IPAC2017 - List of Keywords (positron)

Paper	Title	Other Keywords	Page
MOPAB061	DAΦNE BTF Improvements of the Transverse Beam Diagnostics	software, detector, linac, timing	250
	P. Valente INFN-Roma, Roma, Italy B. Buonomo, D.G.C. Di Giulio, L.G. Foggetta INFN/LNF, Frascati (Roma), Italy
	The DAΦNE BTF (beam-test facility) can provide electrons and positrons, tuning at runtime different beam parameters: energy (from about 50 MeV up to 750 MeV for e^- and 540 MeV for e+), intensity (from single particle up to 10¹⁰/bunch) and pulse length (in the range 1.5-40 ns) up to 49 Hz, depending on the operations of the DAΦNE collider. The beam spot and divergence can be adjusted, down to sub-mm sizes and 2 mrad (downstream of the vacuum beam-pipe exit window), matching the user needs. We describe of the BTF beam transverse monitor systems based on FitPIX detectors, operating in bus synchronization mode externally timed to the BTF beam. We also describe our custom software allowing the acquisition and synchronization of the beam diagnostics with the users data, using TCP/IP calls to MEMCACHED. The performance of the system in a variety of beam intensity, energy and focusing conditions is reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPAB061
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MOPIK080	Research of the Electro-Gravitational Induction by Using COD Signals in Charged Particle Storage Rings	storage-ring, induction, electron, feedback	719
	D. Dong IHEP, Beijing, People's Republic of China J.Y. Dong Binghamton University, State University of New York, Binghamton, New York, USA
	Funding: The project was supported by the National Natural Science Foundation of China under Grant No. 11575215, partly. Form the beam instability in the charged particle storage ring; researchers have known that one kinds of long term beam instability, the period of 12 hours, comes from the gravity changes, the change of acceleration of gravity g, delta g caused by the moon and sun moving relative to the earth, so called the terrestrial tidal forces. Phenomenology, we would say that the gravity changes caused by the moon and sun moving at the storage ring have caused the beam energy changes in the storage ring. If it is true, then it may be the electro-gravitational induction (EGI). In this paper, we will discuss the possibility of EGI, and estimate the maximum value of the gravity coefficient of the induced electromotive force by using the existing beam data from the storage rings.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK080
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MOPVA078	The Window Replacement and Q Recovery of BEPCII Storage Ring SCC	cavity, vacuum, operation, radiation	1046
	T.M. Huang, J.P. Dai, R. Ge, S.P. Li, Z.Q. Li, H.Y. Lin, Q. Ma, W.M. Pan, Y. Sun, G.W. Wang IHEP, Beijing, People's Republic of China P. Sha Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China
	The storage ring RF system for the upgrade of the Beijing Electron Positron Collider (BEPCII) adopted two 500 MHz superconducting cavities: west for the positron ring (BPR); east for the electron ring (BER). The excessive heating of the west window was observed in Nov.2013, and not cured thoroughly. After two years operation, the window cracked suddenly on Nov.18th, 2015. The replacement of the window was subsequently implemented in tunnel. However, the quality factor (Q) of the cavity decayed a lot after the window replacement. 90 degrees Celsius N2 gas baking of the outer surface of the cavity was carried out in situ and the Q recovered in a short time. This paper will present the process of the window replacement and the cavity Q recovery in detail. Tong-ming Huang et al., Chinese Physics C Vol. 40, No. 6 (2016) 067001
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA078
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TUZB2	Commissioning Status of High Luminosity Collider Rings for SuperKEKB	electron, solenoid, emittance, quadrupole	1275
	H. Koiso KEK, Ibaraki, Japan
	SuperKEKB project aims to obtain the world's highest luminosity of 8x10³⁵/cm/s, in order to discover new particle physics beyond the Standard Model. Key technologies for the high luminosity are nano-beam scheme at the collision point and high positron and electron stored current with low emittance, which require the significant upgrade of both the injector and the collider rings. Recently commissioning of the renewal collider rings has been performed without final focus magnets and the Belle II detector (Phase 1). This talk gives results of the Phase 1 commissioning and construction status toward the first beam collisions (Phase 2).
	Slides TUZB2 [64.509 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUZB2
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TUPAB002	Material Tests for the ILC Positron Source	target, electron, photon, operation	1293
	A. Ushakov, G.A. Moortgat-Pick University of Hamburg, Hamburg, Germany K. Aulenbacher, Th. Beiser, P. Heil, V. Tioukine IKP, Mainz, Germany A. Ignatenko, S. Riemann DESY Zeuthen, Zeuthen, Germany A.L. Prudnikava, Y. Tamashevich University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	The positron source is a vital system of the ILC. The conversion target that yields 10¹⁴ positrons per second will undergo high peak and cyclic load during ILC operation. In order to ensure stable long term operation of the positron source the candidate material for the conversion target has to be tested. The intense electron beam at the Mainz Microtron (MAMI) provides a good opportunity for such tests. The first results for Ti6Al4V are presented which is the candidate material for the positron conversion target as well as for the exit window to the photon beam absorber.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB002
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TUPAB003	High Energy Density Irradiation With MAMI LINAC	target, electron, radiation, photon	1296
	P. Heil, K. Aulenbacher, Th. Beiser IKP, Mainz, Germany A. Ignatenko, G.A. Moortgat-Pick, A. Ushakov DESY, Hamburg, Germany S. Riemann DESY Zeuthen, Zeuthen, Germany
	In order to build a positron source for the ILC, a high energy density irradiation is needed to test the used materials. At the MAMI linear accelerator such a radiation can be provided at different electron energies. With a macro pulsed source it is possible to imitate a yearlong radiation at the ILC within several hours. Small transversal beam sizes need to be provided with the focusing system and be measured at high beam currents using transition radiation and current measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB003
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TUPAB004	Progress of 7-GeV SuperKEKB Injector Linac Upgrade and Commissioning	gun, injection, linac, electron	1300
	K. Furukawa, M. Akemoto, D.A. Arakawa, Y. Arakida, H. Ego, A. Enomoto, Y. Enomoto, S. Fukuda, Y. Funahashi, T. Higo, H. Honma, N. Iida, M. Ikeda, H. Kaji, K. Kakihara, T. Kamitani, H. Katagiri, M. Kawamura, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, F. Miyahara, H. Nakajima, K. Nakao, T. Natsui, M. Nishida, Y. Ogawa, Y. Ohnishi, S. Ohsawa, F. Qiu, I. Satake, D. Satoh, M. Satoh, Y. Seimiya, A. Shirakawa, H. Sugimoto, H. Sugimura, T. Suwada, T. Takatomi, T. Takenaka, M. Tanaka, N. Toge, Y. Yano, K. Yokoyama, M. Yoshida, R. Zhang, X. Zhou KEK, Ibaraki, Japan
	KEK injector linac has delivered electrons and positrons for particle physics and photon science experiments for more than 30 years. It is being upgraded for the SuperKEKB project, which aims at a 40-fold increase in luminosity over the previous project KEKB, in order to increase our understanding of new physics beyond the standard model of elementary particle physics. SuperKEKB asymmetric electron and positron collider with its extremely high luminosity requires a high current, low emittance and low energy spread injection beam from the injector. Electron beams will be generated by a new type of RF gun, that will provide a much higher beam current to correspond to a large stored beam current and a short lifetime in the ring. The positron source is another major challenge that enhances the positron bunch intensity from 1 to 4 nC by increasing the positron capture efficiency, and the positron beam emittance is reduced from 2000 micron to 20 micron in the vertical plane by introducing a damping ring, followed by the bunch compressor and energy compressor. The recent status of the upgrade and beam commissioning is reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB004
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TUPAB008	CEPC Linac Design and Beam Dynamics	linac, electron, target, quadrupole	1315
