorbing materials were developed as collimator inserts to fulfil the requirements of HL-LHC higher brightness beams: molybdenum-carbide graphite (MoGr) and copper-diamond (CuCD). These materials were tested under intense beam impacts at CERN HiRadMat facility in 2015, when full jaw prototypes were irradiated. Additional tests in HiRadMat were performed in 2017 on another series of material samples, including also improved grades of MoGr and CuCD, and different coating solutions. This paper summarizes the main results of the two experiments, with a main focus on the behaviour of the novel composite blocks, the metallic housing, as well as the cooling circuit. The experimental campaign confirmed the final choice for the materials and the design solutions for HL-LHC collimators, and constituted a unique chance of benchmarking numerical models. In particular, the tests validated the selection of MoGr for primary and secondary collimators, and CuCD as a valid solution for robust tertiary collimators.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS091
About •	paper received ※ 12 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS092	Numerical and Experimental Evaluation of the DQW Crab Cavity Cryomodule Thermal Budget	cryomodule, cavity, HOM, experiment	1074
	F. Carra, K. Brodzinski, E. Cano-Pleite, O. Capatina CERN, Meyrin, Switzerland
	Funding: Research supported by the HL-LHC project One of the key devices of the HL-LHC project are SRF Crab Cavities. A cryomodule with two Double Quarter Wave (DQW) crab cavities has been fabricated at CERN in 2017 and successfully tested with beam in the Super Proton Synchrotron (SPS) in 2018. The aim of the present study is to present and compare the estimation of the thermal budget for the different components of the cryomodule, performed with numerical and semi-analytical methods, with the experimental measurements carried out on the cryomodule after installation in the SPS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS092
About •	paper received ※ 12 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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MOPTS105	The High Brightness Photo-injector for THz CUR/VUV FEL at NSRRC	electron, emittance, quadrupole, linac	1125
	A.P. Lee, M.C. Chou, H.P. Hsueh, J.-Y. Hwang, W.K. Lau NSRRC, Hsinchu, Taiwan P. Wang NTHU, Hsinchu, Taiwan
	A high brightness photo-injector has been build for THz coherent undulator radiation and VUV free electron laser test facility at NSRRC. In the first phase, the photo-injector was used to produce ultra-short electron bunches for THz CUR generation. The electron beam is generated form a photocathode rf gun followed by a solenoid for emittance compensation. Then A 5.2 m S-band linac accelerates the electron beam and compresses the beam by velocity bunching. Since the beam emittance will grow during the velocity bunching process, a solenoid system was installed to reduce the emmitance growth. Downstream the linac, a quadruple magnet was use for emittance measurement by quadruple scan method and the bunch length was measured by the coherent transition radiation. Finally, the ultra-short electron bunch with about few hundreds picoseconds passes through a U100 planer undulator can produce THz coherent undulator radiation. The instrument setup and results of measurement are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS105
About •	paper received ※ 14 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019
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MOPTS110	FLUKA-MARS15 Simulations To Optimize the Fermilab PIP-II Movable Beam Absorber	linac, MMI, shielding, simulation	1136
	L. Lari, F.G. Garcia, Y. He, I. Kourbanis, N.V. Mokhov, E. Pozdeyev, I.L. Rakhno Fermilab, Batavia, Illinois, USA F. Cerutti, L.S. Esposito, L. Lari CERN, Meyrin, Switzerland
	PIP-II is the Fermilab’s flagship project to provide powerful, high-intensity proton beams to the laboratory’s experiments. The heart of the PIP-II project is an H⁻ 800 MeV superconducting linear accelerator. In order to commission the beam and operate safely the linac, several constraints were evaluated. The design of a movable 5 kW beam absorber was finalized to allow staged beam commissioning in different linac locations. Prompt and residual radiation levels were calculated, and radiation shields were optimized to keep those values within the acceptable levels in the areas surrounding beam absorber. Monte Carlo calculations with FLUKA and MARS15 codes are presented in the paper to support these studies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS110
About •	paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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TUZZPLS3	New Method of Calculation of the Wake due to Radiation and Space Charge Forces in Relativistic Beams	wakefield, electron, space-charge, synchrotron-radiation	1223
	G. Stupakov SLAC, Menlo Park, California, USA
	Funding: This work was supported by the Department of Energy, Contract No. DE-AC02-76SF00515. Radiation reaction force in a relativistic beam, also known as a CSR wakefield, is often computed using a 1D model of a line charge beam. While this model can serve as a useful tool for a quick calculation, in some cases, it may not be sufficiently accurate. In particular, this model misses the so-called compression effects associated with the change of the electromagnetic energy when the beam is compressed longitudinally or transversely. The existing 3D simulation codes that take this effect into account are often slow and are not easy to use. In this work, we propose a new approach to the calculations of radiation and space charge longitudinal forces based on the use of the integrals for the retarded potentials. Our main result expresses the rate of change of particles energy through 2D (in a 2D model) or 3D integrals for a given orbit of the beam. It generalizes the 1D model and includes the transient effects of at the entrance and the exit from the magnet. For a given beam line with known magnetic lattice, and a known distribution function of the beam, the calculation reduces to taking 2D or 3D integrals along the orbit.
	Slides TUZZPLS3 [2.080 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUZZPLS3
About •	paper received ※ 29 April 2019 paper accepted ※ 22 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	vacuum, injection, 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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TUPMP022	Research on Digital Scanning Power Supply Technology for Proton Therapy System	power-supply, proton, controls, scattering	1286
	J. Huang, M. Fan, J. Yang, L.G. Zhang HUST, Wuhan, People’s Republic of China T. Yu, C. Zuo Huazhong University of Science and Technology, State Key Laboratory of Advanced Electromagnetic Engineering and Technology,, Hubei, People’s Republic of China
	Funding: Work supported by The National Key Research and Development Program of China, with grant No. 11505068 Proton has great advantages in the field of cancer radiotherapy because of its good characteristic of Bragg peak. HUST-PTF is a proton therapy facility under development in Huazhong University of science and technology. It delivers the beam to the patients with a pencil beam scanning nozzle. Scanning power supplies are placed in the nozzle of the proton therapy device and they are required high accuracy, high speed and high stability. In this paper，the structure diagram of HUST-PTF is shown. The parameters of scanning magnets and its power supply are introduced. Finally, some test results of power supply are shown. The next work will debug the control system of the scanning power supply and adjust it with the scanning magnet to see if it meets the design requirements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP022
About •	paper received ※ 19 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPMP025	Design of Fast Corrector Magnet Power Supply for HEPS	power-supply, controls, simulation, experiment	1294
	P. Liu, C. Han, F. Long IHEP, Beijing, People’s Republic of China
	High energy photon source is a fourth-generation synchrotron radiation light source with energy of 6Gev and ultra-low emittance (<0.1nm’rad). The ultra-low beam emittance requires high beam stability. Therefore, we develop a fast correction power supply with high bandwidth and low current ripple to improve the performance of the fast close orbit correction sys-tem to prove the high beam stability. The power supply adopts FPGA for full-digital control and use high speed ADC with temperature control. The power sup-ply has a small signal-bandwidth of 10 kHz and output current ripple lower than 20ppm. In this paper, we will describe the hardware design and software control methods and the test results will be demonstrated
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP025
About •	paper received ※ 13 May 2019 paper accepted ※ 22 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, vacuum, 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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TUPMP042	The Beam Cleaning Analysis for the TPS Vacuum System	vacuum, MMI, 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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TUPMP048	Current Status of Turkish Accelerator and Radiation Laboratory	electron, cavity, FEL, status	1359
	A.A. Aksoy, O.F. Elçim Ankara University Institute of Accelerator Technologies, Golbasi, Turkey Ö. Karslı, C. Kaya, B. Koc Ankara University, Accelerator Technologies Institute, Golbasi, Turkey
	Funding: T.R. Presidency Strategy and Budget Office Grand No: 2006K-120470 Turkish Accelerator and Radiation Laboratory (TARLA) which is designed to deliver various accelerator based radiation sources, aims to be outstanding research instrument for users from both Turkey and region. Within the current scope of TARLA its superconducting accelerator will drive two of free electron laser (FEL) beamlines in order to provide Continuous Wave (CW) tunable radiation of high brightness in the mid- and far-infrared range as well as a Bremmstrahlung radiation station. Main components of TARLA, such as injector, superconducting accelerating modules and cryoplant are under commissioning currently. In this paper commissioning results and current status of facility are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP048
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW006	Measurements of the Momentum Compaction Factor of the ESRF Storage Ring	undulator, electron, SRF, synchrotron	1392
	N. Carmignani, W. De Nolf, A. Franchi, C. Sahle, L. Torino ESRF, Grenoble, France B. Nash RadiaSoft LLC, Boulder, Colorado, USA
	In a storage ring, the momentum compaction factor can be obtained by measuring the variation of the beam energy as a function of the RF frequency. In this paper we present the measurement of the momentum compaction factor from two different methods. With the first, we measure the variation of the undulator spectra for different RF frequencies. With the second, we measure the variation of the hard x-rays flux produced by a dipole for different RF frequencies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW006
About •	paper received ※ 29 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW015	Petra III Operation and Studies 2018	operation, vacuum, impedance, undulator	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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TUPGW024	Pulse Shaping Methods for Laser-Induced Generation of THz Radiation at the Delta Storage Ring	laser, electron, storage-ring, experiment	1453
	C. Mai, B. Büsing, A. Glaßl, S. Khan, D. Krieg, A. Meyer auf der Heide DELTA, Dortmund, Germany
	At DELTA, a 1.5-GeV electron storage ring operated as a synchrotron light source by the TU Dortmund University, a dedicated beamline is used for experiments with (sub-)THz radiation. Here, an interaction of short laser pulses with electron bunches to give rise to coherently emitted broadband as well as tunable narrowband radiation from 75 GHz to 5.6 THz. For the narrowband operation of the source, a laser pulse with periodic intensity modulation is used. An interferometric approach, the chirped-pulse beating technique, is routinely employed for this purpose. Recently, pulse shaping techniques using spatial light modulators are investigated to gain more flexible control of the laser pulse shape and the spectrotemporal properties of the resulting THz pulses.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW024
About •	paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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TUPGW025	The DELTA Short-Pulse Source: Upgrade Plans from CHG to EEHG	laser, electron, undulator, optics	1457
	A. Meyer auf der Heide, B. Büsing, S. Khan, D. Krieg, C. Mai, F. Teutenberg DELTA, Dortmund, Germany
	At the synchrotron light source DELTA operated by the TU Dortmund University, coherent harmonic generation (CHG) is employed to provide ultrashort pulses in the vacuum ultraviolet and terahertz (THz) regime. Here, a modulation of the electron energy induced by an interaction of an ultrashort laser pulse with an electron bunch is transformed into a density modulation by a magnetic chicane. This results in coherent emission at harmonics of the laser wavelength as well as THz radiation. With the planned upgrade towards echo-enabled harmonic generation (EEHG), much higher harmonics can be achieved by adding a second laser-electron interaction. The necessary major modifications of the DELTA storage ring and investigations of the laser-electron interaction will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW025
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPGW033	Status of Test-Accelerator as Coherent THz Source (t-ACTS) at ELPH, Tohoku University	electron, undulator, polarization, FEM	1475
	S. Kashiwagi, H. Hama, F. Hinode, K. Kanomata, S. Miura, N.M. Morita, T. Muto, I. Nagasawa, K. Nanbu, S. Ninomiya, H. Saito, K. Takahashi, H. Yamada Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
	A test-Accelerator as Coherent Terahertz Source (t-ACTS) has been under development at the Research Center for Electron Photon Science (ELPH), Tohoku University, in which an intense coherent terahertz radiation is generated from the femtosecond electron pulses. Velocity bunching scheme in a traveling accelerating structure is employed to generate femtosecond electron pulses, and the generation of femtosecond electron pulses was confirmed by spectrum analysis of coherent transition radiation using Michelson interferometer. Coherent transition radiation and coherent undulator radiation in the terahertz (THz) region from the short electron pulses has been demonstrated, and their characteristics such as frequency spectrum, spatial distribution and polarization were measured and compared with theoretical calculations. We have succeeded to generate the coherent transition radiation up to approximately 5 THz and the coherent undulator radiation with narrow bandwidth from 2.6 to 3.4 THz. At present, development of a variable polarized THz light source using a crossed-undulator system is being carried out. In addition, we are developing a nondestructive beam monitor using Cherenkov radiation emitted from the electron pulses. The status of t-ACTS will be presented in this conference.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW033
About •	paper received ※ 17 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPGW037	Systematic Measurements of the Coherent THz Spectra by Magnetic Bunch Compression at the Compact ERL	optics, electron, sextupole, linac	1486
	M. Shimada, Y. Honda, R. Kato, T. Miyajima, N. Nakamura, T. Obina, T. Uchiyama KEK, Ibaraki, Japan T. Hotei Sokendai, Ibaraki, Japan
	Short electron bunch beam is one of the key elements of a Free Electron Laser (FEL) or intense THz coherent light source. The Energy Recovery Linac (ERL) has the strong advantage of operation of such an electron bunch at high repetition rate and is expected to increase the photon flux. At the Compact ERL in KEK site, we have demonstrated the magnetic bunch compression at the 180-degree return arc and measured the THz spectra of the Coherent Transition Radiation (CTR). This paper reports the revamped THz beamline and the improvement of the beam tuning as well as the systematic measurements of the THz spectra by magnetic bunch compression.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW037
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPGW038	Study on Coherent THz Radiation Using Tilt Control of Electron Beam	electron, solenoid, target, experiment	1489
	Y. Tadenuma, M. Brameld, T. Murakami, K. Sakaue, M. Washio Waseda University, Tokyo, Japan
	Funding: This work was supported by a research granted from JSPS KAKENHI 17H02821. The terahertz wave is located in the intermediate frequency band between radio waves and light waves, and researches on the light sources such as terahertz quantum cascade laser and femtosecond laser based THz sources are being conducted. As a new terahertz light source, we are studying coherent Cherenkov radiation by using the tilt control of electron beam and irradiating the target medium. Since the radiation intensity of Cherenkov radiation depends on the target medium, comparison of three kinds of medium with different refractive index and density, and optimization of the target shape were performed. In addition, we are going to try quasi monochromatization of radiation by using multi slit to control the form factor of the electron beam. In this presentation, we will report the experimental results of target optimization and quasi monochromatization and the future prospects. S. S. Dhillon, et al., The 2017 terahertz science and technology roadmap, J. Phys. D: Appl. Phys., 50 (2017) 043001.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW038
About •	paper received ※ 12 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW045	Lattice Design for the Reversible SSMB	electron, emittance, storage-ring, bunching	1507
	C.L. Li SINAP, Shanghai, People’s Republic of China A. Chao SLAC, Menlo Park, California, USA C. Feng, B.C. Jiang Shanghai Advanced Research Institute, Pudong, Shanghai, People’s Republic of China
	Steady State Microbunching (SSMB) aiming at producing high average power radiation in the electron storage ring has been proposed by Ratner and Chao years ago. Reversible seeding scheme is one of the promising scenarios with less challenges on the storage ring lattice design. The key problem for reversible SSMB is the precise cancelation of the laser modulation which will allow producing turn-by-turn coherent radiation without spoiling the transverse emittances and energy spread. In this paper the lattice design for the microbunching generation and its cancelation will be presented. Also a storage ring lattice design will be shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW045
About •	paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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TUPGW051	Generation of Two Terahertz Radiation Pulses with Continuously Tunable Frequency and Time Delay	electron, laser, cathode, gun	1518
	W.X. Wang, Z.G. He, S.M. Jiang, H.R. Zhang USTC/NSRL, Hefei, Anhui, People’s Republic of China
	We propose to generate two narrow band terahertz pulses radiated from two temporally modulated relativistic electron beams, which are generated in a photo-injector. The temporal profile of the drive laser is modulated by means of the paired chirped pulses beating technique, leading to the generation of two pre-bunched electron beams. Coherent transient radiation (CTR) is considered as the mechanism for terahertz radiation generation. The frequencies of the two terahertz pulses can be independently tuned by adjusting the paired beating frequencies, and the interval between the two terahertz pulses can be adjusted by the optical delay line.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW051
About •	paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPGW068	New Source for Bending Magnet Beam Lines at Ultra-Low-Emittance Ring	dipole, lattice, storage-ring, wiggler	1557
	M. Abbaslou, M. Sedaghatizadeh KNTU, Tehran, Iran S. Dastan, J. Rahighi, F. Saeidi ILSF, Tehran, Iran
	The Iranian Light Source Facility (ILSF) is a 3 GeV 3rd synchrotron radiation laboratory in the basic design phase. The Storage Ring (SR) is based on a five-bend achromat (5BA) lattice providing low horizontal emittance of 0.27 nm.rad. Due to the ILSF storage ring, straight section limits the use of the short length wigglers for hard X-ray generation is recommended. Which are removable in the lattice. In this article, the new design of the 3-pole wiggler is investigated and the main parameters of this 3-pole wiggler, by considering the ILSF storage ring characteristics, is modified. Also, the effect of the new 3-pole wiggler on the beam dynamics is investigated and the advantages of the new design are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW068
About •	paper received ※ 28 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPRB012	Design of High Power CW IR-THz Source for the Radiation Source ELBE Upgrade	undulator, electron, FEL, linac	1702
	P.E. Evtushenko, T.E. Cowan, U. Lehnert, P. Michel HZDR, Dresden, Germany
	The Radiation Source ELBE at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) is a user facility based on a 1 mA - 40 MeV CW SRF LINAC. Presently HZDR is considering upgrade options for the ELBE or its replacement with a new CW, SRF LINAC-based user facility. A part of the user requirements is the capability to generate IR and THz pulse in the frequency range from 0.1 through 30 THz, with pulse energies in the range from 100 uJ through a few mJ, at the repetition rate between 100 kHz and 1 MHz. This corresponds to the pulse energy increase, dependent on the wavelength by a factor from 100 through 1000. In this contribution, we outline key aspects of a concept, which would allow to achieve such parameters. Such key aspects are: 1 - use of a beam with longitudinal density modulation and bunching factor of about 0.5 at the fundamental frequency; 2 - achieving the density modulation through the mechanism similar to the one used in optical klystron (OK) and HGHG FEL; 3 - generating necessary for the modulation optical beam by an FEL oscillator, and 4 - using two electron injectors, where one injector provides beam for the FEL oscillator while second high charge injector provides beam for the high energy per pulse generation for user experiments. All-in-all the concept of the new radiation source is very similar to an OK, but operating with two beams simultaneously.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB012
About •	paper received ※ 21 May 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, FEL, simulation, vacuum	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, vacuum, 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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TUPRB035	Stimulated Emission of THz Coherent Diffraction Radiation in an Optical Cavity by a Multibunch Electron Beam	cavity, experiment, resonance, electron	1763
	Y. Honda, A. Aryshev, R. Kato, T. Miyajima, T. Obina, M. Shimada, R. Takai, T. Uchiyama, N. Yamamoto KEK, Ibaraki, Japan
	Funding: JSPS KAKENHI Accelerator-based terahertz (THz) radiation has been expected to realize a high-power broad-band source. Employing a low-emittance and short-bunch electron beam at a high repetition rate, a scheme to resonantly excite optical cavity modes of THz spectrum range via coherent diffraction radiation has been proposed. The confocal cavity design is the special case that resonance conditions of all the eigen modes coincide, resulting in realizing broad-band excitation. But in general cases of non-confocal cavities, the resonance condition depends on the mode, and the resonance peak becomes wide and weak. We performed an experiment with a non-confocal cavity as a follow-up experiment of that we have done with a confocal cavity. The result confirmed that the confocal design is the key for a broad-band source.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB035
About •	paper received ※ 26 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPRB037	Experimental Demonstration of Vector Beam Generation With Tandem Helical Undulators	polarization, undulator, experiment, simulation	1766
	S. Matsuba HSRC, Higashi-Hiroshima, Japan M. Fujimoto, M. Katoh UVSOR, Okazaki, Japan M. Hosaka Nagoya University, Nagoya, Japan K. Kawase QST, Tokai, Japan T. Konomi, N. Yamamoto KEK, Ibaraki, Japan A. Miyamoto Toshiba, Yokohama, Japan S. Sasaki ANL, Argonne, Illinois, USA
	Vector beam is a light beam with spatially modulated polarization state across the beam. Particular examples of vector beam are radial and azimuthal polarization which have donut-shaped intensity and radially and azimuthally oriented linear polarization state. Vector beam has long been interest in the laser community and it is well known that vector beam can be created by superposing two optical vortex beams which have spiral wave fronts. It has been demonstrated that optical vortex beam can be generated from a helical undulator as harmonics. Therefore, we propose a scheme to generate vector beam by superposing two optical vortex beams from two helical undulators in tandem, based on the principle of the ’crossed undulator’. The experiment was carried out at UVSOR BL1U. In this paper, we describe the principle and the experimental details.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB037
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPRB038	Characteristics of Polarized Coherent Radiation in Thz Region From a Crossed-Undulator	undulator, polarization, experiment, electron	1769
	H. Saito, H. Hama, F. Hinode, K. Kanomata, S. Kashiwagi, S. Miura, N.M. Morita, T. Muto, I. Nagasawa, K. Nanbu, S. Ninomiya, K. Takahashi, H. Yamada Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
	A variable polarized THz light source using a crossed-undulator configuration has been developed at Research Center for Electron Photon Science (ELPH), Tohoku University. It consists of two planar undulators of which deflecting planes cross at right angles and a phase shifter for phase adjustment. Polarization of the crossed-undulator has observation angle dependence due to that of radiation wavelength and optical path length difference between two radiations. That limits an angular range maintaining the identical polarization state. Assuming undulator parameters for our experiment (a fundamental frequency 1.9 THz and a number of periods seven) degree of circular polarization larger than 0.9 can be obtained only in the range of 2.2 mrad, i. e. 13% of the radiation angular spread.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB038
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPRB039	Research of Coherent Edge Radiation Generated by Electron Beams Oscillating Free-Electron Lasers	FEL, electron, cavity, experiment	1772
	N. Sei, H. Ogawa AIST, Tsukuba, Ibaraki, Japan K. Hayakawa, Y. Hayakawa, K. Nogami, T. Sakai, Y. Sumitomo, Y. Takahashi, T. Tanaka LEBRA, Funabashi, Japan H. Ohgaki, H. Zen Kyoto University, Kyoto, Japan
	Funding: JSPS KAKENHI Grant Number JP16H03912 We have studied far-infrared coherent radiation with an S-band linac at Laboratory for Electron Beam Research and Application (LEBRA) at Nihon University. We have already developed a couple of terahertz-wave sources based on coherent synchrotron radiation and coherent transition radiation, which have been applied to spectroscopic research. Moreover, we developed coherent edge radiation (CER) at the downstream bending magnets in the FEL sections. Because the edge radiation has an annular shape distribution characterized by the asymmetric first-order Laguerre-Gaussian mode, the CER can be extracted from an optical cavity of the FEL system without a diffraction loss of the FEL beam*. The root-mean-squared bunch length of the electron beam was evaulated by measuring the CER spectra, which was about the same level as the FEL micropulse width. Although the infrared FELs at LEBRA had a long slippage length, the CER intensity can be a guidepost enhancing the FEL power because of the existence of their correlation. In this presentation, the characteristics of the CER including correlation between the CER and the FEL will be reported. N. Sei et al., Jpn. J. Appl. Phys. 56, (2017) 032401. N. Sei et al., J. Opt. Soc. Am. B, 31, (2014) 2150. * N. Sei et al., Phys. Lett. A in press.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB039
About •	paper received ※ 19 April 2019 paper accepted ※ 23 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, vacuum	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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TUPRB041	Simulation of Short-Pulse Generation from a Dynamically Detuned IR-FEL Oscillator and Pulse Stacking at an External Cavity	FEL, cavity, electron, simulation	1778
	Y. Sumitomo, Y. Hayakawa, T. Sakai LEBRA, Funabashi, Japan R. Hajima QST, Tokai, Japan
	Funding: Q-LEAP program supported by Ministry of Education, Culture, Sports, Science and Technology, Japan At the LEBRA facility of Nihon U., we have an IR-FEL oscillator to generate radiations in the range of wavelengths 1-6 um for various experiments. A research program has been established to explore the application of the IR-FEL to generate attosecond UV and X-ray pulses through the high harmonic generation (HHG) in noble gases, where the IR-FEL pulses must have a high-peak power and a short-pulse duration. The property of generated FEL pulse is affected by the cavity length detuning of FEL oscillator as well as the small signal gain and the cavity loss. The operation at a small- or zero-detuning length is necessary to generate a FEL pulse shorter than the bunch length, although it requires a long macro-pulse to reach the saturation. For the short FEL pulse generation within a limited macro-pulse length at the LEBRA LINAC, we apply a dynamical modulation to the electron bunch repetition, that is equivalent to a dynamical detuning of the FEL cavity length. We illustrate the potential performance of the IR-FEL with the dynamical detuning by time-dependent 3D FEL simulations. We also evaluate the enhancement of the FEL pulses by an external cavity stacking for the sake of the HHG application.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB041
About •	paper received ※ 29 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPRB045	Stimulated Excitation by Seeding With Cherenkov Radiation in an Optical Cavity	cavity, electron, GUI, ion-source	1785
	S.M. Jiang, Z.G. He, Q.K. Jia, W.W. Li, L. Wang USTC/NSRL, Hefei, Anhui, People’s Republic of China D. He Anhui Electrical Engineering Professional Technique College, Hefei, People’s Republic of China
	Funding: Work supported by National Foundation of Natural Sciences of China (11775216, 11705198, 11675178), and Fundamental Research Funds for the Central Universities (WK2310000061). By seeding with narrow-band Cherenkov radiation from a dielectric loaded waveguide(DLW), stimulated excitation in an optical cavity is presented. The evolution and energy loss of the field oscillating in optical cavity is analysed by the theoretical and numerical calculation. The results show that the high order TM modes of the Cherenkov radiation can be better preserved after a large number of roundtrips in the optical cavity and this scheme offers a potential method of realizing high power Terahertz radiation source in a compact facility.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB045
About •	paper received ※ 30 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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TUPRB046	Second Order Intensity Correlation and Statistical Properties of a Soft X-Ray Free Electron Laser	laser, FEL, electron, simulation	1788
	C.L. Li, J.H. Chen, Z.C. Chen, X.T. Wang, H.L. Wu SINAP, Shanghai, People’s Republic of China B. Liu, T. Liu SARI-CAS, Pudong, Shanghai, People’s Republic of China
	High degree of transverse field coherence is one of the unique properties of an FEL compared with a 3rd gen-eration storage ring light source. As a result, the FEL advances the development of innovative research and technology that was not previously feasible. A truly coherent source should be coherent in all orders de-scribed from the intensity correlation functions. In this paper, second order intensity correlation of FEL radia-tion is investigated based on the Hanbury Brown-Twiss intensity correlation method. The statistical properties of radiation produced from SASE was also investigated and compared with the statistical proper-ties of a phase-locked laser. The results show that the statistical properties of a SASE mode behave as a cha-otic source, which is significantly different from the properties of a phase-locked laser beam.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB046
About •	paper received ※ 13 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPRB050	The Optical Resonator of CTFEL for Range of 1 to 2 THz	FEL, GUI, electron, coupling	1795
	X.J. Shu, Y.H. Dou Institute of Applied Physics and Computational Mathematics, People’s Republic of China
	A high power THz free electron laser (FEL) facility is under construction at China Academy of Engineering Physics (CTFEL). The radiation frequency of the FEL facility will be tuned in range of 1~3 THz and the average output power is about 10 W. The system mainly consists of a GaAs photoemission DC gun, superconductor accelerator, hybrid wiggler, optical cavity. The first lasing is obtained on Aug. 29, 2017, and CTFEL is operated in range of 2-4THz, but cannot lasing at the frequency below 1.8 THz. The optical resonator of CTFEL must be optimized to ensure lasing in range of 1 to 2 THz.. The lasing strongly depends on the performance of the optical resonator including output efficiency, gain and round-trip loss. The optical resonator consists of metal-coated reflect mirror, the centre-hole output mirror, waveguide. The influence of waveguide on the quality of optical cavity is evaluated by the 3D OSIFEL code. The waveguide size and output hole radius is optimized to different frequencies between 1 THz to 2 THz.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB050
About •	paper received ※ 13 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019
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TUPRB052	The Mini-Period Permanent Magnet Staggered Undulator for Compact X-Ray Free Electron Laser	undulator, FEL, electron, permanent-magnet	1797
	L.G. Yan, D.R. Deng, J. Wang CAEP/IAE, Mianyang, Sichuan, People’s Republic of China
	Funding: Work supported by National Natural Science Foundation of China under grant of 11505174, 11505173 and 11605190. Miniaturization of X-ray free electron laser requires reduction of undulator period length. In this proceeding, a mini-period permanent magnet staggered undulator was proposed, which is free of superconducting solenoid and thus has advantages of easy-manufacture and low-cost. After optimization, it can generate periodic field of peak field 0.71 T with period length 10 mm and pole gap 2 mm, which has been verified on a prototype. Combined with X-band linac, the length of 1 nm XFEL facility using the permanent magnet staggered undulator can be confined within 44 m.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB052
About •	paper received ※ 30 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019
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TUPRB057	THz-Pump and UV-Probe Scheme Based on Storage Ring	laser, electron, bunching, storage-ring	1811
	H.R. Zhang, Z.G. He, S.M. Jiang, W.X. Wang USTC/NSRL, Hefei, Anhui, People’s Republic of China
	We propose a THz-pump and UV-probe scheme based on storage ring for ultra-fast dynamics experiment. In which, two sequential laser pulses, one of which has a periodic intensity envelope, simultaneously interact with different parts of the long electron beam in a modulator; after a chicane, the part that interacts with the periodic pulse will bunch at THz domain and radiate through a bend magnet, another based on high-harmonic generation will bunch at UV domain and radiate at a radiator. The electron beam can be utilized circularly in the storage ring, which will increase its average power. The feasibility of this THz-pump and UV-probe scheme is verified in both theory and simulation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB057
About •	paper received ※ 30 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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TUPRB061	Seeded Free-Electron Lasers Driven by a Transverse Tilted Electron Bunch	laser, FEL, electron, undulator	1817
	Z. Zhao, Q.K. Jia, H.T. Li USTC/NSRL, Hefei, Anhui, People’s Republic of China
	Funding: Work supported by the China Postdoctoral Science Foundation (No. 2018M642542) and the Fundamental Research Funds for the Central Universities (WK2310000081). A transverse tilt of the electron bunch is normally unwanted in free-electron laser (FEL) since only a portion of the bunch can contribute to the FEL radiation. However, the recent researches demonstrate that the tilted bunch can be used to generate FEL with some special features. In this work we investigate the generation of a large tilt of the bunch by using a corrugated structure and a dogleg separately. Based on the tilted bunch, the creation of ultra-short pulse and multi-color pulses are demonstrated in high-gain harmonic generation (HGHG) FEL.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB061
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPRB062	Coherence Time Characterization for Self-Amplified Spontaneous Emission Free-Electron Lasers	electron, FEL, laser, free-electron-laser	1820
	G. Zhou, Y. Jiao, J.Q. Wang IHEP, Beijing, People’s Republic of China T.O. Raubenheimer, J. Wu SLAC, Menlo Park, California, USA C.-Y. Tsai HUST, Wuhan, People’s Republic of China C. Yang USTC/NSRL, Hefei, Anhui, People’s Republic of China
	One of the key challenges in scientific researches based on free-electron lasers (FELs) is the characterization of the coherence time of the ultra-fast hard x-ray pulse, which fundamentally influences the interaction process between x-ray and materials. Conventional optical methods, based on autocorrelation, is very difficult to realize due to the lack of mirrors. Here, we experimentally demonstrate a conceptually new coherence time characterization method and a coherence time of 174.7 attoseonds has been measured for the 6.92 keV FEL pulses at Linac Coherent Light Source. In our experiment, a phase shifter is adopted to control the cross-correlation between x-ray and microbunched electrons. This approach provides critical temporal coherence diagnostics for x-ray FELs, and is decoupled from machine parameters, applicable for any photon energy, radiation brightness, repetition rate and FEL pulse duration, etc. The work was supported by the US Department of Energy (DOE) under contract DE-AC02-76SF00515 and the US DOE Office of Science Early Career Research Program grant FWP-2013-SLAC-100164.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB062
About •	paper received ※ 01 May 2019 paper accepted ※ 28 May 2019 issue date ※ 21 June 2019
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TUPRB071	Considerations on Implementing EEHG with a Strong Linear Chirp	electron, bunching, FEL, linac	1830
	M.A. Pop, S. Werin MAX IV Laboratory, Lund University, Lund, Sweden
	As the ECHO enabled harmonic generation (EEHG) scheme draws such intense focus from the FEL community, we conduct simulations to evaluate the challenges of implementing said scheme in different FEL layouts. Nonlinear processes such as this require extensive simulations to harmonize all system specific properties like seed lasers and electron beam properties. Along with optimizing the original EEHG scheme* one can consider, for example, altering the seed laser pulse to optimize the bunching for a machine specific chirp. We study the EEHG as a possible seeding method aimed at increasing coherence of the photon beam for the prospective SXL FEL beamline at MAXIV. The particular chirp of the electron beam through the MAXIV LINAC generates some specific requirements in implementing EEHG but may also offer an opportunity for exotic operation modes of this FEL. * Xiang D. and Stupakov G. Echo-enabled harmonic generation free electron laser 10.1103/PhysRevSTAB.12.030702
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB071
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TUPRB076	Free Electron Laser Driven by a High-Energy High-Current Energy-Recovery Linac	FEL, electron, linac, undulator	1844
	F. Zimmermann CERN, Geneva, Switzerland H. Aksakal KMSIU, Onikisubat / Kahramanmaras, Turkey A.A. Aksoy Ankara University, Accelerator Technologies Institute, Golbasi, Turkey Z. Nergiz Nigde University, Nigde University Science & Art Faculty, Nigde, Turkey
	Funding: This work was supported by the European Commission under the HORIZON 2020 project ARIES, grant agreement no. 730871. The proposed electron-hadron collider LHeC, based on an energy recovery linac, employs an electron beam of 20 mA current at an energy of tens of GeV. This electron beam could also be used to drive a free electron laser (FEL) operating at sub-Angstrom wavelengths. Here we demonstrate that such FEL would have the potential to provide orders of magnitude higher peak power, peak brilliance and average brilliance, than any other FEL, either existing or proposed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB076
About •	paper received ※ 10 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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TUPRB089	Undulator Radiation Generated by a Single Electron	electron, undulator, photon, experiment	1867
	A. Halavanau, Z. Huang, C. Pellegrini, T.O. Raubenheimer SLAC, Menlo Park, California, USA I. Lobach University of Chicago, Chicago, Illinois, USA S. Nagaitsev Fermilab, Batavia, Illinois, USA D. Seipt HZDR, Dresden, Germany
	Funding: This work was supported by the U.S. Department of Energy Contract No. DE-AC02-76SF00515. The facilities providing single electron beams are currently being commissioned at Fermilab and will be at SLAC. Recently, Fermilab’s IOTA ring routinely demonstrated circulation of a single electron at 100 MeV beam energy. Alternatively, SLAC is working on constructing LCLS-II an X-ray FEL driven by a 4 GeV SRF linac. A parasitic beamline, S30XL, is planned that will extract 4 GeV dark current from between the primary LCLS-II electron bunches. The dark current will be delivered to End Station A and can work independently of LCLS-II experiments. The dark current will be bunched at a frequency of 46 MHz while extracted current varied from single electrons to 10’s of nA. In the present paper, we estimate the feasibility of propagating single electron beams through a conventional undulator, placed in the IOTA and S30XL beamlines. We explore the possible observable effects and experimental parameters range. In addition, we focus on potential applications of such beams in systems for high fidelity quantum measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB089
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TUPRB090	Preliminary Considerations of Atomic Inner-Shell X-Ray Laser for Self-Seeding at LCLS-II	FEL, photon, simulation, experiment	1871
	A. Halavanau, C. Pellegrini, J. Wu SLAC, Menlo Park, California, USA A.I. Benediktovitch EuXFEL, Hamburg, Germany N. Rohringer Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
	Funding: This work was supported by the U.S. Department of Energy Contract No. DE-AC02-76SF00515. The atomic inner-shell X-ray lasing, induced by the irradiation of focused XFEL SASE pulses, was demonstrated in gases, liquid jets and solids. In this proceeding, we discuss the possible use of this concept in self-seeding scheme at LCLS-II. We provide a preliminary study of different lasing media and corresponding SASE XFEL parameters. For the case of noble gas inner-shell X-ray laser, we study the requirements for gas pressure and XFEL pulse focusing. Finally, we discuss possible designs of this system and its advantages in LCLS-II operations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB090
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TUPRB091	Study of XFEL Third Harmonic Radiation at LCLS	undulator, FEL, experiment, bunching	1875
	C. Emma, M.W. Guetg, A. Halavanau, A.A. Lutman, G. Marcus, T.J. Maxwell, C. Pellegrini SLAC, Menlo Park, California, USA
	Funding: This work was supported by the U.S. Department of Energy Contract No. DE-AC02-76SF00515. In this paper, we focus on characterization of the nonlinear third harmonic radiation properties at Linac Coherent Light Source (LCLS). In addition, we experimentally perform third harmonic self-seeding, using diamond crystal attenuator in the hard X-ray self-seeding chicane. We discuss warm beam effects in such scheme, justifying recently proposed two bunch configuration for harmonic lasing.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB091
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TUPRB092	Cherenkov Radiation in Periodic Wire Medium Formed by Transversely Modulated Electron Beams	electron, laser, cathode, experiment	1878
	A. Halavanau SLAC, Menlo Park, California, USA A.I. Benediktovitch EuXFEL, Hamburg, Germany E.A. Gurnevich Belarussian State University, Scientific Research Institute of Nuclear Problems, Minsk, Belarus
	Funding: Work was supported by the U.S. Department of Energy Contract No. DE-AC02-76SF00515. We investigate the properties of Cherenkov, quasi-Cherenkov (parametric) and diffraction radiation generated in the periodic conducting wire medium by transversely modulated electron beams. Such beams were recently obtained at Argonne Wakefield Accelerator (AWA) facility using microlens array (MLA) laser shaping technique. We consider in details the case of one dimensional periodic tungsten wire structure and transverse electron beamlets separation of mm scale. We look at possible enhancements of the radiation field due to transverse periodicity of the electron beam.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB092
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TUPTS032	Radiation Design of New 30 kW Beam Dump of J-PARC Main Ring	neutron, vacuum, proton, 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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TUPTS046	Commissioning of a Compact THz Source Based on FEL	linac, FEL, undulator, cavity	2030
	Y.J. Pei, G. Feng, X.Y. He, Y. Hong, D. Jia, P. Lu, S. Lu, L. Shang, B.G. Sun, Zh.X. Tang, W. Wang, X.Q. Wang, W. Wei USTC/NSRL, Hefei, Anhui, People’s Republic of China L. Cao, Q.S. Chen, Q. Fu, T. Hu, P. Tan, Y.Q. Xiong HUST, Wuhan, People’s Republic of China G. Huang IMP/CAS, Lanzhou, People’s Republic of China L.G. Shen, F. Zhang USTC/PMPI, Hefei, Anhui, People’s Republic of China
	The layout of the THz source based on FEL was de-scribed in this paper. The THz source was based on a FEL which was composed of a compact 8-14MeV LINAC, undulator, optical resonance, THz wave measurement system and so on. The facility was designed in 2013 and the typical running parameter got in 2017 were as the following: energy is of 12.7MeV, energy spread is of 0.3%, macro-pulse is of 4 μs, pulse length of micro-pulse is of 6ps, emittance is of 24 mm.mrad. After that the ma-chine was commissioning for production THz radiation. In November 2018, the THz wave was test and got THz wave signal, the spectrum was also got. This year, we plan to measure the output power of the THz source.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS046
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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	vacuum, Windows, 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]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEXXPLS2
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WEYYPLS3	Development of Methods for Calculation of Bunch Radiation in Presence of Dielectric Objects	target, simulation, vacuum, 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]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEYYPLS3
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Paper

