IPAC2017 - List of Keywords (experiment)

Paper	Title	Other Keywords	Page
MOYAA1	Approaching the Nominal Performance at the LHC	luminosity, operation, emittance, injection	13
	J. Wenninger CERN, Geneva, Switzerland
	In 2015 the Large Hadron Collider (LHC) restarted for Run 2 after an almost two year long shutdown to consolidate the machine for operation at nominal beam energy. Following a month of recommissioning and training of the magnet system, the LHC operated for the first time at an energy of 6.5 TeV. The aim of this first year was to master operation at the higher energy and with beams of 25 ns spacing. In 2016 the performance could be pushed based on the experience of 2015, culminating with a luminosity 40% above the design value of 10³⁴ cm^-2s⁻¹. The status of the machine operation, performance and prospects for the rest of Run 2 and Run 3 will be discussed.
	Slides MOYAA1 [4.639 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOYAA1
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MOOCB2	Laser System Design and Operation for SNS H⁻ Beam Laser Stripping	laser, operation, ion, neutron	57
	Y. Liu, A.V. Aleksandrov, S.M. Cousineau, T.V. Gorlov, A.A. Menshov, A. Webster ORNL, Oak Ridge, Tennessee, USA A. Rakhman ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: This work has been partially supported by U.S. DOE grant DE-FG02-13ER41967. ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE. Recently, a high-efficiency laser assisted hydrogen ion (H⁻) beam stripping was successfully carried out in the Spallation Neutron Source (SNS) accelerator. The experiment was not only an important step toward foil-less H⁻ stripping for charge exchange injection, it also served as a first example of using megawatt ultraviolet (UV) laser in an operational high power proton accelerator facility. This talk reports the design, implementation, and commissioning results of the macropulse laser system, laser transport line, and laser operation for the laser stripping experiment. The macropulse laser consists of a mode-locked picosecond pulsed seed laser and a burst-mode Nd:YAG laser amplifier. The general design concept can be adapted to any temporal beam structures in most accelerators. We have achieved UV pulses with the pulse widths varying between 34 to 54 ps and a maximum peak power over 3.5 MW. A laser transport line is installed to deliver the UV beam to the laser stripping chamber at a transmission efficiency of 70%. Laser operation including remote control and monitor of laser parameters will be described.
	Slides MOOCB2 [11.306 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOOCB2
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MOPAB005	The MultiMat Experiment at CERN HiRadMat Facility: Advanced Testing of Novel Materials and Instrumentation for HL-LHC Collimators	target, instrumentation, real-time, damping	76
	F. Carra, A. Bertarelli, E. Berthomé, C. Fichera, J. Guardia, M. Guinchard, L.K. Mettler, S. Redaelli, O. Sacristan De Frutos CERN, Geneva, Switzerland T.R. Furness University of Huddersfield, Huddersfield, United Kingdom M. Portelli UoM, Msida, Malta
	Funding: Part of the work described in this thesis was developed in the scope of the EuCARD-2 Project, WP11 'ColMat ' HDED', co-funded by the partners and the European Commission under Capacities 7th Framework Programme, Grant Agreement n. 312453. Research supported by the HL-LHC project. The increase of the stored beam energy in future particle accelerators, such as the HL-LHC and the FCC, calls for a radical upgrade in the design, materials and instrumentation of Beam Intercepting Devices (BID), such as collimators Following successful tests in 2015 that validated new composite materials and a novel jaw design conceived for the HL-LHC collimators, a new HiRadMat experiment, named 'HRMT36-MultiMat', is scheduled for autumn 2017. Its objective is to determine the behaviour under high intensity proton beams of a broad range of materials relevant for collimators and beam intercepting devices, thin-film coatings and advanced equipment. The test bench features 16 separate target stations, each hosting various specimens, allowing the exploration of complex phenomena such as dynamic strength, internal damping, nonlinearities due to anisotropic inelasticity and inhomogeneity, effects of energy deposition and radiation on coatings. This paper details the main technical solutions and engineering calculations for the design of the test bench and of the specimens, the candidate target materials and the instrumentation system #federico.carra@cern.ch*
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MOPAB024	Proposal to Observe Half-Bare Electrons on a 40-MeV LINAC	electron, radiation, laser, linac	126
	N. Delerue, S. Jenzer, V. Khodnevych, A. Migayron LAL, Orsay, France N.F. Shul'ga NSC/KIPT, Kharkov, Ukraine S. Trofymenko KhNU, Kharkov, Ukraine
	Funding: CNRS/IN2P3 and Joint Laboratory France-Ukraine IDEATE In different processes of relativistic electron interaction with substance and external fields, the electron loses part of its Coulomb field and becomes half-bare. Such state of electron significantly modifies the characteristics of its electromagnetic radiation during further interaction of the particle with substance. We propose to study the influence of the half-bare state of electron upon its transition radiation (TR). The existence of such influence for the case of electron undressing at its scattering was theoretically predicted. We intend to obtain the electrons in half-bare state in the result of their crossing of a conducting screen such as a TR screen. We propose to investigate the influence of the half-bare state of electron in this process upon TR generated by such electron on a downstream TR screen situated on some distance from the upstream screen which undresses the particle. Calculations are presented for the case of a 45-MeV linac and the distance between the screens in the region between 100 mm and 300 mm. The proposed experiment is expected to reveal new features of TR signal in such process comparing to previous measurements. N.F. Shul'ga, S.V. Trofymenko, V.V. Syshchenko, JETP Lett. 93 (2011) 1. Y. Shibata, K. Ishi, T. Tokahashi et al., Phys. Rev. E 49 (1994) 785.
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MOPAB025	Measurement of the Polarisation of Coherent Smith-Purcell Radiation in the SOLEIL Linac	radiation, polarization, detector, linac	129
	N. Delerue, S. Jenzer, V. Khodnevych LAL, Orsay, France N. Hubert, M. Labat, J.-P. Pollina, M.-A. Tordeux SOLEIL, Gif-sur-Yvette, France
	Funding: CNRS/IN2P3, Université Paris-Sud and ANR (contract ANR-12-JS05-0003-01) SPESO is an experiment installed in the Linac of Synchrotron SOLEIL to study the Coherent Smith-Purcell radiation produced when a grating is approached from the beam. The detectors used to measure this radiation are mounted on 3-translation axis and 2 rotation axis. This allows measurements of the radiation emission map around the grating. In addition a polarizer has been added in 2016 allowing to study the two polarization components of the radiation in this map. Preliminary results of this mapping will be presented.
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MOPAB044	X-Band TDS Project	electron, polarization, diagnostics, cavity	184
	B. Marchetti, R.W. Aßmann, B. Beutner, J. Branlard, F. Christie, R.T.P. D'Arcy, W. Decking, U. Dorda, J. Herrmann, M. Hoffmann, M. Hüning, O. Krebs, G. Kube, S. Lederer, F. Ludwig, F. Marutzky, D. Marx, J. Osterhoff, I. Peperkorn, S. Pfeiffer, F. Poblotzki, J. Rönsch-Schulenburg, J. Rothenburg, H. Schlarb, M. Scholz, S. Schreiber, M. Vogt, A. Wagner, T. Wilksen, K. Wittenburg DESY, Hamburg, Germany M. Bopp, H.-H. Braun, P. Craievich, M. Pedrozzi, E. Prat, S. Reiche, K. Rolli, R. Zennaro PSI, Villigen PSI, Switzerland N. Catalán Lasheras, A. Grudiev, G. McMonagle, W. Wuensch CERN, Geneva, Switzerland
	Based on the success of the X-Band Transverse Deflecting Structure (TDS) diagnostic at LCLS, a collaboration between DESY, PSI and CERN has formed with the aim of developing and building an advanced modular X-Band TDS system. The designed TDS has the new feature of providing variable polarization of the deflecting field. The possibility of changing the orientation of the streaking field of the TDS to an arbitrary azimuthal angle allows for 3D characterization of the phase space using tomographic methods. Moreover the complete 6D characterization of the beam phase space is possible by combining this technique with quadrupole scans and a dipole spectrometer. As this new cavity design requires very high manufacturing precision to guarantee highest azimuthal symmetry of the structure to avoid the deterioration of the polarization of the streaking field, the high precision tuning-free assembly procedures developed at PSI for the SwissFEL C-band accelerating structures will be used for the manufacturing*. The high-power rf system is based on the CERN-based X-band test stands. We summarize in this work the status of the projects and its main technical parameters. C. Behrens et al. , Nat. Comm. 4762 (2014). A. Grudiev, CLIC-note-1067 (2016). * D. Marx et al., contribution to this conference proceedings. **** U. Ellenberger et al., FEL 2013, TUPS017.
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MOPAB045	Reconstruction of the 3D Charge Distribution of an Electron Bunch Using a Novel Variable-Polarization Transverse Deflecting Structure (TDS)	simulation, electron, space-charge, laser	188
	D. Marx, R.W. Aßmann, U. Dorda, U. Dorda, B. Marchetti DESY, Hamburg, Germany P. Craievich PSI, Villigen PSI, Switzerland A. Grudiev, A. Grudiev, A. Grudiev CERN, Geneva, Switzerland
	A TDS is a well-known device for the characterization of the longitudinal properties of an electron bunch in a linear accelerator. So far, the correlation of the slice properties in the horizontal/vertical planes of the electron bunch distribution has been characterized by using a TDS system deflecting in the vertical/horizontal directions respectively and analysing the image on a subsequent screen. Recently, an innovative design for a TDS structure has been proposed, which includes the possibility of continuously varying the angle of the transverse streaking field inside a TDS structure. This allows the beam distribution to be characterized in all transverse directions. By collecting measurements of bunches streaked at different angles and combining them using tomographic techniques, it is possible to retrieve 3D distributions of the charge density. In this paper, a method is proposed and simulation results are presented to show the feasibility of such an approach at the upcoming accelerator R&D facility, SINBAD, at DESY*. M. Roehrs et al., Phys. Rev. ST Accel. Beams 12, 050704 (2009). A. Grudiev, Report No. CLIC-Note-1067, 2016. * B. Marchetti et al. X-band TDS project contribution to these conference proceedings.
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MOPAB067	Response of Scintillating Screens to High Charge Density Electron Beam	electron, quadrupole, linac, diagnostics	268
	F. Miyahara, S. Kishimoto, M. Satoh, Y. Seimiya, T. Suwada KEK, Ibaraki, Japan M. Koshimizu Tohoku University, School of Science, Sendai, Japan
	Inorganic scintillating screens are very useful tool to measure transverse profile of charged particle beams. The cerium-doped yttrium:aluminum:garnet (YAG:Ce) crystal scintillator is used in many accelerating facilities. The scintillating screen shows good resolution comparable to that of OTR screen. However, response to high charge density electron beam, more than 10 nC per square millimeter, has not been clarified. In KEK e⁺/e⁻ injector linac, the charge areal density (σ) will exceed 25 nC per square mm. Thus, beam tests has been performed on YAG:Ce, LYSO, and BGO crystals for 1.5 GeV, 1 nC/bunch electron beam at the linac. Saturation of the luminescence which causes degradation of the resolution has been observed above 1 nC per square mm in those crystals. We will report the response of the scintillating screens to high charge density electron beam and discuss the degradation of the resolution due to the saturation of the light yield.
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MOPAB072	Measurement of Three-Dimensional Distribution of Electron Bunch Using RF Transverse Deflector	electron, laser, gun, solenoid	285
	Y. Nakazato, Y. Koshiba, T. Sasaki, M. Washio Waseda University, Tokyo, Japan K. Sakaue Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan
	We have been studying a high quality electron beam generated by a photocathode RF gun at Waseda University. The electron beam is applied to a pulse radiolysis experiment, laser Compton scattering for soft X-ray generation, and a THz imaging experiment using coherent radiation. In these applications, longitudinal parameters of the electron beam are important. For this reason, we developed the RF deflector system which can directly convert longitudinal distribution of the beam to transverse with high temporal resolution, and performed longitudinal profile measurements of an electron beam from the RF gun. During a series of experiments using an RF deflector, we found that the bunch had a horizontal angle with respect to z axis. Thus we tried to reconstruct the three-dimensional profile of the bunch by computed tomography* in order to visualize the three-dimensional distribution of the bunch. In this conference, we will report the principle of measurement, experimental results of the bunch three-dimensional measurement, and future prospects. * J. Shi, et al., Reconstruction of the three-dimensional bunch profile by tomography technique with RF deflecting cavity, Nucl. Instrum. Methods Phys. Res., A 752 (2014) 36-41
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MOPAB074	Low Intensity Electron Beam Controlling and Monitoring	electron, detector, linac, controls	292
	L. Yu, Y. Li, Y.F. Sui, J.H. Yue IHEP, Beijing, People's Republic of China
	To calibrating a cosmic-ray detector, a low beam current accelerator has been built to generate ultra low intensity electron beams at Institute of High Energy Physics (IHEP). The minimum beam charge obtained was estimated to be about one electron/pulse. Beam commissioning has been carried out. The key technologies for achieving such low intensity electron beams are to control the beam using 8 movable slits and to measure the intensity of the beam using 9 movable current monitors based on scintillator. In this paper, principal of operation, instrumentation and programming of the movable slits and movable current monitors are discussed. Some results of beam commissioning are also presented.
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MOPAB077	Spatial Decoding Electro-Optic Bunch Measurement at Tsinghua Thomson Scattering X-ray Source	laser, electron, diagnostics, scattering	302
	W. Wang, Z.J. Chi, Y.-C. Du, W.-H. Huang, C.-X. Tang, L.X. Yan, Z. Zhang TUB, Beijing, People's Republic of China
	Electron bunches with duration of sub-picosecond are essential in ultraviolet and X-ray free electron laser (XFEL) to reach the desired peak current. Electro-optic (EO) technique is suitable for temporal profile measure-ment of these ultrashort bunches which is one of the key diagnostics in FELs. An electro-optic monitor based on spatial sampling has recently been designed and installed for bunch profile diagnostic at Tsinghua Thomson scat-tering X-ray source (TTX). An ultrashort laser pulse is used to detect the field induced birefringence of the bunch Coulomb field in an electro-optic crystal and the monitor allows direct time-resolved single-shot measure-ment of bunch profile with an accuracy of 135 femtosec-onds for a 40 MeV electron bunch in a non-destructive way, which can simultaneously record the relative time jitter between probe laser and electron bunch. This paper performs the layout of the setup and presents the current measurement results.
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MOPAB080	The Development of Tune Measurement System Based on FPGA at HLSII Storage Ring	FPGA, storage-ring, status, synchrotron	305
	Q.M. Duan, Y.L. Yang USTC/NSRL, Hefei, Anhui, People's Republic of China
	A tune measurement system based on FPGA development board is developed at HLS II. The FPGA development board based on Zynq SOC, have ADC and DAC on board. The FPGA can provide two kinds of signal for exciting the beam: parametric frequency sweep signal and bandwidth limited white noise signal. The FFT algorithms and calculation of tune are running in the ARM CPU. In order to compare performance with the original system which is based on spectrum analyzer, we did experiments with new system based FPGA and original system respectively. The experiments on HLSII storage ring show that the tune measuring accuracy have reached 0.0006 / 0.0001 in horizontal and vertical direction based on sweep frequency of FPGA-based system.
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MOPAB090	Wavefront Distortion Measurement at SSRF	simulation, radiation, synchrotron, synchrotron-radiation	332
	B. Gao, H.J. Chen, J. Chen, Y.B. Leng, K.R. Ye SINAP, Shanghai, People's Republic of China B. Gao University of Chinese Academy of Sciences, Beijing, People's Republic of China N. Zhang SSRF, Shanghai, People's Republic of China
	The Synchrotron Radiation Monitor (SRM) system has been designed and constructed at the Shanghai synchrotron radiation Facility (SSRF) for several years and runs good. However, the monitor extraction mirror deformation is quite common at different facilities, and other reflecting mirrors in the optic path also have surface error and angle error. As we decide to upgrade the SR monitor system at SSRF, this issue is also one of the most import thing what we should overcome. In order to verify the feasibility and evaluate the accuracy, simulations based on SRW code have been done. In this simulation, a dedicated algorithm was developed to reconstruct wavefront. The result and the algorithm is very useful for our experiment and upgrade program. In this paper, the algorithm and the experiments based on Shark-Hartmann wavefront sensor will be presented detailed.
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MOPAB091	Transverse Beam Instability Observation and Investigation Using Bunch by Bunch on-Line DAQ System	feedback, storage-ring, vacuum, data-acquisition	335
	N. Zhang, L.W. Lai, Y.B. Leng SSRF, Shanghai, People's Republic of China
	Funding: supported by National Natural Foundation of China (11375255 and 11375254) Tank impedance of in-vacuum insertion device is one important source of beam transverse instability, which was expected to be suppressed by transverse feedback system (TFB). For the observation and study of transverse instability affected by insertion device and TFB, sets of an in-vacuum undulator narrow gap setting and TFB gain setting were operated in a beam-based experiment. A bunch-by-bunch (BYB) position on-line DAQ system was employed in the measurement to characterize frequencies of individual bunches. Bunch-train transverse oscillation amplitude variation were curved by harmonic analysis. In this paper, we will introduce the BTB ADQ system, and report on the measurement experiment and related data analysis.
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MOPAB093	Bunch Phase Measurement for Storage Ring	storage-ring, simulation, injection, pick-up	341
	Y.M. Zhou, Y.B. Leng, N. Zhang SSRF, Shanghai, People's Republic of China H.J. Chen SINAP, Shanghai, People's Republic of China
	A bunch-by-bunch phase measurement system has been studied to improve the accuracy of phase measurement. Longitudinal phase information will be retrieved from beam signals picked up from the button electrodes. The signals from four electrodes in the BPM are summed by using a 4-way power driver, by which the effect of the transverse beam offset on the phase measurement can be eliminated. Four samples with fixed time interval (typical 100ps) for each bunch, which are taken by a 500MHz waveform recorder with a four channels signal splitting and delaying network, will be used to calculate bunch phase. In this paper, we present the layout of the system and primary experimental results.
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MOPAB095	Development of the Simulation Software Package for the CBPM System	simulation, cavity, network, FEL	349
	J. Chen, L.W. Lai, Y.B. Leng, L.Y. Yu SINAP, Shanghai, People's Republic of China N. Zhang SSRF, Shanghai, People's Republic of China
	In recent years, the development and construction of Free Electron Laser (FEL) facilities are in full swing. For FEL facilities, to generate coherent X-ray, cavity beam position monitor (CBPM) system which consist of cavity BPM, RF front-end and signal processor are employed to measure the transverse position in the undulator section. A generic simulation software package, with the S21 parameters of the real components, for the design of the RF front-end and the optimize of the CBPM system was developed. In this paper, the development of the generic simulation software package, and the experiment results with beam at Shanghai Deep ultraviolet (SDUV) FEL facility to verify the correctness of the simulation soft package will be introduced. The application in the design and optimize of the RF front-end for the Dalian Coherent Source (DCLS) will be addressed as well .
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MOPAB107	A Method for Determining the Roll Angle of the CLIC Accelerating Structures From the Beam Shape Downstream of the Structure	octupole, collider, simulation, emittance	368
	J. Ögren, V.G. Ziemann Uppsala University, Uppsala, Sweden W. Farabolini CEA/DSM/IRFU, France
	The Compact Linear Collider (CLIC) accelerating structures have a four-fold symmetry from the radial waveguides for damping higher order modes. This symmetry allows for an octupole component of the rf fields to co-propagate with the main accelerating field. The effect of this octupole mode has been observed at the CLIC test facility 3. In CLIC the accelerating structures are mounted together on a moveable girders. There are four vertical and four horizontal actuators on the girder, which allows for 5D control in a limited range and for instance we can roll the girder. By observing the beam shape perturbed by the octupole field on a screen downstream from the structure we can determine the roll angle and thus align the structure azimuthally. Here we discuss a possible method and show some preliminary results.
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MOPAB108	Beam-Based Alignment Studies at CTF3 Using the Octupole Component of CLIC Accelerating Structures	octupole, wakefield, alignment, collider	371
	J. Ögren, A.K. Bhattacharyya, M. Holz, R.J.M.Y. Ruber, V.G. Ziemann Uppsala University, Uppsala, Sweden W. Farabolini CEA/DSM/IRFU, France
	The Compact Linear Collider (CLIC) uses normal-conducting accelerating structures that are sensitive to wakefield effects and therefore their alignment is extremely important. Due to the four-fold symmetry of the structures, they allow for an octupole component of the rf fields. By scanning the beam transversely we can determine the center of the structures from the shifts in beam position due to the kicks from the octupole field. We present some initial results from measurements at the CLIC test facility 3 at CERN.
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MOPAB110	Comparison of Transverse Emittance Measurements in the LHC	emittance, luminosity, detector, operation	377
	M. Hostettler, R. Alemany-Fernández, F. Alessio, M. Ferro-Luzzi, K. Fuchsberger, G. Iadarola, R. Matev, S. Papadopoulou, Y. Papaphilippou, G. Papotti, G. Trad CERN, Geneva, Switzerland F. Antoniou The University of Liverpool, Liverpool, United Kingdom G.R. Coombs University of Glasgow, Glasgow, United Kingdom T.B. Hadavizadeh Oxford University, Physics Department, Oxford, Oxon, United Kingdom
	Transverse emittance measurement in a collider is of crucial importance for understanding beam dynamics observations and evaluating the machine performance. Devices measuring the beam emittance face the challenge of dealing with considerable systematic errors that can compromise the quality of the measurement. Having different instruments or techniques that provide beam size estimations in order to compare the outcome and give an unbiased value of the emittance is very important in a collider. The comparison of the different results is as well very useful to identify possible problems in a given equipment which could remain unnoticed if such device is the only source of emittance reconstruction. In the LHC several of these instruments and techniques are available; wire scanners, synchrotron light monitors, emittance reconstruction from transverse convolved beam sizes extracted from luminosity scans at the LHC collision points and from beam-gas imaging in the vertex detector of the LHCb experiment. Those systems are briefly presented in this paper together with the comparison of the emittances reconstructed by each of them during physics production over the 2016 LHC run.
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MOPAB128	The Design of a Non-Destructive Single-Shot Longitudinal Bunch Profile Monitor using Smith-Purcell Radiation	radiation, detector, background, polarization	433
	H. Harrison, G. Doucas, I.V. Konoplev, A.J. Lancaster, H. Zhang JAI, Oxford, United Kingdom A. Aryshev, M. Shevelev, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan
	Funding: This work was supported by the: the STFC UK, the Leverhulme Trust, the JAI (University of Oxford) and the Photon and Quantum Basic Research Coordinated Development (Japan). The conceptual design for a single-shot longitudinal bunch profile monitor using coherent Smith-Purcell radiation (cSPr) has recently been completed. The exploitation of the directionality and the polarization of cSPr to reduce the length of the monitor and to eliminate background radiation are discussed. The linear polarization of cSPr will be used to separate the signal from background radiation and experiments to test this design will be presented. Alongside the conceptual design an investigation to optimize the number of detection channels needed to produce high quality longitudinal bunch profile reconstructions has been carried out. It has been determined that the number of detection channels can be reduced compared to previous experiments if measurement uncertainty and background radiation are minimized effectively.
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MOPAB130	Cross-Calibration of the LHC Transverse Beam-Profile Monitors	emittance, optics, luminosity, proton	437
	R. Alemany-Fernández, F. Alessio, A. Alexopoulos, C. Barschel, F.S. Carlier, J.M. Coello de Portugal, M. Ferro-Luzzi, A. Garcia-Tabares, M. Hostettler, O. Karacheban, E.H. Maclean, R. Matev, T. Persson, P.K. Skowroński, R. Tomás, G. Trad, S. Vlachos, B. Würkner CERN, Geneva, Switzerland G.R. Coombs EPFL, Lausanne, Switzerland T.B. Hadavizadeh Oxford University, Physics Department, Oxford, Oxon, United Kingdom M. Hofer TU Vienna, Wien, Austria L. van Riesen-Haupt University of Oxford, Oxford, United Kingdom
	Calibration of a transverse beam profile monitor is of fundamental importance to guarantee the best possible accuracy and reliability of the instrument over time. In LHC the calibration standard for transverse-profile measurements are the wire scanners. Other profile monitors such as beam synchrotron light telescopes and interferometers are calibrated with respect to them. Additional information about single-bunch sizes can be obtained from beam-gas imaging in the LHCb vertex detector, from the transverse convolved beam sizes extracted from luminosity scans at the collision points, and from the evolution of the luminous-region parameters as reconstructed by ATLAS and CMS inner tracker detectors during such scans. For the first time in LHC, a dedicated cross-calibration of all the above-mentioned systems was carried out with beam in 2016. Additionally, dedicated optics measurements were also performed in order to determine with the highest possible accuracy the amplitude function at the interaction points and at the position of the profile monitors. Results of these measurements are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB130
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MOPAB131	Transverse Emittance Measurements Using LHCb's Beam-Gas Interactions	detector, emittance, real-time, operation	441
	T.B. Hadavizadeh Oxford University, Physics Department, Oxford, Oxon, United Kingdom R. Alemany-Fernández, F. Alessio, C. Barschel, G.R. Coombs, M. Ferro-Luzzi, R. Matev CERN, Geneva, Switzerland
	Measurements of the transverse beam emittance are of great importance at particle accelerators such as the LHC in order to monitor, understand and improve the performance of the machine. A number of profile monitors at the LHC are capable of measuring the transverse emittance from a range of different processes including wire scanners and beam synchrotron light monitors, each having advantages and shortcomings. It is possible additionally to measure the beam profiles using interaction vertices reconstructed in LHCb's vertex locator (Velo). Interactions between colliding beam particles and between beam particles and residual gas nuclei are used to build up a picture of the beam profiles. To guarantee the reliability and quality of the different emittance measurements, a dedicated cross-calibration was performed during a machine development period in October 2016. The results obtained with the LHCb Velo during this cross-calibration are presented here.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB131
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MOPAB139	A Supersonic Gas-Jet Based Beam Induced Fluorescence Prototype Monitor for Transverse Profile Determination	electron, ion, photon, gun	458
	H.D. Zhang, E. Martin, V. Tzoganis, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom E. Barrios Diaz, N. Chritin, O.R. Jones, G. Schneider, R. Veness CERN, Geneva, Switzerland P. Forck, S. Udrea GSI, Darmstadt, Germany P. Forck IAP, Frankfurt am Main, Germany E. Martin, V. Tzoganis, C.P. Welsch, H.D. Zhang The University of Liverpool, Liverpool, United Kingdom S. Udrea TU Darmstadt, Darmstadt, Germany
	Supersonic gas jets have been used in transverse beam profile monitoring as Ionization Profile Monitors (IPMs) and Beam Induced Fluorescence (BIF) monitors. The former method images ions generated by the projectile beam, whilst the latter is based on the detection of photons. This is a promising technology for use in high energy accelerators, such as the High Luminosity Large Hadron Collider (HLLHC). In this paper, the suitability of a supersonic gas jet in combination with a BIF detection system for the measurement of the transverse beam profile of a low energy electron beam is discussed. The technical layout and experimental results from measurements at a test installation at the Cockcroft Institute are also presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB139
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MOPAB140	Phase-Space Analysis Using Tomography for the Muon g-2 Experiment at Fermilab	proton, target, storage-ring, quadrupole	462
	D. Stratakis Fermilab, Batavia, Illinois, USA
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy. In the next decade the Fermilab Muon Campus will host two world class experiments dedicated to the search for signals of new physics. The Muon g-2 experiment will determine with unprecedented precision the anomalous magnetic moment of the muon. The Mu2e experiment will improve by four orders of magnitude the sensitivity on the search for the as-yet unobserved Charged Lepton Flavor Violation process of a neutrinoless conversion of a muon to an electron. Maintaining and preserving a high density of particles in phase-space is an important requirement for both experiments. This paper presents a new experimental method for mapping the transverse phase space of a particle beam based on tomographic principles. We simulate our technique using the tracking code GEANT4, to ascertain accuracy of the reconstruction. Then we apply the technique to a series of proof-of-principle simulation tests to study injection, transport and extraction of muon and proton beams for the Fermilab g-2 and Mu2e Experiments.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB140
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MOPAB141	Instrumentation and Its Interaction With the Secondary Beam for the Fermilab Muon Campus	ion, simulation, vacuum, emittance	466
	D. Stratakis, B.E. Drendel, M.J. Syphers Fermilab, Batavia, Illinois, USA M.J. Syphers Northern Illinois University, DeKalb, Illinois, USA
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy. The Fermilab Muon Campus will host the Muon g-2 experiment - a world class experiment dedicated to the search for signals of new physics. Strict demands are placed on the beam diagnostics in order to ensure delivery of high quality beams to the storage ring with minimal losses. In this study, we briefly describe the available secondary beam diagnostics for the Fermilab Muon Campus. Then, with the aid of numerical simulations we detail their interaction with the secondary beam. Finally, we compare our results against theoretical findings.
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MOPAB150	Imaging the Spatial Modulation of a Relativistic Electron Beam	electron, scattering, quadrupole, emittance	480
	C. Zhang, W.S. Graves, L.E. Malin, J. Spence Arizona State University, Tempe, USA D.B. Cesar, J.M. Maxson, P. Musumeci, A. Urbanowicz UCLA, Los Angeles, USA C. Limborg, E.A. Nanni SLAC, Menlo Park, California, USA
	Funding: Work supported by NSF awards 1632780, 1415583, 1231306 and DOE award de-sc0009914 We describe Bragg diffraction of relativistic electron beams through a patterned Si crystal consisting of alternating thick and thin strips to produce nanometer scale electron density modulations. Multi-slice simulations show that a two-beam situation can be set up where, for a particular thickness of Si, nearly 100% of the electron beam is diffracted. Plans are underway to carry out experiments showing this effect in UCLA's ultrafast electron microscopy lab with 3.5 MeV electrons. We will select either the diffracted beam or the primary beam with a small aperture in the diffraction plane of a magnetic lens, and so record either the dark or bright field magnified image of the strips. Our first goal is to observe the nanopatterned beam at the image plane. We will then investigate various crystal thickness and sample orientations to maximize the contrast in the pattern and explore tuning the period of the modulation through varying magnification.
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MOPAB153	R&D of a Gas-Filled RF Beam Profile Monitor for Intense Neutrino Beam Experiments	cavity, plasma, electron, ion	491
	K. Yonehara, M. Backfish, A. Moretti, A.V. Tollestrup, A.C. Watts, R.M. Zwaska Fermilab, Batavia, Illinois, USA R.J. Abrams, M.A. Cummings, A. Dudas, R.P. Johnson, G.M. Kazakevich, M.L. Neubauer Muons, Inc, Illinois, USA Q. Liu Case Western Reserve University, Cleveland, USA
	Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359 and DOE STTR Grant, No. DE-SC0013764. A MW-power beam facility is desired to produce an intense neutrino beam for study of fundamental particle physics. It is a critical challenge to measure beam profile in extreme radiation environments. To this end, a novel beam profile monitor based on a gas-filled multi-RF cavity is proposed. Charged particles through the gas-filled RF generate plasma that changes the gas permittivity. The modulated RF signal in the cavity due to the permittivity shift will be measured to reconstruct the flux of charged particles in the cavity. The demonstration is proposed to validate the concept of the monitor. We report the progress of the demonstration test.
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MOPIK006	Characterization of the Electron Beam from the Thz Driven Gun for AXSIS	electron, gun, simulation, diagnostics	509
	G. Vashchenko, R.W. Aßmann, U. Dorda, K. Galaydych, B. Marchetti, T. Vinatier DESY, Hamburg, Germany M. Fakhari, A. Fallahi, F.X. Kärtner, N.H. Matlis CFEL, Hamburg, Germany W. Qiao, C. Zhou University of Hamburg, Hamburg, Germany
	Funding: The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement n. 609920 The AXSIS (Attosecond X-ray Science: Imaging and Spectroscopy) project aims for development of a compact, fully coherent, THz-driven, attosecond X-ray source. A compact THz driven gun was developed, produced and tested as a source of the ultra-short electron bunches required for the project. To characterize the low energy, low-charge beam produced by such a gun tailored diagnostic devices were developed and commissioned at a test-stand chamber in CFEL (DESY). Results of the first experiments on the production and characterization of the electron beam are presented.
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MOPIK009	Characterization of Cold Model Cavity for Cryocooled C-Band 2.6-Cell Photocathode RF Gun at 20 K	cavity, gun, cryogenics, simulation	518
	T. Tanaka, K. Hayakawa, Y. Hayakawa, K. Nakao, K. Nogami, T. Sakai, K. Takatsuka LEBRA, Funabashi, Japan M.K. Fukuda, D. Satoh, T. Takatomi, N. Terunuma, J. Urakawa, M. Yoshida KEK, Ibaraki, Japan
	Funding: This work was partly supported by the Photon and Quantum Basic Research Coordinated Development Program of the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT). A cryocooled C-band 2.6-cell photocathode RF electron gun has been studied at Nihon University in cooperation with KEK. The cold model cavity with an input coupler was completed in spring 2016. The RF characteristics measured at room temperature were in agreement with the prediction by the CST Studio simulation. The RF characteristics at 20 K have been measured using a rather simple cavity-cooling vacuum system that was built by using existing components for tentative experiments. A thin-wall stainless-steel R48 waveguide with copper-plated inner walls has been used for the RF power transmission from the room-temperature input port to the 20-K cooled coupler waveguide. The unloaded Q-value of 73000 has been obtained by the reflection coefficient measurement at 20 K, which is in agreement with the result of the CST Studio simulation using the cavity surface resistance predicted by the theory of the anomalous skin effect.
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MOPIK026	Commissioning and Operation of an Ultrafast Electron Diffraction Facility as Part of the ATF-II Upgrade at Brookhaven National Laboratory	electron, operation, laser, photon	554
	M.G. Fedurin, M. Babzien, C. Folz, M. Fulkerson, K. Kusche, J.J. Li, R. Malone, M.A. Palmer, T.V. Shaftan, J. Skaritka, L. Snydstrup, C. Swinson, F.J. Willeke BNL, Upton, Long Island, New York, USA
	Funding: Work supported by the US DOE under contract DE-SC0012704. The Accelerator Test Facility (ATF) at Brookhaven National Laboratory (BNL) is presently carrying out an upgrade, ATF-II, which will provide significantly expanded experimental space and capabilities for its users. One of the new capabilities being integrated into the ATF-II program is an Ultrafast Electron Diffraction (UED) beam line, which was originally deployed in the BNL Source Development Laboratory. Inclusion of the UED in the ATF-II research portfolio will enable ongoing development and extension of the UED capabilities for use in materials research. We describe the design, operation and future plans for the UED beam line at the ATF-II.
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MOPIK048	Experimental Results of Crystal-Assisted Slow Extraction at the SPS	extraction, proton, detector, collimation	623
	M.A. Fraser, S.S. Gilardoni, B. Goddard, V. Kain, D. Mirarchi, S. Montesano, S. Petrucci, S. Redaelli, R. Rossi, W. Scandale, L.S. Stoel, F.M. Velotti CERN, Geneva, Switzerland F.M. Addesa, G. Cavoto, F. Iacoangeli INFN-Roma, Roma, Italy F. Galluccio INFN-Napoli, Napoli, Italy F. Murtas INFN/LNF, Frascati (Roma), Italy
	The possibility of extracting highly energetic particles from the Super Proton Synchrotron (SPS) by means of silicon bent crystals has been explored since the 1990's. The channelling effect of a bent crystal can be used to strongly deflect primary protons and eject them from the synchrotron. Many studies and experiments have been carried out to investigate crystal channelling effects. The extraction of 120 and 270 GeV proton beams has already been demonstrated in the SPS with dedicated experiments located in the ring. Presently in the SPS, the UA9 experiment is performing studies to evaluate the possibility to use bent silicon crystals to steer particle beams in high energy accelerators. Recent studies on the feasibility of extraction from the SPS have been made using the UA9 infrastructure with a longer-term view of using crystals to help mitigate slow extraction induced activation of the SPS. In this paper, the possibility to eject particles into the extraction channel in LSS2 using the bent crystals already installed in the SPS is presented. Details of the concept, simulations and measurements carried out with beam are presented, before the outlook for the future is discussed.
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MOPIK049	SPS Slow Extracted Spill Quality During the 2016 Run	target, extraction, quadrupole, power-supply	627
	V. Kain, J. Bauche, P. Catherine, K. Cornelis, M.A. Fraser, L. Gatignon, C.M. Genton, B. Goddard, K. Kahle, M. Magrans de Abril, O. Michels, L.S. Stoel, F.M. Velotti CERN, Geneva, Switzerland
	The flux of particles slow extracted with the 1/3 integer resonance from the Super Proton Synchrotron at CERN should ideally be constant over the length of the extraction plateau, for optimum use of the beam by the fixed target experiments. The extracted intensity is controlled in feed-forward correction of the horizontal tune via the main SPS quadrupoles. The Mains power supply noise at 50 Hz and harmonics is also corrected in feed-forward by small amplitude tune modulation at the respective frequencies with a dedicated additional quadrupole circuit. In 2016 the spill quality could be much improved with respect to the situation of the previous year with more performant algorithms. In this paper the improved tools are described and the characteristics of the SPS slow extracted spill in terms of macro structure and typical frequency content are shown. Other sources of perturbation were, however, also present in 2016 which frequently caused the spill quality to be much reduced. The different effects are discussed and possible or actual solutions detailed. Finally, the evolution of the spill quality during characteristic periods in the 2016 run is presented.
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MOPIK067	Figure-8 Storage Ring - Ion Beam Injection into a Closed, Magnetic System	injection, detector, storage-ring, ion	680
	H. Niebuhr, A. Ates, M. Droba, O. Meusel, U. Ratzinger IAP, Frankfurt am Main, Germany
	To store high current low-energetic ion beams of up to 10 A, a superconducting storage ring (F8SR) based on solenoidal and toroidal magnetic guiding fields is investigated at Frankfurt University. Besides simulations, a scaled down experimental setup with normalconducting magnets was built. Investigations of beam injection into closed, magnetic guiding fields are in progress. Therefore, a new kind of injection system consisting of a solenoidal injection coil and a special vacuum vessel was constructed. It is used to inject a hydrogen beam from the side between two toroidal magnets. In parallel operation, a second hydrogen beam is transported through both magnets to represent the circulating beam. The current status of the experimental setup and first experimental results will be shown.
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MOPIK085	Linear Optics Calibration at the HLS-II Storage Ring Using Model Independent Analysis	storage-ring, optics, lattice, operation	727
	G. Liu, L. Wang, F.F. Wu, K. Xuan USTC/NSRL, Hefei, Anhui, People's Republic of China
	Linear optics are the main lattice parameters characterizing the linear properties of storage rings. Especially for beta function and phase advance, they are the basic lattice functions which must be accurately calibrated to ensure high quality operation of the machine. Model Independent Analysis (MIA), which adopts mathematical statistical methods to extract the effective lattice information of storage rings by directly analyzing the turn-by-turn beam-position-monitor (BPM) measurements, has been applied at HLS-II to calibrate the linear optics model of the storage ring. The measurements of the turn-by-turn BPM data with all of the 32 BPMs are reported in this paper. The calibration results of the beta function using MIA are presented.
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MOPIK102	Beam Dynamics Studies of the HIE-ISOLDE Transfer Lines in the Presence of Magnetic Stray Fields	quadrupole, shielding, operation, solenoid	768
	J. Mertens, J. Bauche, M.A. Fraser, B. Goddard, R. Ostojić, J.S. Schmidt CERN, Geneva, Switzerland
	The ISOLDE facility at CERN produces radioactive isotopes far from stability for fundamental nuclear physics research. The radioactive beams are accelerated to high-energy using a post-accelerator before being transferred for study in different experiments at the end of a network of High Energy Beam Transfer (HEBT) lines. In the framework of the HIE-ISOLDE project, the energy of post-accelerated beams is to be increased to over 10 MeV/u and new experimental detectors are being proposed for installation to exploit the new energy regime. The stray magnetic fields associated with many of the new detectors will distort the beam trajectories in the HEBT, potentially affecting the transmission of the low intensity beams delivered to the experiments. In this contribution, the influence on the HEBT of the stray field of the proposed ISOL Solenoidal Spectrometer is discussed, correction schemes described and shielding options assessed.
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MOPIK110	Update on Bmad Simulations From Target to Storage Ring for the New Muon G-2 Experiment at Fermilab	storage-ring, proton, polarization, target	791
	M. Korostelev, I.R. Bailey, A.T. Herrod, A. Wolski Cockcroft Institute, Warrington, Cheshire, United Kingdom I.R. Bailey Lancaster University, Lancaster, United Kingdom A.T. Herrod, A. Wolski The University of Liverpool, Liverpool, United Kingdom D. Stratakis Fermilab, Batavia, Illinois, USA V. Tishchenko BNL, Upton, Long Island, New York, USA
	The new muon g-2 experiment at Fermilab (E989) aims to measure the anomalous magnetic moment of the muon to an uncertainty of 140 ppb. The existing accelerator facility at Fermilab is being adapted to the requirements of the g-2 experiment and the baseline lattice design is now established. This paper presents the results of beam simulations and spin tracking carried out using the Bmad software package for the g-2 beam transport system, including a variant which bypasses the delivery ring as proposed for the beam commissioning.
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MOPIK119	Beam Dynamics in g-2 Storage Ring	storage-ring, resonance, quadrupole, dipole	817
	W. Wu, B. Quinn UMiss, University, Mississippi, USA
	The muon anomalous magnetic moment has played an important role in constraining physics beyond the Standard Model. The Fermilab Muon g-2 Experiment has a goal to measure it to unprecedented precision: 0.14 ppm. To achieve this goal, we must understand the beam dynamics systematic effects in the muon storage ring. We will present the muon beam dynamics and discuss two specific topics here: the beam resonance which is related to the muon loss and the fast rotation analysis to determine the muon momentum distribution.
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MOPIK125	Multi-frequency AC LOCO: A Fast and Precise Technique for Lattice Correction	lattice, quadrupole, optics, power-supply	831
	X. Yang, K. Ha, V.V. Smaluk, Y. Tian, L. Yu BNL, Upton, Long Island, New York, USA
	We developed a novel technique to improve the precision and shorten the measurement time of the LOCO (Linear Optics from Closed Orbits) method at NSLS-II [1]. This technique named AC LOCO is based on a sine-wave (AC) beam excitation via fast correctors typically installed at synchrotron light sources for the fast orbit feedback. The beam oscillations are measured by beam position monitors. The narrow band used for the beam excitation and measurement not only allows us to suppress effectively the beam position noise and also makes simultaneously exciting multiple correctors at different frequencies (multi-frequency mode) possible. We demonstrated at NSLS-II that the new technique provides better lattice corrections and achieves two minutes measurement time in the thirty-frequency mode. [1] X. Yang et al., 'Fast and precise technique for magnet lattice correction via sine-wave excitation of fast correctors', Phys. Rev. Accel. Beams, vol. 20, p. 054001, 2017.
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MOPIK127	FAIR Risk Management as a Proactive Steering Tool for the Large Scale Multi Project	factory, project-management, antiproton, ion	839
	S. Deveaux, F. Becker GSI, Darmstadt, Germany
	The Facility for Antiproton and Ion Research (FAIR) is a large scale multi project comprising 10 subprojects in the field of accelerators (pLINAC, SIS100, SuperFRS, p-bar separator, Collector Ring, High Energy Storage Ring), experiments (CBM, APPA, NUSTAR, PANDA) and civil construction. This contribution describes the implementation of a progressive risk management methodology based on a comprehensive assessment on work package level. Complexity factors (number of parts, level of state of the art, level of human interfaces, level of operational complexity) and importance factors (safety, cost, schedule, resources) represent the likelihood of risk occurrence and the eventual value at risk. Relative comparison of the normalized factors together with a supplier assessment enables to derive an event based risk register with a standardized evaluation scheme assigning risk and opportunity classes. This contribution demonstrates the full methodology highlighting some typical examples of the FAIR project.
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MOPIK128	Integrated Project Planning as a Central Steering Tool for the Large Scale Multi Project FAIR	status, project-management, site, controls	842
	N. Winters, F. Becker, M.V. Ricciardi GSI, Darmstadt, Germany
	The Facility for Antiproton and Ion Research (FAIR) is a large scale multi project comprising 10 subprojects in the field of accelerators (pLINAC, SIS100, SuperFRS, p-bar, CR, HESR), experiments (CBM, APPA, NUSTAR, PANDA) and civil construction. This contribution describes the fundamental revamp of FAIR integrated project planning. Main objective is to preserve the advantages of a bottom-up planning topology with the actual and detailed level of information keeping the ~400 work package leader's central role as plan owners in their field of responsibility. Simultaneously different project phases (e.g. civil construction, procurement, installation, commissioning) need to be excluded from detailed plans while being re-integrated in the level-1 project master schedule. Additional cost profiles and resource assignment by name allow a progress tracking and flexible project steering.
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MOPVA012	The Dedicated Accelerator R&D Facility Sinbad at DESY	linac, electron, laser, acceleration	869