	C. Meng, Y.L. Chi, X.P. Li, G. Pei, S. Pei, D. Wang, J.R. Zhang IHEP, Beijing, People's Republic of China
	Circular Electron-Positron Collider (CEPC) is a 100 km ring e⁺ e⁻ collider for a Higgs factory, which is organized and led by the Institute of High Energy Physics (IHEP) of the Chinese Academy of Sciences (CAS) in collaboration with a number of institutions from various countries. The linac of CEPC is a normal con-ducting S-band linac with frequency in 2856.75 MHz and provide electron and positron beam at an energy up to 10 GeV with bunch charge in 1.0 nC and repetition frequency in 100 Hz. The linac scheme will be detailed discussed in this paper, including electron bunching system, positron source design, and main linac. Positrons are generated using a 4 GeV electron beam with bunch charge 10 nC hit tungsten target and the positron source design are presented. The beam dynamic results with longitudinal short Wakefield, transverse Wakefield and errors are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB008
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TUPAB009	Design Study on CEPC Positron Damping Ring and Bunch Compressor	damping, linac, emittance, injection	1318
	D. Wang, Y.L. Chi, J. Gao, X.P. Li, C. Meng, J.R. Zhang IHEP, Beijing, People's Republic of China G. Pei Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China
	The primary purpose of CEPC damping ring is to reduce the transverse phase spaces of positron beam to suitably small value at the beginning of Linac and also adjust the time structure of positron beam for reinjection into the Linac. Longitudinal bunch length control was provided to minimize wake field effects in the Linac by a bunch compressor system after the damping ring. Both designs for damping ring and bunch compressor were discussed in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB009
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TUPAB014	Preliminary Design of FCC-ee Pre-Injector Complex	linac, emittance, damping, booster	1337
	S. Ogur, Y. Papaphilippou, F. Zimmermann CERN, Geneva, Switzerland A.M. Barnyakov, A.E. Levichev, D.A. Nikiforov BINP SB RAS, Novosibirsk, Russia K. Furukawa, N. Iida, F. Miyahara, K. Oide KEK, Ibaraki, Japan
	The design of a 100 km circular e⁺e⁻ collider with extremely high luminosity is an important component of the global Future Circular Collider (FCC) study hosted by CERN. FCC-ee is being designed to serve as Z, W, H and top factory, covering beam energies from 45.6 to 175 GeV. For the injectors, the Z-operation is the most challenging mode, due to the high total charge and low equilibrium emittance in the collider at this energy. Thus, fulfilling the Z-mode will also meet the demands for all other modes of FCC-ee. This goal can be achieved by using a 6 GeV NC linac with an S-band RF frequency of 2.856 GHz and a repetition rate of 100 Hz. This linac will accelerate two bunches per RF pulse, each with a charge of 6.5 nC. Positrons will be generated by sending 4.46 GeV e^- onto a hybrid target so that the e⁺ created can still be accelerated to 1.54 GeV in the remaining part of the same linac. The emittance of the e⁺ beam will then shrink to the nm level in a 1.54 GeV damping ring. After damping, the e⁺ will be reinjected into the linac and accelerated to 6 GeV. The e^- and e⁺ will then be accelerated alternately to 45.6 GeV in the booster, before they are injected into the collider.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB014
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TUPAB018	Initial Data From an Electron Cloud Detector in a Quadrupole Magnet at CesrTA	electron, quadrupole, detector, storage-ring	1352
	J.P. Sikora, S.T. Barrett, M.G. Billing, J.A. Crittenden, K.A. Jones, Y. Li, T.I. O'Connell Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467 and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505 In September 2016, we installed a detector in a quadrupole magnet that measures the electron cloud density using two independent techniques. Stripline electrodes collect cloud electrons which pass through holes in the beam-pipe wall. The array of small holes shields the striplines from the beam-induced electromagnetic pulse. The beam-pipe chamber has also been designed so that microwave measurements of the electron cloud density can be performed. The resonant microwaves are confined to be within the 56 cm length of the quadrupole. The detector is placed in a newly installed quadrupole that is adjacent to an existing lattice quadrupole of the same polarity. Since they are powered independently, their relative strengths can be varied with stored beam – allowing electron cloud measurements to be made as a function of gradient. This paper presents the first data obtained with this detector with trains of positron bunches at 5.3 GeV. The detector is installed in the Cornell Electron Storage Ring and is part of the test accelerator program for the study of electron cloud build-up using electron and positron beams from 2 to 5 GeV.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB018
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TUPIK026	Simulations of Positron Capture and Acceleration in the Linear Wakefield of Plasma	wakefield, plasma, laser, emittance	1737
	M.M. Peng, W. Gai TUB, Beijing, People's Republic of China
	We present the study of positrons capturing dynamics in the wakefield of plasma generated either by a laser or electron beam. Only simplified linear wakefield models were used as first order approximation. By analysing the phase space and beam dynamics, we show that phase space for capturing is rather small, only high brightness beam with very short pulse length can be captured with reasonable rate for wakefields of 1 - 10 GeV/m and wave-length of 100 micron.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK026
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WEOBA3	Studies of a Scheme for Low Emittance Muon Beam Production From Positrons on Target	target, emittance, scattering, simulation	2486
	M. Boscolo, M. Antonelli, M.E. Biagini, O.R. Blanco-García, A. Variola INFN/LNF, Frascati (Roma), Italy A. Bacci Istituto Nazionale di Fisica Nucleare, Milano, Italy I. Chaikovska, R. Chehab LAL, Orsay, France F. Collamati INFN-Roma1, Rome, Italy M. Iafrati ENEA, Agenzia nazionale per le nuove tecnologie, l'energia e lo sviluppo economico sostenibile, Frascati, Italy L. Keller SLAC, Menlo Park, California, USA S.M. Liuzzo, P. Raimondi ESRF, Grenoble, France P. Sievers CERN, Geneva, Switzerland
	We are studying a new scheme to produce very low emittance muon beams using a positron beam of about 45 GeV interacting on electrons on target. This is a challenging and innovative scheme that needs a full design study. One of the innovative topics to be investigated is the behaviour of the positron beam stored in a low emittance ring with a thin target, that is directly inserted in the ring chamber to produce muons. Muons will be immediately collected at the exit of the target and transported to two mu+ and mu- accumulator rings. We focus in this paper on the simulation of the e⁺ beam interacting with the target, its degradation in the 6-D phase space and the optimization of the e⁺ ring design mainly to maximize the energy acceptance. We will investigate the performances of this scheme, ring optics plus target system, comparing different multi-turn simulations.
	Slides WEOBA3 [3.737 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEOBA3
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WEPIK001	Advanced Beam Dump for FCC-ee	collider, simulation, electron, distributed	2906
	A. Apyan ANSL, Yerevan, Armenia B. Goddard, F. Zimmermann CERN, Geneva, Switzerland K. Oide KEK, Ibaraki, Japan
	A modified beam dump for the future electron positron circular collider FCC-ee is discussed. The extraction line with a dilution kicker system distributes bunches at different transverse locations on the face of the beam dump. For a standard absorber the maximum energy deposition of all bunches occurs at the same longitudinal position inside the beam dump. This region experiences an enormous temperature rise compared with the surrounding parts of the beam dump. We propose a novel type of beam dump which spreads out the deposited energy over its whole volume quasi-uniformly, thereby reducing the maximum temperature rise. Results of Monte-Carlo simulations for a multi-material mosaic beam dump and for absorbers with distorted shapes are shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK001