Title

Other Keywords

Page

MOPGW003

Collective Instability Studies for Sirius

simulation, impedance, storage-ring, coupling

61

F.H. de Sá
LNLS, Campinas, Brazil

In this work we will present the estimates of single and multi-bunch instability thresholds and current-dependent effects, such as tune-shifts and potential-well distortion for the Sirius storage ring. The results were obtained by tracking simulations and semi-analytic methods using the updated and detailed impedance budget of the machine, which includes contributions from all the in-vacuum components and the coherent synchrotron radiation (CSR) impedance.

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

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MOPGW018

Perturbation of Synchrotron Motion in the Micro-Bunching Instability

electron, bunching, synchrotron, storage-ring

108

T. Boltz, M. Brosi, E. Bründermann, B. Härer, A.-S. Müller, P. Schreiber, P. Schönfeldt, M. Yan
KIT, Karlsruhe, Germany

Short electron bunches in a storage ring are subject to complex longitudinal dynamics due to self-interaction with their own CSR. Above a particular threshold current, this leads to the formation of dynamically changing micro-structures within the bunch, generally known as the micro-bunching instability. The longitudinal dynamics of this phenomenon can be simulated by solving the Vlasov-Fokker-Planck equation, where the CSR self-interaction can be added as a perturbation to the Hamiltonian. This contribution particularly focuses on the comprehension of synchrotron motion in the micro-bunching instability and how it relates to the formation of the occurring micro-structures. Therefore, we adopt the perspective of a single particle and comment on its implications for collective motion. We explicitly show how the shape of the parallel plates CSR wake potential breaks homogeneity in longitudinal phase space and propose a quadrupole-like mode as potential seeding mechanism of the micro-bunching instability. The gained insights are verified using the passive particle tracking method of the Vlasov-Fokker-Planck solver Inovesa.

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MOPGW029

Preliminary Study of Bunch Compression in the Hefei Light Source

lattice, storage-ring, electron, synchrotron-radiation

151

W. Li, Z.H. Bai, W. Li, J.G. Wang, D.R. Xu, Z. Zhao
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Funding: This work was supported by the Fundamental Research Funds for the Central Universities (Grant No.WK2310000082 and WK2310000077), and the National Natural Science Foundation of China(GrantNo.11475167).
Short electron bunch has interesting applications in the synchrotron radiation light sources, such as the production of powerful coherent THz radiation, time resolving spectrum analysis, etc. In this work, we are interested in acquiring the short bunch in the storage ring with a small circumference like Hefei Light Source. In this paper, we tried to approach the short bunch in two separate methods: by increasing the higher harmonic cavity voltage and by reducing the momentum compaction factor. The preliminary result and observations are shown and discussed.

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

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MOPGW041

Transverse Profile Shaping of a Charged-Particle Beam using Multipole Magnets - Formation of Hollow Beams -

octupole, target, optics, multipole

184

Y. Yuri, T. Yuyama
QST/Takasaki, Takasaki, Japan
M. Fukuda
RCNP, Osaka, Japan

The use of multipole magnets enables us to shape the transverse profile of a charged-particle beam into various ones that can never be realized through linear beam optics. To date, the formation of a large-area beam with a uniform transverse intensity distribution has been actually realized using octupole magnets in several accelerator facilities. In this presentation, we demonstrate the formation of different beam profiles using multipole magnets rather than existing rectangular uniform beams. Results of tracking simulations and beam-formation experiments will be shown on the formation of clear-cut beams with different cross-sectional shapes, depending on the order and strength of applied multipole magnets. The dynamic behavior of a beam focused with multipole magnets is also investigated theoretically to better understand the numerical and experimental results.

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MOPGW048

Design Study of an Electron Storage Ring for the Future Plan of Hiroshima Synchrotron Radiation Center.

storage-ring, synchrotron, emittance, synchrotron-radiation

200

S. Matsuba, M. Katoh, K.S. Shimada
HSRC, Higashi-Hiroshima, Japan
K. Harada
KEK, Ibaraki, Japan
K. Kawase
QST, Tokai, Japan

Hiroshima synchrotron radiation center equips a 700 MeV electron storage ring nicknamed HiSOR. It has been operated for more than 20 years. The emittance of HiSOR is 400 nm, which is larger by one or more orders of magnitude than typical modern synchrotron light sources. Therefore, as the future plan of the facility, a new low emittance storage ring is desired. Several designs have been examined. In the newest version, we have selected the lattice structure similar to ASTRID 2 compact light source in Aarhus University, Denmark. The design goal is the energy of around 500 MeV, the circumference shorter than 50 m and the emittance smaller than 10 nm with straight sections for undulators more than 4. In this conference, we report the latest result from the design study.

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

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MOPGW051

Diffusion Map Analysis in High Energy Storage Ring Based e⁺/e⁻ Collider

dynamic-aperture, synchrotron-radiation, collider, synchrotron

203

J. Wu, Q. Qin, Y. Zhang
IHEP, Beijing, People’s Republic of China
J. Wu, Y. Zhang
University of Chinese Academy of Sciences, Beijing, People’s Republic of China

Funding: Project 11775238 supported by NSFC
In a very high energy e⁺/e⁻ storage ring collider, e.g. Circular Electron Positron Collider (CEPC), the dynamic aperture is limited by the strong synchrotron radiation especially in the vertical direction. Some tracking results also shows that the beam lifetime does not correspond well to the dynamic aperture. Here we develop a method called diffusion map analysis, aiming to describe the beam distribution diffusion in transverse amplitude space by tracking less turns. The diffusion may come from quantum fluctuation of SR, beamstrahlung effect and nonlinearity. Comparing cases with different configuration of sextupoles, the diffusion map analysis presents good consistency with beam lifetime that needs much more turns of tracking. Constraints based on the diffusion map is applied to our dynamic aperture optimization, which could help us achieve enough long beam lifetime.

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MOPGW059

Dynamic Aperture Limitation in e⁺ e⁻ Colliders due to Synchrotron Radiation in Quadrupoles

quadrupole, synchrotron, betatron, synchrotron-radiation

221

A.V. Bogomyagkov, S.A. Glukhov, E.B. Levichev, S.V. Sinyatkin
BINP SB RAS, Novosibirsk, Russia

In a lepton storage ring of very high energy (e.g. in the e⁺e^- Higgs factory) synchrotron radiation from quadrupoles constrains transverse dynamic aperture even in the absence of any magnetic nonlinearities. This was observed in tracking for LEP and the Future Circular e⁺e^- Collider (FCC-ee). Synchrotron radiation in the quadrupoles modulates the particle energy at the double betatron frequency. Energy modulation varies transverse focusing strength at the same frequency and creates a parametric resonance of the betatron oscillations with unusual properties. It occurs at arbitrary betatron frequency and the magnitude of the parameter modulation of the betatron oscillation depends on the oscillation amplitude. Equilibrium between the radiation damping and the resonant excitation gives the boundary of the stable motion. Here we continue comparison of tracking results with analytical calculations of the parametric resonance.