	U. Dorda, R.W. Aßmann, K. Galaydych, W. Kuropka, B. Marchetti, D. Marx, F. Mayet, G. Vashchenko, T. Vinatier, P.A. Walker, J. Zhu DESY, Hamburg, Germany A. Fallahi, F.X. Kärtner, N.H. Matlis CFEL, Hamburg, Germany
	We present an overview of the dedicated R\&D facility SINBAD which is currently under construction at DESY. The facility will host multiple independent experiments on the acceleration of ultra-short electron bunches and advanced acceleration schemes. In its initial phase, SINBAD will host two experiments: AXSIS and ARES. The AXSIS collaboration aims to accelerate fs-electron bunches to 15 MeV in a THz driven dielectric structure and subsequently create X-rays by inverse Compton scattering. The first stage of the ARES experiment is to set up a 100 MeV S-band electron linac to produce ultra-short electron bunches with excellent beam arrival time stability. Once this is achieved, the electrons will be ideally suited to be injected into experiments for testing advanced accelerator concepts e.g. DLA experiments in the context of the ACHIP collaboration. In the long term, external injection into a laser driven plasma acceleration stage is targeted as well.
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MOPVA014	Injector Linac Stability Requirements for High Precision Experiments at MESA	linac, electron, operation, acceleration	876
	F. Hug, R.G. Heine IKP, Mainz, Germany
	Funding: Work supported by DFG through the PRISMA cluster of excellence EXC 1098/2014 and Research Training Group GRK 2128 MESA is a recirculating superconducting accelerator under construction at Johannes Gutenberg-Universität Mainz. It will be used for high precision particle physics experiments in two different operation modes: external beam (EB) mode and energy recovery (ERL) mode. The operating beam current and energy in EB mode is 0.15 mA with polarized electrons at 155 MeV. In ERL mode an unpolarized beam of 1 mA at 10⁵ MeV will be available. In a later construction stage of MESA the beam current in ERL-mode shall be upgraded to 10 mA. In order to achieve high beam stability and low energy spread in recirculating operation the acceleration in the main linac sections will be done on edge of the accelerating field while the return arcs provide longitudinal dispersion. On certain longitudinal working points this can result in a setting where rf jitters from main linac do not contribute to the resulting energy spread of the final beam at all [,]. Then the resulting energy spread is only determined by the energy spread provided by the inector linac. Within this contribution we will investigate the requirements on the stability of the MESA injector linac MAMBO for achieving the experimental goals. [] H. Herminghaus, NIM. A 314 (1992) 209. [**] F. Hug et al., Proc. of LINAC '12 (2012) 531.
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MOPVA018	Resonant Coherent Diffraction Radiation System at ERL Test Accelerator in KEK	cavity, radiation, resonance, emittance	887
	Y. Honda, A. Aryshev, R. Kato, T. Miyajima, T. Obina, M. Shimada, R. Takai, N. Yamamoto KEK, Ibaraki, Japan
	Funding: This work was supported by JSPS KAKENHI Grant Number 16H05991 An Energy Recovery Linac can produce a low emittance and short bunch beam at a high repetition rate. A test accelerator, compact-ERL, has been operating in KEK for development works of technologies related to ERL and CW-Superconducting accelerators. In a special beam operation mode of bunch compression, a short bunch beam of ~150 fs at the repetition rate of CW 1.3 GHz can be realized in the return-loop. One of the promising applications of such a short bunch beam is a high power THz radiation source produced by a coherent radiation. When a charged particle beam passes close to a conductive target, a radiation called diffraction radiation is produced. If the target mirrors form an optical cavity which fundamental frequency matches the repetition frequency of the beam, the radiation resonates in the cavity, resulting in extracting a huge radiation power determined by the loss of the cavity. We plan to perform an experiment of the resonant coherent diffraction mechanism in the return-loop of the compact-ERL to test the feasibility to be a wide band high power THz source. We report the design of the experimental setup to be installed in the summer of 2017.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA018
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MOPVA025	Step-Like Field Magnets to Uniform Beam Distribution and Experiment at CADS Injector-I	simulation, target, dipole, proton	908
	C. Meng, Y. Chen, H. Geng, J.Y. Tang, F. Yan, L. Yu, Y.L. Zhao IHEP, Beijing, People's Republic of China
	High power is the development tendency of proton accelerator, so obtaining uniform beam distribution on target becomes more and more important and critical. The method of using step-like field magnets to obtain a uniform beam distribution on target was presented. In the beamdump line of CADS injector-I test facility four step-like field magnets have been installed to uniform beam distribution to reduce the maximum current density on the beamdump. The magnetic field of step-like field magnets have been measured and discussed in this paper. The simulation results and measurement results of beam uniformization are presented.
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MOPVA027	Measurement of High Power Terahertz with Dielectric Loaded Waveguide at Tsinghua University	radiation, electron, wakefield, extraction	914
	D. Wang, Y.-C. Du, W. Gai, W.-H. Huang, X.L. Su, C.-X. Tang, Q.L. Tian, L.X. Yan TUB, Beijing, People's Republic of China S.P. Antipov Euclid Beamlabs LLC, Bolingbrook, USA Y.F. Liang Tsinghua University, Beijing, People's Republic of China
	Funding: Work supported by the National Nature Science Foundation of China (NSFC Grants No.11475097) and the National Key Scientific Instrument and Equipment Development Project of China (Grants No. 2013YQ12034504) We have measured an intense THz radiation produced by a sub-picosecond, relativistic electron bunch passing through a dielectric loaded waveguide (DLW) at Tsinghua University accelerator beamline. The DLW was 3 cm long quartz tube with 900 'm inner diameter and 100 'm wall thickness metallized on the outside. Radiated energy of the THz pulse was measured to be proportional to the square of the effective charge. The end of the DLW was cut at an angle for efficient THz pulse extraction. Tens of 'J THz energy per pulse were measured outside the vacuum chamber with a calibrated Golay cell in the experiment. wangdan16@mail.tsinghua.edu.cn yanlx@mail.tsinghua.edu.cn
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MOPVA047	Investigation of Trapped Magnetic Flux in Superconducting Niobium Samples with Polarized Neutron Radiography	neutron, niobium, detector, polarization	964
	O. Kugeler, J. Knobloch, M.M. Krzyzagorski, J.M. Köszegi, L. Riik, W. Treimer, R.F. Ziesche HZB, Berlin, Germany
	The dynamics of flux expulsion during superconducting transition and the influence of external AC magnetic fields on expulsion of trapped fields in Nb samples has been investigated with radiography using polarized neu-trons. Results of these experiments are presented.
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MOPVA050	Setup of a Spatially Resolving Vector Magnetometry System for the Investigation of Flux Trapping in Superconducting Cavities	cavity, SRF, niobium, radio-frequency	975
	B. Schmitz, K.Alomari. Alomari, J. Knobloch, O. Kugeler, J.M. Köszegi, Y. Tamashevich HZB, Berlin, Germany
	Flux trapping is the major contribution to the residual resistance of superconducting cavities. In order to gain a better understanding of the mechanisms involved and aiming at an eventual minimization of trapped flux, a measurement setup based on AMR sensors was devised that allows for monitoring the magnetic field vector at various positions near the cavity surface. First results of the efforts are presented.
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MOPVA076	Measurement of Thin Film Coating on Superconductors	cryogenics, controls, FPGA, photon	1043
	Y. Iwashita, Y. Fuwa, H. Tongu Kyoto ICR, Uji, Kyoto, Japan H. Hayano, T. Kubo, T. Saeki KEK, Ibaraki, Japan M. Hino Kyoto University, Research Reactor Institute, Osaka, Japan H. Oikawa Utsunomiya University, Utsunomiya, Japan
	Funding: This research is supported by following programs: Grant-in-Aid for Exploratory Research JSPS KAKENHI Grant Number 26600142 and Photon and Quantum Basic Research Coordinated Development Program from the MEXT. Multilayer thin film coating is a promising technology to enhance performance of superconducting cavities. Until recently, principal parameters to achieve the sufficient performance had not been known, such as the thickness of each layer. We proposed a method to deduce a set of the parameters to exhibit a good performances. In order to verify the scheme, we are trying to make some experiments on the subject at Kyoto. The sample preparation and the test setup for the measurement apparatus will be discussed.
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MOPVA100	Atomic Layer Deposition of Niobium Nitride from Different Precursors	plasma, niobium, controls, simulation	1094
	P. Pizzol, P. Chalker, J.W. Roberts, J. Wrench The University of Liverpool, Liverpool, United Kingdom O.B. Malyshev, R. Valizadeh STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Advancements in technology have taken bulk niobium cavities close to their theoretical operational limits of 45 MV/m, pushing the research to explore novel materials, such as niobium based alloys . Theoretical studies suggest that a composite material composed of alternative superconductor / insulator multilayers would surpass the bulk niobium limits. Chemical vapour deposition (CVD) can deposit mi-crons thick Nb films in less than an hour, at the expense of precise thickness control. Atomic layer deposition (ALD), instead, even if considerably slower than CVD can be used in applications where the thickness of the deposited layers needs to be controlled with a resolution down to the nanometer. This article presents the preliminary results obtained by using plasma assisted ALD techniques to deposit NbN based compounds starting from chlorinated precursors and organic ones, and the design for a new deposition system currently being built at the Daresbury Laboratories.
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MOPVA144	Post-Processing of Nb3Sn Coated Nb	niobium, SRF, superconductivity, cavity	1190
	U. Pudasaini, M.J. Kelley The College of William and Mary, Williamsburg, Virginia, USA G.V. Eremeev, M.J. Kelley, C.E. Reece JLab, Newport News, Virginia, USA M.J. Kelley, J. Tuggle Virginia Polytechnic Institute and State University, Blacksburg, USA
	Funding: Supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DEÂAC05Â06OR23177 and Office of High Energy Physics under grant SC00144475. Practical SRF cavities may be subjected to one or more processes after nominally complete preparation. Successful implementation of such processes in Nb3Sn coated cavities requires the understanding of material's response to these treatments. SRF-grade Nb samples, coated with Nb3Sn by the widely used tin vapor diffusion process were subjected to one or more of the following: hydrofluoric acid (HF) rinsing, oxypolishing, buffered chemical polishing (BCP) or electrochemical treatment. They were examined by materials characterization tech-niques including scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), and X-ray photoelectron spec-troscopy (XPS). The effects compared to niobium are different enough in most cases that further development is desirable to routinely obtain a favorable result.
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TUOBB1	Experimental Demonstration of Energy-Chirp Reduction by a Plasma Dechirper	plasma, electron, laser, linac	1258
	Y.P. Wu, Z. Cheng, Y.-C. Du, J.F. Hua, W. Lu, C.H. Pai, J. Zhang, S.Y. Zhou, Z. Zhou TUB, Beijing, People's Republic of China
	The first experimental study is presented using a low density plasma dechirper to reduce a correlated energy chirp from the 41.5-MeV, 500-fs (RMS) beam at the linac in Tsinghua University. The plasma dechirper operates through the interaction of the electron bunch with its near linear self-wake to dechirp itself, leading to a reduction in energy spread. The experimental results demonstrate that the projected FWHM energy spread of the beam can be reduced from 1.2% to 0.9% with a 12 mm long plasma dechirper, which are in good agreement with full 3D PIC simulations. Theoretical analyses and simulations indicate that by optimizing the plasma density and length, the plasma dechirper can also be used to completely remove the characteristic energy chirp of the ultra-short high-current bunch generated from plasma based accelerator, such that its energy spread can be reduced from one percent level to 0.1 percent level[]. Application of such a simple and effective method can significantly improve the beam quality and provide the path to realize the future compact free electron lasers and colliders driven by plasma based accelerators. [] Y. P. Wu. A plasma dechirper for electron and positron beams in plasma-based accelerators, to be submitted to Scientific Reports
	Slides TUOBB1 [10.555 MB]
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TUOBB2	Starting Up the AWAKE Experiment at CERN	proton, plasma, laser, electron	1261
	E. Gschwendtner CERN, Geneva, Switzerland
	AWAKE, the Advanced Proton Driven Plasma Wake-field Acceleration Experiment at CERN was approved in 2013. The facility was commissioned in 2016 to perform first experiments to demonstrate the self-modulation in-stability (SMI) of a 400 GeV/c SPS proton bunch in a 10 m long Rubidium plasma cell. The plasma is created in Rb vapor via field ionization by a TW laser pulse. In the second phase starting late 2017, the proton driven plasma wakefield will be probed with an externally injected 10 ' 20 MeV/c electron beam. This paper gives an overview of the AWAKE facility, describes the successful commissioning of the laser and proton beam line, the plasma cell and diagnostics and shows the successful synchronization of the proton beam with the laser at the few ps level so that the facility is ready for the SMI physics runs. In addition the status of the electron acceleration exper-iment for late 2017 will be presented.
	Slides TUOBB2 [3.513 MB]
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TUPAB017	Results of the Beam-Loading Breakdown Rate Experiment at the CLIC Test Facility CTF3	beam-loading, operation, klystron, linac	1348
	E. Senes, T. Argyropoulos, N. Catalán Lasheras, R. Corsini, D. Gamba, J. Giner Navarro, A. Grudiev, G. McMonagle, R. Rajamaki, X.F.D. Stragier, I. Syratchev, F. Tecker, W. Wuensch CERN, Geneva, Switzerland J. Giner Navarro IFIC, Valencia, Spain R. Rajamaki Aalto University, School of Science and Technology, Aalto, Finland E. Senes Torino University, Torino, Italy
	The RF breakdown rate is crucial for the luminosity performance of the CLIC linear collider. The required breakdown rate at the design gradient of 100 MV/m has been demonstrated, without beam presence, in a number of 12 GHz CLIC prototype structures. Nevertheless, the beam-loading at CLIC significantly changes the field profile inside the structures, and the behaviour with beam needs to be understood. A dedicated experiment in the CLIC Test Facility CTF3 to determine the effect of beam on the breakdown rate has been collecting breakdown data throughout the year 2016. The complete results of the experiment and the effect of the beam-loading on the breakdown rate are presented.
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TUPAB021	The Study of Focus-Dependent Dark Current for AREAL RF Photogun	electron, gun, solenoid, simulation	1358
	L. Hakobyan, H. Davtyan, B. Grigoryan, A. Vardanyan CANDLE SRI, Yerevan, Armenia
	AREAL (Advanced Research Electron Accelerator Laboratory) is a project of linear accelerator based facility aimed to produce ultra-short electron bunches with small emittance. In the first phase of AREAL project an electron beam with energy up to 5 MeV is produced by the electron RF photogun and used for irradiation experiments in biology, microelectronics and accelerator technology development. For such experiments the exact calculation of absorbed dose and electron bunch peak current is one of important conditions. The presence of a dark current in electron gun affects the electron emission from photocathode, the exact absorbed dose calculation, and in general harms the machine performance. In this paper the estimation of dark current amount, produced in the electron gun, the ways to avoid its influence on experiments are discussed. The dark current measurements are compared with the simulation results. The electron beam separation from a dark current is discussed.
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TUPAB031	Status and Perspectives of the S-DALINAC Polarized-Electron Injector	electron, gun, cathode, laser	1388
	M. Herbert, J. Enders, M. Espig, Y. Fritzsche, N. Kurichiyanil, M. Wagner TU Darmstadt, Darmstadt, Germany
	Funding: Work supported by the Deutsche Forschungsgemeinschaft through grants GRK 2128 and SFB 1245 The S-DALINAC Polarized Injector (SPIn) uses GaAs photocathodes to provide pulsed and/or polarized electron beams for nuclear-structure investigations. Recently, a test facility for Photo-Cathode Activation, Test and Cleaning using atomic-Hydrogen \mbox{(Photo-CATCH)} has been developed. This setup uses an inverted-insulator geometry for the photo-electron gun. Currently, tests and optimizations are conducted at \mbox{Photo-CATCH} in order to implement this new gun design at SPIn. We will present the current status of \mbox{Photo-CATCH}, the planned upgrade of SPIn (aimed at an operational voltage of 200 kV) and future measurements.
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TUPAB050	A Lifetime Study of CsK2Sb Multi-Alkali Cathode	cathode, laser, vacuum, electron	1440
	M. Kuriki, L. Guo, M. Urano, A. Yokota HU/AdSM, Higashi-Hiroshima, Japan K. Negishi Iwate University, Morioka, Iwate, Japan Y. Seimiya KEK, Ibaraki, Japan
	Funding: Quantum beam project by the Ministry of Education, Culture, Sports, Science, and Technology, entitled High Brightness Photon Beam by Laser Compton Scattering and Cooperative supporting Program for Research Education in University by KEK(High Energy Accelerator Research Organization) \rm CsK₂Sb is a high performance photo-cathode for accelerators requiring the high brightness electron beam. It can be driven by a green laser generated as SHG of a solid state laser. The quantum efficiency is as high as 10\%. In this article, the robustness of the cathode was studied experimentally. We found that 1/e lifetime of the cathode was inversely proportional to the vacuum pressure. The normalized temporal life was \rm (4.72± 0.08)× 10^-5~Pa.hour for 532 nm laser. The lifetime regarding to the extracted charge density was also inversely proportional to the vacuum pressure. The normalized charge life was \rm (1.19± 0.03± 0.04)× 10^-4 Pa.C/mm². The cathode is robust enough for a high brightness electron accelerator.
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TUPAB051	Substrate Dependence of CsK2Sb Cathode Performance	cathode, electron, laser, lattice	1443
	M. Kuriki, L. Guo, M. Urano, A. Yokota HU/AdSM, Higashi-Hiroshima, Japan K. Negishi Iwate University, Morioka, Iwate, Japan Y. Seimiya KEK, Ibaraki, Japan
	Funding: Quantum beam project by the Ministry of Education, Culture, Sports, Science, and Technology, entitled High Brightness Photon Beam by Laser Compton Scattering and Cooperative supporting Program for Research and education in University by KEK(High Energy Accelerator Research Organization). \rm CsK₂Sb is a high performance cathode which can be driven with a green laser. The cathode is generated by evaporation on a substrate in a high vacuum environment. The cathode was evaporated on various material and surface condition to evaluate the dependence of the cathode performance. GaAs (100), Si(100), and Si(111) were examined as samples of the substrate. For each materials, the cathode on the cleaned and as-received substrates were examined and those on the cleaned showed better performance than the as-received for all materials. The detail of the experimental results are presented.
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TUPAB053	Proof-of-Principle Experiment of Phase-Combined Undulator	undulator, permanent-magnet, gun, electron	1446
	R. Kinjo, T. Tanaka RIKEN SPring-8 Center, Hyogo, Japan A. Kagamihata JASRI/SPring-8, Hyogo, Japan
	A huge attractive force is the largest concern in designing a mechanical structure of undulators, in which an accurate control and high uniformity of the gap between the upper and lower magnetic girders are required. This problem is especially serious for in-vacuum undulators, in which the girders are located inside the vacuum chamber. We have proposed a new concept called a phase-combined undulator, which has intrinsically no magnetic force. In this undulator, the magnetic forces acting on the girders locally head to the longitudinal axis instead of the attractive direction, and are actually canceled out in total. Numerical calculations have shown that the attractive force will be reduced down to a negligible level. Recently, we performed a proof-of-principle experiment to examine the feasibility of this undulator concept in terms of the force between the girders and magnetic field distribution, which will be reported in the conference. R. Kinjo and T. Tanaka, Phys. Rev. ST Accel. Beams 17, 122401
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TUPAB056	New Achievements of the Laser System for RF-Gun at SuperKEKB Injector	laser, operation, gun, electron	1452
	R. Zhang, T. Natsui, Y. Ogawa, M. Yoshida, X. Zhou KEK, Ibaraki, Japan
	For realizing high charge and low emittance electron and positron beams in SuperKEKB, we have been making improvements in current laser system for RF-gun. In order to realize more excellent thermal management in current laser system at high repetition rate operation, novel soldering Yb:YAG thin disk and copper tungsten heat sink laser head is manufactured via gold tin solder. Comparing with old design, less residual stress is introduced and more efficient thermal removal can be obtained. These new soldering laser heads are placed into a compact vacuum chamber and cooled by Peltier plates directly. This design can realize higher gain and amplification factor in regenerative amplifier and multi-pass amplifier. In addition, the compact and simple cooling method can achieve excellent thermal management for the purpose of realize laser operation at high repetition rate for following phases of SuperKEKB project. A perspective towards the next step experiment is also presented in this paper.
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TUPAB060	Development of the Laser System for the Proof-of-Principle Experiment of Crab Crossing Laser-Compton Scattering	laser, scattering, electron, luminosity	1460
	T. Takahashi, D. Igarashi, Y. Koshiba, S. Ota, M. Washio RISE, Tokyo, Japan K. Sakaue Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan J. Urakawa KEK, Ibaraki, Japan
	An X-ray source via laser-Compton scattering has the advantage of small source, energy tunability and quasi-monochromaticity and is expected to be applied in a wide range of fields such as the industry and medical care. In laser-Compton scattering, the luminosity, which represents the collision frequency between the electrons and the photons, is very important. Increasing the luminosity is strongly required for increasing the scattered photon flux. One way to increase the luminosity is tilting electron bunches at the collision point, which is called crab crossing. It is the way to create the head-on collision artificially. The purpose of this study is the proof-of-principle of the crab crossing laser-Compton scattering. In this conference, we will report the design optimization and construction of the laser system for the collision and future prospects. Variola Alessandro, et al. Luminosity optimization schemes in Compton experiments based on Fabry-Perot optical resonators. Physical Review Special Topics-Accelerators and Beams 14.3 (2011): 031001.
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TUPAB071	Experimental Results on THz Superradiation From the Undulator in Tsinghua University Beamline	radiation, undulator, electron, detector	1488
	X.L. Su, Y.-C. Du, W.-H. Huang, L. Niu, C.-X. Tang, Q.L. Tian, D. Wang, L.X. Yan TUB, Beijing, People's Republic of China Y.F. Liang Tsinghua University, Beijing, People's Republic of China
	In this paper, the first operation of a widely tunable 8-period undulator at terahertz (THz) frequency in Tsinghua University beamline was reported. Superradiate undulator radiation from sub-picosecond electron bunches compressed by chicane was observed. The measured radiation curve shows clearly that the radiation energy is proportional to the charge square, and the THz frequency can be changed from 0.4 THz to 10 THz with narrow-band spectrums. Our results demonstrate a high power and tunable coherent THz source, which could be useful for many applications in the future.
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TUPAB075	Compact High Energy Electron Radiography System Based on Permanent Magnet Quadrupole	electron, quadrupole, target, permanent-magnet	1494
	Z. Zhou, Y.-C. Du, W. Gai, W.-H. Huang, F. Li, T. Rui, C.-X. Tang TUB, Beijing, People's Republic of China W. Gai ANL, Argonne, Illinois, USA
	High energy electron radiography(HEER) is a promising diagnostic method for High Energy Density Physics (HEDP) or Inertial Confinement Fusion (ICF) owing to its capability of picosecond-nanometer spatio-temporal resolution, and is cost-effective in the meantime. A Compact HEER (CHEER) system based on Permanent Magnet Quadrupoles (PMQ) instead of conventional electromagnetic quadrupole is proposed. Its lattice design and beam optics optimization is finished, and experiment is to be carried out on Tsinghua Thomson X-ray source (TTX) beamline after PMQs fabrication and installation.
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TUPAB114	Design Study for a Plasma Undulator Experiment Using Capillary Based Discharge Plasma Source	laser, plasma, electron, undulator	1584
	O. Mete Apsimon, R. Apsimon, Y. Ma, D. Seipt, M.J.V. Streeter, A.G.R. Thomas Cockcroft Institute, Lancaster University, Lancaster, United Kingdom T.H. Pacey, G.X. Xia UMAN, Manchester, United Kingdom
	A plasma undulator is formed when a short laser pulse is injected into plasma off-axis or at an angle that causes the centroid of this laser pulse to oscillate. Ponderomotively driven plasma wake will follow this centroid given that the product of the plasma wave number and the characteristic Rayleigh length of the laser is much larger than one. This oscillating transverse wakefield may work as an undulator forcing particles to follow sinusoidal trajectories and emit synchrotron radiation. In this paper, plans for an experiment are introduced and resulting radiation and injected beam characteristics are discussed. The aforementioned laser centroid oscillations are demonstrated using, EPOCH, a PIC code for laser-plasma interactions.
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TUPAB122	Engineering Optimization of The Support Structure and Drive System for the LCLS-II Soft X-Ray Undulator Segments	undulator, photon, simulation, laser	1602
	A.J. DeMello, D. Arbelaez, D. Bianculli, A.P. Brown, J.N. Corlett, J.R. Dougherty, D.E. Humphries, J.-Y. Jung, M. Leitner, S. Marks, K.A. McCombs, K.L. Ray, D.A. Sadlier, D. Schlueter, E.J. Wallén LBNL, Berkeley, California, USA
	Funding: Work supported by the Director, O'ce of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The Linear Coherent Light Source II (LCLS-II) project, an upgrade to the free-electron laser facility at SLAC, is replacing the undulator system from a fixed gap to a variable gap system to enable tuning of the photon energy range. The LCLS-II project will include a soft x-ray (SXR) beam line and a hard x-ray (HXR) beam line. The SXR undulators are conventional vertical-gap horizontally-polarizing devices while the HXR undulators are novel horizontal-gap vertically-polarizing devices. This paper describes in detail the development of the SXR mechanical support structure and drive system. The effort has included extensive analysis of the various components to ensure that the undulators will perform within the design specifications. Engineering simulations undertaken and experiments performed to validate the computer modeling are presented together with measurement results from prototype and pre-production undulators.
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TUPAB146	Vibration Measurements of Super-Conducting Undulator at SSRF	undulator, data-analysis, data-acquisition, damping	1675
	R.B. Deng, Y. Liu, L. Wang, S. Xiang SINAP, Shanghai, People's Republic of China
	Funding: Work supported by the National Natural Science Foundation of China (Grant No. 11405255) A Super-Conducting Undulator (SCU) is being built at SSRF. Mechanical stability of SCU is critical to beam stability since the central load is supported by special strings in SCU and the vibration of load will cause directly the vibration of beam. In this paper, vibration results of several key components including central load, cold head, frame support, etc, are studied under different working mode of compressors. The ground vibrations at different distances are compared to get the influence of compressors to SCU. Useful suggestions and possible measures are described to mitigate the vibration and improve SCU stability.
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TUPIK001	Upgrade of the Two-Screen Measurement Setup in the AWAKE Experiment	proton, plasma, wakefield, electron	1682
	M. Turner TUG/ITP, Graz, Austria V. Clerc, I. Gorgisyan, E. Gschwendtner, S. Mazzoni, A.V. Petrenko CERN, Geneva, Switzerland
	The AWAKE project at CERN uses a self-modulated §I{400}{GeV/c} proton bunch to drive GV/m wakefields in a §I10{m} long plasma with an electron density of n_pe = 7 × 10¹⁴ \rm{electrons/cm}³. We present the upgrade of a proton beam diagnostic to indirectly prove that the bunch self-modulated by imaging defocused protons with two screens downstream the end of the plasma. The two-screen diagnostic has been installed, commissioned and tested in autumn 2016 and limitations were identified. We plan to install an upgraded diagnostics to overcome these limitations.
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TUPIK017	Next Generation Plasma Cell for PWFA Experiments at PITZ	plasma, laser, electron, Windows	1715
	O. Lishilin, J. Engel, M. Groß, G. Koss, G. Loisch, S. Philipp, R. Schütze, F. Stephan DESY Zeuthen, Zeuthen, Germany R. Brinkmann DESY, Hamburg, Germany F.J. Grüner Center for Free-Electron Laser Science, Universität Hamburg, Hamburg, Germany D. Richter HZB, Berlin, Germany C.B. Schroeder LBNL, Berkeley, California, USA
	A proof-of-principle experiment for the AWAKE experiment is ongoing at the Photo-Injector Test Facility at DESY, Zeuthen site (PITZ). The goal of the experiment is to observe and measure the energy and density self-modulation of a long electron beam passing through a laser-generated Lithium plasma. Key devices of the experiment are a heat pipe based plasma cell, a photocathode laser system which enables production of long electron beams with sharp rising edges and well-developed diagnostics at PITZ, including a transverse deflecting cavity and a high-resolution electron spectrometer. In this report we present the current status of the experiment, including the latest updates of the experimental setup. The plasma cell is a lithium heat pipe oven with inert gas buffers at all input/output ports. An ArF ionization laser is coupled through side ports. Main improvements of the second generation plasma cell are an altered geometry of side arms and a new heat pipe design. Among other updates are an improved ArF laser beamline and new electron windows. We present here measurements of plasma density and homogeneity as well as results of beam transport studies for the experiment. O. Lishilin, M. Gross, et al., Â«First results of the plasma wakefield acceleration experiment at PITZÂ», NIM A, Volume 829, 1 September 2016, Pages 37-42, http://dx.doi.org/10.1016/j.nima.2016.01.005
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TUPIK018	Experimental Investigation of High Transformer Ratio Plasma Wakefield Acceleration at PITZ	plasma, wakefield, acceleration, simulation	1718
	G. Loisch, P. Boonpornprasert, J.D. Good, M. Groß, H. Huck, M. Krasilnikov, O. Lishilin, A. Oppelt, Y. Renier, T. Rublack, F. Stephan DESY Zeuthen, Zeuthen, Germany G. Asova INRNE, Sofia, Bulgaria G. Asova, R. Brinkmann, A. Martinez de la Ossa, T.J. Mehrling, J. Osterhoff DESY, Hamburg, Germany F.J. Grüner CFEL, Hamburg, Germany F.J. Grüner, A. Martinez de la Ossa, T.J. Mehrling University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	Plasma wakefield acceleration (PWFA), the acceleration of particles in a plasma wakefield driven by high current-density particle bunches, is one of the most promising candidates for a future compact accelerator technology. A key aspect of this type of acceleration is the ratio between the accelerating fields experienced by a witness beam and the decelerating fields experienced by the drive beam, called the transformer ratio. As for longitudinally symmetrical bunches this ratio is limited by the fundamental theorem of beamloading to 2 in the linear regime, a transformer ratio above this limit is considered high. This can be reached by using a modulated drive bunch or a shaped train of drive bunches. So far, only the latter case has been shown for wakefields in a RF-structure. We show the experimental setup, simulations and first, preliminary results of high transformer ratio acceleration experiments at the Photoinjector Test Facility at DESY in Zeuthen (PITZ). K. L. F. Bane, P. B. Wilson and T. Weiland, AIP Conference Proceedings 127, p. 875, 1984 ** C. Jing et al., Physical Review Letters 98, 144801, 2007
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TUPIK032	AWAKE Proton Beam Commissioning	proton, plasma, laser, alignment	1747
	J.S. Schmidt, D. Barrientos, M. Barros Marin, B. Biskup, A. Boccardi, T.B. Bogey, T. Bohl, C. Bracco, S. Cettour Cave, H. Damerau, V. Fedosseev, F. Friebel, S.J. Gessner, A. Goldblatt, E. Gschwendtner, L.K. Jensen, V. Kain, T. Lefèvre, S. Mazzoni, J.C. Molendijk, A. Pardons, C. Pasquino, S.F. Rey, H. Vincke, U. Wehrle CERN, Geneva, Switzerland J.T. Moody MPI-P, München, Germany K. Rieger MPI, Muenchen, Germany
	AWAKE will be the first proton driven plasma wakefield acceleration experiment worldwide. The facility is located in the former CNGS area at CERN and will include a proton, laser and electron beam line merging in a 10 m long plasma cell, which is followed by the experimental diagnostics. In the first phase of the AWAKE physics program, which started at the end of 2016, the effect of the plasma on a high energy proton beam will be studied. A proton bunch is expected to experience the so called self-modulation instability, which leads to the creation of micro-bunches within the long proton bunch. The plasma channel is created in a rubidium vapor via field ionization by a TW laser pulse. This laser beam has to overlap with the proton beam over the full length of the plasma cell, resulting in tight requirements for the stability of the proton beam at the plasma cell in the order of ~ 0.1 mm. In this paper the beam commissioning results of the ~810 m long transfer line for proton bunches with 3·10¹¹ protons/bunch and a momentum of 400 GeV/c will be presented with a focus on the challenges of the parallel operation of the laser and proton beam.
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TUPIK038	Muon Sources for Particle Physics - Accomplishments of MAP	collider, factory, proton, target	1766
	D.V. Neuffer, D. Stratakis Fermilab, Batavia, Illinois, USA M.A. Cummings Muons, Inc, Illinois, USA J.-P. Delahaye SLAC, Menlo Park, California, USA M.A. Palmer BNL, Upton, Long Island, New York, USA R.D. Ryne LBNL, Berkeley, California, USA D.J. Summers UMiss, University, Mississippi, USA
	Funding: supported by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the U. S. Department of Energy. The Muon Accelerator Program (MAP) completed a four-year study on the feasibility of muon colliders and on using stored muon beams for neutrinos. That study was broadly successful in its goals, establishing the feasibility of lepton colliders from the 125 GeV Higgs Factory to more than 10 TeV, as well as exploring using a ' storage ring (MSR) for neutrinos, and establishing that MSRs could provide factory-level intensities of 'e (''e) and ''' ('') beams. The key components of the collider and neutrino factory systems were identified. Feasible designs and detailed simulations of all of these components were obtained, including some initial hardware component tests, setting the stage for future implementation where resources are available and clearly associated physics goals become apparent.
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TUPIK047	FAIR Control Centre (FCC) - Concepts and Interim Options for the Existing GSI Main Control Room	controls, operation, proton, ion	1791
	M. Vossberg, K. Berkl, S. Reimann, P. Schütt, R.J. Steinhagen, G. Stephan GSI, Darmstadt, Germany
	The 'Facility for Anti-Proton and Ion Research' (FAIR) which is presently under construction, extends and supersedes the existing GSI. Present operation still largely relies on laborious manual tuning based on analogue signals routed directly to the existing control room. The substantial scope increase from 3 to more than 8 FAIR accelerators requires more intricate and precise control across longer accelerator chains, while providing a high degree of multi-user operation, with facility reconfiguration required on time-scales of a few times per week. A new FAIR Control Centre (FCC) is being planned to accommodate the required larger accelerator crews as well as accelerator-based experiments. While targeting a single control room for up to ~35 people, emphasis is put on ergonomics, operational processes, and minimising unnecessary strain on personnel already during the design stage. This contribution presents digital control room concepts, console layout, and beam-production-chain paradigms aimed at achieving good operational performances and that influence the new FCC design. Prior to FCC completion, interim upgrade options of the existing control room are being investigated.
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TUPIK048	Longitudinal Beam Stabilization at FAIR by Means of a Derivative Estimation	simulation, synchrotron, controls, dipole	1795
	B.R. Reichardt, D. Domont-Yankulova Technische Universität Darmstadt (TU Darmstadt, RMR), Darmstadt, Germany D. Domont-Yankulova, H. Klingbeil TEMF, TU Darmstadt, Darmstadt, Germany H. Klingbeil, D.E.M. Lens GSI, Darmstadt, Germany
	Funding: Supported by the GSI During acceleration in SIS18/SIS100 at GSI/FAIR longitudinal beam-oscillations are expected to occur. To reduce emittance blow-up, dedicated LLRF beam feedback systems are planned. To date longitudinal beam oscillations have been damped in machine experiments with a finite-impulse-response (FIR) filter controller with 3 filter taps[1]. An alternative approach implementing the FIR filter as a derivative estimator controller is simulated and tested. This approach shares the same controller topology and can therefore be easily integrated in the system. It exploits the fact that the sampling rate of the feedback hardware is considerably higher than the frequency of the beam oscillations. It is therefore capable of damping oscillations without overshoot within one oscillation period.
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TUPIK054	The MAMI-C Accelerator: 25 Years of Operation and Strategies for the Next Decade	klystron, operation, microtron, electron	1816
	M. Dehn, K. Aulenbacher, F. Fichtner, R.G. Heine, P. Jennewein, W. Klag, H.-J. Kreidel, J.R. Röthgen, V. Tioukine IKP, Mainz, Germany
	Funding: Work supported by DFG (CRC 1044) and the German federal state of Rheinland-Pfalz The Mainz Microtron Accelerator (MAMI-C) is a staged Race Tack Microtron (RTM) accelerator for 100μA polarised electrons up to 1.6 GeV energy. This report addresses the problems and our strategies to reliably operate the MAMI-C Accelerator for at least another ten years and what lessons have been learned for the new Mainz Energy recovering Superconducting Accelerator (MESA).
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TUPIK061	Data Acquisition and Controls Integration of the AWAKE Experiment at CERN	controls, proton, software, extraction	1833
	V.K.B. Olsen University of Oslo, Oslo, Norway J.J. Batkiewicz, S. Deghaye, S.J. Gessner, E. Gschwendtner CERN, Geneva, Switzerland P. Muggli MPI, Muenchen, Germany
	The AWAKE experiment has been successfully installed in the CNGS facility at CERN, and is currently in its first stage of operation. The experiment seeks to demonstrate self-modulation of an SPS proton beam in a rubidium plasma, driving a wakefield of several gigavolt per meter. We describe the data acquisition and control system of the AWAKE experiment, its integration into the CERN control system and new control developments specifically required for AWAKE.
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TUPIK068	Parameters Calibration and Compensation-Rematch of Failure Cavities in CADS Injector	cavity, simulation, brightness, rfq	1852
	Y.Z. Jia, W.L. Chen, W.P. Dou, P.H. Gao, H. Jia, S.H. Liu, Y.S. Qin, C. Wang, W.S. Wang, Z.J. Wang IMP/CAS, Lanzhou, People's Republic of China
	Now when a failure on the China Accelerator Driven System (CADS) is detected, the beam will be stopped by the machine protection system (MPS) immediately. But because of the demand of the beam trip (more than 5 min) rate which should be less than 50 times per year [1], it is important to avoid cutting beam down or recover the beam in a short time. The compensation and rematch is of great importance. If the failure is on a cavity, the other cavities should retune to compensate the beam energy, position and phase in order to recover the beam in short time depending on the time of online calculation.
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TUPIK121	Dark Sector Experiments at LCLS-II (DASEL) Accelerator Design	kicker, FEL, laser, septum	2008
	Y.M. Nosochkov, T.G. Beukers, A.R. Fry, C. Hast, T.W. Markiewicz, T.K. Nelson, N. Phinney, T.O. Raubenheimer, P.C. Schuster, N. Toro SLAC, Menlo Park, California, USA
	Funding: Work supported by the US DOE Contract DE-AC02-76SF00515. DASEL (Dark Sector Experiments at LCLS-II) is a new accelerator and detector facility proposed to be built at SLAC. Its primary target is a direct observation of dark matter produced in electron-nuclear fixed-target collisions. DASEL takes advantage of the LCLS-II free electron laser (FEL) under construction at SLAC which will deliver a continuous electron beam from a 4-GeV superconducting linac. DASEL will operate parasitically to the LCLS-II FEL by extracting low intensity unused dark current bunches downstream of the FEL kickers. The DASEL key accelerator components include a 46-MHz gun laser system providing controlled intensity and timing of the dark current, a fast (MHz) kicker with 600-ns flat-top, a new transport line connecting the LCLS-II to the existing A-line and to End Station-A where the experiments will take place, and a spoiler and collimator system in the A-line for final shaping of the DASEL beam. An overview of the DASEL accelerator system is presented.
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TUPVA005	Impact of the Crossing Angle on Luminosity Asymmetries at the LHC in 2016 Proton Physics Operation	luminosity, emittance, operation, proton	2035
	M. Hostettler LHEP, Bern, Switzerland F. Antoniou, I. Efthymiopoulos, K. Fuchsberger, G. Iadarola, N. Karastathis, M. Lamont, Y. Papaphilippou, G. Papotti, J. Wenninger CERN, Geneva, Switzerland
	During 2016 proton physics operation at the CERN Large Hadron Collider (LHC), an asymmetry of up to 10% was observed between the luminosities measured by the ATLAS and CMS experiments. As the same bunch pairs collide in both experiments, a difference in luminosities must be of either geometric or instrumental origin. This paper quantifies the impact of the crossing angle on this asymmetry. As the beams cross in different planes in the two experiments, non-round beams are expected to yield an asymmetry due to the crossing angle. Results from crossing angle measurements at both experiments are also shown and the impact on the luminosities is evaluated.
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TUPVA014	The 2016 Proton-Nucleus Run of the LHC	luminosity, proton, operation, ion	2071
	J.M. Jowett, R. Alemany-Fernández, G. Baud, P. Baudrenghien, R. De Maria, R. De Maria, D. Jacquet, M.A. Jebramcik, A. Mereghetti, T. Mertens, M. Schaumann, H. Timko, M. Wendt, J. Wenninger CERN, Geneva, Switzerland
	For five of the LHC experiments the second p-Pb collision run planned in 2016 offered the opportunity to answer a range of important physics questions arising from the surprise discoveries (e.g., flow-like collective phenomena in small systems) made in earlier Pb-Pb, p-Pb and p-p runs. However the diversity of the physics and their respective capabilities led them to request very different operating conditions, in terms of collision energy, luminosity and pile-up. These appeared mutually incompatible within the available one month of operation. Nevertheless, a plan to satisfy most requirements was developed and implemented successfully. It exploited different beam lifetimes at two beam energies of 4 Z TeV and 6.5 Z TeV, a variety of luminosity sharing and bunch filling schemes, and varying beam directions. The outcome of this very complex strategy for repeated re-commissioning and operation of the LHC included the longest ever LHC fill with luminosity levelled for almost 38 h. The peak luminosity achieved exceeded the design value by a factor 7.8 and integrated luminosity substantially exceeded the experiments' requests.
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TUPVA025	Observations of Beam Losses at the LHC During Reduction of Crossing Angle	beam-losses, proton, beam-beam-effects, luminosity	2105
	B. Salvachua, X. Buffat, A.A. Gorzawski, T. Pieloni, S. Redaelli, C. Tambasco, J. Wenninger CERN, Geneva, Switzerland J. Barranco García, A.A. Gorzawski EPFL, Lausanne, Switzerland M.P. Crouch UMAN, Manchester, United Kingdom
	Several machine development studies have been performed in 2016 at the LHC in order to evaluate the effects of reducing the crossing angles in favor of defining the maximum achievable luminosity in the ATLAS and CMS experiments. At the end of the LHC proton-proton run at 6.5TeV the reduction of the crossing angle from 185urad to 140urad was operationally implemented. The observation of beam losses and lifetimes during this process are analysed and discussed.
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TUPVA029	Observations of Emittance Growth in the Presence of External Noise in the LHC	emittance, simulation, damping, brightness	2117
	X. Buffat, C. Tambasco, D. Valuch CERN, Geneva, Switzerland J. Barranco García, T. Pieloni, C. Tambasco EPFL, Lausanne, Switzerland
	Dedicated experiments were perfomed in the LHC to study the impact of noise on colliding high brightness beams. The results are compared to theoretical models and multiparticle tracking simulations. The impacts on the LHC operation and the HL-LHC project are discussed.
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TUPVA032	Beam-Gas Background Observations at LHC	background, detector, simulation, luminosity	2129
	S.M. Gibson Royal Holloway, University of London, Surrey, United Kingdom R. Alemany-Fernández, F. Alessio, G. Bregliozzi, H. Burkhardt, G. Corti, A. Di Mauro, M. Guthoff, A. Manousos, K.N. Sjobak, C. Yin Vallgren CERN, Geneva, Switzerland A. Alici Bologna University, Bologna, Italy S. D'Auria University of Glasgow, Glasgow, United Kingdom S.M. Gibson JAI, Egham, Surrey, United Kingdom D. Lazic BUphy, Boston, Massachusetts, USA
	Observations of beam-induced background at LHC during 2015 and 2016 are presented in this paper. The four LHC experiments use the non-colliding bunches present in the physics-filling pattern of the accelerator to trigger on beam-gas interactions. During luminosity production the LHC experiments record the beam-gas interactions using dedicated background monitors. These data are sent to the LHC control system and are used to monitor the background levels at the experiments during accelerator operation. This is a very important measurement, since poor beam-induced background conditions can seriously affect the performance of the detectors. A summary of the evolution of the background levels during 2015 and 2016 is given in these proceedings.
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TUPVA034	SPS Studies in Preparation for the Crab Cavity Experiment	emittance, luminosity, cavity, simulation	2133
	A. Alekou, A. Alekou, F. Antoniou, F. Antoniou, G. Arduini, G. Arduini, H. Bartosik, H. Bartosik, R. Calaga, R. Calaga, Y. Papaphilippou, Y. Papaphilippou, Y. Papaphilippou CERN, Geneva, Switzerland A. Alekou, R.B. Appleby, R.B. Appleby UMAN, Manchester, United Kingdom R.B. Appleby, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	A local Crab Cavity (CC) scheme will recover head-on collisions at the Interaction Points (IPs) of the High Luminosity LHC (HL-LHC), which aims to increase the LHC luminosity by a factor of 3-10. The first time that CC will ever be tested with proton beams will be in 2018 in the SPS machine. The available dedicated Machine Development (MD) time after the installation of the cavities will be limited and therefore good preparation is essential in order to ensure that the MDs are as efficient as possible. This paper presents the simulations and experimental studies performed in preparation for the future MDs and discusses the next steps.
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TUPVA040	Overview of Design Development of FCC-hh Experimental Interaction Regions	luminosity, optics, detector, dipole	2151
	A. Seryi, J.L. Abelleira, E. Cruz Alaniz, L.J. Nevay, L. van Riesen-Haupt JAI, Oxford, United Kingdom R.B. Appleby, H. Rafique UMAN, Manchester, United Kingdom R.B. Appleby Cockcroft Institute, Warrington, Cheshire, United Kingdom J. Barranco García, T. Pieloni EPFL, Lausanne, Switzerland M. Benedikt, M.I. Besana, X. Buffat, H. Burkhardt, F. Cerutti, A. Langner, R. Martin, W. Riegler, D. Schulte, R. Tomás CERN, Geneva, Switzerland M. Boscolo, F. Collamati INFN/LNF, Frascati (Roma), Italy M. Hofer TU Vienna, Wien, Austria L.J. Nevay Royal Holloway, University of London, Surrey, United Kingdom L. van Riesen-Haupt University of Oxford, Oxford, United Kingdom
	The experimental interaction region is one of the key areas that define the performance of the Future Circular Collider. In this overview we will describe the status and the evolution of the design of EIR of FCC-hh, focusing on design of the optics, energy deposition in EIR elements, beam-beam effects and machine detector interface issues.
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Paper