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WEPIK002	Experimental Activities on High Intensity Positron Sources Using Channeling	target, electron, photon, experiment	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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK002
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WEPIK008	Problems in SuperKEKB Vacuum System During the Phase-1 Commissioning and Their Mitigation Measures	wiggler, vacuum, electron, photon	2925
	Y. Suetsugu, H. Hisamatsu, T. Ishibashi, K. Kanazawa, K. Shibata, M. Shirai, S. Terui KEK, Ibaraki, Japan
	The first (Phase-1) commissioning of the SuperKEKB, an energy-asymmetric electron-positron collider in KEK, Japan, started in February and ended in June, 2016. The vacuum system of the main ring worked well through the commissioning period as a whole, but experienced several problems, such as the electron cloud effect (ECE) in the positron ring, the pressure bursts accompanying beam losses due to dust particles in the beam pipe, an air leak at a connection flange due to the direct hitting of synchrotron radiation (SR), and so on. Towards the next (Phase-2) commissioning, countermeasures to these problems are taken during the shutdown period. For example, permanent magnets generating axial magnetic fields are attached to beam pipes at drift spaces for the suppression of the ECE. Knockers, which can artificially drop dust particles attached to the top surface in beam pipes by continuous impacts, are prepared to the beam pipes at which the pressure bursts had been frequently observed. Bellows chambers with masks are installed to protect the leaked flange from SR. The problems and their mitigation measures will be summarized in the presentation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK008
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WEPIK009	Collimators for SuperKEKB Main Ring	impedance, background, factory, HOM	2929
	T. Ishibashi, Y. Suetsugu, S. Terui KEK, Ibaraki, Japan
	SuperKEKB, which is an upgrade project of KEKB, is an electron-positron collider with extremely high luminosity. Collimators (movable masks) for SuperKEKB have been designed to fit an antechamber scheme of the vacuum system and will be operated to improve backgrounds in the particle detector named Belle II. We are developing two types of collimators; a horizontal and vertical collimator. The collimator has a pair of horizontally or vertically opposed movable jaws with RF fingers. Each jaw travels independently through 5-25 mm horizontally or 2-12 mm vertically in a distance between the beam axis and the tip of the jaw. SuperKEKB will operate with high currents of short bunch lengths, therefore it is important to estimate and decrease the impedance of the collimators. Two horizontal collimators were already installed in the positron ring and operated during Phase-1 commissioning for approximately 5 months, from February to June 2016. In this presentation, the latest design, and the results in the Phase-1 commissioning are presented.
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WEPIK016	CEPC-SppC Towards CDR	collider, luminosity, booster, detector	2954
	J. Gao IHEP, Beijing, People's Republic of China
	Funding: supported by National Key Programme for S&T Research and Development (2016YFA0400400), National Natural Science Foundation of China (11575218, 11605211, 11605210, 11505198), Key Research Program of Frontier Sciences, CAS, (QYZDJ-SSW-SLH004) and CAS Center for Excellence in Particle Physics (CCEPP) In this paper we will give an introduction to Circular Electron Positron Collider (CEPC). The scientific background, physics goal, the collider design requirements and the conceptual design principle of CEPC are described. On CEPC accelerator, the optimization of parameter designs for CEPC with different energies, machine lengthes, single ring and crab-waist collision partial double ring, advanced partial double partial ring and fully partial double ring options, etc. have been discussed systematically, and compared. CEPC accelerator baseline and alternative designs have been proposed based on the luminosity potential in relation with the design goals. The sub-systems of CEPC, such as collider main ring, booster, electron positron injector, etc. ave also been introduced. The detector and MDI design have been briefly mentioned. Finally, the optimization design of Super Proton-Proton Collider (SppC), its energy and luminosity potentials, in the same tunnel of CEPC are also discussed. The CEPC-SppC Progress Report (2015-2016) has been published.
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WEPIK026	VEPP-5 Injection Complex: Two Colliders Operation Experience	injection, collider, operation, extraction	2982
	D.E. Berkaev, A.V. Andrianov, K.V. Astrelina, V.V. Balakin, A.M. Batrakov, O.V. Belikov, M.F. Blinov, D. Bolkhovityanov, A. Butakov, E.V. Bykov, N.S. Dikansky, F.A. Emanov, A.R. Frolov, V.V. Gambaryan, K. Gorchakov, Ye.A. Gusev, S.E. Karnaev, G.V. Karpov, A.S. Kasaev, E. Kenzhebulatov, V.A. Kiselev, S. Kluschev, A.A. Kondakov, I. Koop, I.E. Korenev, N.Kh. Kot, V.R. Kozak, A.A. Krasnov, S.A. Krutikhin, I.V. Kuptsov, G.Y. Kurkin, N.N. Lebedev, A.E. Levichev, P.V. Logatchov, Yu. Maltseva, A.A. Murasev, V. Muslivets, D.A. Nikiforov, An.A. Novikov, A.V. Ottmar, A.V. Pavlenko, I.L. Pivovarov, V.V. Rashchenko, Yu. A. Rogovsky, S.L. Samoylov, N. Sazonov, A.V. Semenov, S.V. Shiyankov, D.B. Shwartz, A.N. Skrinsky, A.A. Starostenko, D.A. Starostenko, A.G. Tribendis, A.S. Tsyganov, S.S. Vasichev, S.V. Vasiliev, V.D. Yudin, I.M. Zemlyansky, A.N. Zhuravlev BINP SB RAS, Novosibirsk, Russia A.V. Andrianov, V.V. Balakin, F.A. Emanov, I. Koop, A.A. Krasnov, A.E. Levichev, D.A. Nikiforov, A.V. Pavlenko, Yu. A. Rogovsky, D.B. Shwartz, A.A. Starostenko NSU, Novosibirsk, Russia A.I. Mickailov Budker INP & NSU, Novosibirsk, Russia A.G. Tribendis NSTU, Novosibirsk, Russia
	Two BINP colliders VEPP-4M and VEPP-2000 e⁺e⁻ colliders are under operation with the beams feeding from VEPP-5 Injection Complex via newly constructed K-500 beam transfer line. Upgraded injection chain demonstrated ability to provide designed luminosity both to VEPP-4M and VEPP-2000 and techniques of reliable operation are under development now. The design and operation experience of Injection Complex and transfer lines are presented.
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WEPIK028	Status of the Electron-Positron Collider VEPP-4	electron, collider, storage-ring, experiment	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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK028
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WEPIK029	High Luminosity at VEPP-2000 Collider With New Injector	luminosity, collider, detector, injection	2989
	P.Yu. Shatunov, O.V. Belikov, D.E. Berkaev, K. Gorchakov, A.S. Kasaev, A.N. Kirpotin, I. Koop, A.A. Krasnov, A.P. Lysenko, S.V. Motygin, E. Perevedentsev, V.P. Prosvetov, D.V. Rabusov, Yu. A. Rogovsky, A.M. Semenov, A.I. Senchenko, Y.M. Shatunov, D.B. Shwartz, M.V. Timoshenko, I.M. Zemlyansky, Yu.M. Zharinov BINP SB RAS, Novosibirsk, Russia E. Perevedentsev, Yu. A. Rogovsky, A.I. Senchenko, D.B. Shwartz NSU, Novosibirsk, Russia
	VEPP-2000 e⁺e⁻ collider at BINP was commissioned and started data taking with two detectors in 2010 with old injection chain. In the middle energy range, where the luminosity was limited by beam-beam effects, the world record values of beam-beam parameter were achieved, ksi=0.12/IP. At the same time the design luminosity value of L = 10³² cm^-2s⁻¹ at top energy (E = 1 GeV per beam) remained unreachable due to limited e⁺ production rate. The injection chain was significantly upgraded in 2013-2016. The experience of upgraded VEPP-2000 complex operation at top energies with Round Colliding Beams will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK029
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WEPIK119	Lost Muon Study for the Muon g-2 Experiment at Fermilab	storage-ring, background, quadrupole, experiment	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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK119
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WEPVA071	Preliminary Conceptual Study of Next Generation Tau-Charm Factory at China	luminosity, factory, collider, electron	3436
	Q. Luo USTC/NSRL, Hefei, Anhui, People's Republic of China
	Funding: Work supported by National Natural Science Foundation of China 11375178 and the Fundamental Research Funds for the Central Universities, Grant No WK2310000046 As BEPC II would accomplish its mission in the next decade, research on high energy science demands a successor. The luminosity of this successor should be one or two orders higher than BEPC II, while the electron beam should be longitudinal polarized at the IP. This paper discusses the feasibility and key technologies of the next tau-charm collider: a greenfield new facility or an upgrade of BEPC II.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA071