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MOPGW060

Cherenkov Radiation at Off-Axis Bunch Passage Through Dielectric Concentrator

target, diagnostics, site, polarization

225

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

Funding: Work supported by the Grant from Russian Foundation for Basic Research (No. 17-52-04107).
Development of tunable systems for non-invasive bunch diagnostics is a modern trend in accelerator physics. Certain dielectric targets are considered in this context, for example, dielectric cones or prisms. Moreover, all-dielectric target which increase the radiated Cherenkov field near the predetermined focus up to several orders of magnitude has been described* and field near its focus and sensitivity of this target have been analyzed**. Here we consider a non-symmetrical case where charge trajectory has a shift with respect to structure axis. We develop analytical approach for description of Cherenkov radiation, perform three-dimensional simulations and compare the results.
* S.N. Galyamin and A.V. Tyukhtin, Phys. Rev. Lett., 113, 064802 (2014).
** S.N. Galyamin and A.V. Tyukhtin, Nucl. Instr. Meth. Phys. Res. B. 2017. V. 402. P.185-189.

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MOPGW061

Radiation from a Dielectrically Loaded Waveguide with Open End

GUI, vacuum, 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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MOPGW062

Radiation of a Charge Moving in a Wire Structure

FEL, simulation, lattice, electron

231

S.N. Galyamin, A.V. Tyukhtin, V.V. Vorobev
Saint Petersburg State University, Saint Petersburg, Russia
A.I. Benediktovitch
EuXFEL, Hamburg, Germany
A.I. Benediktovitch
BSU, Minsk, Belarus, Belarus

Funding: This work is supported by the grant from Russian Foundation for Basic Research (No. 17-52-04107).
In the X-ray frequency region, interaction of relativistic electrons with crystals results in parametric X-ray radiation (PXR), with its frequency being determined by distance between crystallographic planes and direction of electron motion. If instead of crystal one considers an artificial periodic structure with periods of the order of mm, one can expect emission of radiation of a similar nature at terahertz (THz) frequencies. This frequency range is of significant interest during last decade due to its prospective applications. Moreover, artificial wire-like structures are considered as a promising alternative to conventional dielectric structures for wakefield acceleration*. Here we consider electromagnetic (EM) field produced by a charged particle bunch moving through a lattice of parallel conducting wires. We present several approaches for analysis of EM field in the described wire structure. First, conventional two-wave approximation for describing the "short-wave response" is developed. Second, we use the effective medium approach and describe the "long-wave" part of the spectrum. Third, we develop a method based on vibrator antenna theory which can be useful for finite length wire structure.
* P.D. Hoang, et al., Phys. Rev. Lett., V. 120, P. 164801 (2018).

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MOPGW064

On Wakefield in Dielectric Waveguide with Shallow Corrugation of Metallic Wall

GUI, ECR, wakefield, impedance

237

A.V. Tyukhtin, E.R. Akhmatova, T.Yu. Alekhina, 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).
Bunch radiation in periodical waveguides was mainly analyzed for situations when wavelengths are comparable to the structure period (Smith-Purcell emission). However, it is also of interest to study the "long-wave radiation" with wavelengths which are much larger than the structure period*,**. In such situation, the exact boundary conditions on the complicated periodic surface can be replaced with the equivalent boundary conditions (EBC) which must be fulfilled on the smooth surface. Earlier we considered with this approach radiation of the bunch moving along the axis of circular vacuum corrugated waveguide**. Comparison of analytical results with COMSOL simulations showed high accuracy of the EBC method. Here we analyze an analogous problem for the waveguide with corrugated wall and dielectric filling under condition that Cherenkov effect takes place in the dielectric. Due to this fact the radiation differs radically from that in the vacuum waveguide. At the same time, the radiation has essential differences from the one in the usual dielectric waveguide. The radiation properties in the waveguide under consideration and its differences from the radiation in the waveguide with smooth wall are analyzed.
* G. Stupakov, K. Bane, Phys. Rev. ST-AB, 15 (2012) 124401.
** A.V. Tyukhtin et al, J. of Instrumentation, 13 (2018) C04009.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW064

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

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MOPGW100

Bypass Design for Testing Optical Stochastic Cooling at the Cornell Electron Storage Ring (CESR)

optics, sextupole, wiggler, damping

360

W.F. Bergan, M.B. Andorf, M.P. Ehrlichman, V. Khachatryan, D.L. Rubin, S. Wang
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: NSF-1734189 DGE-1650441
Optical Stochastic Cooling (OSC) is a promising method for cooling very dense stored particle beams through the interference of radiation created in an upstream ’pickup’ wiggler and a downstream ’kicker’ wiggler. By correlating a particle’s path length via a bypass between the two wigglers with its betatron coordinates in the pickup, the particle will receive a kick in energy which, through coupling introduced by non-zero horizontal dispersion in the kicker, can reduce its betatron amplitude, thus cooling the beam. A proof-of-principle test of this technique is being planned at the Cornell Electron Storage Ring (CESR). In addition to maintaining standard requirements such as a large dynamic aperture and acceptable lattice functions throughout the ring, the design of the bypass is guided by the mutually competing goals of maximizing the cooling rate while maintaining a sufficiently large cooling acceptance with properly-corrected nonlinearities. We present a design of such a bypass and ring optics so as to best achieve these objectives.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW100

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paper received ※ 14 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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MOPGW116

Validation of a Novel Method for the Calculation of Near-Field Synchrotron Radiation

electron, acceleration, cyclotron, synchrotron

397

F.Y. Li, B.E. Carlsten, R. Garimella, C. Huang, T.J. Kwan
LANL, Los Alamos, New Mexico, USA

Funding: Work supported by the LDRD program at LANL.
The phenomenon of synchrotron radiation (SR) from electrons is at the core of modern accelerator based light sources. While SR in the far field has been well characterized, the near-field SR and its impacts on self-consistent electron beam dynamics remain an ongoing topic. Since it is difficult to experimentally characterize the near fields, it is desirable to develop accurate and efficient numerical methods for the design of these light sources. Here, we investigate a novel method, originally proposed by Shintake and which potentially has both high efficiency and accuracy. We focus on the field calculation of this method and show that the original idea has missed the important terms of fields due to electron acceleration and therefore only applies to a linear motion. To correct this limitation we developed a modified algorithm that gives consistent fields with direct calculations using the Liénard-Wiechert equation. Some basic signatures of the near-field SR fields are also drawn for a cyclotron motion by using this modified approach.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW116

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

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MOPGW124

Coherent Synchrotron Radiation Simulation for CBETA

simulation, linac, lattice, shielding

406

W. Lou, C.M. Gulliford, G.H. Hoffstaetter, D. Sagan
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
C.E. Mayes
SLAC, Menlo Park, California, USA
N. Tsoupas
BNL, Upton, Long Island, New York, USA

CBETA is an energy recovery linac accelerating from 6 MeV to 150 MeV in four linac passes, using a single return beamline accepting all energies from 42 to 150 MeV. While CBETA gives promise to deliver unprecedentedly high beam current with simultaneously small emittance, Coherent Synchrotron Radiation (CSR) can pose detrimental effect on the beam at high bunch charges and short bunch lengths. To investigate the CSR effects on CBETA, we used the established simulation code Bmad to track a bunch with different parameters. We found that CSR causes phase space dilution, and the effect becomes more significant as the bunch charge and recirculation pass increase. Potential ways to mitigate the effect involving vacuum chamber shielding and increasing bunch length are being investigated.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW124

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

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MOPMP013

New Nuclotron Beam Lines and Stations for Applied Researches

target, dipole, heavy-ion, diagnostics

449

E. Syresin, A.A. Baldin, A.V. Butenko, G.A. Filatov, A.A. Slivin, G.N. Timoshenko, G.V. Trubnikov, A. Tuzikov
JINR, Dubna, Moscow Region, Russia
D.V. Bobrovskiy, A.I. Chumakov
MEPhI, Moscow, Russia
M.M. Kats, T. Kulevoy, D.A. Liakin, Y.E. Titarenko
ITEP, Moscow, Russia

New beamlines for applied researches on the Nuclotron are under development within the framework of implementation of the NICA accelerator facility. Ion beams with energies of 150-800 MeV/n extracted from the Nuclotron will be used for radiobiological researches and modeling of cosmic rays interactions with microchips. Equipment of two experimental stations is under development by the JINR-ITEP-MEPhi collaboration for these applied researches. Ion beams with the energy of 3.2 MeV/n extracted from the heavy ion linac HILAc will also be used for irradiation and testing of microchips. The specialized channel will be reconstructed for investigations in the field of relativistic nuclear power at light ion energies of 0.3-4.5 GeV/n. Three new experimental areas are organized for applied physics researches within the framework of implementation of the NICA accelerator facility.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP013

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

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MOPMP035

Effect of Emittance Constraints on Monochromatization at the Future Circular e⁺e⁻ Collider

emittance, luminosity, collider, photon

516

M.A. Valdivia García, F. Zimmermann
CERN, Meyrin, Switzerland

Direct s-channel Higgs production in e+e− collisions is of interest if the collision energy spread can be comparable to the natural width of the standard model Higgs boson. At the Future Circular e⁺e⁻ Collider (FCC-ee), a monochromatization scheme could be employed in order to reduce the collision energy spread to the target value. This may be achieved by introducing a non-zero horizontal dispersion of opposite sign for the two colliding beams at the interaction point. In this case, the beamstrahlung increases the horizontal emittance in addition to energy spread and bunch length. The vertical emittance could either be tuned to a certain minimum value, possibly limited by the diagnostics resolution, or it could scale linearly with the horizontal emittance. For the FCC-ee at 62.5 GeV beam energy, we optimize the IP optics and beam parameters, considering these two different assumptions for the vertical emittance. We derive the maximum achievable luminosity as a function of collision energy spread for either case.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP035

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paper received ※ 16 May 2019 paper accepted ※ 22 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, vacuum, kicker, 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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MOPRB061

Simulations and Measurements of Coherent Synchrotron Radiation at the MAX-IV Short Pulse Facility

detector, simulation, electron, dipole

712

B.S. Kyle
University of Manchester, Manchester, United Kingdom
R.B. Appleby
UMAN, Manchester, United Kingdom
M. Brandin, E. Mansten, S. Thorin
MAX IV Laboratory, Lund University, Lund, Sweden
T.H. Pacey
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
P.H. Williams
Cockcroft Institute, Warrington, Cheshire, United Kingdom
J. Wolfenden
The University of Liverpool, Liverpool, United Kingdom

The Coherent Synchrotron Radiation (CSR) interaction is a source of unwanted correlated energy spread in short-bunch Free-Electron Lasers (FEL), diluting the desired FEL spectrum and reducing the total brightness of the light source. Many accelerator codes make use of 1-dimensional approximations in the calculation of the CSR-wake, which breaks down for bunch dimensions typical within bunch compressor dipoles in FELs. General Particle Tracer simulations of the CSR interaction make use of the 3-dimensional bunch distribution, making it advantageous in modelling the short-bunch, high aspect ratio regimes typical of modern 4th-generation light sources. Measurements of THz CSR emitted from the final bunch compressor dipole of the SP02 beamline at the MAX-IV Short Pulse Facility (SPF) were used, alongside start-to-end GPT and Elegant simulations, to characterize coherent radiation emission across a broad range of bunch lengths.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB061

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

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MOPRB075

Radiation Limits on Permanent Magnets in CBETA

electron, vacuum, 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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MOPRB088

Study of Fluctuations in Undulator Radiation in the IOTA Ring at Fermilab

experiment, undulator, electron, photon

777

I. Lobach
University of Chicago, Chicago, Illinois, USA
A. Halavanau, Z. Huang, V. Yakimenko
SLAC, Menlo Park, California, USA
K. Kim
ANL, Argonne, Illinois, USA
V.A. Lebedev, S. Nagaitsev, A.L. Romanov, G. Stancari, A. Valishev
Fermilab, Batavia, Illinois, USA
A.Y. Murokh
RadiaBeam, Los Angeles, California, USA
T.V. Shaftan
BNL, Upton, Long Island, New York, USA

We study turn-by-turn fluctuations in the number of emitted photons in an undulator, installed in the IOTA electron storage ring at Fermilab with an InGaAs PIN photodiode and an integrating circuit. Our study was motivated by the previous experiment *. We propose a theoretical model for the experimental data from * and in our own experiment we attempted to verify the model in an independent and more systematic way. Moreover, these fluctuations are an interesting subject for a study by itself, since they act as a seed for SASE in FELs. We improve the precision of the measurements from * by subtracting the average signal amplitude using a comb filter with a one-turn IOTA delay, and by using a special algorithm for noise subtraction. We obtain a reasonable agreement between our theoretical model and experiment. Along with repeating the experiment from *, which was performed at a constant beam current, we also collect data for fluctuations in undulator light at different beam current values. Lastly, in our experiment we were able to see the transition from Poisson statistics to Super-Poisson statistics for undulator light, whereas in * only the latter statistics was observed.
* M. Teich et al., PRL, vol. 65, no. 27, p. 3393 (1990).

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

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MOPRB089

Experimental Study of a Single Electron in a Storage Ring via Undulator Radiation

photon, electron, undulator, experiment

781

S. Nagaitsev, A.L. Romanov, G. Stancari
Fermilab, Batavia, Illinois, USA
A. Arodzero, A.Y. Murokh, M. Ruelas
RadiaBeam, Santa Monica, California, USA
I. Lobach
University of Chicago, Chicago, Illinois, USA
T.V. Shaftan
BNL, Upton, Long Island, New York, USA

A single electron orbiting around a ring and emitting single quanta at the rate of about one event per hundred turns could produce a wealth of information about physical processes in large traps (i.e. storage rings) for charged particles. It should be noted that Paul and Penning traps in the 1980s led to the Nobel prize for studying state and motion of single quantum particles, and just recently the Penning trap technique has enabled the measurement of a single proton magnetic moment with an unprecedented precision of 10 decimal places. The information from the storage ring traps could also be used for characterization of a quantum system as well as the "trap" itself, i.e. measuring properties of the storage ring lattice and electron interaction with the laser fields. Although, the interest in single electron quantum processes today is mostly academic in nature, the diagnostics and methodology developed for single electron radiation studies could find subsequent applications in a variety of applied disciplines in quantum technology, including quantum communications and quantum computing.

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

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MOPRB093

eRHIC Electron Ring Design Status

polarization, electron, storage-ring, solenoid

794

C. Montag, M. Blaskiewicz, C. Hetzel, D. Holmes, Y. Li, H. Lovelace III, V. Ptitsyn, K.S. Smith, S. Tepikian, F.J. Willeke, H. Witte, W. Xu
BNL, Upton, Long Island, New York, USA
E. Gianfelice-Wendt
Fermilab, Batavia, Illinois, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
For the proposed electron-ion collider eRHIC, an electron storage ring will be installed in the existing RHIC tunnel. To reach the high luminosity of up to 10³⁴ cm^-2 sec^-1, beam currents up to 2.5A have to be stored. Besides high luminosity the physics program requires spin polarization levels of 70 percent, with both spin "up" and spin "down" orientations present in the fill. This is only feasible by using a full-energy spin polarized injector that replaces bunches faster than the depolarization rate. To limit the repetition rate of that injector to about one hertz, the polarization lifetime in the storage ring has to be maximized by proper spin matching and countermeasures for the machine misalignments. We will give an overview of the electron storage ring design.

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

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MOPTS047

Radiation Measurement in the 1st Beam Commissioning Campaign of the LIPAc RFQ

rfq, neutron, proton, MMI

964

K. Kondo, S. Kwon, K. Sakamoto, T. Shinya, M. Sugimoto
QST, Aomori, Japan
L. Bellan, F. Grespan, F. Scantamburlo
INFN/LNL, Legnaro (PD), Italy
P. Cara
IFMIF/EVEDA, Rokkasho, Japan
H. Dzitko
F4E, Germany
R. Heidinger
Fusion for Energy, Garching, Germany
I. Podadera
CIEMAT, Madrid, Spain

The 1st proton beam acceleration of the Linear IFMIF Prototype Accelerator (LIPAc) through its novel RFQ was succeeded on 13th June 2018. Addition to plenty of beam diagnostics equipped in the beam line, we prepared some radiation detectors placed around the accelerator in order to acquire supplemental information of the beam, as an indirect measurement. In the first day of the beam injec-tion to the RFQ, the gamma-rays corresponding to certain excited states of Al of the low power beam dump were successfully detected by a LaBr3(Ce) scintillation detec-tor. Some neutrons, which would originate from the inter-action of protons with Cu somewhere, were also ob-served. These results proved that the beam was certainly accelerated up to about 2.5 MeV, and provided us a defin-itive confidence that the RFQ was working appropriately from the very beginning of the commissioning. Also, the comparison of the radiation yields with the RFQ trans-mission provided additional information on the beam energy distribution.

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

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MOPTS054

Status of the CLEAR Electron Beam User Facility at CERN

experiment, electron, plasma, operation

983

K.N. Sjobak, E. Adli, C.A. Lindstrøm
University of Oslo, Oslo, Norway
M. Bergamaschi, S. Burger, R. Corsini, A. Curcio, S. Curt, S. Döbert, W. Farabolini, D. Gamba, L. Garolfi, A. Gilardi, I. Gorgisyan, E. Granados, H. Guerin, R. Kieffer, M. Krupa, T. Lefèvre, S. Mazzoni, G. McMonagle, N. Nadenau, H. Panuganti, S. Pitman, V. Rude, A. Schlogelhofer, P.K. Skowroński, M. Wendt, A.P. Zemanek
CERN, Geneva, Switzerland
A. Lyapin
UCL, London, United Kingdom

The CERN Linear Electron Accelerator for Research (CLEAR) has now finished its second year of operation, providing a testbed for new accelerator technologies and a versatile radiation source. Hosting a varied experimental program, this beamline provides a flexible test facility for users both internal and external to CERN, as well as being an excellent accelerator physics training ground. The energy can be varied between 60 and 220 MeV, bunch length between 1 and 4 ps, bunch charge in the range 10 pC to 2 nC, and number of bunches in the range 1 to 200, at a repetition rate of 0.8 to 10 Hz. The status of the facility with an overview of the recent experimental results is presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS054

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paper received ※ 12 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS091

Mechanical Robustness of HL-LHC Collimator Designs

experiment, site, proton, interface

1070

F. Carra, A. Bertarelli, G. Gobbi, J. Guardia, M. Guinchard, F.J. Harden, M. Pasquali, S. Redaelli, E. Skordis
CERN, Meyrin, Switzerland

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.
Two new absorbing materials were developed as collimator inserts to fulfil the requirements of HL-LHC higher brightness beams: molybdenum-carbide graphite (MoGr) and copper-diamond (CuCD). These materials were tested under intense beam impacts at CERN HiRadMat facility in 2015, when full jaw prototypes were irradiated. Additional tests in HiRadMat were performed in 2017 on another series of material samples, including also improved grades of MoGr and CuCD, and different coating solutions. This paper summarizes the main results of the two experiments, with a main focus on the behaviour of the novel composite blocks, the metallic housing, as well as the cooling circuit. The experimental campaign confirmed the final choice for the materials and the design solutions for HL-LHC collimators, and constituted a unique chance of benchmarking numerical models. In particular, the tests validated the selection of MoGr for primary and secondary collimators, and CuCD as a valid solution for robust tertiary collimators.

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paper received ※ 12 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS092

Numerical and Experimental Evaluation of the DQW Crab Cavity Cryomodule Thermal Budget

cryomodule, cavity, HOM, experiment

1074

F. Carra, K. Brodzinski, E. Cano-Pleite, O. Capatina
CERN, Meyrin, Switzerland

Funding: Research supported by the HL-LHC project
One of the key devices of the HL-LHC project are SRF Crab Cavities. A cryomodule with two Double Quarter Wave (DQW) crab cavities has been fabricated at CERN in 2017 and successfully tested with beam in the Super Proton Synchrotron (SPS) in 2018. The aim of the present study is to present and compare the estimation of the thermal budget for the different components of the cryomodule, performed with numerical and semi-analytical methods, with the experimental measurements carried out on the cryomodule after installation in the SPS.

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paper received ※ 12 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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MOPTS105

The High Brightness Photo-injector for THz CUR/VUV FEL at NSRRC

electron, emittance, quadrupole, linac

1125

A.P. Lee, M.C. Chou, H.P. Hsueh, J.-Y. Hwang, W.K. Lau
NSRRC, Hsinchu, Taiwan
P. Wang
NTHU, Hsinchu, Taiwan

A high brightness photo-injector has been build for THz coherent undulator radiation and VUV free electron laser test facility at NSRRC. In the first phase, the photo-injector was used to produce ultra-short electron bunches for THz CUR generation. The electron beam is generated form a photocathode rf gun followed by a solenoid for emittance compensation. Then A 5.2 m S-band linac accelerates the electron beam and compresses the beam by velocity bunching. Since the beam emittance will grow during the velocity bunching process, a solenoid system was installed to reduce the emmitance growth. Downstream the linac, a quadruple magnet was use for emittance measurement by quadruple scan method and the bunch length was measured by the coherent transition radiation. Finally, the ultra-short electron bunch with about few hundreds picoseconds passes through a U100 planer undulator can produce THz coherent undulator radiation. The instrument setup and results of measurement are presented in this paper.

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paper received ※ 14 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019

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MOPTS110

FLUKA-MARS15 Simulations To Optimize the Fermilab PIP-II Movable Beam Absorber

linac, MMI, shielding, simulation

1136

L. Lari, F.G. Garcia, Y. He, I. Kourbanis, N.V. Mokhov, E. Pozdeyev, I.L. Rakhno
Fermilab, Batavia, Illinois, USA
F. Cerutti, L.S. Esposito, L. Lari
CERN, Meyrin, Switzerland

PIP-II is the Fermilab’s flagship project to provide powerful, high-intensity proton beams to the laboratory’s experiments. The heart of the PIP-II project is an H⁻ 800 MeV superconducting linear accelerator. In order to commission the beam and operate safely the linac, several constraints were evaluated. The design of a movable 5 kW beam absorber was finalized to allow staged beam commissioning in different linac locations. Prompt and residual radiation levels were calculated, and radiation shields were optimized to keep those values within the acceptable levels in the areas surrounding beam absorber. Monte Carlo calculations with FLUKA and MARS15 codes are presented in the paper to support these studies.

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

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TUZZPLS3

New Method of Calculation of the Wake due to Radiation and Space Charge Forces in Relativistic Beams

wakefield, electron, space-charge, synchrotron-radiation

1223

G. Stupakov
SLAC, Menlo Park, California, USA

Funding: This work was supported by the Department of Energy, Contract No. DE-AC02-76SF00515.
Radiation reaction force in a relativistic beam, also known as a CSR wakefield, is often computed using a 1D model of a line charge beam. While this model can serve as a useful tool for a quick calculation, in some cases, it may not be sufficiently accurate. In particular, this model misses the so-called compression effects associated with the change of the electromagnetic energy when the beam is compressed longitudinally or transversely. The existing 3D simulation codes that take this effect into account are often slow and are not easy to use. In this work, we propose a new approach to the calculations of radiation and space charge longitudinal forces based on the use of the integrals for the retarded potentials. Our main result expresses the rate of change of particles energy through 2D (in a 2D model) or 3D integrals for a given orbit of the beam. It generalizes the 1D model and includes the transient effects of at the entrance and the exit from the magnet. For a given beam line with known magnetic lattice, and a known distribution function of the beam, the calculation reduces to taking 2D or 3D integrals along the orbit.