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MOYAA1

Approaching the Nominal Performance at the LHC

luminosity, operation, emittance, injection

13

J. Wenninger
CERN, Geneva, Switzerland

In 2015 the Large Hadron Collider (LHC) restarted for Run 2 after an almost two year long shutdown to consolidate the machine for operation at nominal beam energy. Following a month of recommissioning and training of the magnet system, the LHC operated for the first time at an energy of 6.5 TeV. The aim of this first year was to master operation at the higher energy and with beams of 25 ns spacing. In 2016 the performance could be pushed based on the experience of 2015, culminating with a luminosity 40% above the design value of 10³⁴ cm^-2s⁻¹. The status of the machine operation, performance and prospects for the rest of Run 2 and Run 3 will be discussed.

Slides MOYAA1 [4.639 MB]

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MOOCB2

Laser System Design and Operation for SNS H⁻ Beam Laser Stripping

laser, operation, ion, neutron

57

Y. Liu, A.V. Aleksandrov, S.M. Cousineau, T.V. Gorlov, A.A. Menshov, A. Webster
ORNL, Oak Ridge, Tennessee, USA
A. Rakhman
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: This work has been partially supported by U.S. DOE grant DE-FG02-13ER41967. ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE.
Recently, a high-efficiency laser assisted hydrogen ion (H⁻) beam stripping was successfully carried out in the Spallation Neutron Source (SNS) accelerator. The experiment was not only an important step toward foil-less H⁻ stripping for charge exchange injection, it also served as a first example of using megawatt ultraviolet (UV) laser in an operational high power proton accelerator facility. This talk reports the design, implementation, and commissioning results of the macropulse laser system, laser transport line, and laser operation for the laser stripping experiment. The macropulse laser consists of a mode-locked picosecond pulsed seed laser and a burst-mode Nd:YAG laser amplifier. The general design concept can be adapted to any temporal beam structures in most accelerators. We have achieved UV pulses with the pulse widths varying between 34 to 54 ps and a maximum peak power over 3.5 MW. A laser transport line is installed to deliver the UV beam to the laser stripping chamber at a transmission efficiency of 70%. Laser operation including remote control and monitor of laser parameters will be described.

Slides MOOCB2 [11.306 MB]

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MOPAB005

The MultiMat Experiment at CERN HiRadMat Facility: Advanced Testing of Novel Materials and Instrumentation for HL-LHC Collimators

target, instrumentation, real-time, damping

76

F. Carra, A. Bertarelli, E. Berthomé, C. Fichera, J. Guardia, M. Guinchard, L.K. Mettler, S. Redaelli, O. Sacristan De Frutos
CERN, Geneva, Switzerland
T.R. Furness
University of Huddersfield, Huddersfield, United Kingdom
M. Portelli
UoM, Msida, Malta

Funding: *Part of the work described in this thesis was developed in the scope of the EuCARD-2 Project, WP11 'ColMat ' HDED', co-funded by the partners and the European Commission under Capacities 7th Framework Programme, Grant Agreement n. 312453. Research supported by the HL-LHC project.
The increase of the stored beam energy in future particle accelerators, such as the HL-LHC and the FCC, calls for a radical upgrade in the design, materials and instrumentation of Beam Intercepting Devices (BID), such as collimators Following successful tests in 2015 that validated new composite materials and a novel jaw design conceived for the HL-LHC collimators, a new HiRadMat experiment, named 'HRMT36-MultiMat', is scheduled for autumn 2017. Its objective is to determine the behaviour under high intensity proton beams of a broad range of materials relevant for collimators and beam intercepting devices, thin-film coatings and advanced equipment. The test bench features 16 separate target stations, each hosting various specimens, allowing the exploration of complex phenomena such as dynamic strength, internal damping, nonlinearities due to anisotropic inelasticity and inhomogeneity, effects of energy deposition and radiation on coatings. This paper details the main technical solutions and engineering calculations for the design of the test bench and of the specimens, the candidate target materials and the instrumentation system
#federico.carra@cern.ch

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MOPAB024

Proposal to Observe Half-Bare Electrons on a 40-MeV LINAC

electron, radiation, laser, linac

126

N. Delerue, S. Jenzer, V. Khodnevych, A. Migayron
LAL, Orsay, France
N.F. Shul'ga
NSC/KIPT, Kharkov, Ukraine
S. Trofymenko
KhNU, Kharkov, Ukraine

Funding: CNRS/IN2P3 and Joint Laboratory France-Ukraine IDEATE
In different processes of relativistic electron interaction with substance and external fields, the electron loses part of its Coulomb field and becomes half-bare. Such state of electron significantly modifies the characteristics of its electromagnetic radiation during further interaction of the particle with substance. We propose to study the influence of the half-bare state of electron upon its transition radiation (TR). The existence of such influence for the case of electron undressing at its scattering was theoretically predicted. We intend to obtain the electrons in half-bare state in the result of their crossing of a conducting screen such as a TR screen. We propose to investigate the influence of the half-bare state of electron in this process upon TR generated by such electron on a downstream TR screen situated on some distance from the upstream screen which undresses the particle. Calculations are presented for the case of a 45-MeV linac and the distance between the screens in the region between 100 mm and 300 mm. The proposed experiment is expected to reveal new features of TR signal in such process comparing to previous measurements.
N.F. Shul'ga, S.V. Trofymenko, V.V. Syshchenko, JETP Lett. 93 (2011) 1.
Y. Shibata, K. Ishi, T. Tokahashi et al., Phys. Rev. E 49 (1994) 785.

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MOPAB025

Measurement of the Polarisation of Coherent Smith-Purcell Radiation in the SOLEIL Linac

radiation, polarization, detector, linac

129

N. Delerue, S. Jenzer, V. Khodnevych
LAL, Orsay, France
N. Hubert, M. Labat, J.-P. Pollina, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France

Funding: CNRS/IN2P3, Université Paris-Sud and ANR (contract ANR-12-JS05-0003-01)
SPESO is an experiment installed in the Linac of Synchrotron SOLEIL to study the Coherent Smith-Purcell radiation produced when a grating is approached from the beam. The detectors used to measure this radiation are mounted on 3-translation axis and 2 rotation axis. This allows measurements of the radiation emission map around the grating. In addition a polarizer has been added in 2016 allowing to study the two polarization components of the radiation in this map. Preliminary results of this mapping will be presented.

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MOPAB044

X-Band TDS Project

electron, polarization, diagnostics, cavity

184

B. Marchetti, R.W. Aßmann, B. Beutner, J. Branlard, F. Christie, R.T.P. D'Arcy, W. Decking, U. Dorda, J. Herrmann, M. Hoffmann, M. Hüning, O. Krebs, G. Kube, S. Lederer, F. Ludwig, F. Marutzky, D. Marx, J. Osterhoff, I. Peperkorn, S. Pfeiffer, F. Poblotzki, J. Rönsch-Schulenburg, J. Rothenburg, H. Schlarb, M. Scholz, S. Schreiber, M. Vogt, A. Wagner, T. Wilksen, K. Wittenburg
DESY, Hamburg, Germany
M. Bopp, H.-H. Braun, P. Craievich, M. Pedrozzi, E. Prat, S. Reiche, K. Rolli, R. Zennaro
PSI, Villigen PSI, Switzerland
N. Catalán Lasheras, A. Grudiev, G. McMonagle, W. Wuensch
CERN, Geneva, Switzerland

Based on the success of the X-Band Transverse Deflecting Structure (TDS) diagnostic at LCLS*, a collaboration between DESY, PSI and CERN has formed with the aim of developing and building an advanced modular X-Band TDS system. The designed TDS has the new feature of providing variable polarization of the deflecting field**. The possibility of changing the orientation of the streaking field of the TDS to an arbitrary azimuthal angle allows for 3D characterization of the phase space using tomographic methods***. Moreover the complete 6D characterization of the beam phase space is possible by combining this technique with quadrupole scans and a dipole spectrometer. As this new cavity design requires very high manufacturing precision to guarantee highest azimuthal symmetry of the structure to avoid the deterioration of the polarization of the streaking field, the high precision tuning-free assembly procedures developed at PSI for the SwissFEL C-band accelerating structures will be used for the manufacturing****. The high-power rf system is based on the CERN-based X-band test stands. We summarize in this work the status of the projects and its main technical parameters.
* C. Behrens et al. , Nat. Comm. 4762 (2014).
** A. Grudiev, CLIC-note-1067 (2016).
*** D. Marx et al., contribution to this conference proceedings.
**** U. Ellenberger et al., FEL 2013, TUPS017.

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MOPAB045

Reconstruction of the 3D Charge Distribution of an Electron Bunch Using a Novel Variable-Polarization Transverse Deflecting Structure (TDS)

simulation, electron, space-charge, laser

188

D. Marx, R.W. Aßmann, U. Dorda, U. Dorda, B. Marchetti
DESY, Hamburg, Germany
P. Craievich
PSI, Villigen PSI, Switzerland
A. Grudiev, A. Grudiev, A. Grudiev
CERN, Geneva, Switzerland

A TDS is a well-known device for the characterization of the longitudinal properties of an electron bunch in a linear accelerator. So far, the correlation of the slice properties in the horizontal/vertical planes of the electron bunch distribution has been characterized by using a TDS system deflecting in the vertical/horizontal directions respectively and analysing the image on a subsequent screen*. Recently, an innovative design for a TDS structure has been proposed, which includes the possibility of continuously varying the angle of the transverse streaking field inside a TDS structure**. This allows the beam distribution to be characterized in all transverse directions. By collecting measurements of bunches streaked at different angles and combining them using tomographic techniques, it is possible to retrieve 3D distributions of the charge density. In this paper, a method is proposed and simulation results are presented to show the feasibility of such an approach at the upcoming accelerator R&D facility, SINBAD, at DESY***.
* M. Roehrs et al., Phys. Rev. ST Accel. Beams 12, 050704 (2009).
** A. Grudiev, Report No. CLIC-Note-1067, 2016.
*** B. Marchetti et al. X-band TDS project contribution to these conference proceedings.