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WEPVA148	Dynamics of Target Motion Under Exposure of Hard Gamma Undulator Radiation	target, electron, undulator, photon	3618
	A.A. Mikhailichenko Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	We describe time dependent dynamics of the target motion under exposure by undulator radiation in a system for positron production. We took into account inertia of material of target. Calculations carried with help of FlexPDE code.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA148
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THOBA3	A Compact 335 MeV Positron Damping Ring Design for FACET-II	damping, emittance, linac, quadrupole	3652
	G.R. White, Y. Cai, R.O. Hettel, M.A.G. Johansson, V. Yakimenko, G. Yocky SLAC, Menlo Park, California, USA
	Funding: This work was supported by the Department of Energy under Contract Number: DE-AC02-76SF00515. FACET-II will be a new test facility, starting construction in 2018 within the main SLAC Linac. Its purpose is to build on the decades-long experience developed conducting accelerator R&D at SLAC in the areas of advanced acceleration and coherent radiation techniques with high-energy electron and positron beams. The positron system design utilizes an existing W-Re target in Linac Sector 19, driven by 4 nC electrons bunches at 10 GeV. We present the design of a 335 MeV, 21.4 m circumference damping ring required to damp emittance from a modified positron return beamline by a factor of 500. The transverse emittance is calculated to be 6 um-rad, fully coupled, with a bunch length of 4 mm and energy spread 0.06 %, at a bunch charge of 1 nC. The arc magnets need to be especially compact due to tight space constraints (installation will be in the existing SLAC Linac tunnel, Sector 10, with 3 m width available) and were a key design challenge. We present a solution with combined function bend/quadrupole/sextupole magnets which have been modelled in 3D using Opera.
	Slides THOBA3 [8.372 MB]
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THPAB019	PSPA, a Web Platform for Simulation of Particle Accelerator	simulation, lattice, linac, interface	3730
	M.E. Biagini, A. Variola INFN/LNF, Frascati (Roma), Italy L. Garnier, H. Guler, C. Helft, G. Le Meur, M. Nicolas, A. Pérus, F. Touze LAL, Orsay, France
	PSPA (Platform for Simulation of Particle Accelerators) is an original web-based interactive simulation platform for designing and modelling particle accelerators created at Laboratoire de l'Accélérateur Linéaire, Orsay. It aims at eventually containing all the tools to make a start-to-end simulation of an accelerator, and make it possible to run interactively several open source simulations codes available worldwide. At the moment, the focus is on electron/positron accelerators. PSPA will optimize the work of accelerator designers by factoring once and for all the tedious, time-consuming and error prone process of translating data formats between the various codes involved in the modelling of a machine, controlling the repeated execution of these models by easily varying some parameter and managing the associated data. Moreover, as a truly innovative feature, it will provide a convenient means for testing different physical models of a given part of a machine. The status of the project is described in this paper, and examples of its application to the ThomX compact Compton backscattering source at LAL are presented.
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THPAB021	Wake Field and Head-Tail Instability in Beam-Beam Collision with a Large Crossing Angle	wakefield, electron, simulation, dipole	3738
	K. Ohmi, D. Zhou KEK, Ibaraki, Japan N. Kuroo UTTAC, Tsukuba, Ibaraki, Japan K. Oide, F. Zimmermann CERN, Geneva, Switzerland
	Head-tail type of coherent beam-beam instability has been seen in a strong-strong beam-beam simulation for collision with a large Piwinski angle σ_zθ/σ_x>>1, where θ is a half crossing angle. Beta x* is key parameter for the instability. The instability is not serious for SuperKEKB, but can be seen in phase II commissioning stage. It has a large impact for design of FCC-ee. We introduce wake field due to the beam-beam collision. The wake field gives turn-by-turn correlation of head-tail mode. Head-tail instability caused by the wake field explains that seen in the strong-strong beam-beam simulation.
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THPVA034	Comparison of the Coupling of Dipole Motion From Bunch to Bunch in an Electron Beam Caused by Electron Clouds at CesrTA Due to Variations in Bunch Length and Chromaticity	electron, damping, dipole, coupling	4509
	M.G. Billing, L.Y. Bartnik, J.A. Crittenden, M.J. Forster, N.T. Rider, J.P. Shanks, M.B. Spiegel, S. Wang Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA R. Holtzapple CalPoly, San Luis Obispo, California, USA E.C. Runburg University of Notre Dame, Indiana, USA
	Earlier experiments at the Cornell Electron-Positron Storage Ring Test Accelerator (CesrTA) have probed the interaction of the electron cloud (EC) with a 2.1 GeV stored positron beam. Since a very low EC density is expected with the electron bunches, these results characterize the dependence of beam-vacuum chamber impedance interactions, which are common to both positron and electron beams. The experiments were performed on a 30-bunch electron train with a 14 ns spacing, at a fixed current of 0.75mA/bunch, at two different vertical chromaticity settings and for four different bunch lengths (or synchrotron tunes.) The beam dynamics of the stored beam, in the presence of the electron cloud, was quantified using: 20 turn-by-turn beam position monitors in CESR to measure the correlated bunch-by-bunch dipole motion and an x-ray beam size monitor to record the bunch-by-bunch, turn-by-turn vertical size of each bunch within the trains. In this paper we report on the analysis of the observations from these experiments and compare them with effects of the EC on the positron beam's dipole motion and coupling of the motion from each bunch to its succeeding bunches.
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THPVA035	Dependence of the Coupling of Dipole Motion From Bunch to Bunch Caused by Electron Clouds at CesrTA Due to Variations in Bunch Length and Chromaticity	damping, electron, dipole, synchrotron	4512
	M.G. Billing, L.Y. Bartnik, J.A. Crittenden, M.J. Forster, N.T. Rider, J.P. Shanks, M.B. Spiegel, S. Wang Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA R. Holtzapple CalPoly, San Luis Obispo, California, USA E.C. Runburg University of Notre Dame, Indiana, USA
	The Cornell Electron-Positron Storage Ring Test Accelerator (CesrTA) has conducted experiments to probe the interaction of the electron cloud (EC) with a 2.1 GeV stored positron beam. These experiments investigate the dependence of beam'electron cloud interactions vs. bunch length (or synchrotron tune) at two values of the vertical chromaticity. The experiments utilized a 30-bunch positron train with a 14 ns spacing, at a fixed current of 0.75mA/bunch. The beam dynamics of the stored beam, in the presence of the electron cloud, was quantified using: 20 turn-by-turn beam position monitors in CESR to measure the correlated bunch-by-bunch dipole motion and an x-ray beam size monitor to record the bunch-by-bunch, turn-by-turn vertical size of each bunch within the trains. In this paper we report on the observations from these experiments and a more detailed analysis for the coupling of dipole motion via the EC from each bunch to succeeding bunches in the train.
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FRYCA1	The Future of High-energy Accelerators	collider, electron, proton, hadron	4856
	J. Mnich DESY, Hamburg, Germany
	The physics results from high energy colliders, neutrino experiments and from experiments in space are changing the particle physics landscape. In the last decade several accelerator designs and studies have taken shape and reached a high level of maturity both at the high energy and high intensity frontiers. The talk should review the physics questions facing the HEP community and the strategy to address them in view of the next update of the European Strategy for Particle Physics.
	Slides FRYCA1 [9.087 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-FRYCA1
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Paper