Slides TUZZPLS3 [2.080 MB]

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paper received ※ 29 April 2019 paper accepted ※ 22 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

vacuum, injection, 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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TUPMP022

Research on Digital Scanning Power Supply Technology for Proton Therapy System

power-supply, proton, controls, scattering

1286

J. Huang, M. Fan, J. Yang, L.G. Zhang
HUST, Wuhan, People’s Republic of China
T. Yu, C. Zuo
Huazhong University of Science and Technology, State Key Laboratory of Advanced Electromagnetic Engineering and Technology,, Hubei, People’s Republic of China

Funding: Work supported by The National Key Research and Development Program of China, with grant No. 11505068
Proton has great advantages in the field of cancer radiotherapy because of its good characteristic of Bragg peak. HUST-PTF is a proton therapy facility under development in Huazhong University of science and technology. It delivers the beam to the patients with a pencil beam scanning nozzle. Scanning power supplies are placed in the nozzle of the proton therapy device and they are required high accuracy, high speed and high stability. In this paper，the structure diagram of HUST-PTF is shown. The parameters of scanning magnets and its power supply are introduced. Finally, some test results of power supply are shown. The next work will debug the control system of the scanning power supply and adjust it with the scanning magnet to see if it meets the design requirements.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP022

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

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TUPMP025

Design of Fast Corrector Magnet Power Supply for HEPS

power-supply, controls, simulation, experiment

1294

P. Liu, C. Han, F. Long
IHEP, Beijing, People’s Republic of China

High energy photon source is a fourth-generation synchrotron radiation light source with energy of 6Gev and ultra-low emittance (<0.1nm’rad). The ultra-low beam emittance requires high beam stability. Therefore, we develop a fast correction power supply with high bandwidth and low current ripple to improve the performance of the fast close orbit correction sys-tem to prove the high beam stability. The power supply adopts FPGA for full-digital control and use high speed ADC with temperature control. The power sup-ply has a small signal-bandwidth of 10 kHz and output current ripple lower than 20ppm. In this paper, we will describe the hardware design and software control methods and the test results will be demonstrated

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP025

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paper received ※ 13 May 2019 paper accepted ※ 22 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, vacuum, 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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TUPMP042

The Beam Cleaning Analysis for the TPS Vacuum System

vacuum, MMI, 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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TUPMP048

Current Status of Turkish Accelerator and Radiation Laboratory

electron, cavity, FEL, status

1359

A.A. Aksoy, O.F. Elçim
Ankara University Institute of Accelerator Technologies, Golbasi, Turkey
Ö. Karslı, C. Kaya, B. Koc
Ankara University, Accelerator Technologies Institute, Golbasi, Turkey

Funding: T.R. Presidency Strategy and Budget Office Grand No: 2006K-120470
Turkish Accelerator and Radiation Laboratory (TARLA) which is designed to deliver various accelerator based radiation sources, aims to be outstanding research instrument for users from both Turkey and region. Within the current scope of TARLA its superconducting accelerator will drive two of free electron laser (FEL) beamlines in order to provide Continuous Wave (CW) tunable radiation of high brightness in the mid- and far-infrared range as well as a Bremmstrahlung radiation station. Main components of TARLA, such as injector, superconducting accelerating modules and cryoplant are under commissioning currently. In this paper commissioning results and current status of facility are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP048

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

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TUPGW006

Measurements of the Momentum Compaction Factor of the ESRF Storage Ring

undulator, electron, SRF, synchrotron

1392

N. Carmignani, W. De Nolf, A. Franchi, C. Sahle, L. Torino
ESRF, Grenoble, France
B. Nash
RadiaSoft LLC, Boulder, Colorado, USA

In a storage ring, the momentum compaction factor can be obtained by measuring the variation of the beam energy as a function of the RF frequency. In this paper we present the measurement of the momentum compaction factor from two different methods. With the first, we measure the variation of the undulator spectra for different RF frequencies. With the second, we measure the variation of the hard x-rays flux produced by a dipole for different RF frequencies.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW006

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paper received ※ 29 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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TUPGW015

Petra III Operation and Studies 2018

operation, vacuum, impedance, undulator

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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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW015

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

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TUPGW024

Pulse Shaping Methods for Laser-Induced Generation of THz Radiation at the Delta Storage Ring

laser, electron, storage-ring, experiment

1453

C. Mai, B. Büsing, A. Glaßl, S. Khan, D. Krieg, A. Meyer auf der Heide
DELTA, Dortmund, Germany

At DELTA, a 1.5-GeV electron storage ring operated as a synchrotron light source by the TU Dortmund University, a dedicated beamline is used for experiments with (sub-)THz radiation. Here, an interaction of short laser pulses with electron bunches to give rise to coherently emitted broadband as well as tunable narrowband radiation from 75 GHz to 5.6 THz. For the narrowband operation of the source, a laser pulse with periodic intensity modulation is used. An interferometric approach, the chirped-pulse beating technique, is routinely employed for this purpose. Recently, pulse shaping techniques using spatial light modulators are investigated to gain more flexible control of the laser pulse shape and the spectrotemporal properties of the resulting THz pulses.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW024

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

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TUPGW025

The DELTA Short-Pulse Source: Upgrade Plans from CHG to EEHG

laser, electron, undulator, optics

1457

A. Meyer auf der Heide, B. Büsing, S. Khan, D. Krieg, C. Mai, F. Teutenberg
DELTA, Dortmund, Germany

At the synchrotron light source DELTA operated by the TU Dortmund University, coherent harmonic generation (CHG) is employed to provide ultrashort pulses in the vacuum ultraviolet and terahertz (THz) regime. Here, a modulation of the electron energy induced by an interaction of an ultrashort laser pulse with an electron bunch is transformed into a density modulation by a magnetic chicane. This results in coherent emission at harmonics of the laser wavelength as well as THz radiation. With the planned upgrade towards echo-enabled harmonic generation (EEHG), much higher harmonics can be achieved by adding a second laser-electron interaction. The necessary major modifications of the DELTA storage ring and investigations of the laser-electron interaction will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW025

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

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TUPGW033

Status of Test-Accelerator as Coherent THz Source (t-ACTS) at ELPH, Tohoku University

electron, undulator, polarization, FEM

1475

S. Kashiwagi, H. Hama, F. Hinode, K. Kanomata, S. Miura, N.M. Morita, T. Muto, I. Nagasawa, K. Nanbu, S. Ninomiya, H. Saito, K. Takahashi, H. Yamada
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

A test-Accelerator as Coherent Terahertz Source (t-ACTS) has been under development at the Research Center for Electron Photon Science (ELPH), Tohoku University, in which an intense coherent terahertz radiation is generated from the femtosecond electron pulses. Velocity bunching scheme in a traveling accelerating structure is employed to generate femtosecond electron pulses, and the generation of femtosecond electron pulses was confirmed by spectrum analysis of coherent transition radiation using Michelson interferometer. Coherent transition radiation and coherent undulator radiation in the terahertz (THz) region from the short electron pulses has been demonstrated, and their characteristics such as frequency spectrum, spatial distribution and polarization were measured and compared with theoretical calculations. We have succeeded to generate the coherent transition radiation up to approximately 5 THz and the coherent undulator radiation with narrow bandwidth from 2.6 to 3.4 THz. At present, development of a variable polarized THz light source using a crossed-undulator system is being carried out. In addition, we are developing a nondestructive beam monitor using Cherenkov radiation emitted from the electron pulses. The status of t-ACTS will be presented in this conference.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW033

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

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TUPGW037

Systematic Measurements of the Coherent THz Spectra by Magnetic Bunch Compression at the Compact ERL

optics, electron, sextupole, linac

1486

M. Shimada, Y. Honda, R. Kato, T. Miyajima, N. Nakamura, T. Obina, T. Uchiyama
KEK, Ibaraki, Japan
T. Hotei
Sokendai, Ibaraki, Japan

Short electron bunch beam is one of the key elements of a Free Electron Laser (FEL) or intense THz coherent light source. The Energy Recovery Linac (ERL) has the strong advantage of operation of such an electron bunch at high repetition rate and is expected to increase the photon flux. At the Compact ERL in KEK site, we have demonstrated the magnetic bunch compression at the 180-degree return arc and measured the THz spectra of the Coherent Transition Radiation (CTR). This paper reports the revamped THz beamline and the improvement of the beam tuning as well as the systematic measurements of the THz spectra by magnetic bunch compression.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW037

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

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TUPGW038

Study on Coherent THz Radiation Using Tilt Control of Electron Beam

electron, solenoid, target, experiment

1489

Y. Tadenuma, M. Brameld, T. Murakami, K. Sakaue, M. Washio
Waseda University, Tokyo, Japan

Funding: This work was supported by a research granted from JSPS KAKENHI 17H02821.
The terahertz wave is located in the intermediate frequency band between radio waves and light waves, and researches on the light sources such as terahertz quantum cascade laser and femtosecond laser based THz sources are being conducted*. As a new terahertz light source, we are studying coherent Cherenkov radiation by using the tilt control of electron beam and irradiating the target medium. Since the radiation intensity of Cherenkov radiation depends on the target medium, comparison of three kinds of medium with different refractive index and density, and optimization of the target shape were performed. In addition, we are going to try quasi monochromatization of radiation by using multi slit to control the form factor of the electron beam. In this presentation, we will report the experimental results of target optimization and quasi monochromatization and the future prospects.
*S. S. Dhillon, et al., The 2017 terahertz science and technology roadmap, J. Phys. D: Appl. Phys., 50 (2017) 043001.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW038

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

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TUPGW045

Lattice Design for the Reversible SSMB

electron, emittance, storage-ring, bunching

1507

C.L. Li
SINAP, Shanghai, People’s Republic of China
A. Chao
SLAC, Menlo Park, California, USA
C. Feng, B.C. Jiang
Shanghai Advanced Research Institute, Pudong, Shanghai, People’s Republic of China

Steady State Microbunching (SSMB) aiming at producing high average power radiation in the electron storage ring has been proposed by Ratner and Chao years ago. Reversible seeding scheme is one of the promising scenarios with less challenges on the storage ring lattice design. The key problem for reversible SSMB is the precise cancelation of the laser modulation which will allow producing turn-by-turn coherent radiation without spoiling the transverse emittances and energy spread. In this paper the lattice design for the microbunching generation and its cancelation will be presented. Also a storage ring lattice design will be shown.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW045

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

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TUPGW051

Generation of Two Terahertz Radiation Pulses with Continuously Tunable Frequency and Time Delay

electron, laser, cathode, gun

1518

W.X. Wang, Z.G. He, S.M. Jiang, H.R. Zhang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

We propose to generate two narrow band terahertz pulses radiated from two temporally modulated relativistic electron beams, which are generated in a photo-injector. The temporal profile of the drive laser is modulated by means of the paired chirped pulses beating technique, leading to the generation of two pre-bunched electron beams. Coherent transient radiation (CTR) is considered as the mechanism for terahertz radiation generation. The frequencies of the two terahertz pulses can be independently tuned by adjusting the paired beating frequencies, and the interval between the two terahertz pulses can be adjusted by the optical delay line.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW051

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

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TUPGW068

New Source for Bending Magnet Beam Lines at Ultra-Low-Emittance Ring

dipole, lattice, storage-ring, wiggler

1557

M. Abbaslou, M. Sedaghatizadeh
KNTU, Tehran, Iran
S. Dastan, J. Rahighi, F. Saeidi
ILSF, Tehran, Iran

The Iranian Light Source Facility (ILSF) is a 3 GeV 3rd synchrotron radiation laboratory in the basic design phase. The Storage Ring (SR) is based on a five-bend achromat (5BA) lattice providing low horizontal emittance of 0.27 nm.rad. Due to the ILSF storage ring, straight section limits the use of the short length wigglers for hard X-ray generation is recommended. Which are removable in the lattice. In this article, the new design of the 3-pole wiggler is investigated and the main parameters of this 3-pole wiggler, by considering the ILSF storage ring characteristics, is modified. Also, the effect of the new 3-pole wiggler on the beam dynamics is investigated and the advantages of the new design are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW068

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paper received ※ 28 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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TUPRB012

Design of High Power CW IR-THz Source for the Radiation Source ELBE Upgrade

undulator, electron, FEL, linac

1702

P.E. Evtushenko, T.E. Cowan, U. Lehnert, P. Michel
HZDR, Dresden, Germany

The Radiation Source ELBE at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) is a user facility based on a 1 mA - 40 MeV CW SRF LINAC. Presently HZDR is considering upgrade options for the ELBE or its replacement with a new CW, SRF LINAC-based user facility. A part of the user requirements is the capability to generate IR and THz pulse in the frequency range from 0.1 through 30 THz, with pulse energies in the range from 100 uJ through a few mJ, at the repetition rate between 100 kHz and 1 MHz. This corresponds to the pulse energy increase, dependent on the wavelength by a factor from 100 through 1000. In this contribution, we outline key aspects of a concept, which would allow to achieve such parameters. Such key aspects are: 1 - use of a beam with longitudinal density modulation and bunching factor of about 0.5 at the fundamental frequency; 2 - achieving the density modulation through the mechanism similar to the one used in optical klystron (OK) and HGHG FEL; 3 - generating necessary for the modulation optical beam by an FEL oscillator, and 4 - using two electron injectors, where one injector provides beam for the FEL oscillator while second high charge injector provides beam for the high energy per pulse generation for user experiments. All-in-all the concept of the new radiation source is very similar to an OK, but operating with two beams simultaneously.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB012

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paper received ※ 21 May 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, FEL, simulation, vacuum

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, vacuum, 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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TUPRB035

Stimulated Emission of THz Coherent Diffraction Radiation in an Optical Cavity by a Multibunch Electron Beam

cavity, experiment, resonance, electron

1763

Y. Honda, A. Aryshev, R. Kato, T. Miyajima, T. Obina, M. Shimada, R. Takai, T. Uchiyama, N. Yamamoto
KEK, Ibaraki, Japan

Funding: JSPS KAKENHI
Accelerator-based terahertz (THz) radiation has been expected to realize a high-power broad-band source. Employing a low-emittance and short-bunch electron beam at a high repetition rate, a scheme to resonantly excite optical cavity modes of THz spectrum range via coherent diffraction radiation has been proposed. The confocal cavity design is the special case that resonance conditions of all the eigen modes coincide, resulting in realizing broad-band excitation. But in general cases of non-confocal cavities, the resonance condition depends on the mode, and the resonance peak becomes wide and weak. We performed an experiment with a non-confocal cavity as a follow-up experiment of that we have done with a confocal cavity. The result confirmed that the confocal design is the key for a broad-band source.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB035

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

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TUPRB037

Experimental Demonstration of Vector Beam Generation With Tandem Helical Undulators

polarization, undulator, experiment, simulation

1766

S. Matsuba
HSRC, Higashi-Hiroshima, Japan
M. Fujimoto, M. Katoh
UVSOR, Okazaki, Japan
M. Hosaka
Nagoya University, Nagoya, Japan
K. Kawase
QST, Tokai, Japan
T. Konomi, N. Yamamoto
KEK, Ibaraki, Japan
A. Miyamoto
Toshiba, Yokohama, Japan
S. Sasaki
ANL, Argonne, Illinois, USA

Vector beam is a light beam with spatially modulated polarization state across the beam. Particular examples of vector beam are radial and azimuthal polarization which have donut-shaped intensity and radially and azimuthally oriented linear polarization state. Vector beam has long been interest in the laser community and it is well known that vector beam can be created by superposing two optical vortex beams which have spiral wave fronts. It has been demonstrated that optical vortex beam can be generated from a helical undulator as harmonics. Therefore, we propose a scheme to generate vector beam by superposing two optical vortex beams from two helical undulators in tandem, based on the principle of the ’crossed undulator’. The experiment was carried out at UVSOR BL1U. In this paper, we describe the principle and the experimental details.

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

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TUPRB038

Characteristics of Polarized Coherent Radiation in Thz Region From a Crossed-Undulator

undulator, polarization, experiment, electron

1769

H. Saito, H. Hama, F. Hinode, K. Kanomata, S. Kashiwagi, S. Miura, N.M. Morita, T. Muto, I. Nagasawa, K. Nanbu, S. Ninomiya, K. Takahashi, H. Yamada
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

A variable polarized THz light source using a crossed-undulator configuration has been developed at Research Center for Electron Photon Science (ELPH), Tohoku University. It consists of two planar undulators of which deflecting planes cross at right angles and a phase shifter for phase adjustment. Polarization of the crossed-undulator has observation angle dependence due to that of radiation wavelength and optical path length difference between two radiations. That limits an angular range maintaining the identical polarization state. Assuming undulator parameters for our experiment (a fundamental frequency 1.9 THz and a number of periods seven) degree of circular polarization larger than 0.9 can be obtained only in the range of 2.2 mrad, i. e. 13% of the radiation angular spread.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB038

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

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TUPRB039

Research of Coherent Edge Radiation Generated by Electron Beams Oscillating Free-Electron Lasers

FEL, electron, cavity, experiment

1772

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

Funding: JSPS KAKENHI Grant Number JP16H03912
We have studied far-infrared coherent radiation with an S-band linac at Laboratory for Electron Beam Research and Application (LEBRA) at Nihon University. We have already developed a couple of terahertz-wave sources based on coherent synchrotron radiation and coherent transition radiation*, which have been applied to spectroscopic research**. Moreover, we developed coherent edge radiation (CER) at the downstream bending magnets in the FEL sections. Because the edge radiation has an annular shape distribution characterized by the asymmetric first-order Laguerre-Gaussian mode, the CER can be extracted from an optical cavity of the FEL system without a diffraction loss of the FEL beam***. The root-mean-squared bunch length of the electron beam was evaulated by measuring the CER spectra, which was about the same level as the FEL micropulse width. Although the infrared FELs at LEBRA had a long slippage length, the CER intensity can be a guidepost enhancing the FEL power because of the existence of their correlation. In this presentation, the characteristics of the CER including correlation between the CER and the FEL will be reported.
* N. Sei et al., Jpn. J. Appl. Phys. 56, (2017) 032401.
** N. Sei et al., J. Opt. Soc. Am. B, 31, (2014) 2150.
*** N. Sei et al., Phys. Lett. A in press.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB039

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paper received ※ 19 April 2019 paper accepted ※ 23 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, vacuum

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

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TUPRB041

Simulation of Short-Pulse Generation from a Dynamically Detuned IR-FEL Oscillator and Pulse Stacking at an External Cavity

FEL, cavity, electron, simulation

1778

Y. Sumitomo, Y. Hayakawa, T. Sakai
LEBRA, Funabashi, Japan
R. Hajima
QST, Tokai, Japan

Funding: Q-LEAP program supported by Ministry of Education, Culture, Sports, Science and Technology, Japan
At the LEBRA facility of Nihon U., we have an IR-FEL oscillator to generate radiations in the range of wavelengths 1-6 um for various experiments. A research program has been established to explore the application of the IR-FEL to generate attosecond UV and X-ray pulses through the high harmonic generation (HHG) in noble gases, where the IR-FEL pulses must have a high-peak power and a short-pulse duration. The property of generated FEL pulse is affected by the cavity length detuning of FEL oscillator as well as the small signal gain and the cavity loss. The operation at a small- or zero-detuning length is necessary to generate a FEL pulse shorter than the bunch length, although it requires a long macro-pulse to reach the saturation. For the short FEL pulse generation within a limited macro-pulse length at the LEBRA LINAC, we apply a dynamical modulation to the electron bunch repetition, that is equivalent to a dynamical detuning of the FEL cavity length. We illustrate the potential performance of the IR-FEL with the dynamical detuning by time-dependent 3D FEL simulations. We also evaluate the enhancement of the FEL pulses by an external cavity stacking for the sake of the HHG application.

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

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TUPRB045

Stimulated Excitation by Seeding With Cherenkov Radiation in an Optical Cavity

cavity, electron, GUI, ion-source

1785

S.M. Jiang, Z.G. He, Q.K. Jia, W.W. Li, L. Wang
USTC/NSRL, Hefei, Anhui, People’s Republic of China
D. He
Anhui Electrical Engineering Professional Technique College, Hefei, People’s Republic of China

Funding: Work supported by National Foundation of Natural Sciences of China (11775216, 11705198, 11675178), and Fundamental Research Funds for the Central Universities (WK2310000061).
By seeding with narrow-band Cherenkov radiation from a dielectric loaded waveguide(DLW), stimulated excitation in an optical cavity is presented. The evolution and energy loss of the field oscillating in optical cavity is analysed by the theoretical and numerical calculation. The results show that the high order TM modes of the Cherenkov radiation can be better preserved after a large number of roundtrips in the optical cavity and this scheme offers a potential method of realizing high power Terahertz radiation source in a compact facility.

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paper received ※ 30 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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TUPRB046

Second Order Intensity Correlation and Statistical Properties of a Soft X-Ray Free Electron Laser

laser, FEL, electron, simulation

1788

C.L. Li, J.H. Chen, Z.C. Chen, X.T. Wang, H.L. Wu
SINAP, Shanghai, People’s Republic of China
B. Liu, T. Liu
SARI-CAS, Pudong, Shanghai, People’s Republic of China

High degree of transverse field coherence is one of the unique properties of an FEL compared with a 3rd gen-eration storage ring light source. As a result, the FEL advances the development of innovative research and technology that was not previously feasible. A truly coherent source should be coherent in all orders de-scribed from the intensity correlation functions. In this paper, second order intensity correlation of FEL radia-tion is investigated based on the Hanbury Brown-Twiss intensity correlation method. The statistical properties of radiation produced from SASE was also investigated and compared with the statistical proper-ties of a phase-locked laser. The results show that the statistical properties of a SASE mode behave as a cha-otic source, which is significantly different from the properties of a phase-locked laser beam.

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

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TUPRB050

The Optical Resonator of CTFEL for Range of 1 to 2 THz

FEL, GUI, electron, coupling

1795

X.J. Shu, Y.H. Dou
Institute of Applied Physics and Computational Mathematics, People’s Republic of China

A high power THz free electron laser (FEL) facility is under construction at China Academy of Engineering Physics (CTFEL). The radiation frequency of the FEL facility will be tuned in range of 1~3 THz and the average output power is about 10 W. The system mainly consists of a GaAs photoemission DC gun, superconductor accelerator, hybrid wiggler, optical cavity. The first lasing is obtained on Aug. 29, 2017, and CTFEL is operated in range of 2-4THz, but cannot lasing at the frequency below 1.8 THz. The optical resonator of CTFEL must be optimized to ensure lasing in range of 1 to 2 THz.. The lasing strongly depends on the performance of the optical resonator including output efficiency, gain and round-trip loss. The optical resonator consists of metal-coated reflect mirror, the centre-hole output mirror, waveguide. The influence of waveguide on the quality of optical cavity is evaluated by the 3D OSIFEL code. The waveguide size and output hole radius is optimized to different frequencies between 1 THz to 2 THz.

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paper received ※ 13 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019

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TUPRB052

The Mini-Period Permanent Magnet Staggered Undulator for Compact X-Ray Free Electron Laser

undulator, FEL, electron, permanent-magnet

1797

L.G. Yan, D.R. Deng, J. Wang
CAEP/IAE, Mianyang, Sichuan, People’s Republic of China

Funding: Work supported by National Natural Science Foundation of China under grant of 11505174, 11505173 and 11605190.
Miniaturization of X-ray free electron laser requires reduction of undulator period length. In this proceeding, a mini-period permanent magnet staggered undulator was proposed, which is free of superconducting solenoid and thus has advantages of easy-manufacture and low-cost. After optimization, it can generate periodic field of peak field 0.71 T with period length 10 mm and pole gap 2 mm, which has been verified on a prototype. Combined with X-band linac, the length of 1 nm XFEL facility using the permanent magnet staggered undulator can be confined within 44 m.

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paper received ※ 30 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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TUPRB057

THz-Pump and UV-Probe Scheme Based on Storage Ring

laser, electron, bunching, storage-ring

1811

H.R. Zhang, Z.G. He, S.M. Jiang, W.X. Wang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

We propose a THz-pump and UV-probe scheme based on storage ring for ultra-fast dynamics experiment. In which, two sequential laser pulses, one of which has a periodic intensity envelope, simultaneously interact with different parts of the long electron beam in a modulator; after a chicane, the part that interacts with the periodic pulse will bunch at THz domain and radiate through a bend magnet, another based on high-harmonic generation will bunch at UV domain and radiate at a radiator. The electron beam can be utilized circularly in the storage ring, which will increase its average power. The feasibility of this THz-pump and UV-probe scheme is verified in both theory and simulation.