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MOPAB067

Response of Scintillating Screens to High Charge Density Electron Beam

electron, quadrupole, linac, diagnostics

268

F. Miyahara, S. Kishimoto, M. Satoh, Y. Seimiya, T. Suwada
KEK, Ibaraki, Japan
M. Koshimizu
Tohoku University, School of Science, Sendai, Japan

Inorganic scintillating screens are very useful tool to measure transverse profile of charged particle beams. The cerium-doped yttrium:aluminum:garnet (YAG:Ce) crystal scintillator is used in many accelerating facilities. The scintillating screen shows good resolution comparable to that of OTR screen. However, response to high charge density electron beam, more than 10 nC per square millimeter, has not been clarified. In KEK e⁺/e⁻ injector linac, the charge areal density (σ) will exceed 25 nC per square mm. Thus, beam tests has been performed on YAG:Ce, LYSO, and BGO crystals for 1.5 GeV, 1 nC/bunch electron beam at the linac. Saturation of the luminescence which causes degradation of the resolution has been observed above 1 nC per square mm in those crystals. We will report the response of the scintillating screens to high charge density electron beam and discuss the degradation of the resolution due to the saturation of the light yield.

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MOPAB072

Measurement of Three-Dimensional Distribution of Electron Bunch Using RF Transverse Deflector

electron, laser, gun, solenoid

285

Y. Nakazato, Y. Koshiba, T. Sasaki, M. Washio
Waseda University, Tokyo, Japan
K. Sakaue
Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan

We have been studying a high quality electron beam generated by a photocathode RF gun at Waseda University. The electron beam is applied to a pulse radiolysis experiment, laser Compton scattering for soft X-ray generation, and a THz imaging experiment using coherent radiation. In these applications, longitudinal parameters of the electron beam are important. For this reason, we developed the RF deflector system which can directly convert longitudinal distribution of the beam to transverse with high temporal resolution, and performed longitudinal profile measurements of an electron beam from the RF gun. During a series of experiments using an RF deflector, we found that the bunch had a horizontal angle with respect to z axis. Thus we tried to reconstruct the three-dimensional profile of the bunch by computed tomography* in order to visualize the three-dimensional distribution of the bunch. In this conference, we will report the principle of measurement, experimental results of the bunch three-dimensional measurement, and future prospects.
* J. Shi, et al., Reconstruction of the three-dimensional bunch profile by tomography technique with RF deflecting cavity, Nucl. Instrum. Methods Phys. Res., A 752 (2014) 36-41

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MOPAB074

Low Intensity Electron Beam Controlling and Monitoring

electron, detector, linac, controls

292

L. Yu, Y. Li, Y.F. Sui, J.H. Yue
IHEP, Beijing, People's Republic of China

To calibrating a cosmic-ray detector, a low beam current accelerator has been built to generate ultra low intensity electron beams at Institute of High Energy Physics (IHEP). The minimum beam charge obtained was estimated to be about one electron/pulse. Beam commissioning has been carried out. The key technologies for achieving such low intensity electron beams are to control the beam using 8 movable slits and to measure the intensity of the beam using 9 movable current monitors based on scintillator. In this paper, principal of operation, instrumentation and programming of the movable slits and movable current monitors are discussed. Some results of beam commissioning are also presented.

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MOPAB077

Spatial Decoding Electro-Optic Bunch Measurement at Tsinghua Thomson Scattering X-ray Source

laser, electron, diagnostics, scattering

302

W. Wang, Z.J. Chi, Y.-C. Du, W.-H. Huang, C.-X. Tang, L.X. Yan, Z. Zhang
TUB, Beijing, People's Republic of China

Electron bunches with duration of sub-picosecond are essential in ultraviolet and X-ray free electron laser (XFEL) to reach the desired peak current. Electro-optic (EO) technique is suitable for temporal profile measure-ment of these ultrashort bunches which is one of the key diagnostics in FELs. An electro-optic monitor based on spatial sampling has recently been designed and installed for bunch profile diagnostic at Tsinghua Thomson scat-tering X-ray source (TTX). An ultrashort laser pulse is used to detect the field induced birefringence of the bunch Coulomb field in an electro-optic crystal and the monitor allows direct time-resolved single-shot measure-ment of bunch profile with an accuracy of 135 femtosec-onds for a 40 MeV electron bunch in a non-destructive way, which can simultaneously record the relative time jitter between probe laser and electron bunch. This paper performs the layout of the setup and presents the current measurement results.

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MOPAB080

The Development of Tune Measurement System Based on FPGA at HLSII Storage Ring

FPGA, storage-ring, status, synchrotron

305

Q.M. Duan, Y.L. Yang
USTC/NSRL, Hefei, Anhui, People's Republic of China

A tune measurement system based on FPGA development board is developed at HLS II. The FPGA development board based on Zynq SOC, have ADC and DAC on board. The FPGA can provide two kinds of signal for exciting the beam: parametric frequency sweep signal and bandwidth limited white noise signal. The FFT algorithms and calculation of tune are running in the ARM CPU. In order to compare performance with the original system which is based on spectrum analyzer, we did experiments with new system based FPGA and original system respectively. The experiments on HLSII storage ring show that the tune measuring accuracy have reached 0.0006 / 0.0001 in horizontal and vertical direction based on sweep frequency of FPGA-based system.

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MOPAB090

Wavefront Distortion Measurement at SSRF

simulation, radiation, synchrotron, synchrotron-radiation

332

B. Gao, H.J. Chen, J. Chen, Y.B. Leng, K.R. Ye
SINAP, Shanghai, People's Republic of China
B. Gao
University of Chinese Academy of Sciences, Beijing, People's Republic of China
N. Zhang
SSRF, Shanghai, People's Republic of China

The Synchrotron Radiation Monitor (SRM) system has been designed and constructed at the Shanghai synchrotron radiation Facility (SSRF) for several years and runs good. However, the monitor extraction mirror deformation is quite common at different facilities, and other reflecting mirrors in the optic path also have surface error and angle error. As we decide to upgrade the SR monitor system at SSRF, this issue is also one of the most import thing what we should overcome. In order to verify the feasibility and evaluate the accuracy, simulations based on SRW code have been done. In this simulation, a dedicated algorithm was developed to reconstruct wavefront. The result and the algorithm is very useful for our experiment and upgrade program. In this paper, the algorithm and the experiments based on Shark-Hartmann wavefront sensor will be presented detailed.

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MOPAB091

Transverse Beam Instability Observation and Investigation Using Bunch by Bunch on-Line DAQ System

feedback, storage-ring, vacuum, data-acquisition

335

N. Zhang, L.W. Lai, Y.B. Leng
SSRF, Shanghai, People's Republic of China

Funding: supported by National Natural Foundation of China (11375255 and 11375254)
Tank impedance of in-vacuum insertion device is one important source of beam transverse instability, which was expected to be suppressed by transverse feedback system (TFB). For the observation and study of transverse instability affected by insertion device and TFB, sets of an in-vacuum undulator narrow gap setting and TFB gain setting were operated in a beam-based experiment. A bunch-by-bunch (BYB) position on-line DAQ system was employed in the measurement to characterize frequencies of individual bunches. Bunch-train transverse oscillation amplitude variation were curved by harmonic analysis. In this paper, we will introduce the BTB ADQ system, and report on the measurement experiment and related data analysis.

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MOPAB093

Bunch Phase Measurement for Storage Ring

storage-ring, simulation, injection, pick-up

341

Y.M. Zhou, Y.B. Leng, N. Zhang
SSRF, Shanghai, People's Republic of China
H.J. Chen
SINAP, Shanghai, People's Republic of China

A bunch-by-bunch phase measurement system has been studied to improve the accuracy of phase measurement. Longitudinal phase information will be retrieved from beam signals picked up from the button electrodes. The signals from four electrodes in the BPM are summed by using a 4-way power driver, by which the effect of the transverse beam offset on the phase measurement can be eliminated. Four samples with fixed time interval (typical 100ps) for each bunch, which are taken by a 500MHz waveform recorder with a four channels signal splitting and delaying network, will be used to calculate bunch phase. In this paper, we present the layout of the system and primary experimental results.

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MOPAB095

Development of the Simulation Software Package for the CBPM System

simulation, cavity, network, FEL

349

J. Chen, L.W. Lai, Y.B. Leng, L.Y. Yu
SINAP, Shanghai, People's Republic of China
N. Zhang
SSRF, Shanghai, People's Republic of China

In recent years, the development and construction of Free Electron Laser (FEL) facilities are in full swing. For FEL facilities, to generate coherent X-ray, cavity beam position monitor (CBPM) system which consist of cavity BPM, RF front-end and signal processor are employed to measure the transverse position in the undulator section. A generic simulation software package, with the S21 parameters of the real components, for the design of the RF front-end and the optimize of the CBPM system was developed. In this paper, the development of the generic simulation software package, and the experiment results with beam at Shanghai Deep ultraviolet (SDUV) FEL facility to verify the correctness of the simulation soft package will be introduced. The application in the design and optimize of the RF front-end for the Dalian Coherent Source (DCLS) will be addressed as well .

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MOPAB107

A Method for Determining the Roll Angle of the CLIC Accelerating Structures From the Beam Shape Downstream of the Structure

octupole, collider, simulation, emittance

368

J. Ögren, V.G. Ziemann
Uppsala University, Uppsala, Sweden
W. Farabolini
CEA/DSM/IRFU, France

The Compact Linear Collider (CLIC) accelerating structures have a four-fold symmetry from the radial waveguides for damping higher order modes. This symmetry allows for an octupole component of the rf fields to co-propagate with the main accelerating field. The effect of this octupole mode has been observed at the CLIC test facility 3. In CLIC the accelerating structures are mounted together on a moveable girders. There are four vertical and four horizontal actuators on the girder, which allows for 5D control in a limited range and for instance we can roll the girder. By observing the beam shape perturbed by the octupole field on a screen downstream from the structure we can determine the roll angle and thus align the structure azimuthally. Here we discuss a possible method and show some preliminary results.

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MOPAB108

Beam-Based Alignment Studies at CTF3 Using the Octupole Component of CLIC Accelerating Structures

octupole, wakefield, alignment, collider

371

J. Ögren, A.K. Bhattacharyya, M. Holz, R.J.M.Y. Ruber, V.G. Ziemann
Uppsala University, Uppsala, Sweden
W. Farabolini
CEA/DSM/IRFU, France

The Compact Linear Collider (CLIC) uses normal-conducting accelerating structures that are sensitive to wakefield effects and therefore their alignment is extremely important. Due to the four-fold symmetry of the structures, they allow for an octupole component of the rf fields. By scanning the beam transversely we can determine the center of the structures from the shifts in beam position due to the kicks from the octupole field. We present some initial results from measurements at the CLIC test facility 3 at CERN.

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MOPAB110

Comparison of Transverse Emittance Measurements in the LHC

emittance, luminosity, detector, operation

377

M. Hostettler, R. Alemany-Fernández, F. Alessio, M. Ferro-Luzzi, K. Fuchsberger, G. Iadarola, R. Matev, S. Papadopoulou, Y. Papaphilippou, G. Papotti, G. Trad
CERN, Geneva, Switzerland
F. Antoniou
The University of Liverpool, Liverpool, United Kingdom
G.R. Coombs
University of Glasgow, Glasgow, United Kingdom
T.B. Hadavizadeh
Oxford University, Physics Department, Oxford, Oxon, United Kingdom

Transverse emittance measurement in a collider is of crucial importance for understanding beam dynamics observations and evaluating the machine performance. Devices measuring the beam emittance face the challenge of dealing with considerable systematic errors that can compromise the quality of the measurement. Having different instruments or techniques that provide beam size estimations in order to compare the outcome and give an unbiased value of the emittance is very important in a collider. The comparison of the different results is as well very useful to identify possible problems in a given equipment which could remain unnoticed if such device is the only source of emittance reconstruction. In the LHC several of these instruments and techniques are available; wire scanners, synchrotron light monitors, emittance reconstruction from transverse convolved beam sizes extracted from luminosity scans at the LHC collision points and from beam-gas imaging in the vertex detector of the LHCb experiment. Those systems are briefly presented in this paper together with the comparison of the emittances reconstructed by each of them during physics production over the 2016 LHC run.

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MOPAB128

The Design of a Non-Destructive Single-Shot Longitudinal Bunch Profile Monitor using Smith-Purcell Radiation

radiation, detector, background, polarization

433

H. Harrison, G. Doucas, I.V. Konoplev, A.J. Lancaster, H. Zhang
JAI, Oxford, United Kingdom
A. Aryshev, M. Shevelev, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan

Funding: This work was supported by the: the STFC UK, the Leverhulme Trust, the JAI (University of Oxford) and the Photon and Quantum Basic Research Coordinated Development (Japan).
The conceptual design for a single-shot longitudinal bunch profile monitor using coherent Smith-Purcell radiation (cSPr) has recently been completed. The exploitation of the directionality and the polarization of cSPr to reduce the length of the monitor and to eliminate background radiation are discussed. The linear polarization of cSPr will be used to separate the signal from background radiation and experiments to test this design will be presented. Alongside the conceptual design an investigation to optimize the number of detection channels needed to produce high quality longitudinal bunch profile reconstructions has been carried out. It has been determined that the number of detection channels can be reduced compared to previous experiments if measurement uncertainty and background radiation are minimized effectively.

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MOPAB130

Cross-Calibration of the LHC Transverse Beam-Profile Monitors

emittance, optics, luminosity, proton

437

R. Alemany-Fernández, F. Alessio, A. Alexopoulos, C. Barschel, F.S. Carlier, J.M. Coello de Portugal, M. Ferro-Luzzi, A. Garcia-Tabares, M. Hostettler, O. Karacheban, E.H. Maclean, R. Matev, T. Persson, P.K. Skowroński, R. Tomás, G. Trad, S. Vlachos, B. Würkner
CERN, Geneva, Switzerland
G.R. Coombs
EPFL, Lausanne, Switzerland
T.B. Hadavizadeh
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
M. Hofer
TU Vienna, Wien, Austria
L. van Riesen-Haupt
University of Oxford, Oxford, United Kingdom

Calibration of a transverse beam profile monitor is of fundamental importance to guarantee the best possible accuracy and reliability of the instrument over time. In LHC the calibration standard for transverse-profile measurements are the wire scanners. Other profile monitors such as beam synchrotron light telescopes and interferometers are calibrated with respect to them. Additional information about single-bunch sizes can be obtained from beam-gas imaging in the LHCb vertex detector, from the transverse convolved beam sizes extracted from luminosity scans at the collision points, and from the evolution of the luminous-region parameters as reconstructed by ATLAS and CMS inner tracker detectors during such scans. For the first time in LHC, a dedicated cross-calibration of all the above-mentioned systems was carried out with beam in 2016. Additionally, dedicated optics measurements were also performed in order to determine with the highest possible accuracy the amplitude function at the interaction points and at the position of the profile monitors. Results of these measurements are presented in this paper.

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MOPAB131

Transverse Emittance Measurements Using LHCb's Beam-Gas Interactions

detector, emittance, real-time, operation

441

T.B. Hadavizadeh
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
R. Alemany-Fernández, F. Alessio, C. Barschel, G.R. Coombs, M. Ferro-Luzzi, R. Matev
CERN, Geneva, Switzerland

Measurements of the transverse beam emittance are of great importance at particle accelerators such as the LHC in order to monitor, understand and improve the performance of the machine. A number of profile monitors at the LHC are capable of measuring the transverse emittance from a range of different processes including wire scanners and beam synchrotron light monitors, each having advantages and shortcomings. It is possible additionally to measure the beam profiles using interaction vertices reconstructed in LHCb's vertex locator (Velo). Interactions between colliding beam particles and between beam particles and residual gas nuclei are used to build up a picture of the beam profiles. To guarantee the reliability and quality of the different emittance measurements, a dedicated cross-calibration was performed during a machine development period in October 2016. The results obtained with the LHCb Velo during this cross-calibration are presented here.

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MOPAB139

A Supersonic Gas-Jet Based Beam Induced Fluorescence Prototype Monitor for Transverse Profile Determination

electron, ion, photon, gun

458

H.D. Zhang, E. Martin, V. Tzoganis, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
E. Barrios Diaz, N. Chritin, O.R. Jones, G. Schneider, R. Veness
CERN, Geneva, Switzerland
P. Forck, S. Udrea
GSI, Darmstadt, Germany
P. Forck
IAP, Frankfurt am Main, Germany
E. Martin, V. Tzoganis, C.P. Welsch, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom
S. Udrea
TU Darmstadt, Darmstadt, Germany

Supersonic gas jets have been used in transverse beam profile monitoring as Ionization Profile Monitors (IPMs) and Beam Induced Fluorescence (BIF) monitors. The former method images ions generated by the projectile beam, whilst the latter is based on the detection of photons. This is a promising technology for use in high energy accelerators, such as the High Luminosity Large Hadron Collider (HLLHC). In this paper, the suitability of a supersonic gas jet in combination with a BIF detection system for the measurement of the transverse beam profile of a low energy electron beam is discussed. The technical layout and experimental results from measurements at a test installation at the Cockcroft Institute are also presented.

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MOPAB140

Phase-Space Analysis Using Tomography for the Muon g-2 Experiment at Fermilab

proton, target, storage-ring, quadrupole

462

D. Stratakis
Fermilab, Batavia, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy.
In the next decade the Fermilab Muon Campus will host two world class experiments dedicated to the search for signals of new physics. The Muon g-2 experiment will determine with unprecedented precision the anomalous magnetic moment of the muon. The Mu2e experiment will improve by four orders of magnitude the sensitivity on the search for the as-yet unobserved Charged Lepton Flavor Violation process of a neutrinoless conversion of a muon to an electron. Maintaining and preserving a high density of particles in phase-space is an important requirement for both experiments. This paper presents a new experimental method for mapping the transverse phase space of a particle beam based on tomographic principles. We simulate our technique using the tracking code GEANT4, to ascertain accuracy of the reconstruction. Then we apply the technique to a series of proof-of-principle simulation tests to study injection, transport and extraction of muon and proton beams for the Fermilab g-2 and Mu2e Experiments.

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MOPAB141

Instrumentation and Its Interaction With the Secondary Beam for the Fermilab Muon Campus

ion, simulation, vacuum, emittance

466

D. Stratakis, B.E. Drendel, M.J. Syphers
Fermilab, Batavia, Illinois, USA
M.J. Syphers
Northern Illinois University, DeKalb, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy.
The Fermilab Muon Campus will host the Muon g-2 experiment - a world class experiment dedicated to the search for signals of new physics. Strict demands are placed on the beam diagnostics in order to ensure delivery of high quality beams to the storage ring with minimal losses. In this study, we briefly describe the available secondary beam diagnostics for the Fermilab Muon Campus. Then, with the aid of numerical simulations we detail their interaction with the secondary beam. Finally, we compare our results against theoretical findings.

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MOPAB150

Imaging the Spatial Modulation of a Relativistic Electron Beam

electron, scattering, quadrupole, emittance

480

C. Zhang, W.S. Graves, L.E. Malin, J. Spence
Arizona State University, Tempe, USA
D.B. Cesar, J.M. Maxson, P. Musumeci, A. Urbanowicz
UCLA, Los Angeles, USA
C. Limborg, E.A. Nanni
SLAC, Menlo Park, California, USA

Funding: Work supported by NSF awards 1632780, 1415583, 1231306 and DOE award de-sc0009914
We describe Bragg diffraction of relativistic electron beams through a patterned Si crystal consisting of alternating thick and thin strips to produce nanometer scale electron density modulations. Multi-slice simulations show that a two-beam situation can be set up where, for a particular thickness of Si, nearly 100% of the electron beam is diffracted. Plans are underway to carry out experiments showing this effect in UCLA's ultrafast electron microscopy lab with 3.5 MeV electrons. We will select either the diffracted beam or the primary beam with a small aperture in the diffraction plane of a magnetic lens, and so record either the dark or bright field magnified image of the strips. Our first goal is to observe the nanopatterned beam at the image plane. We will then investigate various crystal thickness and sample orientations to maximize the contrast in the pattern and explore tuning the period of the modulation through varying magnification.

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MOPAB153

R&D of a Gas-Filled RF Beam Profile Monitor for Intense Neutrino Beam Experiments

cavity, plasma, electron, ion

491

K. Yonehara, M. Backfish, A. Moretti, A.V. Tollestrup, A.C. Watts, R.M. Zwaska
Fermilab, Batavia, Illinois, USA
R.J. Abrams, M.A. Cummings, A. Dudas, R.P. Johnson, G.M. Kazakevich, M.L. Neubauer
Muons, Inc, Illinois, USA
Q. Liu
Case Western Reserve University, Cleveland, USA

Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359 and DOE STTR Grant, No. DE-SC0013764.
A MW-power beam facility is desired to produce an intense neutrino beam for study of fundamental particle physics. It is a critical challenge to measure beam profile in extreme radiation environments. To this end, a novel beam profile monitor based on a gas-filled multi-RF cavity is proposed. Charged particles through the gas-filled RF generate plasma that changes the gas permittivity. The modulated RF signal in the cavity due to the permittivity shift will be measured to reconstruct the flux of charged particles in the cavity. The demonstration is proposed to validate the concept of the monitor. We report the progress of the demonstration test.

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MOPIK006

Characterization of the Electron Beam from the Thz Driven Gun for AXSIS

electron, gun, simulation, diagnostics

509

G. Vashchenko, R.W. Aßmann, U. Dorda, K. Galaydych, B. Marchetti, T. Vinatier
DESY, Hamburg, Germany
M. Fakhari, A. Fallahi, F.X. Kärtner, N.H. Matlis
CFEL, Hamburg, Germany
W. Qiao, C. Zhou
University of Hamburg, Hamburg, Germany

Funding: The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement n. 609920
The AXSIS (Attosecond X-ray Science: Imaging and Spectroscopy) project aims for development of a compact, fully coherent, THz-driven, attosecond X-ray source. A compact THz driven gun was developed, produced and tested as a source of the ultra-short electron bunches required for the project. To characterize the low energy, low-charge beam produced by such a gun tailored diagnostic devices were developed and commissioned at a test-stand chamber in CFEL (DESY). Results of the first experiments on the production and characterization of the electron beam are presented.

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MOPIK009

Characterization of Cold Model Cavity for Cryocooled C-Band 2.6-Cell Photocathode RF Gun at 20 K

cavity, gun, cryogenics, simulation

518

T. Tanaka, K. Hayakawa, Y. Hayakawa, K. Nakao, K. Nogami, T. Sakai, K. Takatsuka
LEBRA, Funabashi, Japan
M.K. Fukuda, D. Satoh, T. Takatomi, N. Terunuma, J. Urakawa, M. Yoshida
KEK, Ibaraki, Japan

Funding: This work was partly supported by the Photon and Quantum Basic Research Coordinated Development Program of the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT).
A cryocooled C-band 2.6-cell photocathode RF electron gun has been studied at Nihon University in cooperation with KEK. The cold model cavity with an input coupler was completed in spring 2016. The RF characteristics measured at room temperature were in agreement with the prediction by the CST Studio simulation. The RF characteristics at 20 K have been measured using a rather simple cavity-cooling vacuum system that was built by using existing components for tentative experiments. A thin-wall stainless-steel R48 waveguide with copper-plated inner walls has been used for the RF power transmission from the room-temperature input port to the 20-K cooled coupler waveguide. The unloaded Q-value of 73000 has been obtained by the reflection coefficient measurement at 20 K, which is in agreement with the result of the CST Studio simulation using the cavity surface resistance predicted by the theory of the anomalous skin effect.

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MOPIK026

Commissioning and Operation of an Ultrafast Electron Diffraction Facility as Part of the ATF-II Upgrade at Brookhaven National Laboratory

electron, operation, laser, photon

554

M.G. Fedurin, M. Babzien, C. Folz, M. Fulkerson, K. Kusche, J.J. Li, R. Malone, M.A. Palmer, T.V. Shaftan, J. Skaritka, L. Snydstrup, C. Swinson, F.J. Willeke
BNL, Upton, Long Island, New York, USA

Funding: Work supported by the US DOE under contract DE-SC0012704.
The Accelerator Test Facility (ATF) at Brookhaven National Laboratory (BNL) is presently carrying out an upgrade, ATF-II, which will provide significantly expanded experimental space and capabilities for its users. One of the new capabilities being integrated into the ATF-II program is an Ultrafast Electron Diffraction (UED) beam line, which was originally deployed in the BNL Source Development Laboratory. Inclusion of the UED in the ATF-II research portfolio will enable ongoing development and extension of the UED capabilities for use in materials research. We describe the design, operation and future plans for the UED beam line at the ATF-II.

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MOPIK048

Experimental Results of Crystal-Assisted Slow Extraction at the SPS

extraction, proton, detector, collimation

623

M.A. Fraser, S.S. Gilardoni, B. Goddard, V. Kain, D. Mirarchi, S. Montesano, S. Petrucci, S. Redaelli, R. Rossi, W. Scandale, L.S. Stoel, F.M. Velotti
CERN, Geneva, Switzerland
F.M. Addesa, G. Cavoto, F. Iacoangeli
INFN-Roma, Roma, Italy
F. Galluccio
INFN-Napoli, Napoli, Italy
F. Murtas
INFN/LNF, Frascati (Roma), Italy

The possibility of extracting highly energetic particles from the Super Proton Synchrotron (SPS) by means of silicon bent crystals has been explored since the 1990's. The channelling effect of a bent crystal can be used to strongly deflect primary protons and eject them from the synchrotron. Many studies and experiments have been carried out to investigate crystal channelling effects. The extraction of 120 and 270 GeV proton beams has already been demonstrated in the SPS with dedicated experiments located in the ring. Presently in the SPS, the UA9 experiment is performing studies to evaluate the possibility to use bent silicon crystals to steer particle beams in high energy accelerators. Recent studies on the feasibility of extraction from the SPS have been made using the UA9 infrastructure with a longer-term view of using crystals to help mitigate slow extraction induced activation of the SPS. In this paper, the possibility to eject particles into the extraction channel in LSS2 using the bent crystals already installed in the SPS is presented. Details of the concept, simulations and measurements carried out with beam are presented, before the outlook for the future is discussed.

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MOPIK049

SPS Slow Extracted Spill Quality During the 2016 Run

target, extraction, quadrupole, power-supply

627

V. Kain, J. Bauche, P. Catherine, K. Cornelis, M.A. Fraser, L. Gatignon, C.M. Genton, B. Goddard, K. Kahle, M. Magrans de Abril, O. Michels, L.S. Stoel, F.M. Velotti
CERN, Geneva, Switzerland

The flux of particles slow extracted with the 1/3 integer resonance from the Super Proton Synchrotron at CERN should ideally be constant over the length of the extraction plateau, for optimum use of the beam by the fixed target experiments. The extracted intensity is controlled in feed-forward correction of the horizontal tune via the main SPS quadrupoles. The Mains power supply noise at 50 Hz and harmonics is also corrected in feed-forward by small amplitude tune modulation at the respective frequencies with a dedicated additional quadrupole circuit. In 2016 the spill quality could be much improved with respect to the situation of the previous year with more performant algorithms. In this paper the improved tools are described and the characteristics of the SPS slow extracted spill in terms of macro structure and typical frequency content are shown. Other sources of perturbation were, however, also present in 2016 which frequently caused the spill quality to be much reduced. The different effects are discussed and possible or actual solutions detailed. Finally, the evolution of the spill quality during characteristic periods in the 2016 run is presented.

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MOPIK067

Figure-8 Storage Ring - Ion Beam Injection into a Closed, Magnetic System

injection, detector, storage-ring, ion

680

H. Niebuhr, A. Ates, M. Droba, O. Meusel, U. Ratzinger
IAP, Frankfurt am Main, Germany

To store high current low-energetic ion beams of up to 10 A, a superconducting storage ring (F8SR) based on solenoidal and toroidal magnetic guiding fields is investigated at Frankfurt University. Besides simulations, a scaled down experimental setup with normalconducting magnets was built. Investigations of beam injection into closed, magnetic guiding fields are in progress. Therefore, a new kind of injection system consisting of a solenoidal injection coil and a special vacuum vessel was constructed. It is used to inject a hydrogen beam from the side between two toroidal magnets. In parallel operation, a second hydrogen beam is transported through both magnets to represent the circulating beam. The current status of the experimental setup and first experimental results will be shown.

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MOPIK085

Linear Optics Calibration at the HLS-II Storage Ring Using Model Independent Analysis

storage-ring, optics, lattice, operation

727

G. Liu, L. Wang, F.F. Wu, K. Xuan
USTC/NSRL, Hefei, Anhui, People's Republic of China

Linear optics are the main lattice parameters characterizing the linear properties of storage rings. Especially for beta function and phase advance, they are the basic lattice functions which must be accurately calibrated to ensure high quality operation of the machine. Model Independent Analysis (MIA), which adopts mathematical statistical methods to extract the effective lattice information of storage rings by directly analyzing the turn-by-turn beam-position-monitor (BPM) measurements, has been applied at HLS-II to calibrate the linear optics model of the storage ring. The measurements of the turn-by-turn BPM data with all of the 32 BPMs are reported in this paper. The calibration results of the beta function using MIA are presented.

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MOPIK102

Beam Dynamics Studies of the HIE-ISOLDE Transfer Lines in the Presence of Magnetic Stray Fields

quadrupole, shielding, operation, solenoid

768

J. Mertens, J. Bauche, M.A. Fraser, B. Goddard, R. Ostojić, J.S. Schmidt
CERN, Geneva, Switzerland

The ISOLDE facility at CERN produces radioactive isotopes far from stability for fundamental nuclear physics research. The radioactive beams are accelerated to high-energy using a post-accelerator before being transferred for study in different experiments at the end of a network of High Energy Beam Transfer (HEBT) lines. In the framework of the HIE-ISOLDE project, the energy of post-accelerated beams is to be increased to over 10 MeV/u and new experimental detectors are being proposed for installation to exploit the new energy regime. The stray magnetic fields associated with many of the new detectors will distort the beam trajectories in the HEBT, potentially affecting the transmission of the low intensity beams delivered to the experiments. In this contribution, the influence on the HEBT of the stray field of the proposed ISOL Solenoidal Spectrometer is discussed, correction schemes described and shielding options assessed.

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MOPIK110

Update on Bmad Simulations From Target to Storage Ring for the New Muon G-2 Experiment at Fermilab

storage-ring, proton, polarization, target

791

M. Korostelev, I.R. Bailey, A.T. Herrod, A. Wolski
Cockcroft Institute, Warrington, Cheshire, United Kingdom
I.R. Bailey
Lancaster University, Lancaster, United Kingdom
A.T. Herrod, A. Wolski
The University of Liverpool, Liverpool, United Kingdom
D. Stratakis
Fermilab, Batavia, Illinois, USA
V. Tishchenko
BNL, Upton, Long Island, New York, USA

The new muon g-2 experiment at Fermilab (E989) aims to measure the anomalous magnetic moment of the muon to an uncertainty of 140 ppb. The existing accelerator facility at Fermilab is being adapted to the requirements of the g-2 experiment and the baseline lattice design is now established. This paper presents the results of beam simulations and spin tracking carried out using the Bmad software package for the g-2 beam transport system, including a variant which bypasses the delivery ring as proposed for the beam commissioning.

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MOPIK119

Beam Dynamics in g-2 Storage Ring

storage-ring, resonance, quadrupole, dipole

817

W. Wu, B. Quinn
UMiss, University, Mississippi, USA

The muon anomalous magnetic moment has played an important role in constraining physics beyond the Standard Model. The Fermilab Muon g-2 Experiment has a goal to measure it to unprecedented precision: 0.14 ppm. To achieve this goal, we must understand the beam dynamics systematic effects in the muon storage ring. We will present the muon beam dynamics and discuss two specific topics here: the beam resonance which is related to the muon loss and the fast rotation analysis to determine the muon momentum distribution.

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MOPIK125

Multi-frequency AC LOCO: A Fast and Precise Technique for Lattice Correction

lattice, quadrupole, optics, power-supply

831

X. Yang, K. Ha, V.V. Smaluk, Y. Tian, L. Yu
BNL, Upton, Long Island, New York, USA

We developed a novel technique to improve the precision and shorten the measurement time of the LOCO (Linear Optics from Closed Orbits) method at NSLS-II [1]. This technique named AC LOCO is based on a sine-wave (AC) beam excitation via fast correctors typically installed at synchrotron light sources for the fast orbit feedback. The beam oscillations are measured by beam position monitors. The narrow band used for the beam excitation and measurement not only allows us to suppress effectively the beam position noise and also makes simultaneously exciting multiple correctors at different frequencies (multi-frequency mode) possible. We demonstrated at NSLS-II that the new technique provides better lattice corrections and achieves two minutes measurement time in the thirty-frequency mode.
[1] X. Yang et al., 'Fast and precise technique for magnet lattice correction via sine-wave excitation of fast correctors', Phys. Rev. Accel. Beams, vol. 20, p. 054001, 2017.