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Other Keywords

Page

MOPAB061

DAΦNE BTF Improvements of the Transverse Beam Diagnostics

software, detector, linac, timing

250

P. Valente
INFN-Roma, Roma, Italy
B. Buonomo, D.G.C. Di Giulio, L.G. Foggetta
INFN/LNF, Frascati (Roma), Italy

The DAΦNE BTF (beam-test facility) can provide electrons and positrons, tuning at runtime different beam parameters: energy (from about 50 MeV up to 750 MeV for e^- and 540 MeV for e+), intensity (from single particle up to 10¹⁰/bunch) and pulse length (in the range 1.5-40 ns) up to 49 Hz, depending on the operations of the DAΦNE collider. The beam spot and divergence can be adjusted, down to sub-mm sizes and 2 mrad (downstream of the vacuum beam-pipe exit window), matching the user needs. We describe of the BTF beam transverse monitor systems based on FitPIX detectors, operating in bus synchronization mode externally timed to the BTF beam. We also describe our custom software allowing the acquisition and synchronization of the beam diagnostics with the users data, using TCP/IP calls to MEMCACHED. The performance of the system in a variety of beam intensity, energy and focusing conditions is reported.

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MOPIK080

Research of the Electro-Gravitational Induction by Using COD Signals in Charged Particle Storage Rings

storage-ring, induction, electron, feedback

719

D. Dong
IHEP, Beijing, People's Republic of China
J.Y. Dong
Binghamton University, State University of New York, Binghamton, New York, USA

Funding: The project was supported by the National Natural Science Foundation of China under Grant No. 11575215, partly.
Form the beam instability in the charged particle storage ring; researchers have known that one kinds of long term beam instability, the period of 12 hours, comes from the gravity changes, the change of acceleration of gravity g, delta g caused by the moon and sun moving relative to the earth, so called the terrestrial tidal forces. Phenomenology, we would say that the gravity changes caused by the moon and sun moving at the storage ring have caused the beam energy changes in the storage ring. If it is true, then it may be the electro-gravitational induction (EGI). In this paper, we will discuss the possibility of EGI, and estimate the maximum value of the gravity coefficient of the induced electromotive force by using the existing beam data from the storage rings.

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MOPVA078

The Window Replacement and Q Recovery of BEPCII Storage Ring SCC

cavity, vacuum, operation, radiation

1046

T.M. Huang, J.P. Dai, R. Ge, S.P. Li, Z.Q. Li, H.Y. Lin, Q. Ma, W.M. Pan, Y. Sun, G.W. Wang
IHEP, Beijing, People's Republic of China
P. Sha
Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China

The storage ring RF system for the upgrade of the Beijing Electron Positron Collider (BEPCII) adopted two 500 MHz superconducting cavities: west for the positron ring (BPR); east for the electron ring (BER). The excessive heating of the west window was observed in Nov.2013, and not cured thoroughly*. After two years operation, the window cracked suddenly on Nov.18th, 2015. The replacement of the window was subsequently implemented in tunnel. However, the quality factor (Q) of the cavity decayed a lot after the window replacement. 90 degrees Celsius N2 gas baking of the outer surface of the cavity was carried out in situ and the Q recovered in a short time. This paper will present the process of the window replacement and the cavity Q recovery in detail.
* Tong-ming Huang et al., Chinese Physics C Vol. 40, No. 6 (2016) 067001

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TUZB2

Commissioning Status of High Luminosity Collider Rings for SuperKEKB

electron, solenoid, emittance, quadrupole

1275

H. Koiso
KEK, Ibaraki, Japan

SuperKEKB project aims to obtain the world's highest luminosity of 8x10³⁵/cm/s, in order to discover new particle physics beyond the Standard Model. Key technologies for the high luminosity are nano-beam scheme at the collision point and high positron and electron stored current with low emittance, which require the significant upgrade of both the injector and the collider rings. Recently commissioning of the renewal collider rings has been performed without final focus magnets and the Belle II detector (Phase 1). This talk gives results of the Phase 1 commissioning and construction status toward the first beam collisions (Phase 2).

Slides TUZB2 [64.509 MB]

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TUPAB002

Material Tests for the ILC Positron Source

target, electron, photon, operation

1293

A. Ushakov, G.A. Moortgat-Pick
University of Hamburg, Hamburg, Germany
K. Aulenbacher, Th. Beiser, P. Heil, V. Tioukine
IKP, Mainz, Germany
A. Ignatenko, S. Riemann
DESY Zeuthen, Zeuthen, Germany
A.L. Prudnikava, Y. Tamashevich
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

The positron source is a vital system of the ILC. The conversion target that yields 10¹⁴ positrons per second will undergo high peak and cyclic load during ILC operation. In order to ensure stable long term operation of the positron source the candidate material for the conversion target has to be tested. The intense electron beam at the Mainz Microtron (MAMI) provides a good opportunity for such tests. The first results for Ti6Al4V are presented which is the candidate material for the positron conversion target as well as for the exit window to the photon beam absorber.

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TUPAB003

High Energy Density Irradiation With MAMI LINAC

target, electron, radiation, photon

1296

P. Heil, K. Aulenbacher, Th. Beiser
IKP, Mainz, Germany
A. Ignatenko, G.A. Moortgat-Pick, A. Ushakov
DESY, Hamburg, Germany
S. Riemann
DESY Zeuthen, Zeuthen, Germany

In order to build a positron source for the ILC, a high energy density irradiation is needed to test the used materials. At the MAMI linear accelerator such a radiation can be provided at different electron energies. With a macro pulsed source it is possible to imitate a yearlong radiation at the ILC within several hours. Small transversal beam sizes need to be provided with the focusing system and be measured at high beam currents using transition radiation and current measurements.

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TUPAB004

Progress of 7-GeV SuperKEKB Injector Linac Upgrade and Commissioning

gun, injection, linac, electron

1300

K. Furukawa, M. Akemoto, D.A. Arakawa, Y. Arakida, H. Ego, A. Enomoto, Y. Enomoto, S. Fukuda, Y. Funahashi, T. Higo, H. Honma, N. Iida, M. Ikeda, H. Kaji, K. Kakihara, T. Kamitani, H. Katagiri, M. Kawamura, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, F. Miyahara, H. Nakajima, K. Nakao, T. Natsui, M. Nishida, Y. Ogawa, Y. Ohnishi, S. Ohsawa, F. Qiu, I. Satake, D. Satoh, M. Satoh, Y. Seimiya, A. Shirakawa, H. Sugimoto, H. Sugimura, T. Suwada, T. Takatomi, T. Takenaka, M. Tanaka, N. Toge, Y. Yano, K. Yokoyama, M. Yoshida, R. Zhang, X. Zhou
KEK, Ibaraki, Japan

KEK injector linac has delivered electrons and positrons for particle physics and photon science experiments for more than 30 years. It is being upgraded for the SuperKEKB project, which aims at a 40-fold increase in luminosity over the previous project KEKB, in order to increase our understanding of new physics beyond the standard model of elementary particle physics. SuperKEKB asymmetric electron and positron collider with its extremely high luminosity requires a high current, low emittance and low energy spread injection beam from the injector. Electron beams will be generated by a new type of RF gun, that will provide a much higher beam current to correspond to a large stored beam current and a short lifetime in the ring. The positron source is another major challenge that enhances the positron bunch intensity from 1 to 4 nC by increasing the positron capture efficiency, and the positron beam emittance is reduced from 2000 micron to 20 micron in the vertical plane by introducing a damping ring, followed by the bunch compressor and energy compressor. The recent status of the upgrade and beam commissioning is reported.