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

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TUPRB061

Seeded Free-Electron Lasers Driven by a Transverse Tilted Electron Bunch

laser, FEL, electron, undulator

1817

Z. Zhao, Q.K. Jia, H.T. Li
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Funding: Work supported by the China Postdoctoral Science Foundation (No. 2018M642542) and the Fundamental Research Funds for the Central Universities (WK2310000081).
A transverse tilt of the electron bunch is normally unwanted in free-electron laser (FEL) since only a portion of the bunch can contribute to the FEL radiation. However, the recent researches demonstrate that the tilted bunch can be used to generate FEL with some special features. In this work we investigate the generation of a large tilt of the bunch by using a corrugated structure and a dogleg separately. Based on the tilted bunch, the creation of ultra-short pulse and multi-color pulses are demonstrated in high-gain harmonic generation (HGHG) FEL.

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

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TUPRB062

Coherence Time Characterization for Self-Amplified Spontaneous Emission Free-Electron Lasers

electron, FEL, laser, free-electron-laser

1820

G. Zhou, Y. Jiao, J.Q. Wang
IHEP, Beijing, People’s Republic of China
T.O. Raubenheimer, J. Wu
SLAC, Menlo Park, California, USA
C.-Y. Tsai
HUST, Wuhan, People’s Republic of China
C. Yang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

One of the key challenges in scientific researches based on free-electron lasers (FELs) is the characterization of the coherence time of the ultra-fast hard x-ray pulse, which fundamentally influences the interaction process between x-ray and materials. Conventional optical methods, based on autocorrelation, is very difficult to realize due to the lack of mirrors. Here, we experimentally demonstrate a conceptually new coherence time characterization method and a coherence time of 174.7 attoseonds has been measured for the 6.92 keV FEL pulses at Linac Coherent Light Source. In our experiment, a phase shifter is adopted to control the cross-correlation between x-ray and microbunched electrons. This approach provides critical temporal coherence diagnostics for x-ray FELs, and is decoupled from machine parameters, applicable for any photon energy, radiation brightness, repetition rate and FEL pulse duration, etc.
The work was supported by the US Department of Energy (DOE) under contract DE-AC02-76SF00515 and the US DOE Office of Science Early Career Research Program grant FWP-2013-SLAC-100164.

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paper received ※ 01 May 2019 paper accepted ※ 28 May 2019 issue date ※ 21 June 2019

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TUPRB071

Considerations on Implementing EEHG with a Strong Linear Chirp

electron, bunching, FEL, linac

1830

M.A. Pop, S. Werin
MAX IV Laboratory, Lund University, Lund, Sweden

As the ECHO enabled harmonic generation (EEHG) scheme draws such intense focus from the FEL community, we conduct simulations to evaluate the challenges of implementing said scheme in different FEL layouts. Nonlinear processes such as this require extensive simulations to harmonize all system specific properties like seed lasers and electron beam properties. Along with optimizing the original EEHG scheme* one can consider, for example, altering the seed laser pulse to optimize the bunching for a machine specific chirp. We study the EEHG as a possible seeding method aimed at increasing coherence of the photon beam for the prospective SXL FEL beamline at MAXIV. The particular chirp of the electron beam through the MAXIV LINAC generates some specific requirements in implementing EEHG but may also offer an opportunity for exotic operation modes of this FEL.
* Xiang D. and Stupakov G. Echo-enabled harmonic generation free electron laser 10.1103/PhysRevSTAB.12.030702

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

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TUPRB076

Free Electron Laser Driven by a High-Energy High-Current Energy-Recovery Linac

FEL, electron, linac, undulator

1844

F. Zimmermann
CERN, Geneva, Switzerland
H. Aksakal
KMSIU, Onikisubat / Kahramanmaras, Turkey
A.A. Aksoy
Ankara University, Accelerator Technologies Institute, Golbasi, Turkey
Z. Nergiz
Nigde University, Nigde University Science & Art Faculty, Nigde, Turkey

Funding: This work was supported by the European Commission under the HORIZON 2020 project ARIES, grant agreement no. 730871.
The proposed electron-hadron collider LHeC, based on an energy recovery linac, employs an electron beam of 20 mA current at an energy of tens of GeV. This electron beam could also be used to drive a free electron laser (FEL) operating at sub-Angstrom wavelengths. Here we demonstrate that such FEL would have the potential to provide orders of magnitude higher peak power, peak brilliance and average brilliance, than any other FEL, either existing or proposed.

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

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TUPRB089

Undulator Radiation Generated by a Single Electron

electron, undulator, photon, experiment

1867

A. Halavanau, Z. Huang, C. Pellegrini, T.O. Raubenheimer
SLAC, Menlo Park, California, USA
I. Lobach
University of Chicago, Chicago, Illinois, USA
S. Nagaitsev
Fermilab, Batavia, Illinois, USA
D. Seipt
HZDR, Dresden, Germany

Funding: This work was supported by the U.S. Department of Energy Contract No. DE-AC02-76SF00515.
The facilities providing single electron beams are currently being commissioned at Fermilab and will be at SLAC. Recently, Fermilab’s IOTA ring routinely demonstrated circulation of a single electron at 100 MeV beam energy. Alternatively, SLAC is working on constructing LCLS-II an X-ray FEL driven by a 4 GeV SRF linac. A parasitic beamline, S30XL, is planned that will extract 4 GeV dark current from between the primary LCLS-II electron bunches. The dark current will be delivered to End Station A and can work independently of LCLS-II experiments. The dark current will be bunched at a frequency of 46 MHz while extracted current varied from single electrons to 10’s of nA. In the present paper, we estimate the feasibility of propagating single electron beams through a conventional undulator, placed in the IOTA and S30XL beamlines. We explore the possible observable effects and experimental parameters range. In addition, we focus on potential applications of such beams in systems for high fidelity quantum measurements.

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

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TUPRB090

Preliminary Considerations of Atomic Inner-Shell X-Ray Laser for Self-Seeding at LCLS-II

FEL, photon, simulation, experiment

1871

A. Halavanau, C. Pellegrini, J. Wu
SLAC, Menlo Park, California, USA
A.I. Benediktovitch
EuXFEL, Hamburg, Germany
N. Rohringer
Max Planck Institute for the Physics of Complex Systems, Dresden, Germany

Funding: This work was supported by the U.S. Department of Energy Contract No. DE-AC02-76SF00515.
The atomic inner-shell X-ray lasing, induced by the irradiation of focused XFEL SASE pulses, was demonstrated in gases, liquid jets and solids. In this proceeding, we discuss the possible use of this concept in self-seeding scheme at LCLS-II. We provide a preliminary study of different lasing media and corresponding SASE XFEL parameters. For the case of noble gas inner-shell X-ray laser, we study the requirements for gas pressure and XFEL pulse focusing. Finally, we discuss possible designs of this system and its advantages in LCLS-II operations.

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

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TUPRB091

Study of XFEL Third Harmonic Radiation at LCLS

undulator, FEL, experiment, bunching

1875

C. Emma, M.W. Guetg, A. Halavanau, A.A. Lutman, G. Marcus, T.J. Maxwell, C. Pellegrini
SLAC, Menlo Park, California, USA

Funding: This work was supported by the U.S. Department of Energy Contract No. DE-AC02-76SF00515.
In this paper, we focus on characterization of the nonlinear third harmonic radiation properties at Linac Coherent Light Source (LCLS). In addition, we experimentally perform third harmonic self-seeding, using diamond crystal attenuator in the hard X-ray self-seeding chicane. We discuss warm beam effects in such scheme, justifying recently proposed two bunch configuration for harmonic lasing.

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

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TUPRB092

Cherenkov Radiation in Periodic Wire Medium Formed by Transversely Modulated Electron Beams

electron, laser, cathode, experiment

1878

A. Halavanau
SLAC, Menlo Park, California, USA
A.I. Benediktovitch
EuXFEL, Hamburg, Germany
E.A. Gurnevich
Belarussian State University, Scientific Research Institute of Nuclear Problems, Minsk, Belarus

Funding: Work was supported by the U.S. Department of Energy Contract No. DE-AC02-76SF00515.
We investigate the properties of Cherenkov, quasi-Cherenkov (parametric) and diffraction radiation generated in the periodic conducting wire medium by transversely modulated electron beams. Such beams were recently obtained at Argonne Wakefield Accelerator (AWA) facility using microlens array (MLA) laser shaping technique. We consider in details the case of one dimensional periodic tungsten wire structure and transverse electron beamlets separation of mm scale. We look at possible enhancements of the radiation field due to transverse periodicity of the electron beam.

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paper received ※ 14 May 2019 paper accepted ※ 19 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, vacuum, proton, 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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paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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TUPTS046

Commissioning of a Compact THz Source Based on FEL

linac, FEL, undulator, cavity

2030

Y.J. Pei, G. Feng, X.Y. He, Y. Hong, D. Jia, P. Lu, S. Lu, L. Shang, B.G. Sun, Zh.X. Tang, W. Wang, X.Q. Wang, W. Wei
USTC/NSRL, Hefei, Anhui, People’s Republic of China
L. Cao, Q.S. Chen, Q. Fu, T. Hu, P. Tan, Y.Q. Xiong
HUST, Wuhan, People’s Republic of China
G. Huang
IMP/CAS, Lanzhou, People’s Republic of China
L.G. Shen, F. Zhang
USTC/PMPI, Hefei, Anhui, People’s Republic of China

The layout of the THz source based on FEL was de-scribed in this paper. The THz source was based on a FEL which was composed of a compact 8-14MeV LINAC, undulator, optical resonance, THz wave measurement system and so on. The facility was designed in 2013 and the typical running parameter got in 2017 were as the following: energy is of 12.7MeV, energy spread is of 0.3%, macro-pulse is of 4 μs, pulse length of micro-pulse is of 6ps, emittance is of 24 mm.mrad. After that the ma-chine was commissioning for production THz radiation. In November 2018, the THz wave was test and got THz wave signal, the spectrum was also got. This year, we plan to measure the output power of the THz source.

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paper received ※ 15 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

vacuum, Windows, 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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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEXXPLS2

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paper received ※ 14 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

target, simulation, vacuum, 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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WEZPLS1

Control of Laser Plasma Accelerated Electrons: A Route for Compact Free Electron Lasers

electron, laser, undulator, FEL

2280

M.-E. Couprie, T. André, F. Blache, F. Bouvet, F. Briquez, Y. Dietrich, J.P. Duval, M. El Ajjouri, A. Ghaith, C. Herbeaux, N. Hubert, C.A. Kitegi, M. Labat, N. Leclercq, A. Lestrade, A. Loulergue, O. Marcouillé, F. Marteau, D. Oumbarek Espinos, P. Rommeluère, M. Sebdaoui, K.T. Tavakoli, M. Valléau
SOLEIL, Gif-sur-Yvette, France
I.A. Andriyash, S. Corde, J. Gautier, J.-P. Goddet, O.S. Kononenko, G. Lambert, K. Ta Phuoc, A. Tafzi, C. Thaury
LOA, Palaiseau, France
S. Bielawski, C. Evain, E. Roussel, C. Szwaj
PhLAM/CERLA, Villeneuve d’Ascq, France
V. Malka
Weizmann Institute of Science, Physics, Rehovot, Israel

The recent spectacular development of laser plasma ac- celerators that now can deliver GeV electron beams in an extremelyshortdistancemakesthemverypromising. Ap- plications for light sources based on undulator radiation and free electron laser appear as an intermediate step to move from an acceleration concept to an accelerator qual- ification. However, the presently achieved divergence and energy spread require some electron beam manipulations. The COXINEL test line was designed for enabling Free Elec- tron Laser operation with baseline reference parameters. It comprises variable permanent magnet quadrupoles for di- vergence handling, a magnetic chicane for electron energy sorting, a second set of quadrupole for chromatic focusing and an undulator for synchrotron radiation emission and/or free electron laser gain medium. The transport along the line is controlled [1]. The synchrotron radiation emitted by the undulator radiation is studied under different conditions of detection (CCD camera, spectrometer), electron beam manipulation and undulator parameters. These observations pave the way towards Laser Plasma Acceleration based Free Electron Laser.

[1] T. André et al., Control of laser plasma accelerated electrons for light sources, accepted in Nature Comm.

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

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WEPMP007

Current Status of Slow Extraction from J-PARC Main Ring

extraction, operation, proton, experiment

2311

R. Muto, Y. Arakaki, T. Kimura, S. Murasugi, M. Okada, K. Okamura, T. Shimogawa, Y. Shirakabe, M. Tomizawa, T. Toyama, E. Yanaoka
KEK, Ibaraki, Japan
A. Matsumura
Nihon Advanced Technology Co., Ltd, Ibaraki, Nakagun, Tokaimura, Japan

A 30 GeV proton beam accelerated in the J-PARC Main Ring (MR) is slowly extracted by the third integer resonant extraction and delivered to the hadron experimental hall. The slow extraction (SX) from the MR has unique characteristics that can be used to obtain a low beam loss rate. A dynamic bump scheme under achromatic condition drastically reduces beam hit rate on the septa devices. We have attained 50 kW SX operation at 5.2s cycle in current physics run. Slow extraction efficiency has been achieved to be very high, 99.5%. A beam instability during debunching with beam loss can be suppressed by a unique RF phase offset technique at MR injection. A spill duty factor indicating a uniformity for time structure of the extracted beam is typically 50%, which can be obtained by a feedback system using fast response quadrupoles, applying transverse RF field and so on. Future plans to improve present SX performances will be introduced.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP007

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paper received ※ 01 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, vacuum, 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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WEPMP041

Damping Bunch Oscillations Due to Off-Axis Injection

optics, injection, wiggler, damping

2422

F. Zimmermann, O. Etisken, N. Mounet, A. Oeftiger, S. Ogur, Y. Papaphilippou, B. Salvant
CERN, Geneva, Switzerland
K. Oide
KEK, Ibaraki, Japan

Funding: This work was supported by the European Commission under the HORIZON 2020 project ARIES, grant agreement no. 730871.
In the FCC-ee pre-injector complex, a slightly modified SPS can serve as pre-booster. The baseline design foresees injecting the low-emittance electron and positron bunches off-axis into the SPS, and deploying strong wigglers to greatly enhance the radiation damping at the injection energy. We here compare the damping of large injection oscillations by means of radiation damping with the effect of other possible damping mechanisms such as a fast bunch-by-bunch feedback system and/or head-tail damping via nonzero chromaticity. As a by-product, we investigate the transverse beam stability.

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

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WEPMP044

Mu2e Electrostatic Septa Volumetric Exchange of Fc-40 Dielectric in High Radiation Environments

GUI, septum, cathode, extraction

2434

M.L. Alvarez, A. Deshpande, K.R. Hunden, V.P. Nagaslaev, E. Pirtle
Fermilab, Batavia, Illinois, USA

Funding: * Operated by FRA, LLC under Contract No. DEAC02-07CH11359 and Grant Award No. LAB 18-1802 with the United States Department of Energy.
Two electrostatic septa (ESS) are being designed for the slow extraction of 8 GeV proton beam for the Mu2e experiment at Fermilab. Special attention is given to the high voltage feedthrough (HVF), which energizes the cathode creating the bending field. The FC-40 dielectric fluid, surrounding the HV cable breaks down from radiation exposure, which reduces its insulating capabilities. The new HVF design focuses on effective replacement of the exposed fluid and eliminating the stagnant areas of low exchange rate. A preliminary test using a fully transparent prototype HVF and water was conducted to understand the volumetric exchange rate of the high radiation region. Here we discuss the results of these tests and further studies using the FC-40.
** malvare4@fnal.gov
*** vnagasl@fnal.gov

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

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WEPGW006

Development of a Beam Loss Monitor and Transverse Beam Dynamics Studies at ARRONAX C70XP Cyclotron

cyclotron, experiment, operation, quadrupole

2470

A. Sengar, X. Goiziou, F. Gomez Serito, C. Koumeir, F. Poirier
Cyclotron ARRONAX, Saint-Herblain, France
F. Haddad
SUBATECH, Nantes, France

Funding: "Investissements d’Avenir", Equipex Arronax-Plus, Institute of Nuclear and Particle Physics from the National Scientific Research center (CNRS) and the Regional Council of Pays de la Loire, France.
The ARRONAX Interest Public Group uses a multi-particle, high energy and high intensity industrial accelerator which has several beamlines used for various purposes. For improvement of operations, ARRONAX has foster and installed robust air-based Beam Loss Monitors (BLMs) outside the beam pipes. BLMs consist of four active detecting plates and are integrated within the experimental physics and industrial control system (EPICS) monitoring and data acquisition system. Each BLM has been tested for the pre-commissioning phase with beams at low intensity (600pA to 6nA on target). Comparative studies and selection of the BLMs has led to their installation at high intensity beam lines. BLMs are now used in beam dynamics studies to investigate transverse characteristics while in regular operation. They support present and future operations extension foreseen at ARRONAX. The results from experimental studies on BLMs at low beam intensity and status of beam dynamics studies at high intensity (A) are presented here. Keywords: BLM, beam dynamics, EPICS, Gas ionization detector, cyclotron, proton.
*F. Poirier, S. Girault, STUDIES AND UPGRADES ON THE C70 CYCLOTRON ARRONAX, Proceedings of Cyclotrons 2016, Zurich, Switzerland

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

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WEPGW014

A Non-Invasive THz Spectrometer for Bunch Length Characterization at European XFEL

electron, FEL, diagnostics, factory

2495

N.M. Lockmann, C. Gerth, P. Peier, B. Schmidt, S. Wesch
DESY, Hamburg, Germany

The European X-ray Free-Electron Laser provides one of the most powerful X-ray laser pulses to a wide range of experiments. These experiments strongly benefit from the exact knowledge of the electron bunch current profile and demand for stable and shortest-possible pulse lengths. During the 2018 summer shutdown, the 4-staged grating spectrometer CRISP* has been installed at a diffraction radiation (DR) beamline just upstream of the undulator beamline switchyard. The DR at final electron beam energies of up to 17.5 GeV enables non-invasive bunch length characterization based on form factor measurements down to a few micrometers. Fast detectors and electronics allow for the characterization of the whole bunch train with repetition rates above 1 MHz. This contribution will present commissioning results of the THz beamline as well as first measured form factors and reconstructed electron current profiles.
* S. Wesch et al., Nuclear Instruments and Methods in Physics Research Section A 665 (2011) pp. 40-47

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

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WEPGW016

Turn-by-Turn Horizontal Bunch Size and Energy Spread Studies at KARA

synchrotron, detector, synchrotron-radiation, storage-ring

2498

B. Kehrer, M. Brosi, E. Bründermann, S. Funkner, A.-S. Müller, G. Niehues, M.M. Patil, M. Schuh, J.L. Steinmann
KIT, Karlsruhe, Germany
L. Rota
SLAC, Menlo Park, California, USA

Funding: This work is funded by the BMBF under contract number: 05K16VKA
The energy spread is an important beam dynamics parameter. It can be derived from measurements of the horizontal bunch size. At the KIT storage ring KARA a fast-gated camera is routinely used for horizontal bunch size measurements with a single-turn resolution for a limited time span. To overcome the limits of the current camera setup in respect to resolution and time span, a high-speed line array with up to 10 Mfps, the KALYPSO system, is foreseen as a successor. The KALYPSO versions range from 256-pixel to 1024-pixel and allow unlimited turn-by-turn imaging of a single bunch at KARA. We successfully tested such a system at our visible light diagnostics port and present first results in this contribution.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW016

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

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WEPGW018

An Ultra-Fast and Wide-Spectrum Linear Array Detector for High Repetition Rate and Pulsed Experiments

detector, experiment, electron, synchrotron

2504

M.M. Patil, E. Bründermann, M. Caselle, S. Funkner, B. Kehrer, A.-S. Müller, G. Niehues, W. Wang, M. Weber
KIT, Karlsruhe, Germany
C. Gerth
DESY, Hamburg, Germany
D.R. Makowski, A. Mielczarek
TUL-DMCS, Łódź, Poland

Funding: "BMBF: is funded by the BMBF contract number: 05K16VKA" (2016-2018) ("NeoDyn")
Photon science research at accelerators is influenced radically by the developments of sensor and readout technologies for imaging. These technologies enable a wide range of applications in beam diagnostics, tomography and spectroscopy. The repetition rate of commercially available linear array detectors is a limiting factor for the emerging synchrotron applications. To overcome these limitations, KALYPSO(Karlsruhe Linear arraY detector for MHz rePetition rateSpectrOscopy), an ultra-fast and wide-field of view linear array detector operating at several mega-frames per second(Mfps), has been developed. A silicon micro-strip sensor is connected to custom cutting-edge front end ASICs to achieve unprecedented frame rate in continuous readout mode. In this contribution, the third generation of KALYPSO will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW018

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

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WEPGW022

A Numerical Analysis to Choose the Most Performing Optical Transition Radiation Screen

target, electron, brightness, site

2518

F. Cioeta, D. Alesini, A. Variola
INFN/LNF, Frascati (Roma), Italy
M. Ciambrella, A. Mostacci
Sapienza University of Rome, Rome, Italy
D. Cortis, M. Marongiu, V. Pettinacci
INFN-Roma, Roma, Italy

Optical Transition Radiation (OTR) screen represents the most appropriate instrument to measure and verify the characteristics of a beam spot size produced by a particle accelerator. In order to measure such beam properties, OTR screens have to sustain thermal and mechanical stresses due to the energy that several bunches deposit. Owing to these requirements, it is essential to identify the more suitable material to optimize the OTR dimensions and to get reliable measures from the diagnostic system. In this paper, we describe a numerical procedure to choose the most performing material taking into account the physical requirements of a multi-bunch high brightness. The procedure is based on a dedicated ANSYS script able to evaluate the fatigue life time of the material considering a high number of thermal cycles generated by several bunches. The main characteristic of this script is the capability to simulate the real thermal and mechanical effect on the target that the hitting particle beam produces. The numerical procedure has been applied to compare the performance of three relevant materials-Aluminium, Silicon and Graphite simulating a beam hitting with well-known parameters.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW022

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

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WEPGW031

Measurement of Cherenkov Diffraction Radiation from a Short Electron Bunches at t-ACTS

electron, experiment, photon, detector

2536

S. Ninomiya, H. Hama, F. Hinode, K. Kanomata, S. Kashiwagi, S. Miura, N.M. Morita, T. Muto, I. Nagasawa, K. Nanbu, H. Saito, K. Takahashi, H. Yamada
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

Cherenkov Diffraction Radiation (ChDR) can be considered as a tool of non-destructive beam diagnostics. It also has the feature that the photon flux of ChDR is proportional to the thickness of the dielectric used as the radiator and can be much larger than ordinary diffraction radiation. An experimental set-up for the measurement of coherent ChDR from short electron bunches of about 100 fs is being prepared at t-ACTS, Tohoku University. Results of a basic experimental study about coherent ChDR will be presented.

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

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WEPGW046

Key Technologies for Remote Detection of CSNS Radiation Environment

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

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WEPGW052

A Rotation Method to Calibrate BPM Electric Offsets

laser, site, instrumentation, proton

2595

M.W. Wang, X. Guan, P.F. Ma, X.W. Wang, S.X. Zheng
TUB, Beijing, People’s Republic of China
M.T. Qiu, D. Wang, Z.M. Wang
NINT, Shannxi, People’s Republic of China

Beam position monitor is a key instrument for machine commissioning. To measure beam position accurately, offline calibrations to acquire the sensitivity and offsets of the BPM are essential prerequisites. A new method to calibrate the BPM electric offset is proposed in this paper. By measuring the location variation of the BPM electric center after rotatingtheBPM180degrees, theBPMoffsetcanbederived. The method is more convenient, universal and accurate than the traditional methods. The method is successfully applied to calibrate the button BPM of Xi’an Proton Application Facility. The repetitive measurement error is 20.8 um.