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MOPIK127

FAIR Risk Management as a Proactive Steering Tool for the Large Scale Multi Project

factory, project-management, antiproton, ion

839

S. Deveaux, F. Becker
GSI, Darmstadt, Germany

The Facility for Antiproton and Ion Research (FAIR) is a large scale multi project comprising 10 subprojects in the field of accelerators (pLINAC, SIS100, SuperFRS, p-bar separator, Collector Ring, High Energy Storage Ring), experiments (CBM, APPA, NUSTAR, PANDA) and civil construction. This contribution describes the implementation of a progressive risk management methodology based on a comprehensive assessment on work package level. Complexity factors (number of parts, level of state of the art, level of human interfaces, level of operational complexity) and importance factors (safety, cost, schedule, resources) represent the likelihood of risk occurrence and the eventual value at risk. Relative comparison of the normalized factors together with a supplier assessment enables to derive an event based risk register with a standardized evaluation scheme assigning risk and opportunity classes. This contribution demonstrates the full methodology highlighting some typical examples of the FAIR project.

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MOPIK128

Integrated Project Planning as a Central Steering Tool for the Large Scale Multi Project FAIR

status, project-management, site, controls

842

N. Winters, F. Becker, M.V. Ricciardi
GSI, Darmstadt, Germany

The Facility for Antiproton and Ion Research (FAIR) is a large scale multi project comprising 10 subprojects in the field of accelerators (pLINAC, SIS100, SuperFRS, p-bar, CR, HESR), experiments (CBM, APPA, NUSTAR, PANDA) and civil construction. This contribution describes the fundamental revamp of FAIR integrated project planning. Main objective is to preserve the advantages of a bottom-up planning topology with the actual and detailed level of information keeping the ~400 work package leader's central role as plan owners in their field of responsibility. Simultaneously different project phases (e.g. civil construction, procurement, installation, commissioning) need to be excluded from detailed plans while being re-integrated in the level-1 project master schedule. Additional cost profiles and resource assignment by name allow a progress tracking and flexible project steering.

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MOPVA012

The Dedicated Accelerator R&D Facility Sinbad at DESY

linac, electron, laser, acceleration

869

U. Dorda, R.W. Aßmann, K. Galaydych, W. Kuropka, B. Marchetti, D. Marx, F. Mayet, G. Vashchenko, T. Vinatier, P.A. Walker, J. Zhu
DESY, Hamburg, Germany
A. Fallahi, F.X. Kärtner, N.H. Matlis
CFEL, Hamburg, Germany

We present an overview of the dedicated R\&D facility SINBAD which is currently under construction at DESY. The facility will host multiple independent experiments on the acceleration of ultra-short electron bunches and advanced acceleration schemes. In its initial phase, SINBAD will host two experiments: AXSIS and ARES. The AXSIS collaboration aims to accelerate fs-electron bunches to 15 MeV in a THz driven dielectric structure and subsequently create X-rays by inverse Compton scattering. The first stage of the ARES experiment is to set up a 100 MeV S-band electron linac to produce ultra-short electron bunches with excellent beam arrival time stability. Once this is achieved, the electrons will be ideally suited to be injected into experiments for testing advanced accelerator concepts e.g. DLA experiments in the context of the ACHIP collaboration. In the long term, external injection into a laser driven plasma acceleration stage is targeted as well.

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MOPVA014

Injector Linac Stability Requirements for High Precision Experiments at MESA

linac, electron, operation, acceleration

876

F. Hug, R.G. Heine
IKP, Mainz, Germany

Funding: Work supported by DFG through the PRISMA cluster of excellence EXC 1098/2014 and Research Training Group GRK 2128
MESA is a recirculating superconducting accelerator under construction at Johannes Gutenberg-Universität Mainz. It will be used for high precision particle physics experiments in two different operation modes: external beam (EB) mode and energy recovery (ERL) mode. The operating beam current and energy in EB mode is 0.15 mA with polarized electrons at 155 MeV. In ERL mode an unpolarized beam of 1 mA at 10⁵ MeV will be available. In a later construction stage of MESA the beam current in ERL-mode shall be upgraded to 10 mA. In order to achieve high beam stability and low energy spread in recirculating operation the acceleration in the main linac sections will be done on edge of the accelerating field while the return arcs provide longitudinal dispersion. On certain longitudinal working points this can result in a setting where rf jitters from main linac do not contribute to the resulting energy spread of the final beam at all [*,**]. Then the resulting energy spread is only determined by the energy spread provided by the inector linac. Within this contribution we will investigate the requirements on the stability of the MESA injector linac MAMBO for achieving the experimental goals.
[*] H. Herminghaus, NIM. A 314 (1992) 209.
[**] F. Hug et al., Proc. of LINAC '12 (2012) 531.

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MOPVA018

Resonant Coherent Diffraction Radiation System at ERL Test Accelerator in KEK

cavity, radiation, resonance, emittance

887

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

Funding: This work was supported by JSPS KAKENHI Grant Number 16H05991
An Energy Recovery Linac can produce a low emittance and short bunch beam at a high repetition rate. A test accelerator, compact-ERL, has been operating in KEK for development works of technologies related to ERL and CW-Superconducting accelerators. In a special beam operation mode of bunch compression, a short bunch beam of ~150 fs at the repetition rate of CW 1.3 GHz can be realized in the return-loop. One of the promising applications of such a short bunch beam is a high power THz radiation source produced by a coherent radiation. When a charged particle beam passes close to a conductive target, a radiation called diffraction radiation is produced. If the target mirrors form an optical cavity which fundamental frequency matches the repetition frequency of the beam, the radiation resonates in the cavity, resulting in extracting a huge radiation power determined by the loss of the cavity. We plan to perform an experiment of the resonant coherent diffraction mechanism in the return-loop of the compact-ERL to test the feasibility to be a wide band high power THz source. We report the design of the experimental setup to be installed in the summer of 2017.

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MOPVA025

Step-Like Field Magnets to Uniform Beam Distribution and Experiment at CADS Injector-I

simulation, target, dipole, proton

908

C. Meng, Y. Chen, H. Geng, J.Y. Tang, F. Yan, L. Yu, Y.L. Zhao
IHEP, Beijing, People's Republic of China

High power is the development tendency of proton accelerator, so obtaining uniform beam distribution on target becomes more and more important and critical. The method of using step-like field magnets to obtain a uniform beam distribution on target was presented. In the beamdump line of CADS injector-I test facility four step-like field magnets have been installed to uniform beam distribution to reduce the maximum current density on the beamdump. The magnetic field of step-like field magnets have been measured and discussed in this paper. The simulation results and measurement results of beam uniformization are presented.

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MOPVA027

Measurement of High Power Terahertz with Dielectric Loaded Waveguide at Tsinghua University

radiation, electron, wakefield, extraction

914

D. Wang, Y.-C. Du, W. Gai, W.-H. Huang, X.L. Su, C.-X. Tang, Q.L. Tian, L.X. Yan
TUB, Beijing, People's Republic of China
S.P. Antipov
Euclid Beamlabs LLC, Bolingbrook, USA
Y.F. Liang
Tsinghua University, Beijing, People's Republic of China

Funding: Work supported by the National Nature Science Foundation of China (NSFC Grants No.11475097) and the National Key Scientific Instrument and Equipment Development Project of China (Grants No. 2013YQ12034504)
We have measured an intense THz radiation produced by a sub-picosecond, relativistic electron bunch passing through a dielectric loaded waveguide (DLW) at Tsinghua University accelerator beamline. The DLW was 3 cm long quartz tube with 900 'm inner diameter and 100 'm wall thickness metallized on the outside. Radiated energy of the THz pulse was measured to be proportional to the square of the effective charge. The end of the DLW was cut at an angle for efficient THz pulse extraction. Tens of 'J THz energy per pulse were measured outside the vacuum chamber with a calibrated Golay cell in the experiment.
*wangdan16@mail.tsinghua.edu.cn
*yanlx@mail.tsinghua.edu.cn

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MOPVA047

Investigation of Trapped Magnetic Flux in Superconducting Niobium Samples with Polarized Neutron Radiography

neutron, niobium, detector, polarization

964

O. Kugeler, J. Knobloch, M.M. Krzyzagorski, J.M. Köszegi, L. Riik, W. Treimer, R.F. Ziesche
HZB, Berlin, Germany

The dynamics of flux expulsion during superconducting transition and the influence of external AC magnetic fields on expulsion of trapped fields in Nb samples has been investigated with radiography using polarized neu-trons. Results of these experiments are presented.

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MOPVA050

Setup of a Spatially Resolving Vector Magnetometry System for the Investigation of Flux Trapping in Superconducting Cavities

cavity, SRF, niobium, radio-frequency

975

B. Schmitz, K.Alomari. Alomari, J. Knobloch, O. Kugeler, J.M. Köszegi, Y. Tamashevich
HZB, Berlin, Germany

Flux trapping is the major contribution to the residual resistance of superconducting cavities. In order to gain a better understanding of the mechanisms involved and aiming at an eventual minimization of trapped flux, a measurement setup based on AMR sensors was devised that allows for monitoring the magnetic field vector at various positions near the cavity surface. First results of the efforts are presented.

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MOPVA076

Measurement of Thin Film Coating on Superconductors

cryogenics, controls, FPGA, photon

1043

Y. Iwashita, Y. Fuwa, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
H. Hayano, T. Kubo, T. Saeki
KEK, Ibaraki, Japan
M. Hino
Kyoto University, Research Reactor Institute, Osaka, Japan
H. Oikawa
Utsunomiya University, Utsunomiya, Japan

Funding: This research is supported by following programs: Grant-in-Aid for Exploratory Research JSPS KAKENHI Grant Number 26600142 and Photon and Quantum Basic Research Coordinated Development Program from the MEXT.
Multilayer thin film coating is a promising technology to enhance performance of superconducting cavities. Until recently, principal parameters to achieve the sufficient performance had not been known, such as the thickness of each layer. We proposed a method to deduce a set of the parameters to exhibit a good performances. In order to verify the scheme, we are trying to make some experiments on the subject at Kyoto. The sample preparation and the test setup for the measurement apparatus will be discussed.

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MOPVA100

Atomic Layer Deposition of Niobium Nitride from Different Precursors

plasma, niobium, controls, simulation

1094

P. Pizzol, P. Chalker, J.W. Roberts, J. Wrench
The University of Liverpool, Liverpool, United Kingdom
O.B. Malyshev, R. Valizadeh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Advancements in technology have taken bulk niobium cavities close to their theoretical operational limits of 45 MV/m, pushing the research to explore novel materials, such as niobium based alloys . Theoretical studies suggest that a composite material composed of alternative superconductor / insulator multilayers would surpass the bulk niobium limits. Chemical vapour deposition (CVD) can deposit mi-crons thick Nb films in less than an hour, at the expense of precise thickness control. Atomic layer deposition (ALD), instead, even if considerably slower than CVD can be used in applications where the thickness of the deposited layers needs to be controlled with a resolution down to the nanometer. This article presents the preliminary results obtained by using plasma assisted ALD techniques to deposit NbN based compounds starting from chlorinated precursors and organic ones, and the design for a new deposition system currently being built at the Daresbury Laboratories.

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MOPVA144

Post-Processing of Nb3Sn Coated Nb

niobium, SRF, superconductivity, cavity

1190

U. Pudasaini, M.J. Kelley
The College of William and Mary, Williamsburg, Virginia, USA
G.V. Eremeev, M.J. Kelley, C.E. Reece
JLab, Newport News, Virginia, USA
M.J. Kelley, J. Tuggle
Virginia Polytechnic Institute and State University, Blacksburg, USA

Funding: Supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DEÂAC05Â06OR23177 and Office of High Energy Physics under grant SC00144475.
Practical SRF cavities may be subjected to one or more processes after nominally complete preparation. Successful implementation of such processes in Nb3Sn coated cavities requires the understanding of material's response to these treatments. SRF-grade Nb samples, coated with Nb3Sn by the widely used tin vapor diffusion process were subjected to one or more of the following: hydrofluoric acid (HF) rinsing, oxypolishing, buffered chemical polishing (BCP) or electrochemical treatment. They were examined by materials characterization tech-niques including scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), and X-ray photoelectron spec-troscopy (XPS). The effects compared to niobium are different enough in most cases that further development is desirable to routinely obtain a favorable result.

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TUOBB1

Experimental Demonstration of Energy-Chirp Reduction by a Plasma Dechirper

plasma, electron, laser, linac

1258

Y.P. Wu, Z. Cheng, Y.-C. Du, J.F. Hua, W. Lu, C.H. Pai, J. Zhang, S.Y. Zhou, Z. Zhou
TUB, Beijing, People's Republic of China

The first experimental study is presented using a low density plasma dechirper to reduce a correlated energy chirp from the 41.5-MeV, 500-fs (RMS) beam at the linac in Tsinghua University. The plasma dechirper operates through the interaction of the electron bunch with its near linear self-wake to dechirp itself, leading to a reduction in energy spread. The experimental results demonstrate that the projected FWHM energy spread of the beam can be reduced from 1.2% to 0.9% with a 12 mm long plasma dechirper, which are in good agreement with full 3D PIC simulations. Theoretical analyses and simulations indicate that by optimizing the plasma density and length, the plasma dechirper can also be used to completely remove the characteristic energy chirp of the ultra-short high-current bunch generated from plasma based accelerator, such that its energy spread can be reduced from one percent level to 0.1 percent level[*]. Application of such a simple and effective method can significantly improve the beam quality and provide the path to realize the future compact free electron lasers and colliders driven by plasma based accelerators.
[*] Y. P. Wu. A plasma dechirper for electron and positron beams in plasma-based accelerators, to be submitted to Scientific Reports

Slides TUOBB1 [10.555 MB]

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TUOBB2

Starting Up the AWAKE Experiment at CERN

proton, plasma, laser, electron

1261

E. Gschwendtner
CERN, Geneva, Switzerland

AWAKE, the Advanced Proton Driven Plasma Wake-field Acceleration Experiment at CERN was approved in 2013. The facility was commissioned in 2016 to perform first experiments to demonstrate the self-modulation in-stability (SMI) of a 400 GeV/c SPS proton bunch in a 10 m long Rubidium plasma cell. The plasma is created in Rb vapor via field ionization by a TW laser pulse. In the second phase starting late 2017, the proton driven plasma wakefield will be probed with an externally injected 10 ' 20 MeV/c electron beam. This paper gives an overview of the AWAKE facility, describes the successful commissioning of the laser and proton beam line, the plasma cell and diagnostics and shows the successful synchronization of the proton beam with the laser at the few ps level so that the facility is ready for the SMI physics runs. In addition the status of the electron acceleration exper-iment for late 2017 will be presented.

Slides TUOBB2 [3.513 MB]

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TUPAB017

Results of the Beam-Loading Breakdown Rate Experiment at the CLIC Test Facility CTF3

beam-loading, operation, klystron, linac

1348

E. Senes, T. Argyropoulos, N. Catalán Lasheras, R. Corsini, D. Gamba, J. Giner Navarro, A. Grudiev, G. McMonagle, R. Rajamaki, X.F.D. Stragier, I. Syratchev, F. Tecker, W. Wuensch
CERN, Geneva, Switzerland
J. Giner Navarro
IFIC, Valencia, Spain
R. Rajamaki
Aalto University, School of Science and Technology, Aalto, Finland
E. Senes
Torino University, Torino, Italy

The RF breakdown rate is crucial for the luminosity performance of the CLIC linear collider. The required breakdown rate at the design gradient of 100 MV/m has been demonstrated, without beam presence, in a number of 12 GHz CLIC prototype structures. Nevertheless, the beam-loading at CLIC significantly changes the field profile inside the structures, and the behaviour with beam needs to be understood. A dedicated experiment in the CLIC Test Facility CTF3 to determine the effect of beam on the breakdown rate has been collecting breakdown data throughout the year 2016. The complete results of the experiment and the effect of the beam-loading on the breakdown rate are presented.

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TUPAB021

The Study of Focus-Dependent Dark Current for AREAL RF Photogun

electron, gun, solenoid, simulation

1358

L. Hakobyan, H. Davtyan, B. Grigoryan, A. Vardanyan
CANDLE SRI, Yerevan, Armenia

AREAL (Advanced Research Electron Accelerator Laboratory) is a project of linear accelerator based facility aimed to produce ultra-short electron bunches with small emittance. In the first phase of AREAL project an electron beam with energy up to 5 MeV is produced by the electron RF photogun and used for irradiation experiments in biology, microelectronics and accelerator technology development. For such experiments the exact calculation of absorbed dose and electron bunch peak current is one of important conditions. The presence of a dark current in electron gun affects the electron emission from photocathode, the exact absorbed dose calculation, and in general harms the machine performance. In this paper the estimation of dark current amount, produced in the electron gun, the ways to avoid its influence on experiments are discussed. The dark current measurements are compared with the simulation results. The electron beam separation from a dark current is discussed.

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TUPAB031

Status and Perspectives of the S-DALINAC Polarized-Electron Injector

electron, gun, cathode, laser

1388

M. Herbert, J. Enders, M. Espig, Y. Fritzsche, N. Kurichiyanil, M. Wagner
TU Darmstadt, Darmstadt, Germany

Funding: Work supported by the Deutsche Forschungsgemeinschaft through grants GRK 2128 and SFB 1245
The S-DALINAC Polarized Injector (SPIn) uses GaAs photocathodes to provide pulsed and/or polarized electron beams for nuclear-structure investigations. Recently, a test facility for Photo-Cathode Activation, Test and Cleaning using atomic-Hydrogen \mbox{(Photo-CATCH)} has been developed. This setup uses an inverted-insulator geometry for the photo-electron gun. Currently, tests and optimizations are conducted at \mbox{Photo-CATCH} in order to implement this new gun design at SPIn. We will present the current status of \mbox{Photo-CATCH}, the planned upgrade of SPIn (aimed at an operational voltage of 200 kV) and future measurements.

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TUPAB050

A Lifetime Study of CsK2Sb Multi-Alkali Cathode

cathode, laser, vacuum, electron

1440

M. Kuriki, L. Guo, M. Urano, A. Yokota
HU/AdSM, Higashi-Hiroshima, Japan
K. Negishi
Iwate University, Morioka, Iwate, Japan
Y. Seimiya
KEK, Ibaraki, Japan

Funding: Quantum beam project by the Ministry of Education, Culture, Sports, Science, and Technology, entitled High Brightness Photon Beam by Laser Compton Scattering and Cooperative supporting Program for Research Education in University by KEK(High Energy Accelerator Research Organization)
\rm CsK₂Sb is a high performance photo-cathode for accelerators requiring the high brightness electron beam. It can be driven by a green laser generated as SHG of a solid state laser. The quantum efficiency is as high as 10\%. In this article, the robustness of the cathode was studied experimentally. We found that 1/e lifetime of the cathode was inversely proportional to the vacuum pressure. The normalized temporal life was \rm (4.72± 0.08)× 10^-5~Pa.hour for 532 nm laser. The lifetime regarding to the extracted charge density was also inversely proportional to the vacuum pressure. The normalized charge life was \rm (1.19± 0.03± 0.04)× 10^-4 Pa.C/mm². The cathode is robust enough for a high brightness electron accelerator.

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TUPAB051

Substrate Dependence of CsK2Sb Cathode Performance

cathode, electron, laser, lattice

1443

M. Kuriki, L. Guo, M. Urano, A. Yokota
HU/AdSM, Higashi-Hiroshima, Japan
K. Negishi
Iwate University, Morioka, Iwate, Japan
Y. Seimiya
KEK, Ibaraki, Japan

Funding: Quantum beam project by the Ministry of Education, Culture, Sports, Science, and Technology, entitled High Brightness Photon Beam by Laser Compton Scattering and Cooperative supporting Program for Research and education in University by KEK(High Energy Accelerator Research Organization).
\rm CsK₂Sb is a high performance cathode which can be driven with a green laser. The cathode is generated by evaporation on a substrate in a high vacuum environment. The cathode was evaporated on various material and surface condition to evaluate the dependence of the cathode performance. GaAs (100), Si(100), and Si(111) were examined as samples of the substrate. For each materials, the cathode on the cleaned and as-received substrates were examined and those on the cleaned showed better performance than the as-received for all materials. The detail of the experimental results are presented.

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TUPAB053

Proof-of-Principle Experiment of Phase-Combined Undulator

undulator, permanent-magnet, gun, electron

1446

R. Kinjo, T. Tanaka
RIKEN SPring-8 Center, Hyogo, Japan
A. Kagamihata
JASRI/SPring-8, Hyogo, Japan

A huge attractive force is the largest concern in designing a mechanical structure of undulators, in which an accurate control and high uniformity of the gap between the upper and lower magnetic girders are required. This problem is especially serious for in-vacuum undulators, in which the girders are located inside the vacuum chamber. We have proposed a new concept called a phase-combined undulator, which has intrinsically no magnetic force*. In this undulator, the magnetic forces acting on the girders locally head to the longitudinal axis instead of the attractive direction, and are actually canceled out in total. Numerical calculations have shown that the attractive force will be reduced down to a negligible level. Recently, we performed a proof-of-principle experiment to examine the feasibility of this undulator concept in terms of the force between the girders and magnetic field distribution, which will be reported in the conference.
* R. Kinjo and T. Tanaka, Phys. Rev. ST Accel. Beams 17, 122401

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TUPAB056

New Achievements of the Laser System for RF-Gun at SuperKEKB Injector

laser, operation, gun, electron

1452

R. Zhang, T. Natsui, Y. Ogawa, M. Yoshida, X. Zhou
KEK, Ibaraki, Japan

For realizing high charge and low emittance electron and positron beams in SuperKEKB, we have been making improvements in current laser system for RF-gun. In order to realize more excellent thermal management in current laser system at high repetition rate operation, novel soldering Yb:YAG thin disk and copper tungsten heat sink laser head is manufactured via gold tin solder. Comparing with old design, less residual stress is introduced and more efficient thermal removal can be obtained. These new soldering laser heads are placed into a compact vacuum chamber and cooled by Peltier plates directly. This design can realize higher gain and amplification factor in regenerative amplifier and multi-pass amplifier. In addition, the compact and simple cooling method can achieve excellent thermal management for the purpose of realize laser operation at high repetition rate for following phases of SuperKEKB project. A perspective towards the next step experiment is also presented in this paper.

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TUPAB060

Development of the Laser System for the Proof-of-Principle Experiment of Crab Crossing Laser-Compton Scattering

laser, scattering, electron, luminosity

1460

T. Takahashi, D. Igarashi, Y. Koshiba, S. Ota, M. Washio
RISE, Tokyo, Japan
K. Sakaue
Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan
J. Urakawa
KEK, Ibaraki, Japan

An X-ray source via laser-Compton scattering has the advantage of small source, energy tunability and quasi-monochromaticity and is expected to be applied in a wide range of fields such as the industry and medical care. In laser-Compton scattering, the luminosity, which represents the collision frequency between the electrons and the photons, is very important. Increasing the luminosity is strongly required for increasing the scattered photon flux. One way to increase the luminosity is tilting electron bunches at the collision point, which is called crab crossing. It is the way to create the head-on collision artificially. The purpose of this study is the proof-of-principle of the crab crossing laser-Compton scattering. In this conference, we will report the design optimization and construction of the laser system for the collision and future prospects.
Variola Alessandro, et al. Luminosity optimization schemes in Compton experiments based on Fabry-Perot optical resonators. Physical Review Special Topics-Accelerators and Beams 14.3 (2011): 031001.

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TUPAB071

Experimental Results on THz Superradiation From the Undulator in Tsinghua University Beamline

radiation, undulator, electron, detector

1488

X.L. Su, Y.-C. Du, W.-H. Huang, L. Niu, C.-X. Tang, Q.L. Tian, D. Wang, L.X. Yan
TUB, Beijing, People's Republic of China
Y.F. Liang
Tsinghua University, Beijing, People's Republic of China

In this paper, the first operation of a widely tunable 8-period undulator at terahertz (THz) frequency in Tsinghua University beamline was reported. Superradiate undulator radiation from sub-picosecond electron bunches compressed by chicane was observed. The measured radiation curve shows clearly that the radiation energy is proportional to the charge square, and the THz frequency can be changed from 0.4 THz to 10 THz with narrow-band spectrums. Our results demonstrate a high power and tunable coherent THz source, which could be useful for many applications in the future.

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TUPAB075

Compact High Energy Electron Radiography System Based on Permanent Magnet Quadrupole

electron, quadrupole, target, permanent-magnet

1494

Z. Zhou, Y.-C. Du, W. Gai, W.-H. Huang, F. Li, T. Rui, C.-X. Tang
TUB, Beijing, People's Republic of China
W. Gai
ANL, Argonne, Illinois, USA

High energy electron radiography(HEER) is a promising diagnostic method for High Energy Density Physics (HEDP) or Inertial Confinement Fusion (ICF) owing to its capability of picosecond-nanometer spatio-temporal resolution, and is cost-effective in the meantime. A Compact HEER (CHEER) system based on Permanent Magnet Quadrupoles (PMQ) instead of conventional electromagnetic quadrupole is proposed. Its lattice design and beam optics optimization is finished, and experiment is to be carried out on Tsinghua Thomson X-ray source (TTX) beamline after PMQs fabrication and installation.

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TUPAB114

Design Study for a Plasma Undulator Experiment Using Capillary Based Discharge Plasma Source

laser, plasma, electron, undulator

1584

O. Mete Apsimon, R. Apsimon, Y. Ma, D. Seipt, M.J.V. Streeter, A.G.R. Thomas
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
T.H. Pacey, G.X. Xia
UMAN, Manchester, United Kingdom

A plasma undulator is formed when a short laser pulse is injected into plasma off-axis or at an angle that causes the centroid of this laser pulse to oscillate. Ponderomotively driven plasma wake will follow this centroid given that the product of the plasma wave number and the characteristic Rayleigh length of the laser is much larger than one. This oscillating transverse wakefield may work as an undulator forcing particles to follow sinusoidal trajectories and emit synchrotron radiation. In this paper, plans for an experiment are introduced and resulting radiation and injected beam characteristics are discussed. The aforementioned laser centroid oscillations are demonstrated using, EPOCH, a PIC code for laser-plasma interactions.

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TUPAB122

Engineering Optimization of The Support Structure and Drive System for the LCLS-II Soft X-Ray Undulator Segments

undulator, photon, simulation, laser

1602

A.J. DeMello, D. Arbelaez, D. Bianculli, A.P. Brown, J.N. Corlett, J.R. Dougherty, D.E. Humphries, J.-Y. Jung, M. Leitner, S. Marks, K.A. McCombs, K.L. Ray, D.A. Sadlier, D. Schlueter, E.J. Wallén
LBNL, Berkeley, California, USA

Funding: Work supported by the Director, O'ce of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The Linear Coherent Light Source II (LCLS-II) project, an upgrade to the free-electron laser facility at SLAC, is replacing the undulator system from a fixed gap to a variable gap system to enable tuning of the photon energy range. The LCLS-II project will include a soft x-ray (SXR) beam line and a hard x-ray (HXR) beam line. The SXR undulators are conventional vertical-gap horizontally-polarizing devices while the HXR undulators are novel horizontal-gap vertically-polarizing devices. This paper describes in detail the development of the SXR mechanical support structure and drive system. The effort has included extensive analysis of the various components to ensure that the undulators will perform within the design specifications. Engineering simulations undertaken and experiments performed to validate the computer modeling are presented together with measurement results from prototype and pre-production undulators.

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TUPAB146

Vibration Measurements of Super-Conducting Undulator at SSRF

undulator, data-analysis, data-acquisition, damping

1675

R.B. Deng, Y. Liu, L. Wang, S. Xiang
SINAP, Shanghai, People's Republic of China

Funding: Work supported by the National Natural Science Foundation of China (Grant No. 11405255)
A Super-Conducting Undulator (SCU) is being built at SSRF. Mechanical stability of SCU is critical to beam stability since the central load is supported by special strings in SCU and the vibration of load will cause directly the vibration of beam. In this paper, vibration results of several key components including central load, cold head, frame support, etc, are studied under different working mode of compressors. The ground vibrations at different distances are compared to get the influence of compressors to SCU. Useful suggestions and possible measures are described to mitigate the vibration and improve SCU stability.

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TUPIK001

Upgrade of the Two-Screen Measurement Setup in the AWAKE Experiment

proton, plasma, wakefield, electron

1682

M. Turner
TUG/ITP, Graz, Austria
V. Clerc, I. Gorgisyan, E. Gschwendtner, S. Mazzoni, A.V. Petrenko
CERN, Geneva, Switzerland

The AWAKE project at CERN uses a self-modulated §I{400}{GeV/c} proton bunch to drive GV/m wakefields in a §I10{m} long plasma with an electron density of n_pe = 7 × 10¹⁴ \rm{electrons/cm}³. We present the upgrade of a proton beam diagnostic to indirectly prove that the bunch self-modulated by imaging defocused protons with two screens downstream the end of the plasma. The two-screen diagnostic has been installed, commissioned and tested in autumn 2016 and limitations were identified. We plan to install an upgraded diagnostics to overcome these limitations.

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TUPIK017

Next Generation Plasma Cell for PWFA Experiments at PITZ

plasma, laser, electron, Windows

1715

O. Lishilin, J. Engel, M. Groß, G. Koss, G. Loisch, S. Philipp, R. Schütze, F. Stephan
DESY Zeuthen, Zeuthen, Germany
R. Brinkmann
DESY, Hamburg, Germany
F.J. Grüner
Center for Free-Electron Laser Science, Universität Hamburg, Hamburg, Germany
D. Richter
HZB, Berlin, Germany
C.B. Schroeder
LBNL, Berkeley, California, USA

A proof-of-principle experiment for the AWAKE experiment is ongoing at the Photo-Injector Test Facility at DESY, Zeuthen site (PITZ). The goal of the experiment is to observe and measure the energy and density self-modulation of a long electron beam passing through a laser-generated Lithium plasma*. Key devices of the experiment are a heat pipe based plasma cell, a photocathode laser system which enables production of long electron beams with sharp rising edges and well-developed diagnostics at PITZ, including a transverse deflecting cavity and a high-resolution electron spectrometer. In this report we present the current status of the experiment, including the latest updates of the experimental setup. The plasma cell is a lithium heat pipe oven with inert gas buffers at all input/output ports. An ArF ionization laser is coupled through side ports. Main improvements of the second generation plasma cell are an altered geometry of side arms and a new heat pipe design. Among other updates are an improved ArF laser beamline and new electron windows. We present here measurements of plasma density and homogeneity as well as results of beam transport studies for the experiment.
*O. Lishilin, M. Gross, et al., Â«First results of the plasma wakefield acceleration experiment at PITZÂ», NIM A, Volume 829, 1 September 2016, Pages 37-42, http://dx.doi.org/10.1016/j.nima.2016.01.005

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TUPIK018

Experimental Investigation of High Transformer Ratio Plasma Wakefield Acceleration at PITZ

plasma, wakefield, acceleration, simulation

1718

G. Loisch, P. Boonpornprasert, J.D. Good, M. Groß, H. Huck, M. Krasilnikov, O. Lishilin, A. Oppelt, Y. Renier, T. Rublack, F. Stephan
DESY Zeuthen, Zeuthen, Germany
G. Asova
INRNE, Sofia, Bulgaria
G. Asova, R. Brinkmann, A. Martinez de la Ossa, T.J. Mehrling, J. Osterhoff
DESY, Hamburg, Germany
F.J. Grüner
CFEL, Hamburg, Germany
F.J. Grüner, A. Martinez de la Ossa, T.J. Mehrling
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

Plasma wakefield acceleration (PWFA), the acceleration of particles in a plasma wakefield driven by high current-density particle bunches, is one of the most promising candidates for a future compact accelerator technology. A key aspect of this type of acceleration is the ratio between the accelerating fields experienced by a witness beam and the decelerating fields experienced by the drive beam, called the transformer ratio. As for longitudinally symmetrical bunches this ratio is limited by the fundamental theorem of beamloading to 2 in the linear regime*, a transformer ratio above this limit is considered high. This can be reached by using a modulated drive bunch or a shaped train of drive bunches. So far, only the latter case has been shown for wakefields in a RF-structure**. We show the experimental setup, simulations and first, preliminary results of high transformer ratio acceleration experiments at the Photoinjector Test Facility at DESY in Zeuthen (PITZ).
* K. L. F. Bane, P. B. Wilson and T. Weiland, AIP Conference Proceedings 127, p. 875, 1984
** C. Jing et al., Physical Review Letters 98, 144801, 2007

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TUPIK032

AWAKE Proton Beam Commissioning

proton, plasma, laser, alignment

1747

J.S. Schmidt, D. Barrientos, M. Barros Marin, B. Biskup, A. Boccardi, T.B. Bogey, T. Bohl, C. Bracco, S. Cettour Cave, H. Damerau, V. Fedosseev, F. Friebel, S.J. Gessner, A. Goldblatt, E. Gschwendtner, L.K. Jensen, V. Kain, T. Lefèvre, S. Mazzoni, J.C. Molendijk, A. Pardons, C. Pasquino, S.F. Rey, H. Vincke, U. Wehrle
CERN, Geneva, Switzerland
J.T. Moody
MPI-P, München, Germany
K. Rieger
MPI, Muenchen, Germany

AWAKE will be the first proton driven plasma wakefield acceleration experiment worldwide. The facility is located in the former CNGS area at CERN and will include a proton, laser and electron beam line merging in a 10 m long plasma cell, which is followed by the experimental diagnostics. In the first phase of the AWAKE physics program, which started at the end of 2016, the effect of the plasma on a high energy proton beam will be studied. A proton bunch is expected to experience the so called self-modulation instability, which leads to the creation of micro-bunches within the long proton bunch. The plasma channel is created in a rubidium vapor via field ionization by a TW laser pulse. This laser beam has to overlap with the proton beam over the full length of the plasma cell, resulting in tight requirements for the stability of the proton beam at the plasma cell in the order of ~ 0.1 mm. In this paper the beam commissioning results of the ~810 m long transfer line for proton bunches with 3·10¹¹ protons/bunch and a momentum of 400 GeV/c will be presented with a focus on the challenges of the parallel operation of the laser and proton beam.