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TUPAB008

CEPC Linac Design and Beam Dynamics

linac, electron, target, quadrupole

1315

C. Meng, Y.L. Chi, X.P. Li, G. Pei, S. Pei, D. Wang, J.R. Zhang
IHEP, Beijing, People's Republic of China

Circular Electron-Positron Collider (CEPC) is a 100 km ring e⁺ e⁻ collider for a Higgs factory, which is organized and led by the Institute of High Energy Physics (IHEP) of the Chinese Academy of Sciences (CAS) in collaboration with a number of institutions from various countries. The linac of CEPC is a normal con-ducting S-band linac with frequency in 2856.75 MHz and provide electron and positron beam at an energy up to 10 GeV with bunch charge in 1.0 nC and repetition frequency in 100 Hz. The linac scheme will be detailed discussed in this paper, including electron bunching system, positron source design, and main linac. Positrons are generated using a 4 GeV electron beam with bunch charge 10 nC hit tungsten target and the positron source design are presented. The beam dynamic results with longitudinal short Wakefield, transverse Wakefield and errors are presented.

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TUPAB009

Design Study on CEPC Positron Damping Ring and Bunch Compressor

damping, linac, emittance, injection

1318

D. Wang, Y.L. Chi, J. Gao, X.P. Li, C. Meng, J.R. Zhang
IHEP, Beijing, People's Republic of China
G. Pei
Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China

The primary purpose of CEPC damping ring is to reduce the transverse phase spaces of positron beam to suitably small value at the beginning of Linac and also adjust the time structure of positron beam for reinjection into the Linac. Longitudinal bunch length control was provided to minimize wake field effects in the Linac by a bunch compressor system after the damping ring. Both designs for damping ring and bunch compressor were discussed in this paper.

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TUPAB014

Preliminary Design of FCC-ee Pre-Injector Complex

linac, emittance, damping, booster

1337

S. Ogur, Y. Papaphilippou, F. Zimmermann
CERN, Geneva, Switzerland
A.M. Barnyakov, A.E. Levichev, D.A. Nikiforov
BINP SB RAS, Novosibirsk, Russia
K. Furukawa, N. Iida, F. Miyahara, K. Oide
KEK, Ibaraki, Japan

The design of a 100 km circular e⁺e⁻ collider with extremely high luminosity is an important component of the global Future Circular Collider (FCC) study hosted by CERN. FCC-ee is being designed to serve as Z, W, H and top factory, covering beam energies from 45.6 to 175 GeV. For the injectors, the Z-operation is the most challenging mode, due to the high total charge and low equilibrium emittance in the collider at this energy. Thus, fulfilling the Z-mode will also meet the demands for all other modes of FCC-ee. This goal can be achieved by using a 6 GeV NC linac with an S-band RF frequency of 2.856 GHz and a repetition rate of 100 Hz. This linac will accelerate two bunches per RF pulse, each with a charge of 6.5 nC. Positrons will be generated by sending 4.46 GeV e^- onto a hybrid target so that the e⁺ created can still be accelerated to 1.54 GeV in the remaining part of the same linac. The emittance of the e⁺ beam will then shrink to the nm level in a 1.54 GeV damping ring. After damping, the e⁺ will be reinjected into the linac and accelerated to 6 GeV. The e^- and e⁺ will then be accelerated alternately to 45.6 GeV in the booster, before they are injected into the collider.

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TUPAB018

Initial Data From an Electron Cloud Detector in a Quadrupole Magnet at CesrTA

electron, quadrupole, detector, storage-ring

1352

J.P. Sikora, S.T. Barrett, M.G. Billing, J.A. Crittenden, K.A. Jones, Y. Li, T.I. O'Connell
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work is supported by the US National Science Foundation PHY-0734867, PHY-1002467 and the US Department of Energy DE-FC02-08ER41538, DE-SC0006505
In September 2016, we installed a detector in a quadrupole magnet that measures the electron cloud density using two independent techniques. Stripline electrodes collect cloud electrons which pass through holes in the beam-pipe wall. The array of small holes shields the striplines from the beam-induced electromagnetic pulse. The beam-pipe chamber has also been designed so that microwave measurements of the electron cloud density can be performed. The resonant microwaves are confined to be within the 56 cm length of the quadrupole. The detector is placed in a newly installed quadrupole that is adjacent to an existing lattice quadrupole of the same polarity. Since they are powered independently, their relative strengths can be varied with stored beam – allowing electron cloud measurements to be made as a function of gradient. This paper presents the first data obtained with this detector with trains of positron bunches at 5.3 GeV. The detector is installed in the Cornell Electron Storage Ring and is part of the test accelerator program for the study of electron cloud build-up using electron and positron beams from 2 to 5 GeV.

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TUPIK026

Simulations of Positron Capture and Acceleration in the Linear Wakefield of Plasma

wakefield, plasma, laser, emittance

1737

M.M. Peng, W. Gai
TUB, Beijing, People's Republic of China

We present the study of positrons capturing dynamics in the wakefield of plasma generated either by a laser or electron beam. Only simplified linear wakefield models were used as first order approximation. By analysing the phase space and beam dynamics, we show that phase space for capturing is rather small, only high brightness beam with very short pulse length can be captured with reasonable rate for wakefields of 1 - 10 GeV/m and wave-length of 100 micron.

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WEOBA3

Studies of a Scheme for Low Emittance Muon Beam Production From Positrons on Target

target, emittance, scattering, simulation

2486

M. Boscolo, M. Antonelli, M.E. Biagini, O.R. Blanco-García, A. Variola
INFN/LNF, Frascati (Roma), Italy
A. Bacci
Istituto Nazionale di Fisica Nucleare, Milano, Italy
I. Chaikovska, R. Chehab
LAL, Orsay, France
F. Collamati
INFN-Roma1, Rome, Italy
M. Iafrati
ENEA, Agenzia nazionale per le nuove tecnologie, l'energia e lo sviluppo economico sostenibile, Frascati, Italy
L. Keller
SLAC, Menlo Park, California, USA
S.M. Liuzzo, P. Raimondi
ESRF, Grenoble, France
P. Sievers
CERN, Geneva, Switzerland

We are studying a new scheme to produce very low emittance muon beams using a positron beam of about 45 GeV interacting on electrons on target. This is a challenging and innovative scheme that needs a full design study. One of the innovative topics to be investigated is the behaviour of the positron beam stored in a low emittance ring with a thin target, that is directly inserted in the ring chamber to produce muons. Muons will be immediately collected at the exit of the target and transported to two mu+ and mu- accumulator rings. We focus in this paper on the simulation of the e⁺ beam interacting with the target, its degradation in the 6-D phase space and the optimization of the e⁺ ring design mainly to maximize the energy acceptance. We will investigate the performances of this scheme, ring optics plus target system, comparing different multi-turn simulations.

Slides WEOBA3 [3.737 MB]

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WEPIK001

Advanced Beam Dump for FCC-ee

collider, simulation, electron, distributed

2906

A. Apyan
ANSL, Yerevan, Armenia
B. Goddard, F. Zimmermann
CERN, Geneva, Switzerland
K. Oide
KEK, Ibaraki, Japan

A modified beam dump for the future electron positron circular collider FCC-ee is discussed. The extraction line with a dilution kicker system distributes bunches at different transverse locations on the face of the beam dump. For a standard absorber the maximum energy deposition of all bunches occurs at the same longitudinal position inside the beam dump. This region experiences an enormous temperature rise compared with the surrounding parts of the beam dump. We propose a novel type of beam dump which spreads out the deposited energy over its whole volume quasi-uniformly, thereby reducing the maximum temperature rise. Results of Monte-Carlo simulations for a multi-material mosaic beam dump and for absorbers with distorted shapes are shown.