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

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WEPGW055

Beam Longitudinal Distribution Reconstructed by GESPAR Method at CAEP THz FEL

electron, FEL, laser, experiment

2602

D. Wu, T.H. He, P. Li, J. Liu, X. Luo, Q. Pan, L.J. Shan, X. Shen, J. Wang, D.X. Xiao, L.G. Yan, P. Zhang, K. Zhou
CAEP/IAE, Mianyang, Sichuan, People’s Republic of China

Funding: Work supported by National Natural Science Foundation of China with grant (11505173, 11505174, 11575264, and 11605190)
Coherent radiation can be used to measure the longitudinal distribution of the electron beam bunch of any length, as long as the coherent radiation spectrum can be measured. In many cases, the Kramers-Krönig relationship is used to reconstruct the temporal distribution of the beam from the coherent radiation spectrum. However, the extrapolation of the low frequency will introduce the uncertainty of the reconstruction. In this paper, GrEedy Sparse PhAse Retrieval (GESPAR) method was used to reconstruct the beam longitudinal distribution measured by coherent transition radiation on the THz FEL facility of China Academy of Engineering Physics. The results indicate that the GESPAR method works well for the complex and ultrashort distribution. It will be an effective tool to accurately measure the femtosecond bunch temporal structure.

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paper received ※ 14 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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WEPGW068

Measurements of Beam Parameters at the Last Track of the ERL-Based Novosibirsk Free Electron Laser

FEL, electron, diagnostics, undulator

2632

V.M. Borin, Ya.V. Getmanov, A.S. Matveev, O.I. Meshkov, O.A. Shevchenko, N.A. Vinokurov
BINP SB RAS, Novosibirsk, Russia
V.L. Dorokhov
BINP, Novosibirsk, Russia
Ya.V. Getmanov
NSU, Novosibirsk, Russia
A.I. Mickailov
Budker INP & NSU, Novosibirsk, Russia

Parameters and dynamics of the electron beam of the Novosibirsk infrared Free Electron Laser are studied. The Novosibirsk FEL is based on the multi-turn energy recovery linac (ERL). The ERL operate in CW mode with an average beam current about 5 mA. Therefore non-destructive beam diagnostic methods are preferable. The beam energy at the last track of the ERL is 42 MeV. As a result, significant part of synchrotron radiation from bending magnets is in the visible range and can be used for diagnostic purposes. The transverse beam dimensions were measured with the optical diagnostics before (transition radiation) and after (synchrotron radiation from a bending magnet) the undulator applied for generation of middle-infrared coherent radiation. The obtained data are used to calculate the beam energy distribution and emittance.

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

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WEPGW077

Recent Results using Incoherent Cherenkov Diffraction Radiation for Non-Invasive Beam Diagnostics

experiment, photon, diagnostics, beam-diagnostic

2654

M. Bergamaschi, R. Kieffer, T. Lefèvre, S. Mazzoni
CERN, Geneva, Switzerland
A. Aryshev
KEK, Ibaraki, Japan
P. Karataev
Royal Holloway, University of London, Surrey, United Kingdom
P. Karataev, K. Lekomtsev
JAI, Egham, Surrey, United Kingdom
A. Potylitsyn
TPU, Tomsk, Russia
A. Schloegelhofer
TU Vienna, Wien, Austria

When a relativistic charged particle travels at a short distance from the surface of dielectric material Cherenkov Diffraction Radiation (ChDR) is produced inside the dielectric. Recent observation of incoherent ChDR in the visible spectrum has opened the possibility of using this radiation for non-invasive beam size and position measurements. An experimental test to study this technique for highly directional beam position measurement has been initiated on the CLEAR facility at CERN, whilst another experimental investigation is underway at the Accelerator Test Facility 2 (ATF2) at KEK, Japan, to measure the resolution limit of ChDR for beam imaging diagnostics. This contribution presents the latest experimental results from both of these test facilities.

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

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WEPGW078

Development and Test of a Beam Imaging System Based on Radiation Tolerant Optical Fiber Bundles

laser, experiment, target, site

2658

D. Celeste, E. Bravin, S. Burger, F. Roncarolo
CERN, Geneva, Switzerland

Many of the beam image systems at CERN are located in high radiation environments. In order to cope with this issue, VIDICON cameras are presently used but their production has been nowadays discontinued worldwide. The development of an alternative beam imaging system is described here, based on radiation tolerant optical fibre bundles. Such an optical line relays the image of a scintillating screen to a standard CMOS camera, located away from the high radiation zone. A prototype system based on a 10m long bundle with 10⁴ fibres has been tested in the TT2 transfer line at CERN. The light transmission is rather low, but is compensated by the sensitivity of the CMOS camera. The system had a field of view of 60 mm and a spatial resolution of ~1 mm. The radiation hardness of such a fiber bundle was tested at the IRMA-CEA facility in Saclay, France. The bundle was irradiated at a rate of 3.6 kGy/h for 8 consecutive day. The total integrated dose achieved was ~700 kGy, which corresponds to about ten years of operation at the beam imaging station with the highest radiation dose at CERN. While the light transmission was reduced by 50%, this is still adequate to provide acceptable images.

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

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WEPGW082

The Beam Gas Vertex Profile Monitoring Station for HL-LHC

detector, target, real-time, dipole

2672

R. Kieffer, A. Alexopoulos, L. Fosse, M. Gonzalez Berges, H. Guerin, O.R. Jones, T. Marriott-Dodington, J.W. Storey, R. Veness, S. Vlachos, B. Würkner, C. Zamantzas
CERN, Meyrin, Switzerland
S.M. Gibson
Royal Holloway, University of London, Surrey, United Kingdom

A new instrument is under development for the high luminosity upgrade of the Large Hadron Collider at CERN (HL-LHC) to provide non-invasive beam size measurements throughout the acceleration cycle. The Beam Gas Vertex (BGV) detector consists of a very low pressure gas target inside the beam pipe with a series of particle tracking stations located downstream. Inelastic collisions between the beam and the gas target produce secondary particles which are detected by the tracking stations. The beam size is measured from the spatial distribution of several thousand beam-gas interaction vertices, which are identified by means of the reconstructed tracks. A demonstrator device, operated over the past 3 years, has proven the feasibility of the BGV concept and has motivated development of a fully operational device for the HL-LHC. The status of current design studies for the future instrument will be presented, with particular emphasis on potential tracking detector technologies, readout schemes, and expected performance.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW082

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

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WEPGW095

Coherent Transition Radiation Spatial Imaging as a Bunch Length Monitor

electron, detector, simulation, focusing

2713

J. Wolfenden, R.B. Fiorito, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
M. Brandin, E. Mansten, S. Thorin
MAX IV Laboratory, Lund University, Lund, Sweden
R.B. Fiorito, C.P. Welsch, J. Wolfenden
Cockcroft Institute, Warrington, Cheshire, United Kingdom
B.S. Kyle, T.H. Pacey, T.H. Pacey
UMAN, Manchester, United Kingdom
B.S. Kyle
University of Manchester, Manchester, United Kingdom
E. Mansten
Lund University, Division of Atomic Physics, Lund, Sweden
T.H. Pacey
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
A.G. Shkvarunets
UMD, College Park, Maryland, USA

Funding: This work was supported by the EU under Grant Agreement No. 624890 and the STFC Cockcroft Institute core Grant No. ST/G008248/1.
High-resolution bunch length measurement is a key component in the optimisation of beam quality in FELs, storage rings, and plasma-based accelerators. Simulations have shown that the profile of a coherent transition radiation (CTR) image produced by a charged particle beam is sensitive to bunch length and can thus be used as a diagnostic. This contribution presents the development progress of a novel bunch length monitor based on imaging the spatial distribution of CTR. Due to the bunch lengths studied, 10fs-100fs FWHM, the radiation of interest was in the THz range. This led to the development of a THz imaging system, which can be applied to both high and low energy electron beams. The associated benefits of this imaging distribution methodology over the typical angular distribution measurement are discussed. Building upon preliminary multi-shot proof of concept results last year, a new series of experiments have been conducted in the short pulse facility (SPF) at MAX IV. Single-shot measurements have been used to measure the exact point of maximum compression. Analysis from the proof of concept results last year, and initial results from the new measurements this year are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW095

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

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WEPGW096

Development of Supersonic Gas-Sheet-Based Beam Profile Monitors

electron, photon, background, monitoring

2717

H.D. Zhang, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
M. Ady, J. Glutting, O.R. Jones, T. Marriott-Dodington, S. Mazzoni, A. Rossi, G. Schneider, R. Veness
CERN, Geneva, Switzerland
P. Forck, S. Udrea
GSI, Darmstadt, Germany
A. Salehilashkajani, C.P. Welsch, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom

Funding: HL-LHC project funded by STFC and CERN, and the STFC Cockcroft core grant No. ST/G008248/1.
Non-destructive beam profile monitoring is very desirable, essentially for any particle accelerator but particularly for high-energy and high-intensity machines. Supersonic gas jet-based monitors, detecting either the ionization or fluorescence of a gas sheet interacting with the primary beam to be characterized, allow for minimally invasive measurements. They can also be used over a wide energy range, from keV to TeV beams. This contribution gives an overview of the jet-based ionization and fluorescence beam profile monitors which have been developed, built and tested at the Cockcroft Institute. It discusses gas sheet generation, vacuum considerations, choice of gas species and detection methods.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW096

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

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WEPGW099

Development of a Beam Halo Monitor

synchrotron-radiation, synchrotron, electron, optics

2721

V.G. Dudnikov, R.P. Johnson, M. Popovic
Muons, Inc, Illinois, USA
M.A. Cummings
Northern Illinois University, DeKalb, Illinois, USA
R.M. Thurman-Keup
Fermilab, Batavia, Illinois, USA

Our innovative approach is to design the Beam Halo Monitor, where beam induced synchrotron radiation will be used to monitor the beam Halo. This involves an original scheme of light collection using a coronograph for measuring beam halo.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW099

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

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WEPGW103

Synchrotron Radiation Beam Diagnostics at IOTA - Commissioning Performance and Upgrade Efforts

electron, optics, experiment, detector

2732

N. Kuklev, Y.K. Kim
University of Chicago, Chicago, Illinois, USA
J.D. Jarvis, A.L. Romanov, J.K. Santucci, G. Stancari
Fermilab, Batavia, Illinois, USA

Funding: Work supported by National Science Foundation award PHY-1549132, the Center for Bright Beams. Fermi Research Alliance operates Fermilab under Contract DE-AC02-07CH11359 with the US Dept. of Energy.
The Integrable Optics Test Accelerator is a research electron and proton storage ring recently commissioned at the Fermilab Accelerator Science and Technology facility. A key part of its beam diagnostics suite are synchrotron radiation monitors, used for measuring transverse beam profile, position, and intensity. In this paper, we report on the performance and uses of this system during the year 1 run. We demonstrate sub-100nm statistical beam position uncertainty and high dynamic range from 10⁹ electrons down to a single electron. Commissioning challenges and operational issues are discussed. We conclude by outlining current upgrade efforts, including improved modularity, small emittance measurements, and a multi-anode photomultiplier system for turn-by-turn acquisition.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW103

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paper received ※ 15 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

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WEPGW110

Feasibility Study of Beam Profile Measurements Using Interferometer and Diffractometer Techniques for ALS-U

electron, synchrotron, storage-ring, lattice

2752

C. Sun, S. De Santis, D. Filippetto, F. Sannibale, C. Steier
LBNL, Berkeley, California, USA

Funding: Work supported by the Director Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
ALS-U is an ongoing upgrade of Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory. The upgraded ALS will replace the existing Triple-Bend Achromat (TBA) storage ring lattice with a compact Multi-Bend Achromat (MBA) lattice. This MBA technology allows us to tightly focus electron beams down to about 10 μm to reach diffraction limit in a soft x-ray region. The beam size measurement is a challenging task for this tightly focused beam. The interferometer technique with visible light from synchrotron radiation has been developed in many facilities to measure their beam size at a micrometer-level accuracy. In this paper, we will present the feasibility study of this technique for the ALS-U storage ring beam size measurement.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW110

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

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WEPRB025

High Density Mapping for Superconducting Cavities

cavity, cryogenics, status, operation

2860

Y. Iwashita, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
Y. Fuwa
Kyoto University, Research Reactor Institute, Osaka, Japan
R.L. Geng
JLab, Newport News, Virginia, USA
H. Hayano
KEK, Ibaraki, Japan

High density mapping system for superconducting cavities are under development. Testing on the stiffener X-ray mapping system at JLAB showed consistent results in comparison with simultaneously taken GM tube or ion chamber output signals. The system provides better visi-bility as shown by data briefly reported here. In addition to the temperature and the X-ray mapping, a sensitive magnetic field mapping system with high spatial density is also under development. The magnetic field sensor is AF755B, whose operations at cryogenic temperatures are already reported by other group. Our development status using the magnetic field sensor will be reported.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB025

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

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WEPRB054

Design of the Multiplexing Optical Measurement System for a Pre-bunched THz Free Electron Laser

laser, detector, FEL, electron

2931

Y.K. Zhao, W. Li, B.G. Sun, Y.G. Tang, F.F. Wu, T.Y. Zhou
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Funding: Work supported by the the Fundamental Research Funds for the Central Universities (WK2310000080, WK2310000057), and the National Science Foundation of China (11705203, 11575181)
A new and compact a pre-bunched terahertz (THz) free electron laser (FEL) at the National Synchrotron Radiation Laboratory, University of Science and Technology of China is being constructed and aims to generate the tunable radiation frequency ranges from 0.5 THz to 5 THz at 11-18 Mev electron energy. This system is expected to use for imaging, basic researches as well as industrial applications as a result of the significant merits of simple, compact and cost-effective. Due to the THz laser measurement system plays an important part in the pre-bunched THz FEL facility. Therefore, a multiplexing THz laser sensing measurement system model is developed for measuring the output laser power and the optical spectrum of THz radiation with the excellent advantages of robustness, high sensitivity and low-cost in this paper.
Corresponding author (email: tiany86@ustc.edu.cn)
Corresponding author (email: wufangfa@ustc.edu.cn)

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB054

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

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WEPRB059

Dark Current Analysis at CERN’s X-band Facility

operation, electron, ECR, linac

2944

D. Banon-Caballero, M. Boronat, V. Sánchez Sebastián, A. Vnuchenko
IFIC, Valencia, Spain
N. Catalán Lasheras, S. Pitman, M. Widorski, W. Wuensch, V. del Pozo Romano
CERN, Meyrin, Switzerland
A. Faus-Golfe
LAL, Orsay, France
B. Gimeno
UVEG, Burjasot (Valencia), Spain
T.G. Lucas, M. Volpi
The University of Melbourne, Melbourne, Victoria, Australia
W.L. Millar
Lancaster University, Lancaster, United Kingdom
J. Paszkiewicz
University of Oxford, Oxford, United Kingdom

Dark current is particularly relevant during operation in high-gradient linear accelerators. Resulting from the capture of field emitted electrons, dark current produces additional radiation that needs to be accounted for in experiments. In this paper, an analysis of dark current is presented for four accelerating structures that were tested and conditioned in CERN’s X-band test facility for CLIC. The dependence on power, and therefore on accelerating gradient, of the dark current signals is presented. The Fowler-Nordheim equation for field emission seems to be in accordance with the experimental data. Moreover, the analysis shows that the current intensity decreases as a function of time due to conditioning, but discrete jumps in the dark current signals are present, probably caused by breakdown events that change the emitters’ location and intensity.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB059

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

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WEPRB073

CW Room Temperature Accelerating Structures

impedance, operation, electron, SRF

2990

S.P. Antipov, P.V. Avrakhov, E. Gomez, S.V. Kuzikov
Euclid TechLabs, LLC, Solon, Ohio, USA
A.A. Vikharev
IAP/RAS, Nizhny Novgorod, Russia

To this day CW linear electron accelerators were based only on expensive and bulky (embedded in a cryostat) superconducting accelerating structures. CW regime can in principle be realized with normal conducting structures provided the shunt impedance is high. Such structures can be designed using dielectrics (ultra-pure ceramics in C-band and diamond in mm-waves) with ultra-low loss tangent (~10-6). The use of dielectrics allows to concentrate the electromagnetic energy density in the dielectric region and thus minimize fields and ohmic loss on metallic walls. The thermal loss in dielectric can be relatively low given the loss tangent is small. We report here the design of structures with shunt impedance on the order of 10⁴ MOhm/m, which is several orders of magnitude higher than shut impedance in copper structures in GHz and THz range. High shunt impedance makes it possible to accelerate electrons to 1 MeV using kW-level CW RF sources like magnetrons in C-band and gyrotrons in THz range. Such CW accelerators will find applications in sterilization, food irradiation, industrial radiography and cargo inspection.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB073

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

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WEPRB106

Simulation of the Transition Radiation Transport Through an Optic System

simulation, electron, optics, diagnostics

3059

M. Marongiu, A. Mostacci, L. Palumbo
Sapienza University of Rome, Rome, Italy
F.G. Bisesto, E. Chiadroni, G. Di Pirro, G. Franzini, A. Giribono, V. Shpakov, A. Stella, A. Variola
INFN/LNF, Frascati, Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
A. Mostacci, L. Palumbo
INFN-Roma, Roma, Italy

Optical Transition Radiation (OTR) screens are widely used for beam profile measurements. The radiation is emitted when a charged particle beam crosses the boundary between two media with different optical properties. The main advantages of OTR are the instantaneous emission process allowing fast single shot measurements (i.e. bunch by bunch measurements in a multi bunch machine), and the good linearity with the beam charge (if coherent effects can be neglected). Furthermore, OTR angular distribution strongly depends on beam energy. Since OTR screens are typically placed in several positions along the Linac to monitor beam envelope, one may perform a distributed energy measurement along the machine: this will be useful, for instance, during the commissioning phase of a machine. This paper deals with the studies of an algorithm to optimize the generation and the transport of the transition radiation through an optic system using the simulation tool Zemax. The algorithm, in combination with a particle tracking code (i.e. Elegant), will allow to simulate the radiation generated by a beam and, so, to take into account beam divergence and energy spread or chromatic effects in the optic system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB106

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

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WEPRB116

X-ray Pinhole Camera for Emittance Measurements in Solaris Storage Ring

emittance, storage-ring, photon, diagnostics

3084

A. Kisiel, A.M. Marendziak, M. Ptaszkiewicz, A.I. Wawrzyniak
Solaris National Synchrotron Radiation Centre, Jagiellonian University, Kraków, Poland

X-ray pinhole camera is widely used system for the transverse beam profile measurement and emittance feedback. However this method is predominantly applied to the middle and high energy storage rings. At Solaris storage ring with the nominal energy of 1.5 GeV, the design of the beamline was modified to provide sufficient X-ray photon flux for proper imaging. The successful installation and commissioning of the X-ray pinhole beamline allows now to measure the emittance and helps in proper 3rd harmonic cavities tuning against the coupled bunch mode instabilities. The paper describes the design details, simulations and measurement results obtained during the beamline operation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB116

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

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WEPTS015

Synchronous Measurements of Electron Bunches Under the Influence of the Microbunching Instability

synchrotron, bunching, simulation, storage-ring

3119

M. Brosi, T. Boltz, E. Bründermann, S. Funkner, B. Kehrer, A.-S. Müller, M.J. Nasse, G. Niehues, M.M. Patil, P. Schreiber, P. Schönfeldt, J.L. Steinmann
KIT, Karlsruhe, Germany

Funding: This work has been supported by the German Federal Ministry of Education and Research (Grant No. 05K16VKA). We acknowledge the support by the Helmholtz International Research School for Teratronics.
The microbunching instability is a longitudinal collective instability which occurs for short electron bunches in a storage ring above a certain threshold current. The instability leads to a charge modulation in the longitudinal phase space. The resulting substructures on the longitudinal bunch profile vary over time and lead to fluctuations in the emitted power of coherent synchrotron radiation (CSR). To study the underlying longitudinal dynamics on a turn-by-turn basis, the KIT storage ring KARA (Karlsruhe Research Accelerator) provides a wide variety of diagnostic systems. By synchronizing the single-shot electro-optical spectral decoding setup (longitudinal profile), the bunch-by-bunch THz detection systems (THz power) and the horizontal bunch size measurement setup (energy spread), three important properties of the bunch during this instability can be measured at every turn for long time scales. This allows a deep insight into the dynamics of the bunch under the influence of the microbunching instability. This contribution will discuss effects like the connection between the emitted CSR power and the deformations in the longitudinal bunch profile on the time scale of the instability.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS015

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

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WEPTS017

Synchrotron Radiation Module in OCELOT Toolkit

electron, undulator, simulation, FEL

3127

S. Tomin, G. Geloni
EuXFEL, Hamburg, Germany

Synchrotron radiation (SR) sources based on single-pass accelerators (e.g. linacs, plasma accelerators) have to cope with electron beams with a rather complicated phase space distribution. In this case, the convolution method usually employed to calculate radiation properties can give poor accuracy or be not applicable at all. Moreover, dynamical effects can also play a role in the emission mechanism. This happens when the beam parameters (e.g. beam current) significantly change during the passage through the undulator. In this work, we present a dedicated SR module of the OCELOT toolkit, which is well suited to deal with these situations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS017

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

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WEPTS051

Comparison of Electron Cloud Build-Up Simulations Against Heat Load Measurements for the LHC Arcs With Different Beam Configurations

electron, simulation, operation, synchrotron-radiation

3232

G. Skripka, G. Iadarola, L. Mether, G. Rumolo, E.G.T. Wulff
CERN, Meyrin, Switzerland
P. Dijkstal
PSI, Villigen PSI, Switzerland

Electron cloud effects are among the main performance limitations for the operation of the Large Hadron Collider (LHC) with 25 ns bunch spacing. A large number of electrons impacting on the beam screens of the cold magnets induces significant heat load, reaching values close to the full cooling capacity available from the cryogenic system. Interestingly, it is observed that parts of the machine that are by design identical show very different heat loads. We used numerical simulations to investigate the possibility that these differences are induced by different surface properties, in particular maximum Secondary Electron Yield (SEY) for the different cryomagnets. Using the PyECLOUD code, the electron cloud build-up was simulated assuming different values of SEY in the LHC cold magnets. Comparing the measured heat loads to the simulation results for the 25 ns beams at 450 GeV we have identified the SEY values that match the observations in these conditions. These SEY values were found to be in good agreement with the heat loads measured with different beam configurations (changing the bunch pattern, the bunch intensity and the beam energy).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS051

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

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WEPTS058

BDSIM: Recent Developments and New Features Beyond V1.0

simulation, detector, site, experiment

3259

L.J. Nevay, A. Abramov, J. Albrecht, S.E. Alden, S.T. Boogert, H. Garcia Morales, S.M. Gibson, W. Shields, S.D. Walker
JAI, Egham, Surrey, United Kingdom
J. Snuverink
PSI, Villigen PSI, Switzerland

BDSIM is a program that creates a 3D model of an accelerator from an optical beam line description using a suite of high energy physics software including Geant4, CLHEP and ROOT. In one single simulation the passage of particles can be tracked accurately through an accelerator including the interaction with the accelerator material and subsequent secondary radiation production and transport. BDSIM is regularly used to simulate beam loss and energy deposition as well as machine detector interface studies. In this paper we present the latest developments beyond BDSIM V1.0 added for ongoing studies. For simulation of collimation systems several new additions are described including new element geometry, enhanced sensitivity and output information. The output has been further enhanced with aperture impact information and dose information from scoring meshes. As well as supporting the full suite of Geant4 physics lists, a new user interface is described allowing custom physics lists and user components to be easily included in BDSIM. New undulator, crystal collimator and wire-scanner elements are also described.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS058