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TUPIK038

Muon Sources for Particle Physics - Accomplishments of MAP

collider, factory, proton, target

1766

D.V. Neuffer, D. Stratakis
Fermilab, Batavia, Illinois, USA
M.A. Cummings
Muons, Inc, Illinois, USA
J.-P. Delahaye
SLAC, Menlo Park, California, USA
M.A. Palmer
BNL, Upton, Long Island, New York, USA
R.D. Ryne
LBNL, Berkeley, California, USA
D.J. Summers
UMiss, University, Mississippi, USA

Funding: supported by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the U. S. Department of Energy.
The Muon Accelerator Program (MAP) completed a four-year study on the feasibility of muon colliders and on using stored muon beams for neutrinos. That study was broadly successful in its goals, establishing the feasibility of lepton colliders from the 125 GeV Higgs Factory to more than 10 TeV, as well as exploring using a ' storage ring (MSR) for neutrinos, and establishing that MSRs could provide factory-level intensities of 'e (''e) and ''' ('') beams. The key components of the collider and neutrino factory systems were identified. Feasible designs and detailed simulations of all of these components were obtained, including some initial hardware component tests, setting the stage for future implementation where resources are available and clearly associated physics goals become apparent.

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TUPIK047

FAIR Control Centre (FCC) - Concepts and Interim Options for the Existing GSI Main Control Room

controls, operation, proton, ion

1791

M. Vossberg, K. Berkl, S. Reimann, P. Schütt, R.J. Steinhagen, G. Stephan
GSI, Darmstadt, Germany

The 'Facility for Anti-Proton and Ion Research' (FAIR) which is presently under construction, extends and supersedes the existing GSI. Present operation still largely relies on laborious manual tuning based on analogue signals routed directly to the existing control room. The substantial scope increase from 3 to more than 8 FAIR accelerators requires more intricate and precise control across longer accelerator chains, while providing a high degree of multi-user operation, with facility reconfiguration required on time-scales of a few times per week. A new FAIR Control Centre (FCC) is being planned to accommodate the required larger accelerator crews as well as accelerator-based experiments. While targeting a single control room for up to ~35 people, emphasis is put on ergonomics, operational processes, and minimising unnecessary strain on personnel already during the design stage. This contribution presents digital control room concepts, console layout, and beam-production-chain paradigms aimed at achieving good operational performances and that influence the new FCC design. Prior to FCC completion, interim upgrade options of the existing control room are being investigated.

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TUPIK048

Longitudinal Beam Stabilization at FAIR by Means of a Derivative Estimation

simulation, synchrotron, controls, dipole

1795

B.R. Reichardt, D. Domont-Yankulova
Technische Universität Darmstadt (TU Darmstadt, RMR), Darmstadt, Germany
D. Domont-Yankulova, H. Klingbeil
TEMF, TU Darmstadt, Darmstadt, Germany
H. Klingbeil, D.E.M. Lens
GSI, Darmstadt, Germany

Funding: Supported by the GSI
During acceleration in SIS18/SIS100 at GSI/FAIR longitudinal beam-oscillations are expected to occur. To reduce emittance blow-up, dedicated LLRF beam feedback systems are planned. To date longitudinal beam oscillations have been damped in machine experiments with a finite-impulse-response (FIR) filter controller with 3 filter taps[1]. An alternative approach implementing the FIR filter as a derivative estimator controller is simulated and tested. This approach shares the same controller topology and can therefore be easily integrated in the system. It exploits the fact that the sampling rate of the feedback hardware is considerably higher than the frequency of the beam oscillations. It is therefore capable of damping oscillations without overshoot within one oscillation period.

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TUPIK054

The MAMI-C Accelerator: 25 Years of Operation and Strategies for the Next Decade

klystron, operation, microtron, electron

1816

M. Dehn, K. Aulenbacher, F. Fichtner, R.G. Heine, P. Jennewein, W. Klag, H.-J. Kreidel, J.R. Röthgen, V. Tioukine
IKP, Mainz, Germany

Funding: Work supported by DFG (CRC 1044) and the German federal state of Rheinland-Pfalz
The Mainz Microtron Accelerator (MAMI-C) is a staged Race Tack Microtron (RTM) accelerator for 100μA polarised electrons up to 1.6 GeV energy. This report addresses the problems and our strategies to reliably operate the MAMI-C Accelerator for at least another ten years and what lessons have been learned for the new Mainz Energy recovering Superconducting Accelerator (MESA).

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TUPIK061

Data Acquisition and Controls Integration of the AWAKE Experiment at CERN

controls, proton, software, extraction

1833

V.K.B. Olsen
University of Oslo, Oslo, Norway
J.J. Batkiewicz, S. Deghaye, S.J. Gessner, E. Gschwendtner
CERN, Geneva, Switzerland
P. Muggli
MPI, Muenchen, Germany

The AWAKE experiment has been successfully installed in the CNGS facility at CERN, and is currently in its first stage of operation. The experiment seeks to demonstrate self-modulation of an SPS proton beam in a rubidium plasma, driving a wakefield of several gigavolt per meter. We describe the data acquisition and control system of the AWAKE experiment, its integration into the CERN control system and new control developments specifically required for AWAKE.

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TUPIK068

Parameters Calibration and Compensation-Rematch of Failure Cavities in CADS Injector

cavity, simulation, brightness, rfq

1852

Y.Z. Jia, W.L. Chen, W.P. Dou, P.H. Gao, H. Jia, S.H. Liu, Y.S. Qin, C. Wang, W.S. Wang, Z.J. Wang
IMP/CAS, Lanzhou, People's Republic of China

Now when a failure on the China Accelerator Driven System (CADS) is detected, the beam will be stopped by the machine protection system (MPS) immediately. But because of the demand of the beam trip (more than 5 min) rate which should be less than 50 times per year [1], it is important to avoid cutting beam down or recover the beam in a short time. The compensation and rematch is of great importance. If the failure is on a cavity, the other cavities should retune to compensate the beam energy, position and phase in order to recover the beam in short time depending on the time of online calculation.

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TUPIK121

Dark Sector Experiments at LCLS-II (DASEL) Accelerator Design

kicker, FEL, laser, septum

2008

Y.M. Nosochkov, T.G. Beukers, A.R. Fry, C. Hast, T.W. Markiewicz, T.K. Nelson, N. Phinney, T.O. Raubenheimer, P.C. Schuster, N. Toro
SLAC, Menlo Park, California, USA

Funding: Work supported by the US DOE Contract DE-AC02-76SF00515.
DASEL (Dark Sector Experiments at LCLS-II) is a new accelerator and detector facility proposed to be built at SLAC. Its primary target is a direct observation of dark matter produced in electron-nuclear fixed-target collisions. DASEL takes advantage of the LCLS-II free electron laser (FEL) under construction at SLAC which will deliver a continuous electron beam from a 4-GeV superconducting linac. DASEL will operate parasitically to the LCLS-II FEL by extracting low intensity unused dark current bunches downstream of the FEL kickers. The DASEL key accelerator components include a 46-MHz gun laser system providing controlled intensity and timing of the dark current, a fast (MHz) kicker with 600-ns flat-top, a new transport line connecting the LCLS-II to the existing A-line and to End Station-A where the experiments will take place, and a spoiler and collimator system in the A-line for final shaping of the DASEL beam. An overview of the DASEL accelerator system is presented.

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TUPVA005

Impact of the Crossing Angle on Luminosity Asymmetries at the LHC in 2016 Proton Physics Operation

luminosity, emittance, operation, proton

2035

M. Hostettler
LHEP, Bern, Switzerland
F. Antoniou, I. Efthymiopoulos, K. Fuchsberger, G. Iadarola, N. Karastathis, M. Lamont, Y. Papaphilippou, G. Papotti, J. Wenninger
CERN, Geneva, Switzerland

During 2016 proton physics operation at the CERN Large Hadron Collider (LHC), an asymmetry of up to 10% was observed between the luminosities measured by the ATLAS and CMS experiments. As the same bunch pairs collide in both experiments, a difference in luminosities must be of either geometric or instrumental origin. This paper quantifies the impact of the crossing angle on this asymmetry. As the beams cross in different planes in the two experiments, non-round beams are expected to yield an asymmetry due to the crossing angle. Results from crossing angle measurements at both experiments are also shown and the impact on the luminosities is evaluated.

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TUPVA014

The 2016 Proton-Nucleus Run of the LHC

luminosity, proton, operation, ion

2071

J.M. Jowett, R. Alemany-Fernández, G. Baud, P. Baudrenghien, R. De Maria, R. De Maria, D. Jacquet, M.A. Jebramcik, A. Mereghetti, T. Mertens, M. Schaumann, H. Timko, M. Wendt, J. Wenninger
CERN, Geneva, Switzerland

For five of the LHC experiments the second p-Pb collision run planned in 2016 offered the opportunity to answer a range of important physics questions arising from the surprise discoveries (e.g., flow-like collective phenomena in small systems) made in earlier Pb-Pb, p-Pb and p-p runs. However the diversity of the physics and their respective capabilities led them to request very different operating conditions, in terms of collision energy, luminosity and pile-up. These appeared mutually incompatible within the available one month of operation. Nevertheless, a plan to satisfy most requirements was developed and implemented successfully. It exploited different beam lifetimes at two beam energies of 4 Z TeV and 6.5 Z TeV, a variety of luminosity sharing and bunch filling schemes, and varying beam directions. The outcome of this very complex strategy for repeated re-commissioning and operation of the LHC included the longest ever LHC fill with luminosity levelled for almost 38 h. The peak luminosity achieved exceeded the design value by a factor 7.8 and integrated luminosity substantially exceeded the experiments' requests.

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TUPVA025

Observations of Beam Losses at the LHC During Reduction of Crossing Angle

beam-losses, proton, beam-beam-effects, luminosity

2105

B. Salvachua, X. Buffat, A.A. Gorzawski, T. Pieloni, S. Redaelli, C. Tambasco, J. Wenninger
CERN, Geneva, Switzerland
J. Barranco García, A.A. Gorzawski
EPFL, Lausanne, Switzerland
M.P. Crouch
UMAN, Manchester, United Kingdom

Several machine development studies have been performed in 2016 at the LHC in order to evaluate the effects of reducing the crossing angles in favor of defining the maximum achievable luminosity in the ATLAS and CMS experiments. At the end of the LHC proton-proton run at 6.5TeV the reduction of the crossing angle from 185urad to 140urad was operationally implemented. The observation of beam losses and lifetimes during this process are analysed and discussed.

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TUPVA029

Observations of Emittance Growth in the Presence of External Noise in the LHC

emittance, simulation, damping, brightness

2117

X. Buffat, C. Tambasco, D. Valuch
CERN, Geneva, Switzerland
J. Barranco García, T. Pieloni, C. Tambasco
EPFL, Lausanne, Switzerland

Dedicated experiments were perfomed in the LHC to study the impact of noise on colliding high brightness beams. The results are compared to theoretical models and multiparticle tracking simulations. The impacts on the LHC operation and the HL-LHC project are discussed.

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TUPVA032

Beam-Gas Background Observations at LHC

background, detector, simulation, luminosity

2129

S.M. Gibson
Royal Holloway, University of London, Surrey, United Kingdom
R. Alemany-Fernández, F. Alessio, G. Bregliozzi, H. Burkhardt, G. Corti, A. Di Mauro, M. Guthoff, A. Manousos, K.N. Sjobak, C. Yin Vallgren
CERN, Geneva, Switzerland
A. Alici
Bologna University, Bologna, Italy
S. D'Auria
University of Glasgow, Glasgow, United Kingdom
S.M. Gibson
JAI, Egham, Surrey, United Kingdom
D. Lazic
BUphy, Boston, Massachusetts, USA

Observations of beam-induced background at LHC during 2015 and 2016 are presented in this paper. The four LHC experiments use the non-colliding bunches present in the physics-filling pattern of the accelerator to trigger on beam-gas interactions. During luminosity production the LHC experiments record the beam-gas interactions using dedicated background monitors. These data are sent to the LHC control system and are used to monitor the background levels at the experiments during accelerator operation. This is a very important measurement, since poor beam-induced background conditions can seriously affect the performance of the detectors. A summary of the evolution of the background levels during 2015 and 2016 is given in these proceedings.

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TUPVA034

SPS Studies in Preparation for the Crab Cavity Experiment

emittance, luminosity, cavity, simulation

2133

A. Alekou, A. Alekou, F. Antoniou, F. Antoniou, G. Arduini, G. Arduini, H. Bartosik, H. Bartosik, R. Calaga, R. Calaga, Y. Papaphilippou, Y. Papaphilippou, Y. Papaphilippou
CERN, Geneva, Switzerland
A. Alekou, R.B. Appleby, R.B. Appleby
UMAN, Manchester, United Kingdom
R.B. Appleby, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

A local Crab Cavity (CC) scheme will recover head-on collisions at the Interaction Points (IPs) of the High Luminosity LHC (HL-LHC), which aims to increase the LHC luminosity by a factor of 3-10. The first time that CC will ever be tested with proton beams will be in 2018 in the SPS machine. The available dedicated Machine Development (MD) time after the installation of the cavities will be limited and therefore good preparation is essential in order to ensure that the MDs are as efficient as possible. This paper presents the simulations and experimental studies performed in preparation for the future MDs and discusses the next steps.

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TUPVA040

Overview of Design Development of FCC-hh Experimental Interaction Regions

luminosity, optics, detector, dipole

2151

A. Seryi, J.L. Abelleira, E. Cruz Alaniz, L.J. Nevay, L. van Riesen-Haupt
JAI, Oxford, United Kingdom
R.B. Appleby, H. Rafique
UMAN, Manchester, United Kingdom
R.B. Appleby
Cockcroft Institute, Warrington, Cheshire, United Kingdom
J. Barranco García, T. Pieloni
EPFL, Lausanne, Switzerland
M. Benedikt, M.I. Besana, X. Buffat, H. Burkhardt, F. Cerutti, A. Langner, R. Martin, W. Riegler, D. Schulte, R. Tomás
CERN, Geneva, Switzerland
M. Boscolo, F. Collamati
INFN/LNF, Frascati (Roma), Italy
M. Hofer
TU Vienna, Wien, Austria
L.J. Nevay
Royal Holloway, University of London, Surrey, United Kingdom
L. van Riesen-Haupt
University of Oxford, Oxford, United Kingdom

The experimental interaction region is one of the key areas that define the performance of the Future Circular Collider. In this overview we will describe the status and the evolution of the design of EIR of FCC-hh, focusing on design of the optics, energy deposition in EIR elements, beam-beam effects and machine detector interface issues.

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TUPVA079

Model of Statistical Errors in the Search for the Deuteron EDM in the Storage Ring

detector, simulation, scattering, dipole

2258

A.E. Aksentyev, V. Senichev
FZJ, Jülich, Germany

In this work we investigate the standard error of the spin precession frequency estimate in an experiment for the search for the electric dipole moment (EDM) of the deuteron using the polarimeter. The basic principle of polarimetry is the scattering of a polarized beam on a carbon target. Since the number of particles in one fill is limited, we must maximize the utility of the beam. This raises the question of sampling efficiency, as the signal, being an oscillating function, varies in informational content. To address it, we define a numerical measurement model, and compare two sampling strategies (uniform and frequency-modulated) in terms of beam-use efficiency. The upshot is the formulation of the conditions necessary for the effective use of the modulated sampling strategy, and the evaluation of its advantage over the uniform strategy. The simulation results are also used to compare two competing analytical models for the standard error of the frequency estimate.

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TUPVA080

Stochastic Cooling Hardware for Low Energy Deuterons at COSY

pick-up, kicker, impedance, electron

2261

B. Breitkreutz, R. Greven, N. Shurkhno, R. Stassen, H. Stockhorst
FZJ, Jülich, Germany

One of the central utilizations of the COSY facility nowadays is to host experiments for the JEDI (Jülich Electric Dipole moment Investigations) collaboration. These experiments use polarized deuteron beams at momenta below 1 GeV/c, that are stored for several minutes. In order to increase the spin coherence time, beam cooling is necessary. Electron cooling is applied to pre-cool the beam, but the solenoids of the electron cooler may not be perfectly compensated. Thus, stochastic cooling would be desirable instead. Unfortunately, the existing stochastic cooling system is not sensitive at low beam velocities. This paper presents newly developed stochastic cooling pickups and kickers for a system dedicated to low beam velocities of approximately 0.5c. The design is based on the slot-ring type pickups that have been developed for the High Energy Storage Ring (HESR), but optimized for low particle velocities and a low frequency band of 350-700 MHz. Since the structures get much bigger in comparison to the HESR version, mechanical properties must be reconsidered and a trade-off between electrical properties, cooling performance and constructability must be found.

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TUPVA084

Quasi-Frozen Spin Concept of Deuteron Storage Ring as an Instrument to Search for the Electric Dipole Moment

lattice, dipole, sextupole, cavity

2275

V. Senichev, A.E. Aksentyev
FZJ, Jülich, Germany
A.E. Aksentyev
MEPhI, Moscow, Russia
S.N. Andrianov, A.N. Ivanov
St. Petersburg State University, St. Petersburg, Russia
M. Berz, E. Valetov
MSU, East Lansing, Michigan, USA
S. Chekmenev, J. Pretz
RWTH, Aachen, Germany

One of the possible arguments for the breaking of CP invariance is the existence of non-vanishing electric dipole moments (EDM) of elementary particles. Currently, the Jülich Electric Dipole Moment Investigation (JEDI) collaboration works under the conceptual design of the ring specifically for search of the deuteron electrical dipole moment (dEDM). The proposed Quasi-Frozen Spin concept differs from the Frozen Spin concept in that the spin of the reference particle is alternately deflected by a few degrees in different directions relative to momentum in the electric and magnetic parts of the ring. The QFS concept will allow using the existing COSY ring as pilot facility. The paper presents conceptual approach to ring design based on results of a study of spin decoherence and systematic errors, as well as the sensitivity estimation of the method to the determination of EDM.

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TUPVA102

Effect of Beam Losses on Radio Frequency Quadrupole

rfq, proton, ion, operation

2325

Q. Fu, P.P. Gan, S.L. Gao, F.J. Jia, H.P. Li, Y.R. Lu, Z. Wang, K. Zhu
PKU, Beijing, People's Republic of China

Funding: the National Basic Research Program of China (2014CB845503)
Most of existing high-current RFQs in the world encounter the degrade of beam transmission or unstable operation, even RF ramping can't go up to nominal design voltage after several years or long time beam commissioning. One of the main reasons is that the irradiation damage to electrode surface, caused by beam losses, influences RF performance of RFQ cavity. This is especially serious for high-current RFQ. By simulation and irradiation experiments, proton irradiation damage to copper target has been studied. The simulation results showed that normally incident proton beams with input energy lower than 1 MeV damage the copper surface in the range of one skin depth at 162.5 MHz, which indicated that almost all the lost beams with small incident angles impact RF performance of RFQ cavity. By the irradiation experiments, the damage within 60 nm depth from surface was proved to have a greater impact on surface finish. The conclusion is that low energy beam losses also need to be kept as low as possible to prolong the life of the RFQ electrodes, especially in high-current RFQ design.

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TUPVA123

Status of DESIREE

ion, injection, storage-ring, detector

2379

A. Simonsson, M. Björkhage, M. Blom, H. Cederquist, K. Chartkunchand, G. Eklund, A. Källberg, P. Löfgren, H. Motzkau, P. Reinhed, S. Rosén, H.T. Schmidt
Stockholm University, Stockholm, Sweden

DESIREE, the double electrostatic storage rings in Stockholm has been running since 2011(?). In the cold (13 K) environment with an excellent vacuum, very long storage times in both rings have been achieved, which has enabled the preparation of beams in a single quantum state. The status of DESIREE is presented with particular emphasis on measurements of stored beam currents in the sub-nA range. We also discuss the ongoing work towards stochastic cooling of very slow beams.

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TUPVA124

The Beam Lines Design for the CERN Neutrino Platform in the CERN North Area and an Outlook on Their Expected Performance

target, instrumentation, detector, proton

2382

N.C. Charitonidis, M. Brugger, I. Efthymiopoulos, L. Gatignon, E.M. Nowak, I. Ortega Ruiz
CERN, Geneva, Switzerland
Y. Karyotakis
IN2P3-LAPP, Annecy-le-Vieux, France
P.R. Sala
Istituto Nazionale di Fisica Nucleare, Milano, Italy

In the framework of the CERN Neutrino Platform project, extensions to the existing SPS North Area H2 and H4 secondary beam lines, able to provide low-energy charged particles in the momentum range of 0.4 to 12 GeV, have been designed. The parameters of these very low energy beam lines, the expected beam composition as seen by the experiments as well as an outlook on their expected performance are summarized in this paper. Results from Monte-Carlo simulations, important for the optimization of the future instrumentation of the beam lines (serving both the purpose of beam tuning and the experiments' needs for particle identification and momentum measurements), are presented.

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TUPVA126

The SPS Beam Dump Facility

target, extraction, proton, operation

2389

M. Lamont, G. Arduini, M. Battistin, M. Brugger, M. Calviani, F. B. Dos Santos Pedrosa, M.A. Fraser, L. Gatignon, S.S. Gilardoni, B. Goddard, J.L. Grenard, C. Heßler, R. Jacobsson, V. Kain, K. Kershaw, E. Lopez Sola, J.A. Osborne, A. Perillo-Marcone, H. Vincke
CERN, Geneva, Switzerland

The proposed SPS beam dump facility (BDF) is a fixed-target facility foreseen to be situated at the North Area of the SPS. Beam dump in this context implies a target aimed at absorbing the majority of incident protons and containing most of the cascade generated by the primary beam interaction. The aim is a general purpose fixed target facility, which in the initial phase is aimed at the Search for Hidden Particles (SHiP) experiment. Feasibility studies are ongoing at CERN to address the key challenges of the facility. These challenges include: slow resonant extraction from the SPS; a target that has the two-fold objective of producing charged mesons as well as stopping the primary proton beam; and radiation protection considerations related to primary proton beam with a power of around 355 kW. The aim of the project is to complete the key technical feasibility studies in time for the European Strategy for Particle Physics (ESPP) update foreseen in 2020. This is in conjunction with the recommendation by the CERN Research Board to the SHiP experiment to prepare a comprehensive design study as input to the ESPP.

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TUPVA134

Accelerators Validating Antimatter Physics (AVA)

antiproton, electron, storage-ring, diagnostics

2414

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

Funding: This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sk'odowska-Curie grant agreement No 721559.
Antimatter experiments are at the cutting edge of science. They are, however, very difficult to realize and have been limited by the performance of the only existing facility in the world, the Antiproton Decelerator (AD) at CERN. The Extra Low Energy Antiproton ring (ELENA) will be a critical upgrade to this unique facility and commissioned from autumn 2016. This will significantly enhance the beam quality and enable new experiments. To fully exploit the discovery potential of this facility, advances are urgently required in numerical tools that can adequately model beam transport, life time and interaction, beam diagnostics tools and detectors to characterize the beam's properties, as well as in novel experiments that exploit the enhanced beam quality that ELENA will provide. AVA is a new European research and training initiative between universities, research centers and industry that will carry out R&D into ELENA and related facilities. This contribution gives an overview of the AVA research programme across its three scientific work packages.

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TUPVA146

6D Phase Space Measurement of Low Energy, High Intensity Hadron Beam

simulation, hadron, dipole, quadrupole

2441

B.L. Cathey
ORNL RAD, Oak Ridge, Tennessee, USA
A.V. Aleksandrov, S.M. Cousineau, A.P. Zhukov
ORNL, Oak Ridge, Tennessee, USA

Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. The work has been partially supported by NSF grant 1535312
The goal of this experiment is to measure the full 6D phase space of a low energy, high intensity hadron beam. We use 4D emittance measurement techniques for the transverse plane combined with dispersion measurement and a beam shape monitor to provide the longitudinal phase space. The Beam Testing Facility (BTF) at the Spallation Neutron Source (SNS), a 2.5 MeV functional duplicate front end of the SNS accelerator is being used to facilitate the measurement. Early 6D measurements will be presented.

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TUPVA148

FODO Lattice Design for Beam Halo Research at SNS

lattice, quadrupole, simulation, rfq

2449

Z.L. Zhang
ORNL RAD, Oak Ridge, Tennessee, USA
A.V. Aleksandrov, S.M. Cousineau
ORNL, Oak Ridge, Tennessee, USA

Beam halo is a big challenge for high intensity accelerators. Knowledge of the mechanisms of halo formation could help to prevent it. The Spallation Neutron Source (SNS) Beam Test Facility (BTF) is a functional duplicate of the SNS front end with enhanced diagnostics capable of accelerating 50 mA H⁻ or protons to 2.5 MeV. To explore halo development in both matched and mismatched beams, a dedicated FODO lattice is being designed as an extension to the BTF. The FODO lattice will be 3.5 meters in length and is comprised of 16 quadrupole magnets, with dedicating matching magnets. Simulations of the design lattice show halo can be seen clearly in the phase space density plot when beam is mismatched. Details of the FODO design will be presented in the paper.

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WEOAA2

Status of Radioactive Ion Beam Post-Acceleration at CERN-ISOLDE

linac, cryomodule, cryogenics, operation

2466

Y. Kadi, W. Andreazza, J. Bauche, A. Behrens, A.P. Bernardes, J.A. Ferreira Somoza, F. Formenti, M.A. Fraser, M.J. Garcia Borge, N. Guillotin, K. Johnston, G. Kautzmann, Y. Leclercq, M. Martino, A. Miyazaki, R. Mompo, A. Papageorgiou Koufidou, O. Pirotte, J.A. Rodriguez, S. Sadovich, E. Siesling, M. Therasse, D. Valuch, W. Venturini Delsolaro
CERN, Geneva, Switzerland

Funding: We acknowledge funding from the Belgian Big Science program of the FWO (Research Foundation Flanders) and the Research Council K.U. Leuven.
The HIE-ISOLDE project* (High Intensity and Energy ISOLDE) reached an important milestone in September 2016 when the first physics run was carried out with radioactive beams at 6 MV/m. This is the first stage in the upgrade of the REX post-accelerator, whereby the energy of the radioactive ion beams was increased from 3 to 5.5 MeV per nucleon. The facility will ultimately be equipped with four high-beta cryomodule that will accelerate the beams up to 10 MeV per nucleon for the heaviest isotopes available at ISOLDE. The first 2 cryomodules of the new linac, hosting each five superconducting cavities and one solenoid, were commissioned in August 2016. Besides demonstrating the experimental capabilities of the facility, this successful first run validated the technical choices of the HIE ISOLDE team and provided a fitting reward for eight years of rigorous R&D efforts. At the start of 2018, HIE-ISOLDE is expected to complete the energy upgrade, reaching 10 MeV/u and becoming an attractive facility for a wide variety of experiments. This contribution will focus on the results of the commissioning and on the main technical issues that were highlighted.
* M.J.G. Borge and K. Riisager (2016), HIE-ISOLDE, the project and the physics opportunities, European Physical Journal A 52: 334, DOI: 10.1140/epja/i2016-16334-4

Slides WEOAA2 [7.659 MB]

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WEOBA2

Hollow Electron Beam Collimation for HL-LHC - Effects on the Beam Core

electron, emittance, simulation, operation

2482

M. Fitterer, G. Stancari, A. Valishev
Fermilab, Batavia, Illinois, USA
R. Bruce, G. Papotti, S. Redaelli, D. Valuch, C. Xu
CERN, Geneva, Switzerland
G. Valentino
University of Malta, Information and Communication Technology, Msida, Malta

Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the US Department of Energy.
Collimation with hollow electron beams is currently one of the most promising concepts for active halo control in the High Luminosity Large Hadron Collider (HL-LHC). To ensure the successful operation of the hollow beam collimator the unwanted effects on the beam core, which might arise from the operation with a pulsed electron beam, must be minimized. This paper gives a summary of the effect of hollow electron lenses on the beam core in terms of sources, provides estimates for HL-LHC and discusses the possible mitigation methods.

Slides WEOBA2 [2.074 MB]

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WEOAB1

Hénon-Heiles Single Particle Dynamics at IOTA

sextupole, lattice, synchrotron, electron

2508

S. A. Antipov
University of Chicago, Chicago, Illinois, USA
S. Nagaitsev
Fermilab, Batavia, Illinois, USA

A Hénon-Heiles system is a simple, classical nonlinear Hamiltonian system offering a wide range of particle dynamics from regular orbits to resonant behavior to chaotic trajectories. Initially proposed to describe the motion of stars around a galactic center, it remains a vivid topic in Dynamics and Mathematical Physics since its discovery in 1964. Although the system and its modifications have been extensively studied numerically, its dynamics has never been observed in a controlled experiment. In this report we show that it is possible to create the Hénon-Heiles Hamiltonian using sextupoles in a realistic accelerator lattice. We propose a special sextupole channel to create the desired potential at the IOTA ring and study the 3D single particle dynamics by frequency map analysis and Poincare cross-sections. The proposed experiment would allow real world testing of regular and chaotic motion with a controlled strength of the nonlinearity.

Slides WEOAB1 [4.685 MB]

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WEOCB3

The Radiation Damage in Accelerator Target Environments (RaDIATE) Collaboration R&D Program - Status and Future Activities

target, proton, radiation, status

2550

P. Hurh
Fermilab, Batavia, Illinois, USA

Funding: Work supported by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
The RaDIATE collaboration (Radiation Damage In Accelerator Target Environments), founded in 2012, has grown to over 50 participants and 14 institutions globally. The primary objective is to harness existing expertise in nuclear materials and accelerator targets to generate new and useful materials data for application within the accelerator and fission/fusion communities. Current activities include post-irradiation examination of materials taken from existing beamlines (such as the NuMI beryllium primary beam window and graphite target fins from Fermilab) as well as new irradiations of candidate target materials at low energy and high energy beam facilities (such as titanium and aluminum alloys, glassy carbon, TZM and tungsten). In addition, the program includes thermal shock experiments utilizing high intensity proton beam pulses available at the HiRadMat facility at CERN. Status of current RaDIATE activities as well as future plans will be discussed, including highlights of preliminary results from various ongoing RaDIATE activities and the high level plan to explore the high-power accelerator target relevant thermal shock and radiation damage parameter space.

Slides WEOCB3 [10.635 MB]

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WEPAB007

Pseudo Single Bunch Qualities Added to Short Pulse Operation of BESSY II

synchrotron, timing, operation, radiation

2574

R. Müller, T. Birke, F. Falkenstern, K. Holldack, A. Jankowiak, M. Ries, A. Schälicke
HZB, Berlin, Germany

Funding: Work supported by the German Bundesministerium für Bildung und Forschung, Land Berlin and grants of Helmholtz Association
BESSY II features sophisticated filling patterns as well as manipulation and separation techniques of custom bunches to serve both timing and photon hungry experiments at the same time*. Recently, the low alpha operation mode, providing bunch lengths as short as 2 ps, was extended by pseudo single bunch options. A robust technique to excite one bunch with constant displacement and enlargement was implemented for pulse picking by resonant excitation (PPRE)** users. In addition, reliable scraping of an isolated bunch to provide zero current bunch length is opening new timing opportunities. The simultaneous usage of different photon characteristics: high intensity CSR, non-bursting CSR, short duration as well as operation mode specific X-rays impose new challenges. Sensitive tune measurements and feedback mechanisms had to be developed for all three dimensions. Negative alpha is in consideration to overcome the top up efficiency constraints.
*R. Müller et.al. BESSY II Supports an Extensive Suite of Timing Experiments, IPAC16
**K. Holldack et.al. Single bunch X-ray pulses on demand from a multi-bunch SR source, Nature Comm.5, 2014

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WEPAB009

Pilot Experiments and New Developments at the DELTA Short-Pulse Facility

laser, electron, radiation, undulator

2578

S. Khan, B. Büsing, F. Götz, M.A. Jebramcik, N.M. Lockmann, C. Mai, A. Meyer auf der Heide, R. Niemczyk, B. Riemann, G. Shayeganrad, M. Suski, P. Ungelenk, D. Zimmermann
DELTA, Dortmund, Germany
U. Bovensiepen, S. Döring, A. Eschenlohr, M. Ligges, L. Plucinski, M. Plötzing, C.M. Schneider, S. Xiao
Universität Duisburg-Essen, Duisburg, Germany
S. Cramm
Forschungszentrum Jülich, Peter-Gruenberg-Institut-6, Jülich, Germany
M. Gehlmann
Forschungszentrum Jülich, Peter Gruenberg Institut, Jülich, Germany

Funding: BMBF 05K16PEA, BMBF 05K16PEB, Mercur Pr-2014-0047
At the 1.5-GeV synchrotron light source DELTA operated by the TU Dortmund University, ultrashort radiation pulses in the vacuum ultraviolet (VUV) and terahertz (THz) regime are routinely generated by the interaction of electron bunches with femtosecond laser pulses. A laser-induced energy modulation is converted into a density modulation (microbunching) by a magnetic chicane, leading to coherent emission at harmonics of the initial laser wavelength (coherent harmonic generation, CHG). Path length differences of the energy-modulated electrons along the magnetic lattice lead to a dip in the longitudinal charge distribution, which gives rise to the coherent emission of THz radiation. In first pump-probe photoemission experiments, the spatial and temporal overlap of laser pump and CHG probe pulse on the sample was demonstrated. Furthermore, the effect of two temporally separated seed pulses was studied in the VUV and (sub-)THz regime.