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WEPIK002

Experimental Activities on High Intensity Positron Sources Using Channeling

target, electron, photon, experiment

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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WEPIK008

Problems in SuperKEKB Vacuum System During the Phase-1 Commissioning and Their Mitigation Measures

wiggler, vacuum, electron, photon

2925

Y. Suetsugu, H. Hisamatsu, T. Ishibashi, K. Kanazawa, K. Shibata, M. Shirai, S. Terui
KEK, Ibaraki, Japan

The first (Phase-1) commissioning of the SuperKEKB, an energy-asymmetric electron-positron collider in KEK, Japan, started in February and ended in June, 2016. The vacuum system of the main ring worked well through the commissioning period as a whole, but experienced several problems, such as the electron cloud effect (ECE) in the positron ring, the pressure bursts accompanying beam losses due to dust particles in the beam pipe, an air leak at a connection flange due to the direct hitting of synchrotron radiation (SR), and so on. Towards the next (Phase-2) commissioning, countermeasures to these problems are taken during the shutdown period. For example, permanent magnets generating axial magnetic fields are attached to beam pipes at drift spaces for the suppression of the ECE. Knockers, which can artificially drop dust particles attached to the top surface in beam pipes by continuous impacts, are prepared to the beam pipes at which the pressure bursts had been frequently observed. Bellows chambers with masks are installed to protect the leaked flange from SR. The problems and their mitigation measures will be summarized in the presentation.

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WEPIK009

Collimators for SuperKEKB Main Ring

impedance, background, factory, HOM

2929

T. Ishibashi, Y. Suetsugu, S. Terui
KEK, Ibaraki, Japan

SuperKEKB, which is an upgrade project of KEKB, is an electron-positron collider with extremely high luminosity. Collimators (movable masks) for SuperKEKB have been designed to fit an antechamber scheme of the vacuum system and will be operated to improve backgrounds in the particle detector named Belle II. We are developing two types of collimators; a horizontal and vertical collimator. The collimator has a pair of horizontally or vertically opposed movable jaws with RF fingers. Each jaw travels independently through 5-25 mm horizontally or 2-12 mm vertically in a distance between the beam axis and the tip of the jaw. SuperKEKB will operate with high currents of short bunch lengths, therefore it is important to estimate and decrease the impedance of the collimators. Two horizontal collimators were already installed in the positron ring and operated during Phase-1 commissioning for approximately 5 months, from February to June 2016. In this presentation, the latest design, and the results in the Phase-1 commissioning are presented.

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WEPIK016

CEPC-SppC Towards CDR

collider, luminosity, booster, detector

2954

J. Gao
IHEP, Beijing, People's Republic of China

Funding: supported by National Key Programme for S&T Research and Development (2016YFA0400400), National Natural Science Foundation of China (11575218, 11605211, 11605210, 11505198), Key Research Program of Frontier Sciences, CAS, (QYZDJ-SSW-SLH004) and CAS Center for Excellence in Particle Physics (CCEPP)
In this paper we will give an introduction to Circular Electron Positron Collider (CEPC). The scientific background, physics goal, the collider design requirements and the conceptual design principle of CEPC are described. On CEPC accelerator, the optimization of parameter designs for CEPC with different energies, machine lengthes, single ring and crab-waist collision partial double ring, advanced partial double partial ring and fully partial double ring options, etc. have been discussed systematically, and compared. CEPC accelerator baseline and alternative designs have been proposed based on the luminosity potential in relation with the design goals. The sub-systems of CEPC, such as collider main ring, booster, electron positron injector, etc. ave also been introduced. The detector and MDI design have been briefly mentioned. Finally, the optimization design of Super Proton-Proton Collider (SppC), its energy and luminosity potentials, in the same tunnel of CEPC are also discussed. The CEPC-SppC Progress Report (2015-2016) has been published.

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WEPIK026

VEPP-5 Injection Complex: Two Colliders Operation Experience

injection, collider, operation, extraction

2982

D.E. Berkaev, A.V. Andrianov, K.V. Astrelina, V.V. Balakin, A.M. Batrakov, O.V. Belikov, M.F. Blinov, D. Bolkhovityanov, A. Butakov, E.V. Bykov, N.S. Dikansky, F.A. Emanov, A.R. Frolov, V.V. Gambaryan, K. Gorchakov, Ye.A. Gusev, S.E. Karnaev, G.V. Karpov, A.S. Kasaev, E. Kenzhebulatov, V.A. Kiselev, S. Kluschev, A.A. Kondakov, I. Koop, I.E. Korenev, N.Kh. Kot, V.R. Kozak, A.A. Krasnov, S.A. Krutikhin, I.V. Kuptsov, G.Y. Kurkin, N.N. Lebedev, A.E. Levichev, P.V. Logatchov, Yu. Maltseva, A.A. Murasev, V. Muslivets, D.A. Nikiforov, An.A. Novikov, A.V. Ottmar, A.V. Pavlenko, I.L. Pivovarov, V.V. Rashchenko, Yu. A. Rogovsky, S.L. Samoylov, N. Sazonov, A.V. Semenov, S.V. Shiyankov, D.B. Shwartz, A.N. Skrinsky, A.A. Starostenko, D.A. Starostenko, A.G. Tribendis, A.S. Tsyganov, S.S. Vasichev, S.V. Vasiliev, V.D. Yudin, I.M. Zemlyansky, A.N. Zhuravlev
BINP SB RAS, Novosibirsk, Russia
A.V. Andrianov, V.V. Balakin, F.A. Emanov, I. Koop, A.A. Krasnov, A.E. Levichev, D.A. Nikiforov, A.V. Pavlenko, Yu. A. Rogovsky, D.B. Shwartz, A.A. Starostenko
NSU, Novosibirsk, Russia
A.I. Mickailov
Budker INP & NSU, Novosibirsk, Russia
A.G. Tribendis
NSTU, Novosibirsk, Russia

Two BINP colliders VEPP-4M and VEPP-2000 e⁺e⁻ colliders are under operation with the beams feeding from VEPP-5 Injection Complex via newly constructed K-500 beam transfer line. Upgraded injection chain demonstrated ability to provide designed luminosity both to VEPP-4M and VEPP-2000 and techniques of reliable operation are under development now. The design and operation experience of Injection Complex and transfer lines are presented.

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WEPIK028

Status of the Electron-Positron Collider VEPP-4

electron, collider, storage-ring, experiment

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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WEPIK029

High Luminosity at VEPP-2000 Collider With New Injector

luminosity, collider, detector, injection

2989

P.Yu. Shatunov, O.V. Belikov, D.E. Berkaev, K. Gorchakov, A.S. Kasaev, A.N. Kirpotin, I. Koop, A.A. Krasnov, A.P. Lysenko, S.V. Motygin, E. Perevedentsev, V.P. Prosvetov, D.V. Rabusov, Yu. A. Rogovsky, A.M. Semenov, A.I. Senchenko, Y.M. Shatunov, D.B. Shwartz, M.V. Timoshenko, I.M. Zemlyansky, Yu.M. Zharinov
BINP SB RAS, Novosibirsk, Russia
E. Perevedentsev, Yu. A. Rogovsky, A.I. Senchenko, D.B. Shwartz
NSU, Novosibirsk, Russia

VEPP-2000 e⁺e⁻ collider at BINP was commissioned and started data taking with two detectors in 2010 with old injection chain. In the middle energy range, where the luminosity was limited by beam-beam effects, the world record values of beam-beam parameter were achieved, ksi=0.12/IP. At the same time the design luminosity value of L = 10³² cm^-2s⁻¹ at top energy (E = 1 GeV per beam) remained unreachable due to limited e⁺ production rate. The injection chain was significantly upgraded in 2013-2016. The experience of upgraded VEPP-2000 complex operation at top energies with Round Colliding Beams will be presented.