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

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WEPTS102

Helical Wiggler Model for Fast Tracking

wiggler, electron, optics, undulator

3356

W.F. Bergan, V. Khachatryan, D.L. Rubin
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: NSF-1734189 DGE-1650441
In order to test the process of Optical Stochastic Cooling (OSC) at the Cornell Electron Storage Ring (CESR), we plan to use helical wigglers as both the pickup and kicker, since the required radiation wavelength of 800nm can be achieved with lower magnetic field strength in helical as compared to planar wigglers. In order to simulate the lattice with such wigglers, it is useful to be able to model the effect of the wiggler on the optics without resorting to direct tracking, which is time-consuming and so ill-suited for the repeated evaluations necessary in running an optimizer. We generate a Taylor map to third order for this element using analytic field expressions, enabling easy determination of the effects of such an element on linear and nonlinear optics. This model is compared with the results of direct tracking and shows good agreement.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS102

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

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WEPTS104

Synchrotron Radiation Reflections in the CLIC Beam Delivery System

photon, detector, collider, synchrotron

3363

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

Synchrotron radiation (SR) reflection is an important issue for future linear colliders. High fluxes of the SR might impact the performance of the detector, through irradiation of the forward luminosity and beam quality calorimeters or of the innermost layers of the vertex detector. The photon reflections depend on the beam pipe apertures’ size, their shape, and materials used with various surface roughness. In this work, we present a study of SR including reflection for the 380 GeV and 3 TeV beam parameters and optics of the Compact Linear Collider’s Final Focus System. The simulations of the SR reflections using the Synrad+ software are presented and the impact on the detector is discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS104

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

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WEPTS106

Accelerator Optimization using Big Data Science Techniques

plasma, experiment, electron, proton

3370

C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: This project has received funding from STFC under grant reference ST/P006752/1.
Managing, analyzing and interpreting large, complex datasets and high rates of data flow is a growing challenge for many areas of science and industry. At particle accelerators and light sources, this data flow occurs both, in the experiments as well as the machine itself. The Liverpool Big Data Science Center for Doctoral Training (LIV. DAT) was established in 2017 to tackle the challenges in Monte Carlo modelling, high performance computing, machine learning and data analysis across particle, nuclear and astrophysics, as well as accelerator science. LIV. DAT is currently training 24 PHD students, making it one of the largest initiatives of this type in the world. This contribution presents research results obtained to date in projects that focus on the application of big data techniques within accelerator R&D.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS106

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

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WEPTS107

Designing the European Spallation Source Tuning Dump Beam Imaging System

proton, target, linac, optics

3374

M.G. Ibison, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
E. Adli, G. Christoforo, H. Gjersdal
University of Oslo, Oslo, Norway
M.G. Ibison, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
T.J. Shea, C.A. Thomas
ESS, Lund, Sweden

Funding: In-Kind Agreement, ESS/Norway
The first section of the European Spallation Source (ESS) to receive high-energy protons when live operation begins will be the Tuning Dump beam-line. The dump line will be used during accelerator commissioning to tune the linac, and must accept the full range of ESS energies up to 2 GeV, from 5µs probe pulse to full 2.86ms pulse length, and beam sizes up to the 250 mm limit of the physical aperture, although the allowed pulse rate will be restricted by the thermal capacity of the dump. An imaging system has been developed to view remotely the transverse beam profile in the section immediately before the dump entrance, using insertable scintillator screens. This contribution presents the principal design parameters for this system, with particular reference to the techniques used in assessing the radiation and thermal environments and their impact on the selection of locations for the imaging cameras, and the specification of the mechanical screen actuators. The predicted optical performance of the system is also summarised.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS107

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

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THXPLS1

Review of Ion Therapy Machine and Future Perspective

synchrotron, operation, controls, proton

3391

K. Noda
NIRS, Chiba-shi, Japan

Cancer therapy with ion beams presents several advantages as compared to proton therapy or conventional radiation therapy but its diffusion is limited by the size and cost of the accelerator facility. The ion therapy facilities are presently in operation have generated important developments in particular to the gantry, beam delivery technique, and beam scanning system, while new treatment facilities being planned in United States, Europe, and Asia. This talk will present the current status of this field, as well as the future perspective.

Slides THXPLS1 [26.303 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THXPLS1

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

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THYYPLS3

A Remote-Controlled Robot-Car in the TPS Tunnel

photon, controls, operation, laser

3435

T.Y. Lee, B.Y. Chen, T.W. Hsu, B.Y. Huang, C.H. Kuo, W.Y. Lin
NSRRC, Hsinchu, Taiwan

A remote-controlled robot-car named ’PhotonBot’ was put into the TPS accelerator tunnel and is equipped with a 360 degrees LiDAR for SLAM and navigation, two cameras for perception and first-person view, and a thermal imaging system. The robot can be remotely controlled and can send data to a remote PC through Wi-Fi. With SLAM, it can go more freely without being restricted to a designated path. In order to ensure it can work continuously, there is a wireless charging station in case of a low battery.

Slides THYYPLS3 [18.013 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THYYPLS3

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paper received ※ 09 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPMP002

Optics Design and Beam Dynamics Simulation for a VHEE Radiobiology Beam Line at PRAE Accelerator

linac, gun, electron, optics

3444

A. Faus-Golfe, B. Bai, Y. Han, C. Vallerand
LAL, Orsay, France
R. Delorme, Y. Prezado
IMNC, Orsay, France
M. Dosanjh
CERN, Meyrin, Switzerland
P. Duchesne
IPN, Orsay, France
V. Favaudon, C. Fouillade, P.M. Poortmans, F. Pouzoulet
Institut Curie - Centre de Protonthérapie d’Orsay, Orsay, France

The Platform for Research and Applications with Electrons (PRAE) is a multidisciplinary R&D facility gathering subatomic physics, instrumentation, radiobiology and clinical research around a high-performance electron accelerator with beam energies up to 70 MeV. In this paper we report the complete optics design and performance evaluation of a Very High Energy Electron (VHEE) innovative radiobiology study, in particular by using Grid mini-beam and FLASH methodologies, which could represent a major breakthrough in Radiation Therapy (RT) treatment modality.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP002

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paper received ※ 27 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPMP008

Feasibility Study on Mo-99 Production Using Hybrid Method Based on High Power Electron Accelerator

target, neutron, electron, photon

3462

A. Taghibi Khotbeh-Sara, F. Rahmani
KNTU, Tehran, Iran
F. Ghasemi
NSTRI, Tehran, Iran
H. Khalafi
AEOI, Tehran, Iran
M. Mohseni Kejani
Shahid Beheshti University, Tehran, Iran

In this study, the idea 99Mo production using hybrid method based on electron accelerator has been pre-sented. Two different main production channels of 100Mo(γ,n)99Mo and 98Mo(n,γ)99Mo can be used for 99Mo production in this system. By considering high power Linac (30 MeV, 1 mA in average beam current) and one-stage approach, the calculation of 100Mo(γ,n)99Mo reactions in the optimized 100Mo target in two different designs (strip and disc) has been simu-lated. It is predicted that about 61 and 53 Ci of 99Mo activity per 24-hour irradiation on the strip target and the disc plates can be achieved, respectively. The threshold energy of photoneutron at 100Mo is about 9 MeV, so a large part of bremsstrahlung photons cannot participate in photoneutron reaction. For feasibility study, new hybrid approach has been tested by 10 MeV Rhodotron. Due to the low threshold of photo-neutron in deuteron (about 2.2 MeV) and significant low energy photons in 100Mo, photoneutron flux is available. So, Molybdenum target in heavy water Tank increases the production yield of 99Mo using neutron absorption reaction in 98Mo. The total activity of 99Mo has been predicted about 0.23 Ci per 24 hours e-beam irradiation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP008

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

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THPMP011

Optics and Commissioning of the CNAO Experimental Beam Line

experiment, proton, MMI, optics

3472

S. Savazzi, E. Bressi, L. Falbo, V. Lante, C. Priano, M.G. Pullia
CNAO Foundation, Pavia, Italy
P. Meliga
University of Pavia, Pavia, Italy

CNAO (National Centre for Oncological Hadronthera-py) in Pavia is one of the six centres worldwide in which hadrontherapy is administered with both protons and carbon ions. The main accelerator is a 25 m diameter synchrotron designed to accelerate carbon ions up to an energy of 400 MeV/u and protons up to an energy of 250 MeV. It was designed with three treatment rooms and an ’experimental room’ where research can be carried out. The room itself was built since the beginning, but the beam line was planned to be installed in a second moment in order to give priority to treatments. The beam line of the experimental room (XPR) is designed to be "general purpose", for research activities in different fields. In October 2018 the installation phase of the line was started and it ended in January 2019. In this paper a short description of the optics layout and commissioning strategy is given.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP011

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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, electron, linac, vacuum

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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THPMP025

Modern Heavy Ion Based Test Facilities For Spacecrafts Electronics Qualification

detector, heavy-ion, monitoring, electron

3497

P.A. Chubunov
ISDE, Moscow, Russia
V.S. Anashin
United Rocket and Space Corporation, Institute of Space Device Engineering, Moscow, Russia
I.V. Kalagin, S.V. Mitrofanov, V.A. Skuratov
JINR, Dubna, Moscow Region, Russia

All spacecraft electronics should be subject to radiation hardness qualifications. For modern semiconductor technologies, individual high-energy particles of outer space are the greatest danger, causing upsets and failures in satellite equipment. For ground tests at single event effects, heavy ion-based modeling facilities are used. The report describes the test benches used for testing space-based electronics, created on the basis of the U-400, U-400M ion accelerators in the FLNR JINR (Dubna, Russia) at the request of ISDE (Moscow, Russia).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP025

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paper received ※ 18 May 2019 paper accepted ※ 26 May 2019 issue date ※ 21 June 2019

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THPMP026

Mobile Accelerator Based on Ironless Pulsed Betatron for Dynamic Objects Radiographing

betatron, electron, ion-source, target

3500

V.A. Fomichev, A.A. Chinin, S.G. Kozlov, Yu.P. Kuropatkin, V.I. Nizhegorodtsev, I.N. Romanov, K.V. Savchenko, V.D. Selemir, O.A. Shamro, E.V. Urlin
RFNC-VNIIEF, Sarov, Nizhniy Novgorod region, Russia

The paper concerns a mobile accelerator based on the ironless pulsed betatron. The accelerator has a possibility to obtain up to three frames in a single pulse and is aimed to radiograph dynamic objects with a large optical thickness. The block diagram of the accelerator, the temporal diagram of its separate systems operation and oscillograms of the betatron output parameters are provided. The testing powering in a single frame mode was carried out in 2018. The capacitance of the storage of the betatron electromagnet pulsed powering system that defines the electron beam energy was equal to 1800 μF. The following test results have been obtained. The thickness of the lead test object examined with X-rays reached 140 mm at 4 m from the tantalum target of the betatron. The full width of the output gamma pulse at half maximum in a single frame mode was equal to 120 ns; the dimension of the radiation source was 6 mm x 3 mm; the dimension of the tantalum target was 6 mm x 6 mm. The application of these accelerators within the radiographic complex* enables the optimization of the hydrodynamic experiments geometry resulting in the increase of the test efficiency.
* Pat. 2548585 C1 RU MPK G03B 42/02. D.I. Zenkov and others. «Mobile radiographic complex and radiation source of betatron type for radiographic complex» (in Russian), 2015.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP026

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

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THPMP027

Concept of Radiographic Complex Based on Ironless Pulsed Betatrons for Small-Angle Tomography

betatron, experiment, collimation, ion-source

3503

O.A. Shamro, A.A. Chinin, V.A. Fomichev, Yu.P. Kuropatkin, V.I. Nizhegorodtsev, K.V. Savchenko, V.D. Selemir
RFNC-VNIIEF, Sarov, Nizhniy Novgorod region, Russia

The active research complexes intended for the radiography of dynamic objects with a high optical density are reviewed. The concept of a multi-beam radiographic complex for a small-angle tomography based on ironless pulsed betatrons is proposed*. It is possible to use up to 18 compact facilities in a complex; they are located in three horizontal planes. The test object is placed in the explosion-proof chamber. Each facility consists of two typical units: an accelerator unit, and a unit of the electromagnet pulsed powering system. The output parameters of the facility are the maximum translucent capacity of 200 mm of the lead at 1 m from the betatron target, the resolution of less than 1 mm, the gamma-pulse full width at half maximum of 100 ns in a single frame mode, the gamma-pulse full width at half maximum of 150 ns in a three-frame mode. The complex will be able to obtain up to 54 frames in one hydrodynamic experiment at the operation of each facility in a three-frame mode. The complex is compact. Its diameter with a service area will be 20 m.
* Pat. 2515053 С1 RU МPK G03B 42/02. Yu.P. Kuropatkin, others. «Method of Radiograph. Image Form. of Fast Processes in Inhomogeneity and Radiograph. Complex for its Implementation», 2014.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP027

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paper received ※ 25 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019

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THPMP033

Beam Characterisation Using MEDIPIX3 and EBT3 Film at the Clatterbridge Proton Therapy Beamline

proton, detector, simulation, experiment

3510

J.S.L. Yap, J. Resta-López, R. Schnuerer, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
N.J.S. Bal
ASI, Amsterdam, The Netherlands
N.J.S. Bal, M. Fransen, F. Linde
NIKHEF, Amsterdam, The Netherlands
A. Kacperek
The Douglas Cyclotron, The Clatterbridge Cancer Centre NHS Foundation Trust, Wirral, United Kingdom
J.L. Parsons
Cancer Research Centre, University of Liverpool, Liverpool, United Kingdom
J. Resta-López, R. Schnuerer, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: EU FP7 grant agreement 215080, H₂020 Marie Skłodowska-Curie grant agreement No 675265 - Optimization of Medical Accelerators (OMA) project and the Cockcroft Institute core grant STGA00076-01.
The Clatterbridge Cancer Centre (CCC) in the UK is a particle therapy facility providing treatment for ocular cancers using a 60 MeV passively scattered proton therapy beam. A model of the beamline using the Monte Carlo Simulation toolkit Geant4 has been developed for accurate characterisation of the beam. In order to validate the simulation, a study of the beam profiles along the delivery system is necessary. Beam profile measurements have been performed at multiple positions in the CCC beam line using both EBT3 GAFchromic film and Medipix3, a single quantum counting chip developed specifically for medical applications, typically used for x-ray detection. This is the first time its performance has been tested within a clinical, high proton flux environment. EBT3 is the current standard for conventional radiotherapy film dosimetry and was used to determine the dose and for correlation to fluence measured by Medipix3. The count rate linearity and doses recorded with Medipix3 were evaluated across the full range of available beam intensities, up to 3.12 x 10¹⁰ protons/s. The applicability of Medipix3 for proton therapy dosimetry is discussed and compared against the performance of EBT3.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP033

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paper received ※ 14 May 2019 paper accepted ※ 22 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, vacuum, 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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THPMP041

A Comparative Study of Biological Effects of Electrons and Co-60 Gamma Rays on pBR322 Plasmid DNA

electron, experiment, controls, proton

3533

K.L. Small, R.M. Jones
UMAN, Manchester, United Kingdom
D. Angal-Kalinin, M. Surman
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A. Chadwick, N.T. Henthorn, K. Kirkby, M.J. Merchant, R. Morris, E. Santina
The Christie NHS Foundation Trust, Manchester, United Kingdom
R. Edge
Dalton Cumbrian Facility, University of Manchester, Cumbria, United Kingdom
R.J. Smith
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Very High-Energy Electron (VHEE) therapy is a rapidly developing field motivated by developments in high-gradient linacs. Advantages include sufficient penetration (>30 cm) for treatment of deep-seated tumours, measured insensitivity to inhomogeneities and rapid delivery time, making VHEE viable for treatment of heterogeneous regions, e.g. lung or bowel. Researchers at the University of Manchester and CERN have routinely produced accelerating gradients of ~100 MeV/m for the CLIC project. Suitable modification can result in a high gradient medical linac producing 250 MeV electrons within a treatment room. Radiobiological research for VHEE is vital to understand its use in radiotherapy and how it compares with conventional modalities. The goal of radiotherapy is to destroy tumour cells while sparing healthy cells, primarily by damaging DNA within the cancer cell. The study aim is to understand the fundamental interactions between VHEE and biological structures through plasmid irradiation studies - both computational, using the Monte Carlo GEANT4-DNA code, and experimental. Plasmid irradiation experiments have been carried out at using Co-60 gammas at the Dalton Cumbrian Facility and using 6-15 MeV electrons at the Christie NHS Foundation Trust to determine the type and quantity of damage caused to DNA by electron irradiation. These experiments are a world first in VHEE radiobiology, with further studies planned at higher energies using the CLARA and CLEAR facilities at Daresbury and CERN. These studies will also consider the effective dose range of VHEE with energy, as well as implications of damage on DNA. Research into this area of radiotherapy can provide a valuable addition to tools currently available to physicians in the fight against cancer.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP041

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

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THPMP044

Radiation Hard Sensor for Reactor Applications

laser, GUI, timing, detector

3545

R.J. Abrams, M.A. Cummings, R.P. Johnson, T.J. Roberts
Muons, Inc, Illinois, USA
D.M. Kaplan
Illinois Institute of Technology, Chicago, Illinois, USA

A novel method of measuring temperature of the coolant inside a reactor core is presented. The method, which is both standoff and non-invasive, is based on the interaction between an ultrasonic pulse and a delayed light pulse in the coolant. In the interaction, the light pulse, which is scattered backward by Brillouin scattering, is frequency-shifted. The frequency shift is dependent on the temperature and other parameters of the coolant. The light pulses and the ultrasound pulses are generated and detected outside of the core.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP044

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

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THPGW015

Proposed Beam Test of a Transverse Gradient Undulator at the SINBAD Facility at DESY

undulator, linac, electron, experiment

3609

R. Rossmanith, A. Bernhard, K. Damminsek, J. Gethmann, S. Richter
KIT, Karlsruhe, Germany
R.W. Aßmann, F. Burkart, U. Dorda, F. Jafarinia, B. Marchetti
DESY, Hamburg, Germany
M. Kaluza
IOQ, Jena, Germany

While Laser Plasma Accelerators produce beams with the high output energy required for FELs, up to now the relatively high energy spread has prohibited FEL lasing. Therefore it was proposed to replace the normal FEL undulators by Transverse Gradient Undulators (TGUs). For a first, small scale test of the TGU concept, a 40 period prototype high gradient superconductive TGU was built at KIT and will be tested with beam at the ARES-linac in the new accelerator test facility SINBAD (Short Innovative Bunches and Accelerators at Desy) at DESY. The proposed tests are summarized in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW015

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

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THPGW036

Development of Supercontinuum Light Production System Using Er Fiber Laser for Pulse Radiolysis*

laser, experiment, electronics, electron

3660

T. Uchida, S. Hanai, K. Sakaue, M. Washio
Waseda University, Tokyo, Japan

Pulse radiolysis is one of the methods to elucidate radiation chemical reactions. In order to elucidate that, not only high temporal resolution, but also a light source with a broad spectrum band is required. A Xe flash lamp is mentioned as a light source having a broad spectrum band. However, in measurement using a Xe flash lamp, the time resolution is limited to the nanosecond order. In this research, we have developed supercontinuum light as a light source that enables picosecond time resolution and has a broader spectrum band. In this paper, we developed a light source using an Er doped fiber laser for pulse radiolysis measurement, and report the results and future prospects here.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW036

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

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THPGW042

Applications of Compact Laser Plasma Accelerator (CLAPA) Beamline in Peking University

proton, laser, acceleration, plasma

3676

D.Y. Li, J.E. Chen, Y.X. Geng, X.Y. Hu, C.C. Li, Q. Liao, C. Lin, H.Y. Lu, W.J. Ma, M.J. Wu, X.H. Xu, X.Q. Yan, T. Yang, Y.Y. Zhao, J.G. Zhu, K. Zhu
PKU, Beijing, People’s Republic of China

Proton beam with energies less than 10 MeV, <1% energy spread, several to tens of pC charge can be stably produced and transported in Compact LAser Plasma Accelerator (CLAPA) at Peking University. The CLAPA beam line is an object-image point analysing system, which ensures the transmission efficiency and energy selection accuracy for proton beams with initial large divergence angle and energy spread. A spread-out Bragg peak (SOBP) is produced with high precision beam control, which is essential for cancer therapy. Other primary application experiments based on laser-accelerated proton beam have also been carried out, such as proton radiograph, stress testing for tungsten, irradiation of semi-conductor sensor to simulate the space irradiation environment and so on.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW042

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

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THPGW048

Temporal Characterization of Electron Bunches From Self-Injection and Ionization Injection in a Laser Wakefield Accelerator

injection, electron, laser, plasma

3693

J. Zhang, Y.X. He, J.F. Hua, D.X. Liu, W. Lu, Y. Ma, C.H. Pai, Y.P. Wu
TUB, Beijing, People’s Republic of China
Z. Nie, Q. Su
UCLA, Los Angeles, California, USA

Plasma based accelerators (PBAs) have a proven capability to generate high energy electron beams with ultrashort duration (~ 10 fs) and high peak current (~ 10 kA), which opens the opportunity for compact free electron lasers. To meet the requirements of such challenging applications, controllable injection is highly needed to produce high-quality and highly stable electron beams. As we know, the beam parameters，including the current profile, strongly depend on the injection process. To explore the underlying physics and optimize beam parameters in PBAs, a temporal characterization is highly required for different injection schemes. Based on coherent transition radiation(CTR) method, the preliminary experiment to measure beam temporal profiles from both self-injection and ionization injection schemes in a single-shot mode has been performed at Tsinghua University. And the simulations using the similar experimental parameters have been performed to interpret the different injection processes, which show some agreement with the experimental results, especially for the features of bunch durations

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

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THPGW051

MCP Based Detectors of European XFEL

FEL, detector, photon, electron

3703

E. Syresin, O.I. Brovko, A.Yu. Grebentsov
JINR, Dubna, Moscow Region, Russia
W. Freund, J. Grünert
EuXFEL, Schenefeld, Germany
M.V. Yurkov
DESY, Hamburg, Germany

Radiation detectors based on microchannel plates (MCP) are used for measurements of the SASE process of the European XFEL. Detectors operate in a wide dynamic range from the level of spontaneous emission to the saturation level (between a few nJ and 25 mJ) and in a wide wavelength range from 0.05 nm to 0.4 nm for SASE1 and SASE2 and from 0.4 nm to 4.43 nm for SASE3. Photon pulse energies are measured by the MCPs with an anode and by a photodiode. The MCP imager measures the photon beam image with a phosphor screen. Three MCP detectors are installed, one behind each SASE undulator (SASE1, SASE2, and SASE3). Calibration and first experiments with the MCP detectors are under discussion.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW051

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

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THPGW058

Design and Study of a 6 Degree-Of-Freedom Universal Adjustment Platform for HL-LHC Components

alignment, operation, ECR, target

3720

M. Sosin, T. Blaszczyk, A. Herty, J. Jaros, H. Mainaud Durand
CERN, Meyrin, Switzerland

In the accelerator domain, the safe and easy alignment of components located in radioactive areas, is a main concern. The position of devices, such as magnets and collimators, has to be adjusted in a fast and ergonomic way to decrease the ionizing dose received by the personnel. Each equipment type has its own unique set of requirements such as the weight, or the desired position accuracy. The two opposite approaches are, on one hand, a simple and time-consuming manual adjustment, using regulating screws and shims, and, on the other hand, the use of precise and expensive automatic positioning stages and platforms. In the frame of the High Luminosity LHC project, in order to fulfill the safety and technical requirements of alignment for lightweight components, a standardized system is under development. It will provide easy, low-cost and fast adjustment capability for several types of components that could be embarked on it. This paper describes the design, the study and the test results of such a universal adjustment solution. The engineering approach, the lessons learned, the issues and the mechanical components behavior are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW058