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WEPAB014

PETRA III Operation

operation, photon, timing, optics

2589

M. Bieler, I.V. Agapov, H. Ehrlichmann, 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 challenges of daily operation, including different bunch patterns and their side effects, a procedure to clear spurious bunches, the operational statistics and the main contributions to down time.

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WEPAB021

Experience with Multi-Beam and Multi-Beamline FEL-Operation

laser, undulator, operation, FEL

2615

J. Rönsch-Schulenburg, B. Faatz, K. Honkavaara, M. Kuhlmann, S. Schreiber, R. Treusch, M. Vogt
DESY, Hamburg, Germany

DESY's free-electron laser FLASH provides soft X-ray pulses for scientific users at wavelengths down to 4 nm simultaneously in two undulator beamlines. They are driven by a common linear superconducting accelerator with a beam energy of up to 1.25 GeV. The superconducting technology allows the acceleration of electron bunch trains of several hundred bunches with a spacing of 1 microsecond or more and a repetition rate of 10 Hz. A fast kicker-septum system directs one part of the bunch train to FLASH1 and the other part to FLASH2 keeping the full 10 Hz repetition rate for both. The unique setup of FLASH allows independent FEL pulse parameters for both beamlines. In April 2016, simultaneous operation of FLASH1 and FLASH2 for external users started. This paper reports on our operating experience with this type of multi-beam, multi-beamline set-up.

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WEPAB025

Status of the Soft X-Ray Free Electron Laser FLASH

laser, FEL, photon, operation

2628

M. Vogt, B. Faatz, K. Honkavaara, M. Kuhlmann, J. Rönsch-Schulenburg, S. Schreiber, R. Treusch
DESY, Hamburg, Germany

The superconducting free-electron laser user facility FLASH at DESY in Hamburg, routinely produces several thousand photon pulses per second. The operational parameters cover a wavelength range from 90 nm down to 4 nm with pulse energies from several uJ up to 1 mJ and with pulse durations of several hundred fs down to a few fs. The FLASH injector and linac drives two undulator beam lines (FLASH1, FLASH2) and therefore FLASH is capable of serving 2 independent experiments with photon pulse (sub-) trains of several 100 bunches at the full train repetition frequency of 10 Hz. We summarize here the highlights of the user operation at FLASH1/2 and the study program (machine development and FEL optimization) of the FLASH facility.

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WEPAB034

Control of Seeded FEL Pulse Duration Using Laser Heater Pulse Shaping

laser, electron, FEL, simulation

2654

V. Grattoni
Università degli Studi di Trieste, Trieste, Italy
E. Allaria, L. Badano, M.B. Danailov, A.A. Demidovich, S. Di Mitri, L. Giannessi, G. Penco, E. Roussel, P. Sigalotti, S. Spampinati, M. Trovò, M. Veronese
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
E. Ferrari
PSI, Villigen PSI, Switzerland

New Free-Electron Laser facilities deliver VUV and X-ray radiation with pulse length in the range of hundreds and tens of fs. A further reduction of the FEL pulse length is desired by those experiments aiming at probing ultrafast phenomena. Unlike SASE FEL, where the pulse duration is mainly driven by the electron bunch duration, in a seeded FEL the pulse duration can be determined by the seed laser properties. The use of techniques able to locally deteriorate the electron beam properties such as emittance or energy spread have been used in SASE FELs to reduce the region of the electron beam that is able to produce FEL radiation and hence reduce the FEL pulse length. The temporal shaping of the laser heater can be used to create an electron beam characterized by a very large energy spread all along the bunch except for a small region. We report measurements of the effect of the laser heater shaping on the electron beam phase-space performed at FERMI. Impact on the final FEL pulse properties are predicted with a series of numerical simulations.

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WEPAB039

Development Perspectives at FERMI

FEL, laser, linac, electron

2666

M. Svandrlik, E. Allaria, L. Badano, F. Bencivenga, C. Callegari, F. Capotondi, F. Cilento, P. Cinquegrana, M. Coreno, I. Cudin, G. D'Auria, M.B. Danailov, R. De Monte, G. De Ninno, P. Delgiusto, A.A. Demidovich, M. Di Fraia, S. Di Mitri, B. Diviacco, A. Fabris, R. Fabris, W.M. Fawley, M. Ferianis, P. Furlan Radivo, G. Gaio, D. Gauthier, F. Gelmetti, L. Giannessi, F. Iazzourene, S. Krecic, M. Lonza, N. Mahne, M. Malvestuto, C. Masciovecchio, M. Milloch, F. Parmigiani, G. Penco, A. Perucchi, L. Pivetta, O. Plekan, M. Predonzani, E. Principi, L. Raimondi, P. Rebernik Ribič, F. Rossi, E. Roussel, L. Rumiz, C. Scafuri, C. Serpico, P. Sigalotti, M. Trovò, A. Vascotto, M. Veronese, R. Visintini, D. Zangrando, M. Zangrando
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

FERMI is the seeded Free Electron Laser (FEL) user facility at the Elettra laboratory in Trieste, operating in the ultraviolet to soft X-rays spectral range; the radiation produced by the seeded FEL is characterized by a number of desirable properties, such as wavelength stability, low temporal jitter and longitudinal coherence. In this paper, after an overview of the FEL performances, we will present the development plans under consideration for the next 3 to 5 years. These include an upgrade of the linac and of the existing FEL lines, the possibility to perform multipulse experiments in different configurations and an Echo Enabled Harmonic Generation (EEHG) experiment on FEL-2, the FEL line extending to 4 nm (310 eV).

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WEPAB074

On the Coherence Properties of FEL

FEL, laser, undulator, simulation

2753

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

Free Electron Lasers (FEL) are one of the most brilliant light sources in the world and their unique properties are driving worldwide research in understanding and improving them. Numerous papers have already been published describing the output of the FEL in terms of coherence and bandwidth. In this contribution, however, we focus on how the coherence evolves along the FEL undulator and on what factors influence it the most. Using Genesis⁻¹.3* we have been able to follow and record the light field as it is being produced in the undulator. Our analysis method takes advantage of the extensively studied double pinhole experiment and uses the principles behind it to create a tool for extracting coherence information from the radiation field. We will present the scope, limitations and advantages of these virtual experiments as well as an application on an example FEL, to showcase what kind of information can be extracted using this method.
* Numerical simulation code used for particle and field distribution tracking along the undulator developed by Sven Reiche

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WEPAB122

Experimental Demonstration of Ballistic Bunching with Dielectric-Lined Waveguides at Pitz

electron, linac, bunching, wakefield

2857

F. Lemery
University of Hamburg, Hamburg, Germany
G.A. Amatuni, B. Grigoryan
CANDLE, Yerevan, Armenia
P. Boonpornprasert, Y. Chen, J.D. Good, M. Krasilnikov, O. Lishilin, G. Loisch, S. Philipp, H.J. Qian, Y. Renier, F. Stephan
DESY Zeuthen, Zeuthen, Germany
P. Piot
Fermilab, Batavia, Illinois, USA
P. Piot
Northern Illinois University, DeKalb, Illinois, USA

We report on the experimental demonstration of ballistic bunching of photoinjected, nC-scale electron bunches at the PITZ facility. In the experiment, electron bunches emanating from the photocathode were directly focused into a mm-scale dielectric-lined waveguide. The wakefield excited by the bunch acts back onto itself, leading to an energy modulation, which at a relatively low energy of 6~MeV, is converted into a density modulation before entering the linac ∼ 1~m downstream. We discuss the basic theory, experimental layout and results.

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WEPAB129

Study of Ionization Cooling with the MICE Experiment

emittance, solenoid, optics, detector

2874

C.T. Rogers
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

The international Muon Ionization Cooling Experiment (MICE) will demonstrate the ionization cooling of muons; the only known technique that can provide high brightness muon beams suitable for applications such as a Neutrino Factory or Muon Collider. MICE is underway at the Rutherford Appleton Laboratory and has recently taken the data necessary to characterise the physical processes that underlie the ionization-cooling effect. Measurements of the change in normalised transverse amplitude are presented in two configurations. The measurements of the ionization-cooling effect are discussed.

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WEPAB132

Research Program and Recent Results at the Argonne Wakefield Accelerator Facility (AWA)

wakefield, electron, emittance, acceleration

2885

M.E. Conde, S.P. Antipov, D.S. Doran, W. Gai, Q. Gao, G. Ha, C.-J. Jing, W. Liu, N.R. Neveu, J.G. Power, J.Q. Qiu, J.H. Shao, Y.R. Wang, C. Whiteford, E.E. Wisniewski, L.M. Zheng
ANL, Argonne, Illinois, USA
S.P. Antipov, C.-J. Jing, J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA
Q. Gao, L.M. Zheng
TUB, Beijing, People's Republic of China
G. Ha
POSTECH, Pohang, Kyungbuk, Republic of Korea
N.R. Neveu
IIT, Chicago, Illinois, USA
Y.R. Wang
IMP/CAS, Lanzhou, People's Republic of China

Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-06CH11357
We give an overview of the research program at the Argonne Wakefield Accelerator Facility (AWA), including some highlights of recent experiments. The AWA facility is dedicated to the study of beam physics and the development of technology for future particle accelerators. Two independent electron linacs are used to study wakefield acceleration: 70 MeV high charge electron bunches of up to 100 nC are used to drive wakefields, which can be probed by bunches originating from the same linac or from the 15 MeV linac. Recent Two-Beam-Acceleration (TBA) experiments operating at 11.7 GHz reached accelerating gradients of up to 150 MV/m. No indication of witness beam quality degradation was observed, and bunch charge was preserved during the acceleration process. Two identical TBA setups were used in series in order to demonstrate staging capabilities. Dielectric loaded structures operating at 26 GHz are also used in TBA experiments. Another main thrust of the research program consists of exploring and developing techniques to manipulate the phase space of electron bunches. These efforts include bunch shaping and the exchange of emittances in the transverse and the longitudinal phase spaces

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WEPAB133

A Wedge Absorber Experiment at MICE

emittance, collider, optics, scattering

2888

D.V. Neuffer
Fermilab, Batavia, Illinois, USA
T.A. Mohayai
IIT, Chicago, Illinois, USA
C.T. Rogers
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
P. Snopok
Illinois Institute of Technology, Chicago, Illlinois, USA
D.J. Summers
UMiss, University, Mississippi, USA

Emittance exchange mediated by wedge absorbers is required for longitudinal ionization cooling and for final transverse emittance minimization for a muon collider. A wedge absorber within the MICE beam line could serve as a demonstration of the type of emittance exchange needed for 6-D cooling, including the configurations needed for muon colliders, as well as configurations for low-energy muon sources. Parameters for this test are explored in simulation and possible experimental configurations with simulated results are presented.

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WEPAB135

Novel Implementation of Non-parametric Density Estimation in MICE

emittance, lattice, beam-cooling, solenoid

2895

T.A. Mohayai
IIT, Chicago, Illinois, USA
D.V. Neuffer, P. Snopok
Fermilab, Batavia, Illinois, USA
C.T. Rogers
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
P. Snopok
Illinois Institute of Technology, Chicago, Illlinois, USA

Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC05-06OR23100.
Cooled muon beams are essential to enable future Neutrino Factory and Muon Collider facilities. The international Muon Ionization Cooling Experiment (MICE) aims to demonstrate muon beam cooling through ionization energy loss in material. A figure of merit for muon cooling in MICE is the transverse root-mean-square (RMS) emittance reduction and to measure this, the individual muon positions and momenta are reconstructed using two scintillating-fiber tracking detectors housed in spectrometer solenoid modules. The reconstructed positions and momenta before and after a low-Z absorbing material are then used for constructing the covariance matrix and measuring normalized transverse RMS emittance of MICE muon beam. In this study, the direct measurement of phase-space density and volume as measures of the efficacy of muon beam cooling in MICE, using the density estimation techniques is described.

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WEPAB138

Prototyping High-Gradient mm-Wave Accelerating Structures

accelerating-gradient, interface, cavity, RF-structure

2902

E.A. Nanni, V.A. Dolgashev, A.A. Haase, J. Neilson, S.G. Tantawi
SLAC, Menlo Park, California, USA
S.C. Schaub
MIT, Cambridge, Massachusetts, USA
B. Spataro
INFN/LNF, Frascati (Roma), Italy
R.J. Temkin
MIT/PSFC, Cambridge, Massachusetts, USA

We present single-cell accelerating structures designed for high-gradient testing at 110 GHz. The purpose of this work is to study the basic physics of ultrahigh vacuum RF breakdown in high-gradient RF accelerators. The accelerating structures are pi-mode standing-wave cavities fed with a TM01 circular waveguide. The structures are fabricated using precision milling out of two metal blocks, and the blocks are joined with diffusion bonding and brazing. The impact of fabrication and joining techniques on the cell geometry and RF performance will be discussed. First prototypes had a measured Qo of 2800, approaching the theoretical design value of 3300. The geometry of these accelerating structures are as close as practical to single-cell standing-wave X-band accelerating structures more than 40 of which were tested at SLAC. This wealth of X-band data will serve as a baseline for these 110 GHz tests. The structures will be powered with short pulses from a MW gyrotron oscillator. RF power of 1 MW may allow us to reach an accelerating gradient of 400 MeV/m.

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WEPIK002

Experimental Activities on High Intensity Positron Sources Using Channeling

positron, target, electron, photon

2910

I. Chaikovska, R. Chehab, H. Guler, V. Kubytskyi
LAL, Orsay, France
X. Artru
IN2P3 IPNL, Villeurbanne, France
K. Furukawa, T. Kamitani, F. Miyahara, M. Satoh, Y. Seimiya, T. Suwada
KEK, Ibaraki, Japan
V. Rodin
National Taras Shevchenko University of Kyiv, The Faculty of Physics, Kyiv, Ukraine
P. Sievers
CERN, Geneva, Switzerland

The positron source under investigation is using channeling radiation of multi-GeV electrons in a tungsten crystal. The radiated photons are impinging on the amorphous targets creating e⁺e⁻ pairs. A dipole magnet between the crystal-radiator and the amorphous-converter allows the charged particles to be swept off and only emitted photons to generate e⁺e⁻ pairs in the converter. Granular targets of different thicknesses, made of small tungsten spheres, have been recently investigated as a target-converter. This paper is describing the experimental studies conducted at the KEKB linac with such device. After the description of the experimental set-up and beam parameters, the measurement methods and preliminary results are presented.

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WEPIK028

Status of the Electron-Positron Collider VEPP-4

electron, collider, storage-ring, positron

2985

P.A. Piminov
BINP SB RAS, Novosibirsk, Russia

The next phase of the e⁺e⁻ collider VEPP-4 (Budker INP, Novosibirsk) is focused on experiments in the energy range from 4 to 10 GeV (c.m.). To recover the lack of positrons at high energy a new positron source was connected to the collider. The paper discusses the facility performance with new injection and other aspects of experimental study at high energy including laser polarimeter for precise energy calibration.

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WEPIK056

Compensation of Transient Beam Loading with Detuned Cavities at BESSY II

cavity, operation, beam-loading, synchrotron

3056

M. Ruprecht, P. Goslawski, F. Kramer, M. Ries
HZB, Berlin, Germany

This paper presents operational experience and use cases of cavity operation in the synchrotron light source BESSY II, where an active or passive cavity is detuned by a small fraction of the harmonic number. If the detuning is an integer multiple of the fundamental RF harmonic, the distortion of the longitudinal phase space is periodic with the revolution, which allows for the compensation of fill pattern induced transients. Measurements at BESSY II are presented, where a fundamental cavity is detuned to decrease the effects of transient beam loading. Thus, reducing the phase transient and increasing the beam life time. Calculations depicting the application of this scheme for the future project BESSY VSR[*] are presented.
* A. Jankowiak, J. Knobloch, P. Goslawski, and N. Neumann, eds., BESSY VSR - Technical Design Study, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 2015.

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WEPIK119

Lost Muon Study for the Muon g-2 Experiment at Fermilab

storage-ring, positron, background, quadrupole

3230

J.D. Crnkovic, W. Morse
BNL, Upton, Long Island, New York, USA
S. Ganguly
University of Illinois at Urbana-Champaign, Urbana, USA
D. Stratakis
Fermilab, Batavia, Illinois, USA

The Fermilab Muon g-2 Experiment has a goal of measuring the muon anomalous magnetic moment to a precision of 140 ppb - a fourfold improvement over the 540 ppb precision obtained by the BNL Muon g-2 Experiment. Some muons in the storage ring will interact with material and undergo bremsstrahlung, emitting radiation and loosing energy. These so called lost muons will curl in towards the center of the ring and be lost, but some of them will be detected by the calorimeters. A systematic error will arise if the lost muons have a different average spin phase than the stored muons. Algorithms are being developed to estimate the relative number of lost muons, so as to optimize the stored muon beam. This study presents initial testing of algorithms that can be used to estimate the lost muons by using either double or triple detection coincidences in the calorimeters.

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WEPIK120

Simulated performance of the Production Target for the Muon g-2 Experiment at Fermilab

target, proton, polarization, storage-ring

3234

D. Stratakis, M.E. Convery, J.P. Morgan, D.A. Still, M.J. Syphers
Fermilab, Batavia, Illinois, USA
M.J. Syphers
Northern Illinois University, DeKalb, Illinois, USA
V. Tishchenko
BNL, Upton, Long Island, New York, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy.
The Muon g-2 Experiment plans to use the Fermilab Recycler Ring for forming the proton bunches that hit its production target. The proposed scheme uses one RF system, 80 kV of 2.5 MHz RF. In order to avoid bunch rotations in a mismatched bucket, the 2.5 MHz is ramped adiabatically from 3 to 80 kV in 90 ms. In this study, the interaction of the primary proton beam with the production target for the Muon g-2 Experiment is numerically examined.

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WEPVA007

Simulations and Plans for a Dielectric Laser Acceleration Experiment at SINBAD

laser, electron, linac, simulation

3264

F. Mayet, R.W. Aßmann, U. Dorda, W. Kuropka, B. Marchetti, J. Zhu
DESY, Hamburg, Germany
W. Kuropka, F. Mayet
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
J. Zhu
University of Hamburg, Hamburg, Germany

Funding: GBMF - Gordon and Betty Moore Foundation
In this work we present the outline of an experimental setup for dielectric laser acceleration of relativistic electron bunches produced by the ARES linac under construction at the SINBAD facility (DESY Hamburg). The experiment will be performed as part of the Accelerator on a Chip International Program (ACHIP), funded by the Gordon and Betty Moore Foundation. At SINBAD we plan to test the acceleration of already pre-accelerated relativistic electron bunches in a laser-illuminated dielectric grating structure. In addition to the conceptual layout of the experiment we present first start-to-end simulation results for different ARES working points. The simulations are performed using a combination of the well known particle tracking code ASTRA and the self-consistent particle in cell code VSim.

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WEPVA011

Development of a Laser Driven Dielectric Accelerator for Radiobiology Research

electron, laser, acceleration, simulation

3272

K. Koyama, M. Yoshida
KEK, Ibaraki, Japan
Z. Chen, H. Okamoto
The University of Tokyo, Tokyo, Japan
M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan

Funding: This work was supported by KAKENHI, (Grant-in-Aid for Scientific Research) Grant Number 15H03595 and partly supported by NIMS Nanofabrication Platform in Nanotechnology Platform Project sponsored by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.
A laser-driven dielectric accelerator below 1 MeV is under development for applying a sub-micron size electron-beam to radiobiological research. Simulations of the electric field and electron trajectories in the proximity of the dielectric structure (transmission grating) were performed in order to fix parameters of the demonstration experiment. Serious deflection of electron beam towards the grating limited the injection phase as well as the height from the structure. The energy gain of 50-keV electron was estimated to be 1 keV in 30-micron length at the optimum condition. Transmission gratings for the experiment were fabricated by using facilities of the NIMS Nanofabrication Platform. In addition to the acceleration experiment using the simple grating, a resonator type accelerator structure was designed for exciting the acceleration field by a moderately small laser.

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WEPVA018

Drive-Witness Acceleration Scheme Based on Corrugated Dielectric mm-Scale Capillary

acceleration, wakefield, laser, electron

3292

K. Lekomtsev, S.T. Boogert, P. Karataev, A. Lyapin
JAI, Egham, Surrey, United Kingdom
A. Aryshev, M. Shevelev, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
A.A. Tishchenko
MEPhI, Moscow, Russia

Funding: This project has received funding from the European Union Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 655179.
In this paper, we investigate a corrugated mm-scale capillary as a compact accelerating structure in a drive-witness acceleration scheme, and suggest a methodology to measure acceleration of a witness bunch. Two typical measurements and the energy gain in a witness bunch as a function of the distance between bunches are discussed. A corrugated capillary is considered as an accelerator/decelerator with an adjustable wakefield pattern depending on a transverse beam position.

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WEPVA022

RECENT TWO-BEAM ACCELERATION ACTIVITIES AT ARGONNE WAKEFIELD ACCELERATOR FACILITY

acceleration, accelerating-gradient, wakefield, impedance

3305

J.H. Shao, S.P. Antipov, M.E. Conde, W. Gai, Q. Gao, G. Ha, W. Liu, N.R. Neveu, J.G. Power, Y.R. Wang, E.E. Wisniewski, L.M. Zheng
ANL, Argonne, Illinois, USA
C.-J. Jing, J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA
J. Shi, D. Wang
TUB, Beijing, People's Republic of China

The Two-Beam Acceleration (TBA) is a modified approach to the structure-based wakefield acceleration which may meet the luminosity, efficiency, and cost requirement of a future linear collider. Recently, various TBA experiments have been carried out at the Argonne Wakefield Accelerator Facility (AWA). With X-band metallic power extractors and accelerators, a 70 MeV/m average accelerating gradient has been demonstrated in two stages while a 150 MeV/m gradient as well as 300 MW extracted power have been achieved in a single stage. In addition, low cost K-band dielectric power extractor and accelerator have also been developed. The preliminary results show power extraction of 55 MW and an average accelerating gradient of 28 MeV/m.

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WEPVA034

ELENA - From Installation to Commissioning

antiproton, injection, ion, ion-source

3327

T. Eriksson, W. Bartmann, P. Belochitskii, L. Bojtár, H. Breuker, F. Butin, C. Carli, B. Dupuy, P. Freyermuth, L.V. Jørgensen, B. Lefort, J. Mertens, R. Ostojić, S. Pasinelli, G. Tranquille
CERN, Geneva, Switzerland
W. Oelert
Johannes Gutenberg University Mainz, Institut für Physik, Mainz, Germany

ELENA (Extra Low ENergy Antiproton ring) is an upgrade project at the CERN AD (Antiproton Decelerator). The smaller ELENA ring will further decelerate 5.3 MeV antiprotons from the AD ring down to 100 keV using electron cooling to obtain good deceleration efficiency and dense beams. An increase of up to two orders of magnitude in trapping efficiency is expected at the AD experiments. This paper will report on the current status of ELENA where beam commissioning of the ring is now taking place. Phase one of the project installation has been completed with ring and injection lines in place, while phase two will finalize the project with installation of 100 keV transfer lines connecting the experiments to ELENA and is planned to take place in 2019/2020.

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WEPVA038

Tail Repopulation Measurements in the PSB

kicker, emittance, simulation, injection

3343

E. Benedetto, M. Cieslak-Kowalska, P. Zisopoulos
CERN, Geneva, Switzerland
M. Cieslak-Kowalska
EPFL, Lausanne, Switzerland

The PS Booster (PSB) is the first circular accelerator in the LHC injector chain providing protons for the full CERN complex. Each of its four rings provides beams in a range of intensities varying from 40 e11 p/cycle to 0.8 e13 p/cycle. Low intensity beams are produced by transverse shaving, that is by scraping the tails, in order to tailor the intensity and transverse emittances. Eventually, tails repopulate and the beam profile reshapes, under the effect of space charge, which is dominant at low energy in the PS Booster. This paper describes the results of the measurements after the shaving process, where the tails are scraped but finally re-appear in the transverse profile, and it provides a first benchmark with space-charge simulations. It highlights the challenges encountered and the lessons learned, to guide the future experiments. The final outcome of these studies is the characterisation of the halo creation mechanism and the determination of the diffusion speed, important for the design of the future PS Booster scraping system.

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WEPVA054

Study of The New Return Yoke for The Upgraded Superconducting Cyclotron of INFN-LNS

extraction, ion, cyclotron, acceleration

3381

A. Calanna, L. Allegra, L. Calabretta, G. Costa, G. D'Agostino, G. Gallo, D. Rifuggiato, A.D. Russo
INFN/LNS, Catania, Italy
G. D'Agostino
Universita Degli Studi Di Catania, Catania, Italy

The LNS Superconducting Cyclotron (CS) has been working for 20 years making available a wide range of ions and energies. Its operational diagram is peculiar and many experiment are performed each year. In the near future a major upgrade is planned. This will allow to overcome the major limitation of the CS, which is the beam power limited at 100 W. In the new version of the CS, the extracted beam power will be increased up to a factor 100. This improvement will be reached adding a new extraction line dedicated to a specific set of light ions and energies extracted by stripping. The new design could affect the beam dynamics strongly. Indeed, the iron yoke penetrations don't respect the three folds symmetry of our cyclotron. This inhomogeneity produces unwanted field harmonics, which have to be reduced as much as possible to avoid beam precession or second order effects. Here the study accomplished to minimize the perturbation of the non-three fold field symmetry using the current sheet approximation (CSA) is presented, along with the state-of-art configuration of the updated cyclotron

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WEPVA067

Preliminary Results on the Resonant Excitation of THz Wakefield in a Multi-Mode Dielectric Loaded Waveguide by Bunch Train

electron, wakefield, radiation, space-charge

3426

D. Wang, Y.-C. Du, W. Gai, W.-H. Huang, L. Niu, X.L. Su, C.-X. Tang, Q.L. Tian, L.X. Yan
TUB, Beijing, People's Republic of China
S.P. Antipov
Euclid TechLabs, LLC, Solon, Ohio, USA
Y.F. Liang
Tsinghua University, Beijing, People's Republic of China

Funding: Work supported by the National Nature Science Foundation of China (NSFC Grants No.11475097) and the National Key Scientific Instrument and Equipment Development Project of China (Grants No. 2013YQ12034504)
We report the preliminary experimental results on the resonant excitation of THz wakefield in a multi-mode dielectric loaded waveguide (DLW) by electron bunch train at the Tsinghua University accelerator beamline. The bunch train with certain longitudinal periodicity was generated based on nonlinear longitudinal space charge oscillation [1]. By passing such bunch train through a multi-mode DLW, we observed selective excitation of the fifth longitudinal mode (TM05 mode) was resonantly excited. Future experiment plan is to tune the bunch train interval with a chicane in the beamline in order to selectively excite arbitrary mode for tunable THz radiation source with multi-mode DLWs.
*wangdan16@mail.tsinghua.edu.cn
*yanlx@mail.tsinghua.edu.cn

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WEPVA068

Design and Development of Accelerator Magnet Power Supply Based on SiC-MOSFET

power-supply, controls, interface, operation

3429

L. Yang, F. Long, Z.H. ZhenHua
IHEP, Beijing, People's Republic of China

SiC is a new type of semiconducting material with rapid development after the first generation and the second generation of semiconductor materials represented by silicon and gallium arsenide. SiC-MOSFET has a high frequency, high breakdown voltage, high temperature, radiation and many other points, suitable for future use in the accelerator magnet power supply. In this paper, the development and operation of a SiC-MOSFET-based accelerator magnet power supply are described in detail. The experiment results show that the performance of this power supply is superior to that of the same specification using Si-MOSFET. The power supply adopts one-way AC power supply, and the output stage adopts the full bridge circuit topology. The power device adopts C2M0040120D SiC-MOSFET, the working frequency is 30 kHz, the output current is ± 20A, the output voltage is ± 20V, and power is 400W. The Digital Power Supply Control Module (DPSCM) is used to realize high-precision digital closed-loop control, which supports on-line debugging and PC control. Power supply can be used to correct the magnet power, with high efficiency, high stability, and fast response and so on.

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WEPVA085

Development of High Stabile Magnet Power Supply

FPGA, power-supply, interface, dipole

3455

K.-H. Park, J.H. Han, S.-H. Jeong, Y.G. Jung, D.E. Kim, H.-G. Lee, S.B. Lee, B.G. Oh, H.S. Suh
PAL, Pohang, Kyungbuk, Republic of Korea

A high stable magnet power supply (MPS) was devel-oped, which was a bipolar type with 200A of the output current at the 40V of output voltage. The MPS has been implemented by the digital signal processing technology using the DSP, FPGA, ADCs and so on. The output cur-rent stability of the MPS showed about 4 ppm peak-to-peak in a short term experiment at the 200A of its full output current. This paper shows the several design con-siderations being implemented to this high stable MPS. Some experimental data such as output stability, some waveforms and so on are given in this paper.

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WEPVA105

Upgrading of Ageing CERN Underground Infrastructure to Fulfil the Space Requirements of New Facilities at CERN

monitoring, gun, electron, interface

3510

A. Martínez Sellés, E. Carlier, V. Di Murro, B. Goddard, E. Gschwendtner, F.J. Magnin, R.F. Morton, J.A. Osborne
CERN, Geneva, Switzerland
V. Di Murro
University of Cambridge, Cambridge, United Kingdom

Particle accelerator technology is constantly being developed, and new equipment and machines replace the former ones to keep pushing the energy and intensity frontiers. Therefore, in order to meet the space requirements of new equipment, the infrastructure often needs to be modified, and given its rigid nature, this presents a challenge for the civil engineers to provide the needed space without compromising the safety and serviceability of the structures. In this paper two underground works are presented: a new cross-passage tunnel for the AWAKE experiment completed in 2014 and the future SPS Beam Dump. The challenges that must be faced are: (a) to make sure that the movements of the adjacent structures remain within admissible limits, (b) to design and execute the works such that the life span of the structure is not reduced, (c) To ensure the effectiveness of existing and new drainage systems during and after the works. For these purposes, in the frame of future tunnel asset management, the use of novel and conventional monitoring techniques plays a crucial role as it can predict in real time potential tunnel deformations which can lead, in the worst scenario, to tunnel failure

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WEPVA106

A Consolidation Roadmap for the CERN Power Converters

controls, hardware, operation, software

3514

D. Nisbet, J.-P. Burnet
CERN, Geneva, Switzerland

At CERN the Electrical Power Converter group is re-sponsible for the design and exploitation of more than 5000 power systems throughout the accelerator complex, powering predominantly magnet circuits, in addition to RF and electro-static systems. Currently, a variety of systems are in operation, in some cases these are over 30 years old. Furthermore, the group must maintain operationally a total of six hardware platforms, each with dedicated software. In light of this, a consolidation roadmap has been determined to rejuvenate the power converter complex and to reduce the total number of control platforms. This paper presents a summary of the CERN power converter equipment to be consolidated, and the roadmap to achieve consolidation.

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WEPVA111

Change of Critical Current Density in Nb-Ti and Nb3Sn Strands After Millisecond Heating

superconducting-magnet, dipole, collider, luminosity

3528

V. Raginel, K. Kulesz, M. Mentink, R. Schmidt, A.P. Verweij, D. Wollmann
CERN, Geneva, Switzerland
D. Kleiven
NTNU, Trondheim, Norway

The damage mechanisms and limits of superconducting magnet components due to direct beam impact are not well understood. The energy deposition from beam losses can cause significant temperature rise and mechanical stress in the magnet coils, which can lead to a degradation of the insulation strength and critical current of the superconductor. An improved understanding of these mechanisms is not only important for the LHC in view of the planned increase in beam brightness, but also for other high energy accelerators using superconducting magnets. An experimental road map has been defined to study these damage mechanisms. Experiments have been performed with Nb-Ti and Nb3Sn strands and cable stacks at room temperature. This contribution focuses on the experimental study on the effect of millisecond heating on superconducting strands.

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WEPVA113

Thermo-Physical and Mechanical Characterisation of Novel Materials under Development for HL-LHC Beam Intercepting Devices

luminosity, radiation, laser, framework

3536

O. Sacristan De Frutos, A. Bertarelli, L. Bianchi, F. Carra, J. Guardia, M. Guinchard, S. Redaelli
CERN, Geneva, Switzerland

Funding: The research leading to these results has received funding from the European Commission under the FP7 Research Infrastructures project EuCARD-2, grant agreement no.312453
The collimation system for high energy particle accelerators as HL-LHC, must be designed to withstand the close interaction with intense and energetic particle beams, safely operating over an extended range of temperatures in extreme conditions (pressure, strain-rate, radiation), which are to become more demanding with the High Luminosity LHC. In order to withstand such conditions, the candidate materials must possess among other properties outstanding thermal shock resistance and high thermal and electrical conductivity, condition only met by advanced or novel materials. Therefore, an extensive R&D program has been launched to develop novel materials capable of replacing or complementing materials used for present collimators. So far, Molybdenum Carbide - Graphite and Copper-Diamond composites have been identified as the most promising materials. Literature data are scarce or non-existing for these materials. For this reason the successive characterisation campaigns constitute a linchpin of the R&D program. This paper reviews the experimental program followed for the thermo-physical and mechanical characterisation of the materials, and discusses the most relevant results.