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WEPIK119

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

storage-ring, background, quadrupole, experiment

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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WEPVA071

Preliminary Conceptual Study of Next Generation Tau-Charm Factory at China

luminosity, factory, collider, electron

3436

Q. Luo
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Work supported by National Natural Science Foundation of China 11375178 and the Fundamental Research Funds for the Central Universities, Grant No WK2310000046
As BEPC II would accomplish its mission in the next decade, research on high energy science demands a successor. The luminosity of this successor should be one or two orders higher than BEPC II, while the electron beam should be longitudinal polarized at the IP. This paper discusses the feasibility and key technologies of the next tau-charm collider: a greenfield new facility or an upgrade of BEPC II.

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WEPVA148

Dynamics of Target Motion Under Exposure of Hard Gamma Undulator Radiation

target, electron, undulator, photon

3618

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

We describe time dependent dynamics of the target motion under exposure by undulator radiation in a system for positron production. We took into account inertia of material of target. Calculations carried with help of FlexPDE code.

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THOBA3

A Compact 335 MeV Positron Damping Ring Design for FACET-II

damping, emittance, linac, quadrupole

3652

G.R. White, Y. Cai, R.O. Hettel, M.A.G. Johansson, V. Yakimenko, G. Yocky
SLAC, Menlo Park, California, USA

Funding: This work was supported by the Department of Energy under Contract Number: DE-AC02-76SF00515.
FACET-II will be a new test facility, starting construction in 2018 within the main SLAC Linac. Its purpose is to build on the decades-long experience developed conducting accelerator R&D at SLAC in the areas of advanced acceleration and coherent radiation techniques with high-energy electron and positron beams. The positron system design utilizes an existing W-Re target in Linac Sector 19, driven by 4 nC electrons bunches at 10 GeV. We present the design of a 335 MeV, 21.4 m circumference damping ring required to damp emittance from a modified positron return beamline by a factor of 500. The transverse emittance is calculated to be 6 um-rad, fully coupled, with a bunch length of 4 mm and energy spread 0.06 %, at a bunch charge of 1 nC. The arc magnets need to be especially compact due to tight space constraints (installation will be in the existing SLAC Linac tunnel, Sector 10, with 3 m width available) and were a key design challenge. We present a solution with combined function bend/quadrupole/sextupole magnets which have been modelled in 3D using Opera.

Slides THOBA3 [8.372 MB]

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THPAB019

PSPA, a Web Platform for Simulation of Particle Accelerator

simulation, lattice, linac, interface

3730

M.E. Biagini, A. Variola
INFN/LNF, Frascati (Roma), Italy
L. Garnier, H. Guler, C. Helft, G. Le Meur, M. Nicolas, A. Pérus, F. Touze
LAL, Orsay, France

PSPA (Platform for Simulation of Particle Accelerators) is an original web-based interactive simulation platform for designing and modelling particle accelerators created at Laboratoire de l'Accélérateur Linéaire, Orsay. It aims at eventually containing all the tools to make a start-to-end simulation of an accelerator, and make it possible to run interactively several open source simulations codes available worldwide. At the moment, the focus is on electron/positron accelerators. PSPA will optimize the work of accelerator designers by factoring once and for all the tedious, time-consuming and error prone process of translating data formats between the various codes involved in the modelling of a machine, controlling the repeated execution of these models by easily varying some parameter and managing the associated data. Moreover, as a truly innovative feature, it will provide a convenient means for testing different physical models of a given part of a machine. The status of the project is described in this paper, and examples of its application to the ThomX compact Compton backscattering source at LAL are presented.

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THPAB021

Wake Field and Head-Tail Instability in Beam-Beam Collision with a Large Crossing Angle

wakefield, electron, simulation, dipole

3738

K. Ohmi, D. Zhou
KEK, Ibaraki, Japan
N. Kuroo
UTTAC, Tsukuba, Ibaraki, Japan
K. Oide, F. Zimmermann
CERN, Geneva, Switzerland

Head-tail type of coherent beam-beam instability has been seen in a strong-strong beam-beam simulation for collision with a large Piwinski angle σ_zθ/σ_x>>1, where θ is a half crossing angle. Beta x* is key parameter for the instability. The instability is not serious for SuperKEKB, but can be seen in phase II commissioning stage. It has a large impact for design of FCC-ee. We introduce wake field due to the beam-beam collision. The wake field gives turn-by-turn correlation of head-tail mode. Head-tail instability caused by the wake field explains that seen in the strong-strong beam-beam simulation.

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THPVA034

Comparison of the Coupling of Dipole Motion From Bunch to Bunch in an Electron Beam Caused by Electron Clouds at CesrTA Due to Variations in Bunch Length and Chromaticity

electron, damping, dipole, coupling

4509

M.G. Billing, L.Y. Bartnik, J.A. Crittenden, M.J. Forster, N.T. Rider, J.P. Shanks, M.B. Spiegel, S. Wang
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
R. Holtzapple
CalPoly, San Luis Obispo, California, USA
E.C. Runburg
University of Notre Dame, Indiana, USA

Earlier experiments at the Cornell Electron-Positron Storage Ring Test Accelerator (CesrTA) have probed the interaction of the electron cloud (EC) with a 2.1 GeV stored positron beam. Since a very low EC density is expected with the electron bunches, these results characterize the dependence of beam-vacuum chamber impedance interactions, which are common to both positron and electron beams. The experiments were performed on a 30-bunch electron train with a 14 ns spacing, at a fixed current of 0.75mA/bunch, at two different vertical chromaticity settings and for four different bunch lengths (or synchrotron tunes.) The beam dynamics of the stored beam, in the presence of the electron cloud, was quantified using: 20 turn-by-turn beam position monitors in CESR to measure the correlated bunch-by-bunch dipole motion and an x-ray beam size monitor to record the bunch-by-bunch, turn-by-turn vertical size of each bunch within the trains. In this paper we report on the analysis of the observations from these experiments and compare them with effects of the EC on the positron beam's dipole motion and coupling of the motion from each bunch to its succeeding bunches.

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THPVA035

Dependence of the Coupling of Dipole Motion From Bunch to Bunch Caused by Electron Clouds at CesrTA Due to Variations in Bunch Length and Chromaticity

damping, electron, dipole, synchrotron

4512

M.G. Billing, L.Y. Bartnik, J.A. Crittenden, M.J. Forster, N.T. Rider, J.P. Shanks, M.B. Spiegel, S. Wang
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
R. Holtzapple
CalPoly, San Luis Obispo, California, USA
E.C. Runburg
University of Notre Dame, Indiana, USA

The Cornell Electron-Positron Storage Ring Test Accelerator (CesrTA) has conducted experiments to probe the interaction of the electron cloud (EC) with a 2.1 GeV stored positron beam. These experiments investigate the dependence of beam'electron cloud interactions vs. bunch length (or synchrotron tune) at two values of the vertical chromaticity. The experiments utilized a 30-bunch positron train with a 14 ns spacing, at a fixed current of 0.75mA/bunch. The beam dynamics of the stored beam, in the presence of the electron cloud, was quantified using: 20 turn-by-turn beam position monitors in CESR to measure the correlated bunch-by-bunch dipole motion and an x-ray beam size monitor to record the bunch-by-bunch, turn-by-turn vertical size of each bunch within the trains. In this paper we report on the observations from these experiments and a more detailed analysis for the coupling of dipole motion via the EC from each bunch to succeeding bunches in the train.

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FRYCA1

The Future of High-energy Accelerators

collider, electron, proton, hadron

4856

J. Mnich
DESY, Hamburg, Germany

The physics results from high energy colliders, neutrino experiments and from experiments in space are changing the particle physics landscape. In the last decade several accelerator designs and studies have taken shape and reached a high level of maturity both at the high energy and high intensity frontiers. The talk should review the physics questions facing the HEP community and the strategy to address them in view of the next update of the European Strategy for Particle Physics.

Slides FRYCA1 [9.087 MB]

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