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

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THPGW062

The New CERN East Area Primary and Secondary Beams

target, secondary-beams, optics, proton

3730

E. Montbarbon, D. Banerjee, J. Bernhard, D. Brethoux, M. Brugger, B.D. Carlsen, N. Charitonidis, A. Ebn Rahmoun, S. Evrard, L. Gatignon, A. Gerbershagen, E. Harrouch, M. Lazzaroni, B. Rae, M.S. Rosenthal, M.W.U. Van Dijk
CERN, Geneva, Switzerland

The East Area is one of the intensely used facilities at CERN, now serving for over 56 years beams to more than 20 user teams and experiments for about 200 days of running each year. Besides primary proton and ion beams for the irradiation facilities IRRAD and CHARM, mixed secondary beams of hadrons, electrons and muons within a range of 0.5 GeV/c to 12 GeV/c are provided. The CERN management approved an upgrade and renovation of the full facility to meet reliably future beam test and physics requirements. We present new, flexible beam optics that will assure better purity of the secondary beams, even with the new possibility of highly pure electron, hadron or muon beams. The upgrade also includes a pulsed powering scheme with energy recovering power supplies and new laminated magnets that will reduce both power and cooling requirements. The renovation phase started already and first beams in the new facility will be delivered from 2021 on.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW062

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paper received ※ 03 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPGW063

The "Physics Beyond Colliders" Projects for the CERN M2 Beam

experiment, optics, hadron, detector

3734

D. Banerjee, J. Bernhard, M. Brugger, N. Charitonidis, L. Gatignon, A. Gerbershagen, E. Montbarbon, B. Rae, M.S. Rosenthal, M.W.U. Van Dijk, B. Veit, V. de Jesus
CERN, Geneva, Switzerland
S. Cholak
Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
G. D’Alessandro
JAI, Egham, Surrey, United Kingdom

Physics Beyond Colliders is an exploratory study aimed at exploiting the full scientiﬁc potential of CERN’s accelerator complex up to 2040 and its scientiﬁc infrastructure through projects complementary to the existing and possible future colliders. Within the Conventional Beam Working Group (CBWG), several pro-jects for the M2 beam line in the CERN North Area were proposed, such as a successor for the COMPASS experiment, a muon programme for NA64 dark sector physics, and the MuonE proposal aiming at investigating the hadronic contribution to the vacuum polarisation. We present integration and beam optics studies for 100-160 GeV/c muon beams as well as an outlook for improvements on hadron beams, which include RF-separated options and low-energy antiproton beams and radiation studies for high intensity beams. In addition, necessary beam instrumentation upgrades for beam particle identiﬁcation and momentum measurements are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW063

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

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THPGW070

Design of the Cockcroft Beamline: Adjustable Transport of Laser Wakefield Electrons to an Undulator

undulator, electron, laser, plasma

3749

K.A. Dewhurst, H.L. Owen
UMAN, Manchester, United Kingdom
E. Brunetti, D.A. Jaroszynski, S.M. Wiggins
USTRAT/SUPA, Glasgow, United Kingdom
B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
M.J. de Loos, S.B. van der Geer
Pulsar Physics, Eindhoven, The Netherlands

Funding: Work supported by U.K. STFC (Grant No. ST/G008248/1), EuPRAXIA (Grant No. 653782), ECs LASERLAB-EUROPE (Grant No. 654148), U.K. EPSRC (Grant No. EP/J018171/1, EP/J500094/1 and EP/N028694/1).
The Cockcroft Beamline is being designed to transport 1 GeV electrons from a laser wakefield accelerator (LWFA) to an undulator at the Scottish Centre for the Application of Plasma-based Accelerators (SCAPA) in Glasgow, UK. To demonstrate undulator radiation in the X-ray spectral region and potentially free electron laser (FEL) gain, electrons should be transported between the LWFA and the undulators with high fidelity. In this paper we present the design of an adjustable beam line to transport LWFA electrons to the undulator for a range of energies, from 0.5 GeV to 1 GeV, while preserving the electron beam properties and matching the undulator-beam coupling.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW070

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

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THPGW071

Genetic Optimisation of Beamline Design for DIAMOND

synchrotron, framework, photon, experiment

3753

F. Bakkali Taheri, M. Apollonio, R. Bartolini, B. Singh
DLS, Oxfordshire, United Kingdom
R. Bartolini, J. Li
JAI, Oxford, United Kingdom
R. Bartolini
Oxford University, Physics Department, Oxford, Oxon, United Kingdom

The problem of optimisation of beamline structures is studied, from the point of view of multi-objective genetic algorithms. While this approach has been successfully used in the exploration of potential particle accelerator lattices, it has never been applied to beamline design. In this paper, the Non-Dominated Sorting Genetic Algorithm II (NGSA II) is used to optimize a structure where photons are assumed to propagate through the optical elements according to the wavefront model as implemented in SRW. It is shown that appropriate objective functions can help to set up an interesting set of parameters, with competitive computational resources compared to the traditional approach. Examples illustrating this optimization method are shown in the context of DIAMOND.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPGW071

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

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THPRB030

Novel FPGA-based Instrumentation for Personnel Safety Systems in Particle Accelerator Facility

FPGA, controls, monitoring, operation

3872

S. Pioli, M. Belli, M.M. Beretta, B. Buonomo, P. Ciambrone, D.G.C. Di Giulio, O. Frasciello, A. Variola
INFN/LNF, Frascati, Italy
P. Valente
INFN-Roma, Roma, Italy

Personnel safety system for particle accelerator facility involves different devices to monitor gates, shielding doors, dosimetry stations, search and emergency buttons. In order to achieve the proper reliability, fail-safe and fail-proof capabilities, these systems are developed compliant with safety standards (like the IEC-61508 on ’Functional Safety’, ANSI N43.1 ’Radiation Safety for the design and operation of Particle Accelerator’ and NCRP report 88) involving stable technologies like electro-mechnaical relays and, recently, PLC. As part of the Singularity project at Frascati National Laboratories of INFN, this work will report benchmark of a new FPGA-based system from the design to the validation phase of the prototype currently operating as personnel safety system at the Beam Test Facility (BTF) of Dafne facility. This novel instrument is capable of: devices monitoring in real-time at 1 kHz, dual modular redundancy, fail-safe and fail-proof, multi-node distributed solution on optical link, radiation damage resistance and compliant with IEC-61508, ANSI N43.1 and NCRP report 88. The aim of this FPGA-based system is to illustrate the feasibility of FPGA technology in the field of personnel safety for particle accelerator in order to take advantage of a fully digital system integrated with facility control system, evaluate the related reliability and availability and realize a standard, scalable and flexible hardware solution also for other fields with similar requirements like machine protection systems.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB030

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

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THPRB053

Upgrade of the Historical Data Query and Analysis System for HLS-II

database, status, real-time, operation

3928

Z.Y. Xie, C. Li, G. Liu, Z.X. Shao, Y. Song, J.G. Wang, K. Xuan
USTC/NSRL, Hefei, Anhui, People’s Republic of China

The current historical data query and analysis system for the Hefei Light Source II (HLS-II) was developed with Apache Struts2. However, Apache Struts2 need to be fixed from time to time to avoid being attacked. Therefore, a new system based on Spring Boot and Vue.js is developed. Meanwhile, the performance of the system is optimized, and the radiation monitor module is added. This paper will detail the system architecture and software implementation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB053

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

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THPRB059

Radiation Safety at SOLARIS 1.5 GeV Storage Ring

storage-ring, injection, electron, MMI

3940

M.B. Jaglarz
SOLARIS, Kraków, Poland
A.I. Wawrzyniak, J. Wikłacz
Solaris National Synchrotron Radiation Centre, Jagiellonian University, Kraków, Poland

Radiation measurements at Solaris are continuously performed by using 9 radiation monitor stations (RMS) located around the storage ring and the beamlines area. 4 of RMS are connected to the Personal Safety System and in case of exceeding alarm level dump the beam or close safety shutters. Moreover thermoluminescence dosimeters (TLDs) are used to registered doses in the classified areas according to the Polish regulation. Measurements are performed since 2015 when the commissioning of the storage ring has started. Since that time several improvements to the radiation shielding was done to fulfill the ALARA principle. Moreover the electron beam optimizations during the injection, ramping and operation were performed to decrease the electrons losses and the radiation level. This presentation will report on radiation measurements results obtained before and after the chopper installation. Additionally problems with radiation level while the beam current is increasing to the designed 500mA value will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB059

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

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THPRB083

Detailed Analysis Of The Baseline Dose Levels And Localized Radiation Spikes In The Arc Sections Of The Large Hadron Collider During Run 2

operation, experiment, ECR, monitoring

4009

K. Bilko, M. Brugger, R. Garcia Alia, F.J. Harden, Y. Kadi, O. Stein
CERN, Geneva, Switzerland

The Large Hadron Collider (LHC) has eight insertion regions (IRs) which house the large experiments or accelerator equipment. These IRs are interconnected with the arc sections consisting of a periodic magnet structure. During the operation of the LHC small amounts of the beam particles are lost, creating prompt radiation fields in the accelerator tunnels and the adjacent caverns. One of the main loss mechanisms in the LHC arc sections is the interaction of the beam particles with the residual gas molecules. The analysis of the dose levels based on the beam loss measurement data shows that the majority of the measurements have similar levels, which allow to define baseline values for each arc section. The baseline levels decreased during the years 2015, 2016 and stabilised in 2017 and 2018 at annual dose levels below 50 mGy, which can be correlated with the residual gas densities in the LHC arcs. In some location of the arcs radiation spikes exceed the base line by more than two orders of magnitude. In addition to the analysis of these dose levels, a novel approach of identifying local dose maxima and the main driving mechanisms creating these radiation spikes will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB083

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

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THPRB084

Run 2 Prompt Dose Distribution and Evolution at the Large Hadron Collider and Implications for Future Accelerator Operation

operation, collimation, proton, luminosity

4013

O. Stein, K. Bilko, M. Brugger, R. Garcia Alia, F.J. Harden, Y. Kadi, A. Lechner, G. Lerner
CERN, Geneva, Switzerland

During the operation of the Large Hadron Collider (LHC) small fractions of beam particles are lost, creating prompt radiation fields in the accelerator tunnels. Exposed electronics and accelerator components show lifetime degradation and stochastic Single Event Effects (SEEs) which can lead to faults and downtime of the LHC. Close to the experiments the radiation levels scale nicely with the integrated luminosity since the luminosity debris is the major contributor for creating the radiation fields in this area of the LHC. In the collimation regions it was expected that the radiation fields scale with the integrated beam intensities since the beams are continuously cleaned from particles which exceed the accelerator’s acceptance. The analysis of radiation data shows that the dose measurements in the collimation regions normalised with the integrated beam intensities for 2016 and 2017 are comparable. Against expectations, the intensity normalised radiation datasets of 2018 in these regions differ significantly from the previous years. Especially in the betatron collimation region the radiation levels are up to a factor 3 higher. The radiation levels in the collimation regions correlate with the levelling of beta-star and the crossing angle in the high luminosity experiments ATLAS and CMS. These increased normalised doses have direct implications on the expected dose levels during future LHC operation, including the High-Luminosity LHC (HL-LHC) upgrade.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB084

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

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THPRB085

HiRadMat: A Facility Beyond the Realms of Materials Testing

proton, experiment, target, instrumentation

4016

F.J. Harden, A. Bouvard, N. Charitonidis, Y. Kadi
CERN, Geneva, Switzerland

The ever-expanding requirements of high-power targets and accelerator equipment has highlighted the need for facilities capable of accommodating experiments with a diverse range of objectives. HiRadMat, a High Radiation to Materials testing facility at CERN has, throughout operation, established itself as a global user facility capable of going beyond its initial design goals. Pulsed high energy, high intensity, proton beams have been delivered to experiments ranging from materials testing, detector’s prototype validation, radiation to electronics assessment and beam instrumentation. A 440 GeV/c proton beam is provided directly from the CERN SPS. Up to 288 bunches/pulse at a maximum pulse intensity of 3.5 x 10¹³ protons/pulse can be delivered. Through collaborative efforts, HiRadMat has developed into a state-of-the-art facility with improved in situ measurement routines, beam diagnostic systems and data acquisition techniques, offered to all users. This contribution summarises the recent experimental achievements, highlights previous facility enhancements and discusses potential future upgrades with particular focus on HiRadMat as a facility open to novel experiments.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB085

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

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THPRB086

Design & Optimization of the Alignment Supports for the New Laminated Magnets for the CERN East Area Consolidation Project

alignment, operation, GUI, secondary-beams

4020

R. Vanhoutte, D. Brethoux, A. Ebn Rahmoun, S. Evrard, F.J. Harden, E. Harrouch, M. Lazzaroni, M. Lino Diogo dos Santos, R. Lopez, D.E. Nogtikov, J. Renedo Anglada
CERN, Meyrin, Switzerland

The East Area is one of CERNs experimental area, running since its foundation in 1958. Extracting a 24GeV proton beam from the Proton Synchrotron accelerator, the primary beam is divided into different secondary beams, serving various experiments and user’s facilities such as CLOUD, CHARM, IRRAD. Due to improved optics and an energy saving scheme, the facility will go under a renovation between 2019 and 2020, including the replacement of the magnets with new laminated ones to allow a cycled powering scheme. Those magnets need improved supports, and in some cases even a new design, to optimize the alignment operations in those areas. This article will mainly address the different proposed solutions for plug-in supports as well as for conventional ones.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB086

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

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THPRB087

Study of the Energy Savings Resulting from the East Area Renovation

ECR, experiment, operation, power-supply

4023

B.LM. Lamaille, F. Dragoni, S. Evrard, F.J. Harden, E. Harrouch, M. Lazzaroni, R. Lopez, K.D. Papastergiou
CERN, Meyrin, Switzerland

CERN’s East Experimental Area, situated on the Swiss side of the Meyrin site, with its four beamlines, has served physics for more than 40 years. As the building and equipment are reaching their end of life, a thorough consolidation project has been initiated in order to pro-vide many more years of reliable operation. This article addresses the different proposed solutions to reduce significantly the energy consumption of the East Area. It outlines the methodology applied to estimate as precisely as possible the future attained energy savings, which will result in an estimated reduction of approximately 80% in electricity usage (from 11 GWh to 2 GWh per year) and of approximately 65% in gas usage for heating purpose (from 3 GWh to 1 GWh per year).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB087

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

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THPRB088

Optimizing The Reliability of The Fire Alarm System in The Taiwan Photon Source

detector, controls, shielding, storage-ring

4026

W.S. Chan, F.-D. Chang, C.S. Chen, Y.F. Chiu, J.C. Liu, Z.-D. Tsai
NSRRC, Hsinchu, Taiwan

The fire alarm system plays a critical role for the safety of building occupants. However, in the past two years from 2016 to 2017, occasionally false alarms at the Taiwan Photon Source (TPS) occurred. Results of more detailed observations indicated that radiation and/or electromagnetic interference (EMI) of the TPS accelerator disturb smoke detectors and signal line circuits (SLCs). Lead shielding covers, adjusting of the detector alarm verification time and a laser-based aspi-rating smoke detector were used to reduce the probabil-ity that fire alarms become activated to less than 0.5 times per year.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB088

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

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THPRB098

FETS Personnel & Machine Interlock Systems

controls, timing, ion-source, status

4057

J.H. Macgregor
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The Front End Test Stand (FETS) [1] is a high energy pulsed proton driver that aims to produce a perfectly chopped 50 Hz, 60 mA, 2 ms H’ beam. FETS consists of a Penning Ion source, Low Energy Beam Transport (LEBT), 4 m long bolted construction 324 MHz four vane Radio Frequency Quadrupole (RFQ). The H’ Beam will be perfectly chopped so that bunches of particles can be trapped and accelerated with very low loss into a circular accelerator. To protect personnel from X-ray radiation along with prompt neutrons & gamma radiation, a concrete block-house has been built around the facility and a personnel interlock and search system developed. This paper discusses the mechanical and electrical systems used to ensure personnel safety via the Personnel Protection System (PPS) and machine safety by use of a Programmable Logic Controller, (PLC), used as the Machine Interlock Systems.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB098

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paper received ※ 09 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPRB118

Study on the Influence of the Range Shifter Material in a Scanning Nozzle for Proton Therapy Based on Monte Carlo Method

proton, neutron, ECR, scattering

4100

Y.C. Yu, H.D. Guo, Y.Y. Hu, X.Y. Li, Y.J. Lin, P. Tan, X.D. Tu, L.G. Zhang
HUST, Wuhan, People’s Republic of China

Range shifter plays a key role in decreasing the energy of the proton beam to realize shallow tumours treatment with the scanning nozzle in Huazhong University of Science and Technology Proton Therapy Facility (HUST-PTF). To control the transverse scattering and decrease the damage to healthy tissue caused by secondary particle, influence of the range shifter material was studied. In this paper, the Monte Carlo software Geant4 and FLUKA are applied to analyse the transport process of proton beam in the range shifters made of six different materials: PMMA, Lexan, Lucite, Polyethylene, Polystyrene, and Wax. The beam spot sizes at the iso-center with or without range shifter was calculated for the HUST-PTF scanning nozzle. The relationship between the thickness of the range shifters of the six materials and the proton energy was obtained. The secondary neutron yield at the end of the nozzle was also analysed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB118

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

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THPTS036

Quench Detection and Diagnostic Systems for the Superconducting Circuits for the HL-LHC

dipole, luminosity, data-acquisition, electronics

4183

R. Denz, D.O. Calcoen, E. De Matteis, V. Froidbise, S. Georgakakis, S. Haas, S. Mundra, T. Podzorny, A.P. Siemko, J. Spasic, J. Steckert
CERN, Geneva, Switzerland
D. Blasco Serrano
CIEMAT, Madrid, Spain

The High Luminosity LHC project (HL-LHC) will incorporate a new generation of superconducting elements such as high field superconducting magnets based on Nb₃Sn conductors and MgB₂ based high temperature superconducting links for magnet powering. In addition, the HL-LHC will also feature new generations of NbTi based magnets. The proper protection and diagnostics of those elements require the development of a new generation of integrated quench detection and data acquisition systems as well as novel methods for quench detection. The next generation of quench detection systems is to a large extent software defined and serves at the same time as high performance data acquisition system. The contribution will discuss the specific needs of HL-LHC in terms of quench detection and present recent results from tests with prototype magnets. The contribution will show the implementation of new quench detection methods such as current derivative sensors. Measures for increasing the system dependability and easing its maintenance will be explained, as well as the improved supervision architecture using Ethernet based field-bus systems for fast data transmission.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS036

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paper received ※ 07 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPTS046

The Limited B-Field Integral of Superconducting Longitudinal Gradient Bend Magnet

simulation, emittance, storage-ring, synchrotron-radiation

4213

C. Chen, L. Wang, H.R. Zhang, T. Zhang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

The National Synchrotron Radiation Laboratory (NSRL) is planning a fourth generation diffraction-limited light source–Hefei Advanced Light Source (HALS), it is based on a seven-bend achromat lattice providing an ultralow natural emittance of 34 pm rad. The emittance can be even lower with the use of longitudinal gradient bends (LGBs) and anti-bends (ABs). The designed energy for HALS is 2.4 GeV, superconducting LGB might be employed instead of normal bending magnet since it can improve radiated beam critical energy to hard x-ray regions without using up any straight sections. To get a peak field about 6 T and small B-field profile full width half maximum, SLS-2 type LGB is considered. In this paper, the limited B-field integral (along the beam path) is trying to be find with some restrictions.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS046

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

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THPTS067

Characterisation of the Radiation Hardness of Cryogenic Bypass Diodes for the HL-LHC Inner Triplet Quadrupole Circuit

neutron, experiment, quadrupole, luminosity

4268

D. Wollmann, C. Cangialosi, C. Cangialosi, F. Cerutti, G. D’Angelo, S. Danzeca, R. Denz, M. Favre, R. Garcia Alia, D. Hagedorn, A. Infantino, G. Kirby, L. Kistrup, T. Koettig, J. Lendaro, B. Lindstrom, A. Monteuuis, F. Rodriguez-Mateos, A.P. Siemko, K. Stachon, A. Tsinganis, M. Valette, A.P. Verweij, A. Will
CERN, Meyrin, Switzerland
A. Bernhard, A.-S. Müller
KIT, Karlsruhe, Germany

Funding: Work supported by the HL-LHC Project.
The powering layout of the new HL-LHC Nb₃Sn triplet circuits is the use of cryogenic bypass diodes, where the diodes are located inside an extension to the magnet cryostat, operated in superfluid helium and exposed to radiation. Therefore, the radiation hardness of different type of bypass diodes has been tested at low temperatures in CERN’s CHARM irradiation facility during the operational year 2018. The forward characteristics, the turn on voltage and the reverse blocking voltage of each diode were measured weekly at 4.2 K and 77 K, respectively, as a function of the accumulated radiation dose. The diodes were submitted to a dose close to 12 kGy and a 1 MeV equivalent neutron fluence of 2.2x10¹⁴,n/cm². After the end of the irradiation campaign the annealing behaviour of the diodes was tested by increasing the temperature slowly to 300 K. This paper describes the experimental setup, the measurement procedure and discusses the results of the measurements.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS067

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

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THPTS073

Radiation Damage to Undulator Electronics at an Electron Accelerator

electron, electronics, photon, neutron

4285

T.Y. Chung, C.-H. Chang, A.Y. Chen, Y.W. Chen, J.C. Huang, J.C. Jan
NSRRC, Hsinchu, Taiwan

Experience gained from commissioning and operation of three elliptical polarization undulators (EPU) at the TPS taught us that undulator driving systems can behave erratically following a beam dump or loss. In this work, we discuss possible harmful radiation sources in a storage ring and analyse the effect of lack of electronic component radiation resistance in the system. According to measurements of spatial radiation distribution at the TPS, we propose solutions and an improved design for Phase-II EPUs.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS073

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

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THPTS077

Beam Instability Induced by RF System of an FEL-THZ Source

electron, FEL, linac, target

4298

X.D. Tu, G. Feng, S.J. He, T. Hu, J. Jiang, S.Y. Lu, Y.Q. Xiong
HUST, Wuhan, People’s Republic of China

An SLAC-like Compact Linac installed on the HUST FEL-THz has been used as an injector to produce high power THz radiation. To meet the requirements of monochromaticity and repeatability for FEL, performance of electron beam and stability of RF system are notable. According to the existing facility, based on measurement results of RF jitter, instability of beam has been calculated, and it has been verified in relevant experiments. Furthermore, stability targets in RF system has been pro-posed in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS077

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paper received ※ 14 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, vacuum, synchrotron, 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.

DOI •

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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FRXXPLS3

Application of a Phase Space Beam Position and Size Monitor for Synchrotron Radiation

electron, synchrotron, detector, synchrotron-radiation

4376

N. Samadi
University of Saskatchewan, Saskatoon, Canada
L.D. Chapman, L.O. Dallin
CLS, Saskatoon, Saskatchewan, Canada
X. Shi
ANL, Argonne, Illinois, USA

We will report on a system (ps-BPM) that can measure the electron source vertical position and angular motion along with the vertical source size and angular size at a single location in a synchrotron bend magnet beamline*. This system uses a combination of a monochromator and a filter with a K-edge to which the monochromator was tuned in energy. The vertical distribution of the beam with and without the filter was simultaneously visualized with an imaging detector. The small range of angles from the source onto the monochromator crystals creates an energy range that allows part of the beam to be below the K-edge and the other part above. Measurement of the beam vertical location without the absorber and edge vertical location with the absorber allowes measurement of the source position and angle. The beam width and edge width give information about the vertical electron source size and angular distribution. The ps-BPM measurements have been made where the electron beam size and angular distribution was adjusted using skew quads. The ps-BPM measurements correlate well with modeling of the ps-BPM system as well as conventional beam size measurements using a pinhole.
* A phase-space beam position monitor for synchrotron radiation. J Synchrotron Radiat, 2015. 22(4): p. 946-55.

Slides FRXXPLS3 [4.593 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-FRXXPLS3

About •

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

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