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WEPVA114

Optimising Machine-Experiment Interventions in HL-LHC

shielding, operation, radiation, vacuum

3540

F. Sanchez Galan, C. Adorisio, I. Bergstrom, D. Brethoux, S. Evrard, A. Gaddi, L.P. Krzkempek, M. Lazzaroni, J. Perez Espinos, M. Raymond, H. Vincke
CERN, Geneva, Switzerland

Funding: This Research is supported by the HL-LHC project
The luminosity reach of the HL-LHC experiments implies new constraints for the protection of the inner triplets from the machine debris. In general activation levels will increase a factor of 15-30 from the 2015 values (LS1), affecting both radiation tolerance of equipment and maintenance scenarios. The design of new equipment takes into account these constraints and the entire layout of tunnel equipment near the interaction regions will al-low for simplified maintenance. In particular, new ab-sorbers will replace the existing protection of the ma-chine-experiment cavern boundaries, with an optimised layout of the region. This paper summarises the main constraints (both physical and operational) existing at the region, together with the solutions adopted to reduce worker's dose.

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WEPVA138

The RaDIATE High-Energy Proton Materials Irradiation Experiment at the Brookhaven Linac Isotope Producer Facility

target, proton, radiation, linac

3593

K. Ammigan, P. Hurh, R.M. Zwaska
Fermilab, Batavia, Illinois, USA
A. Amroussia, C.J. Boehlert
Michigan State University, East Lansing, Michigan, USA
M.S. Avilov, F. Pellemoine
FRIB, East Lansing, USA
M. Calviani, E. Fornasiere, A. Perillo-Marcone, C. Torregrosa
CERN, Geneva, Switzerland
A.M. Casella, D.J. Senor
PNNL, Richland, Washington, USA
C.J. Densham
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
T. Ishida, S. Makimura
KEK, Ibaraki, Japan
V.I. Kuksenko, S.G. Roberts
University of Oxford, Oxford, United Kingdom
Y. Lee, T.J. Shea, C.A. Thomas
ESS, Lund, Sweden
L.F. Mausner, D. Medvedev, N. Simos
BNL, Upton, Long Island, New York, USA
E. Wakai
KEK/JAEA, Ibaraki-Ken, Japan

Funding: Work supported by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
The RaDIATE collaboration (Radiation Damage In Accelerator Target Environments) was founded in 2012 to bring together the high-energy accelerator target and nuclear materials communities to address the challenging issue of radiation damage effects in beam-intercepting materials. Success of current and future high intensity accelerator target facilities requires a fundamental understanding of these effects including measurement of materials property data. Toward this goal, the RaDIATE collaboration organized and carried out a materials irradiation run at the Brookhaven Linac Isotope Producer facility (BLIP). The experiment utilized a 181 MeV proton beam to irradiate several capsules, each containing many candidate material samples for various accelerator components. Materials included various grades/alloys of beryllium, graphite, silicon, iridium, titanium, TZM, CuCrZr, and aluminum. Attainable peak damage from an 8-week irradiation run ranges from 0.03 DPA (Be) to 7 DPA (Ir). Helium production is expected to range from 5 appm/DPA (Ir) to 3,000 appm/DPA (Be). The motivation, experimental parameters, as well as the post-irradiation examination plans of this experiment are described.

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WEPVA142

Active Compensation Coils in the Fermilab g-2 Experiment

multipole, dipole, simulation, storage-ring

3602

K.E. Badgley
Texas A&M University, College Station, USA
B. Kiburg
Fermilab, Batavia, Illinois, USA
M.W. Smith
University of Washington, CENPA, Seattle, USA

The recently commissioned Fermilab muon g-2 experiment is aiming to determine the anomalous magnetic moment of the muon to 140 ppb. To achieve this level of precision, the magnetic field seen by the muon must be know at fraction of a ppm level, which puts limits on the required magnetic field uniformity. In addition to the mechanical adjustments made to magnet pole tips, a set of 200 trim coils were added to the ring. These coils form concentric rings with 100 on the top pole and 100 on the bottom. Measurements of the remaining integrated filed errors were made using NMR probes. The use of these trim coils to reduce the remaining higher order field errors will be discussed.

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THPAB007

Short Bunches at the Transition From Strong to Weak Longitudinal Instability

shielding, simulation, synchrotron, damping

3696

P. Kuske
HZB, Berlin, Germany

The interaction of particles with their vacuum sur-roundings can lead to longitudinal instabilities of the whole bunch of particles. Most of these instabilities are strong and the growth rates are large compared to the damping rate. For a weak instability the opposite is true and with just a resistive impedance the instability would always be weak and independent of the bunch length. The interaction of a bunch with its own radiation emitted midway between parallel plates leads to a strong instabil-ity for long bunches and a transition to weak instability if the bunch length becomes shorter. This regime is ana-lysed numerically with a Vlasov-Fokker-Planck solver. The results are compared to recent observations at ANKA. An attempt is made to explain the remaining discrepan-cies by including higher order terms of the momentum compaction factor into these calculations. There are indi-cations that the simple model needs refinements in order to take radiation from upstream dipoles into account.

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THPAB017

Investigation of High Repetition Rate Femtosecond Electron Diffraction at PITZ

electron, laser, gun, emittance

3727

H.J. Qian, M. Groß, M. Krasilnikov, A. Oppelt, F. Stephan
DESY Zeuthen, Zeuthen, Germany

PITZ is a photoinjector test facility for FLASH and European XFEL, and it has been proposed to be a prototype machine to develop an accelerator based THz/IR source for European XFEL pump-probe experiment. In addition, the machine can also support femtosecond electron diffraction at the same beam repetition rate as European XFEL, which brings XFEL users more flexibility for different experiments. In this paper, a femtosecond electron diffraction scheme based on the PITZ accelerator setup is investigated.

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THPAB031

Study of Beam Break Up in Irradiation Linacs

wakefield, linac, electron, simulation

3767

X.C. Meng, H.B. Chen, W. Gai, J. Shi, S.X. Zheng
TUB, Beijing, People's Republic of China
G.H. Li, J.S. Liu, Y.H. Liu
NUCTECH, Beijing, People's Republic of China
F.H. de Sá
LNLS, Campinas, Brazil

Many recent experiments of the irradiation linacs produced at Tsinghua University indicate that beam power is limited by beam break up (BBU). Limits exist while the beam current or the pulse width is increased. In this paper, we illustrate the bream break up (BBU) phenomenon in the cases of both the 10MeV travelling-wave linac and 10MeV backward travelling-wave linac. The higher order modes in the linacs are analysed and the wake fields are calculated both with theoretical analysis and numerical simulation. Also, the beam dynamics is studied on the basis of the wakefield results to find a BBU threshold in these structures.

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THPAB072

Application of Voronoi Diagram to Mask-Based Intercepting Phase-Space Measurements

emittance, electron, linac, laser

3872

A. Halavanau, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
Q. Gao, J.G. Power, E.E. Wisniewski
ANL, Argonne, Illinois, USA
Q. Gao
TUB, Beijing, People's Republic of China
G. Ha
POSTECH, Pohang, Kyungbuk, Republic of Korea
P. Piot
Fermilab, Batavia, Illinois, USA

Intercepting multi-aperture masks (e.g. pepper pot or multislit mask) combined with a downstream transverse-density diagnostics (e.g. based on optical transition radiation or employing scintillating media) are commonly used for characterizing the phase space of charged particle beams and the associated emittances. The required data analysis relies on precise calculation of the RMS sizes and positions of the beamlets originated from the mask which drifted up to the analyzing diagnostics. Voronoi diagram is an efficient method for splitting a plane into subsets according to the distances between given vortices. The application of the method to analyze data from pepper pot and multislit mask based measurement is validated via numerical simulation and applied to experimental data acquired at the Argonne Wakefield Accelerator facility. We also discuss the application of the Voronoi diagrams to quantify transversely-modulated beams distortion.

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THPAB088

Comparison of Theory, Simulation, and Experiment for Dynamical Extinction of Relativistic Electron Beams Diffracted Through a Si Crystal Membrane

electron, simulation, scattering, emittance

3924

L.E. Malin, W.S. Graves, J. Spence, C. Zhang
Arizona State University, Tempe, USA
R.K. Li, C. Limborg, E.A. Nanni, X. Shen, S.P. Weathersby
SLAC, Menlo Park, California, USA

Diffraction in the transmission geometry through a single-crystal silicon slab is exploited to control the intensity of a relativistic electron beam. The choice of crystal thickness and incidence angle can extinguish or maximize the transmitted beam intensity via coherent multiple Bragg scattering; thus, the crystal acts as a dynamical beam stop through the Pendel'sung effect, a well-known phenomenon in X-ray and electron diffraction. In an initial experiment, we have measured the ability of this method to transmit or extinguish the primary beam and diffract into a single Bragg peak. Using lithographic etching of patterns in the crystal we intend to use this method to nanopattern an electron beam for production of coherent x-rays. We compare the experimental results with simulations using the multislice method to model the diffraction pattern from a perfect silicon crystal of uniform thickness, considering multiple scattering, crystallographic orientation, temperature effects, and partial coherence from the momentum spread of the beam. The simulations are compared to data collected at the ASTA UED facility at SLAC for a 340 nm thick Si(100) wafer with a beam energy of 2.35 MeV.

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THPAB106

Experience with Single Cavity and Piezo Controls for Short, Long Pulse and CW Operation

cavity, feedback, operation, controls

3966

K.P. Przygoda, V. Ayvazyan, R. Rybaniec, H. Schlarb, Ch. Schmidt, J.K. Sekutowicz
DESY, Hamburg, Germany
P. Echevarria
HZB, Berlin, Germany

We present a compact RF control system for SCRF single cavities based on MicroTCA.4 equipped with specialized advanced mezzanine cards (AMCs) and rear transition modules (RTMs). To sense the RF signals from the cavity and to drive the high power source, a DRTM-DWC8VM1 module is used equipped with 8 analog field detectors and one RF vector modulator. Fast cavity frequency tuning is achieved by piezo-actuators attached to the cavity and a RTM piezo-driver module (DRTM-PZT4). Data processing of the RF signals and the real-time control algorithms are implemented on a Virtex-6 FPGA and a Spartan FPGAs within two AMCs (SIS8300-L2V2 and DAMC-FMC20). The compact single cavity control system was tested at Cryo Module Test Bench (CMTB) at DESY. Software and firmware were developed to support all possible modes, the short pulse (SP), the long pulse (LP) and CW operation mode with duty cycles ranging from 1 % to 100%. The SP mode used a high power multi-beam klystron at low QL ~3·10⁶. For the LP mode (up to 50% duty cycle) and the CW mode a 120 kW IOT tube was used at QL up to 1.5·10⁷. Within this paper we present the achieved performance and report on the operation experience on such system.

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THPAB128

Beam Arrival Time Analisis Based on CBPM at DCLS

simulation, cavity, FEL, undulator

4023

S.S. Cao, J. Chen, L.W. Lai, Y.B. Leng
SINAP, Shanghai, People's Republic of China
N. Zhang
SSRF, Shanghai, People's Republic of China

Dalian Coherent Light Source is the first high gain free electron lasers (FEL) user facility in China, which is dedicated at extreme ultraviolet (EUV) spectral regime of 150-50nm for various scientific fields. In its undulator section, the beam-line was equipped with ten pair of high-precision cavity beam position monitor (CBPM), which can be used for beam position and beam arrival time (BAT) measurement. Based on this, we have done some preliminary research about the beam fight time with the reference cavities of CBPMs for the future research on BAT. In this paper, we presented the scheme of the beam fight time (BFT) research, analyzed the results, and evaluated the consistency and stability of BFT.

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THPIK001

Copper Accelerating Structure Fabrication With Controled Cu-Ag Joining Conditions

vacuum, controls, data-analysis, distributed

4104

V. Danielyan, V.S. Avagyan, S.G. Dekhtiarov, T.H. Mkrtchyan, S. Naghdalyan, A.S. Simonyan, V. V. Vardanyan
CANDLE SRI, Yerevan, Armenia
A.V. Tsakanian
HZB, Berlin, Germany

The paper is devoted to the development of technological processes of copper accelerating structures fabrication from oxygen-free copper. The experimental set-up for vacuum brazing of long accelerating structures with optimal Cu-Ag joining conditions is described. The experimental results of precise machining and subsequent vacuum brazing of Ag-Cu eutectic are presented

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THPIK023

Concept of the High Power RF Systems for MESA

cavity, linac, SRF, LLRF

4147

R.G. Heine, F. Fichtner
IKP, Mainz, Germany

Funding: work supported by DFG under the cluster od Excellence PRISMA, EXC 1098/2014
The Mainz Energy-recovering Superconducting Accelerator (MESA) is currently designed and built at the Institut für Kernphysik (KPH) at Johannes Gutenberg-Universität Mainz. The main accelerator incorporates four superconducting cavities of the TESLA type, while the preaccelerator MAMBO (Milliampere Booster) is a room temperature linac. The MESA high power RF-systems have to cover a vast power range starting at some 10kW per cavity for the main linac modules and more 50kW per cavity for MAMBO. In this paper we will present the concept of a unified high power RF system for both main accelerator and preaccelertor, based on solid state technology.

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THPIK050

Measurement and Tuning of the RF Field for the CSNS DTL

DTL, cavity, operation, coupling

4210

A.H. Li, M.X. Fan, B. Li, J. Peng, P.H. Qu, Y. Wang, X.L. Wu
CSNS, Guangdong Province, People's Republic of China
Q. Chen, S. Fu, K.Y. Gong, H.C. Liu
IHEP, Beijing, People's Republic of China

The CSNS DTL accelerates negative hydrogen ions from 3MeV to 80MeV with resonant frequency of 324MHz and peak current of 15mA. The CSNS includes four DTL cavities with diameter of 56.6cm and each length of 9 meters. RF properties research and measurement have been done to make sure the design and manufacture validate for beam operation. A new automatic system has been developed for measuring field distribution. The secondary derivation method is used to calculate the amount of the tuners to tune axial field flatness. The tilt of TS curve is used to judge the gap between the post couplers and drift tubes to achieve stability. At last the tanks have good flatness and strong stabilization, the field deviation is 2% with the standard deviation of 0.96%, and the maximum TS parameter is 65%/MHz. After the low power RF tuning experiment, the four tans have been installed in the tunnel, and have gotten good results of high power test and beam acceleration experiment.

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THPIK059

Experimental Study on PM-AM Method in Pulse Compression System

LLRF, klystron, cavity, acceleration

4230

P. Wang, H.B. Chen, C. Cheng, M.M. Peng, J. Shi, X.W. Wu, J. Yang, H. Zha
TUB, Beijing, People's Republic of China

We experimentally demonstrate the PM-AM method (Phase Modulation to Amplitude Modulation) at the S-band high power test stand, which consists of two S-band klystrons, a SLED type pulse compressor and two high power stainless steel RF loads, in Tsinghua University. A LLRF (low level RF) system has been developed to modulate the phases of the two klystrons in real time such that pulse compressor could generate a flat output pulse. Experimental results presents that the efficiency of the pulse compression system is 45% and the power gain is 2.9.

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THPIK124

Using Conductive Nanoparticles to Reduce the Surface Charging of Ceramics

cryogenics, electron, vacuum, cavity

4392

M.L. Neubauer, A. Dudas
Muons, Inc, Illinois, USA
F. Marhauser
JLab, Newport News, Virginia, USA

Beam pipe ceramics used for various purposes suffer from the problem of surface charging in the presence of an electron beam. A novel technique has been proposed for a method for reducing the charging effects by filling nano sized pores in the ceramic with a conductive medium. Pores in ceramics can be formed in a chain with varying depths depending on sintering temperatures and methods for creating the pores. In the pre-formed condition of these novel ceramics, a nanoparticle slurry is infused by capillary action into the ceramic and fired at temperatures and atmospheres to stabilize the conductive medium inside the ceramic. The microwave characteristics of these ceramics will be investigated in a Phase I program with the design of a complete beam pipe lossy ceramic in a Phase II.

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THPIK125

Ultra High Gradient Breakdown Rates in X-Band Cryogenic Normal Conducting Rf Accelerating Cavities

accelerating-gradient, cryogenics, cavity, electron

4395

A.D. Cahill, J.B. Rosenzweig
UCLA, Los Angeles, California, USA
V.A. Dolgashev, S.G. Tantawi, S.P. Weathersby
SLAC, Menlo Park, California, USA

Funding: Work Supported by DOE/SU Contract DE-AC02-76-SF00515, US NSF Award PHY-1549132, the Center for Bright Beams, and DOE SCGSR Fellowship.
RF breakdown is one of the major factors limiting the operating accelerating gradient in rf particle accelerators. We conjecture that the breakdown rate is linked to the movements of crystal defects induced by periodic mechanical stress. Pulsed surface heating possibly creates a major part of this stress. By decreasing crystal mobility and increasing yield strength we hope to reduce the breakdown rate for the same accelerating gradient. We can achieve these properties by cooling a copper accelerating cavity to cryogenic temperatures. We tested an 11.4 GHz cryogenic copper accelerating cavity at high power and observed that the rf and dark current signals are consistent with Q₀ changing during rf pulses. To take this change in Q₀ into account, we created a non-linear circuit model in which the Q₀ is allowed to vary inside the pulse. We used this model to process the data obtained from the high power test of the cryogenic accelerating structure. We present the results of measurements with low rf breakdown rates for surface electric fields near 500 MV/m for a shaped rf pulse with 150 ns of flat gradient.

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THPIK126

Design of a Field-Emission X-Band Gun Driven by Solid-State RF Source

electron, gun, cavity, linac

4399

E.A. Nanni, V.A. Dolgashev, J. Neilson, S.G. Tantawi
SLAC, Menlo Park, California, USA
B.E. Carlsten, J.W. Lewellen, D.C. Nguyen
LANL, Los Alamos, New Mexico, USA
M. Othman
UCI, Irvine, California, USA

We present the design of a field-emission X-band gun designed to be powered using a solid-state RF source. The source of the electron beam is a field emission nano-tip array. The RF gun is intended to be a beam source for 1 MeV solid-state driven linac for deployment on a satellite to map magnetic fields in the magnetosphere. The gun has to satisfy strict requirements on both average and peak power consumption, as well as rapid turn on time. In order to achieve low power consumption, the RF gun operates at relatively low accelerating gradient of 2 MeV/m. The beam exit energy is ~20 keV for an RF power 1.5 kW. Each cell of the RF gun is separately powered by commercially available, GaN high electron mobility transistors. In proof of principle experiments we successfully powered a 9.3 GHz accelerating cavity with a 100 W transistor and a 1% duty cycle.

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THPVA005

Investigation of Electron Beam Assisted Density Boosting in Plasma Traps Using the Example of a Gabor Plasma Lens

electron, plasma, simulation, space-charge

4421

C. Beberweil, M. Droba, S. Klaproth, O. Meusel, D. Noll, H. Podlech, K. Schulte, K.I. Thoma
IAP, Frankfurt am Main, Germany
S. Gammino, D. Mascali
INFN/LNS, Catania, Italy
L. Malferrari, A. Montanari, F. Odorici
INFN-Bologna, Bologna, Italy

Gabor lenses are plasma traps that can be used for focusing an ion beam linearly without aberrations* by the electric field of a confined electron cloud. They combine strong electrostatic focusing with the possibility of space charge compensation and provide an attractive alternative to conventional ion beam optics in a LEBT section. The focusing performance strongly depends on the density and distribution of the enclosed electron plasma*. As the Gabor lens is usually operated close to the ion source, residual gas ionization is supposed to be the central electron generation mechanism. An electron source is introduced in order to investigate the possibility of boosting the electron density in plasma traps using the example of a Gabor lens. This way, a Gabor lens could be operated under XUHV conditions, where residual gas ionization is suppressed. The particle in cell code bender** was used to simulate the injection into the confining fields of the space charge lens in different geometrical configurations and a prototype experiment was constructed consisting of a Gabor lens and an electron source system. In this contribution, simulations and measurements will be presented.
* Schulte, K., et al. Electron cloud dynamics in a Gabor space charge lens. 2012
** Noll, D., et al. The particle-in-cell code bender and its application to non-relativistic beam transport. 2015

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THPVA017

Integer Spin Resonance Crossing With Preserving Beam Polarization on VEPP-4M

polarization, resonance, acceleration, solenoid

4451

A.K. Barladyan, A.Yu. Barnyakov, S.A. Glukhov, S.E. Karnaev, E.B. Levichev, S.A. Nikitin, I.B. Nikolaev, I.N. Okunev, P.A. Piminov, A.G. Shamov, A.N. Zhuravlev
BINP SB RAS, Novosibirsk, Russia

The method to preserve the electron beam polarization on the VEPP-4M storage ring during acceleration with crossing the integer spin resonance energy E=1763 MeV is described. It is based on the use of the non-compensated longitudinal magnetic field of the KEDR detector. This method has been successfully applied for the needs of the R measurement experiment.

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THPVA027

Commissioning and First Results of the IBEX Paul Trap

ion, electron, gun, focusing

4481

S.L. Sheehy, E. Carr, L. Martin
JAI, Oxford, United Kingdom
K. Budzik
Warsaw University, Warsaw, Poland
D.J. Kelliher, S. Machida
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
C.R. Prior
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The Intense Beam Experiment (IBEX) is a linear Paul trap designed to replicate the dynamics of intense particle beams in accelerators. Similar to the S-POD apparatus at Hiroshima University, IBEX is a small scale experiment which has been constructed and recently commissioned at the Rutherford Appleton Laboratory in the UK. Its aim is to support theoretical studies of next-generation high intensity proton and ion accelerators, complementing existing computer simulation approaches. Here we report on the status of commissioning and first results obtained.

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THPVA033

Towards commissioning the Fermilab Muon g-2 Experiment

proton, target, storage-ring, operation

4505

D. Stratakis, J.P. Morgan, M.J. Syphers
Fermilab, Batavia, Illinois, USA
A. Fiedler, M.J. Syphers
Northern Illinois University, DeKalb, Illinois, USA
S-C. Kim
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
M. Korostelev
Cockcroft Institute, Warrington, Cheshire, United Kingdom
M. Korostelev
Lancaster University, Lancaster, United Kingdom

Funding: Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy.
Starting this summer, Fermilab will host a key exper-iment dedicated to the search for signals of new phys-ics: The Fermilab Muon g-2 Experiment. Its aim is to precisely measure the anomalous magnetic moment of the muon. In full operation, in order to avoid contami-nation, the newly born secondary beam is injected into a 505 m long Delivery Ring (DR) wherein it makes several revolutions before being send to the experi-ment. Part of the commissioning scenario will execute a running mode wherein the passage from the DR will be skipped. With the aid of numerical simulations, we provide estimates of the expected performance.

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THPVA040

Magnetic Field Computation for PMTs Shielding Optimization

shielding, simulation, quadrupole, photon

4522

E. Bouquerel, O. Dorvaux, S. Kihel, M. Krauth, P. Peaupardin
IPHC, Strasbourg Cedex 2, France
C. Ciemala
IFJ-PAN, Kraków, Poland

The Photon Array for the studies of Radioactive and Ion Stable beams (PARIS) is a multidetector of clusters. Each cluster is composed of 9 units of two-shells phoswiches of LaBr3/NaI scintillators optically coupled to one photomultiplier tube. PARIS will be used in combination with the VAMOS spectrometer at GANIL. During the experiment, PMTs will be exposed to the constant magnetic fringe fields produced by a quadrupole. Magnetic shielding is essential to efficiently lower the magnetic field inside the PMTs. The design and the optimization of this shield is presented. A comparison is done between the simulated and the experimental values.

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THPVA044

Detector Structure Development Using Active And Passive Thermography

detector, target, laser, cavity

4531

E. Rosenthal, D. Grunwald, G. Natour
Forschungszentrum Jülich GmbH, Central Institute of Engineering, Electronics and Analytics, Jülich, Germany

During the development and production of the mechanical support structures of the PANDA-Micro-Vertex-Detector(MVD)* experiments of passive and active thermography were applied and shown. The combination of mostly carbon-based materials enables the development of lightweight structures, which satisfy the mechanical stability and thermal requirements. The carrier structure of the MVD stripe detector is mainly composed of carbon foams, high fiber content CFC materials and PMI-based foams. This enables to selectively cool areas where heat is generated and to decouple them from the temperature-sensitive areas of the sensor system. Passive thermography is used during our development work mainly to validate the results of thermal simulations, for design optimization and for the functional control of the carrier structure. Additionally active thermography allows us to identify anomalies and thermal disturbances, which remain unnoticed in static processes. Also the investigation and characterization of adhesive layers are possible. For this purpose we developed special software algorithms which are sensitive to small-scale differences in temperature conductivity.
* PANDA Collaboration: W. Erni et al., arXiv: 1207.6581

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THPVA051

Vibration Study of Magnet Girder of the HEPS-TF

photon, factory, quadrupole, emittance

4554

Z. Wang, C. H. Li, H. Qu, H. Wang
IHEP, Beijing, People's Republic of China

Abstract: There are stringent requirements on beam stability in the High Energy Photon Source (HEPS). The stability of the magnet girder is an extremely important factor for the beam stability. This paper will discuss the influence of ground vibration to the beam stability. This influence will determine the scope of the vibration magnification of the magnet girder. By improving the stiffness of the magnet girder, the influence will be reduced and the beam stability shall be improved. Besides, the progress of the HEPS-TF girder prototype and the vibration test will be described.

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THPVA073

Latest Results on Fast Kicker for g-2 E-989 Experiment at Fermilab

kicker, impedance, storage-ring, injection

4616

A.A. Mikhailichenko, D. L. Rubin
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

We are describing the latest results on fabrication and measurements of kicker and pulser and beam dynamics in E-989 experiment at FERMILAB on precise measurement of anomalous magnetic moment of muon.

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THPVA081

Radiation Tests of Aerospace Components at ELBE

electron, radiation, gun, detector

4641

Ch. Schneider, D. Bemmerer, P. Michel, D. Stach
HZDR, Dresden, Germany

The cw electron accelerator ELBE operates mainly in the beam energy range 6 to 32 MeV and beam current range 1μA to 1mA. For most experiments a thermionic gun is used as electron source. The cw electron pulse structure so as the pulse charge is realized by applying electrical pulses with specific amplitudes and frequencies on the grid of the gun. The standard cw operation frequency is 13 MHz but can be divided sequentially by the factor 2 down to 101 kHz. For very special pulse structures a so called single pulser module exist performing different patterns also with dark current suppression via a macro pulser gate. For evaluating the performance and hardness under irradiation of e.g. aerospace components much lower doses respectively currents lower than the μA range are required. Furthermore reproducible and stable doses in a specific area for consecutively radiation of samples are necessary. In the presentation the investigations and concepts used at ELBE for the irradiation of different aerospace components are described.

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THPVA098

Development of a 3.95 Mev X-Band Linac-Driven X-Ray Combined Neutron Source

neutron, target, detector, linac

4692

J.M. Bereder, K. Dobashi, Y. Mitsuya, M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
M. Ishida, Y. Ohshima
PWRI, Ibaraki, Japan
J. Kusano
Accuthera Inc., Kawasaki, Kanagawa, Japan
Y. Takahashi
The University of Tokyo, Tokyo, Japan
Y. Tanaka
The University of Tokyo, Institute of Industrial Science, Tokyo, Japan

Funding: Council for Science, Technology and Innovation (CSTI), Cross-Ministrial Strategic Innovation Promo-tion Program (SIP), Japan Science and Technoogy Agency (JST)
The existing non-destructive inspection method employed for concrete structures uses high energy X-rays to detect internal flaws in concrete structures and iron reinforcing rods. In addition to this conventional method, the authors are developing an innovative inspection system that uses a mobile compact linac-driven neutron source that utilizes neutron backscattering, to measure the moisture content in concrete structures and estimate the corrosion probability distribution of iron reinforcing rods. By combining the knowledge of the moisture distribution in concrete structures with the information of its inner structure, the remaining life of concrete structures can be estimated. Further experiments will be conducted in the laboratory, and the moisture detection experiment in the real bridge is scheduled for 2017.

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THPVA102

Structural Analysis and Evaluation of Actual PC Bridge Using 950 keV/3.95 MeV X-Band Linacs

linac, site, detector, target

4701

H. Takeuchi, R. Yano
The University of Tokyo, Tokyo, Japan
K. Dobashi, Y. Mitsuya, M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
M. Ishida, Y. Ohshima
PWRI, Ibaraki, Japan
J. Kusano
Accuthera Inc., Kawasaki, Kanagawa, Japan
I. Ozawa
The University of Tokyo, The School of Engineering, Tokyo, Japan

Funding: This work was supported by Council for Science, Technology and Innovation(CSTI), Cross-ministerial Strategic Innovation Promotion Program (SIP) (Funding agency: JST).
In Japan, bridges constructed in the highly economic growth era are facing to aging problem and advanced maintenance methods have been strongly required recently. To meet this demand, we develop the on-site inspection system using 950 keV/3.95 MeV X-band (9.3 GHz) linac X-ray sources*. These systems can visualize in seconds the inner states of bridge, including cracks of concrete, location and state of tendons (wires) and other imperfections. We focused on the inspection for wires which are critical to the safety of bridge. At the on-site inspections, the X-ray inspection system exhibited sufficient accuracy to detect the wire's corrosion. We also evaluated the maximum thickness of concrete to which our system can be applied. Using the 950 keV system, we conducted on-site inspection for real bridges and performed structural analysis to evaluate the bearing capacity of the bridge using finite element method. We plan to apply the 3.95 MeV linac for actual bridge inspection to extend the applicable range in 2017. For accurate visualization, the parallel motion CT technique for bridge inspection is in progress.
* Mitsuru Ueaska et al, On-site nondestructive inspection by upgraded portable 950keV/3.95MeV X-band linac x-ray sources, J. Phys. B: At. Mol. Opt. Phys. 47(2014) 234008 (9pp)

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THPVA129

Spatial Distributions of natU(n, f), 238U(n, g) Reaction Rates in Spallation Neutron Fields Produced by Deuterons and 12C Ions on the Massive Uranium Target

target, detector, neutron, simulation

4753

A. Zhadan, V.V. Sotnikov, V.A. Voronko
NSC/KIPT, Kharkov, Ukraine
S.I. Tyutyunnikov
JINR, Dubna, Moscow Region, Russia
P. Zhivkov
INRNE, Sofia, Bulgaria

The results of the experiments carried out within the framework of Energy and Transmutation of RAW at JINR NUCLOTRON accelerator are presented. The target assembly QUINTA consisting of 512 kg natural uranium was irradiated by deuteron and carbon beams with energies 1, 2, 4 and 8 GeV (deuterons), 24 and 48 GeV (carbon). Spatial distribution and total number of capture reaction and fission reaction rates was obtained using the activation technique. The integral number of fissions reactions in the volume of uranium target remains approximately constant within our statistical errors for 1, 2, 4 and 8 GeV deuteron beams and for 24 and 48 GeV carbon beams (per one primary particle and per 1 GeV of beam energy). For the integral number of capture reactions with deuteron beams we have seen maximum at 2 GeV. Some of the obtained experimental data was analyzed using the MCNPX transport code. For spatial distribution of reaction rates in case of 4 and 8 GeV deuteron beams we have seen a discrepancy between the experimental and calculated values in backward direction.

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THPVA131

Biological Effectiveness of Proton and Ion Beam Therapy: Studies Using G4-DNA

proton, ion, simulation, target

4761

R.J. Barlow
University of Huddersfield, Huddersfield, United Kingdom
P. Thongjerm
IIAA, Huddersfield, United Kingdom

We have used the Geant4-DNA program to investigate on a radiobiological level the interaction of various types of particles within cells, to identify relationships between irradiation and damage to DNA, leading to cell death. Although the physical attributes of particle therapy clearly hold a benefit over conventional radiotherapy, the biological effects hold uncertainties, and modelling the way particles interact with tissue on a cellular level can reduce these. The understanding of the energy deposition pattern along the particle track and consequent probabilities of producing DNA cluster breaks enables us to predict the effects of a particle beam on a microscopic level, which can aid treatment planning.

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THPVA139

Relative Insensitivity to Inhomogeneities on Very High Energy Electron Dose Distributions

electron, simulation, radiation, photon

4791

A. Lagzda, R.M. Jones
UMAN, Manchester, United Kingdom
D. Angal-Kalinin, J.K. Jones
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
K. Kirkby
The Christie NHS Foundation Trust, Manchester, United Kingdom

Funding: Science and Technology Facilities Council, United Kingdom Cockroft Institute, United Kingdom Christie Hospital, Manchester, United Kingdom
We investigated the effects of heterogeneous regions on dose deposition of very high-energy electrons (VHEE) using both Geant4 simulations and experiments performed at the CALIFES facility at CERN. Small air and acetal plastic (bone equivalent) cavities were embedded in a water phantom and irradiated with a 197 MeV electron beam. Experimentally determined transverse dose profiles were acquired using radiation sensitive EBT3 Gafchromic films embedded in the water phantom at various depths. EBT3 Gafchromic films were found to be a suitable dosimeter for relative dose dosimetry of VHEE beams. Simulated and measured results were found to be consistent with each other and the largest discrepancy was found to be no more than 5%. Dose profiles of VHEE beams were found to be relatively insensitive to embedded high and low density geometries.

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THPVA141

Non-Destructive Measurement of Electron Microbunch Separation

electron, laser, radiation, gun

4798

H. Zhang, G. Doucas, H. Harrison, I.V. Konoplev, A.J. Lancaster
JAI, Oxford, United Kingdom
A. Aryshev, M. Shevelev, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan

With the development of femtosecond lasers, the generation of micro-bunched beams directly from a photocathode becomes routine; however, the monitoring of the separation is still a challenge. We present the results of proof-of-principle experiments measuring the distance between two bunches via the amplitude modulation analysis of a monochromatic radiation signal. Good agreement with theoretical prediction is shown.

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