IPAC2014 - List of Keywords (positron)

Paper	Title	Other Keywords	Page
MOPRO001	Upgrade Status of Injector LINAC for SuperKEKB	electron, linac, emittance, gun	59
	T. Miura, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, Y. Funakoshi, K. Furukawa, T. Higo, H. Honma, R. Ichimiya, N. Iida, M. Ikeda, E. Kadokura, H. Kaji, K. Kakihara, T. Kamitani, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, F. Miyahara, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, Y. Ohnishi, S. Ohsawa, F. Qiu, M. Satoh, T. Shidara, A. Shirakawa, H. Sugimoto, T. Suwada, T. Takenaka, M. Tanaka, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou KEK, Ibaraki, Japan D. Satoh TIT, Tokyo, Japan
	The SuperKEKB collider is under construction to achieve 40-times higher luminosity than that of previous KEKB collider. The injector LINAC should provide high-intensity and low-emittance beams of 7-GeV electron and 4-GeV positron for SuperKEKB based on a nano-beam scheme. A photocathode RF-gun for low emittance electron beam has been already installed and the commissioning has started. The construction of positron capture section using a flux-concentrator and the dumping ring for low emittance positron beam is in progress. The simultaneous top-up injections to four storage-rings including photon factories is also required. In the upstream of dumping ring, the compatible optics between positron and electron has been designed. In the downstream of dumping ring, RF phase, focusing, and steering magnets will be switched by pulse to pulse against each beam-mode for optimising beam-transportation. This paper describes recent upgrade status toward the SuperKEKB.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO001
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MOPRO018	Booster of Electrons and Positrons (BEP) Upgrade to 1 GeV	dipole, injection, booster, vacuum	102
	D.B. Shwartz, D.E. Berkaev, D.V. Bochek, I. Koop, I.E. Korenev, A.A. Krasnov, I.K. Sedlyarov, P.Yu. Shatunov, Y.M. Shatunov, I.M. Zemlyansky BINP SB RAS, Novosibirsk, Russia
	At present new electron and positron injection complex in BINP is comissioned and ready to feed VEPP-2000 collider with intensive beams with energy of 450 MeV. To obtain peak luminosity limited only by beam-beam effects in whole energy range of 160-1000 MeV and to perform high average luminosity with small dead time the top-up injection is needed. Booster BEP upgrade to 1 GeV includes modification of all magnetic elements, including warm dipoles magnetic field increase up to 2.6 T, vacuum chamber, RF-system, injection-extraction system. BEP comissioning is scheduled to the end of 2014.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO018
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MOPME027	Parallel Three-dimensional PIC Code for Beam-beam Simulation in Linear Colliders	simulation, collider, linear-collider, beam-beam-effects	439
	M.A. Boronina, V.D. Korneev, V.A. Vshivkov ICM&MG SB RAS, Novosibirsk, Russia
	We present our parallel 3D3V particle-in-cell code for the numerical simulations of ultrarelativistic charged beams in supercolliders. In the algorithm we employ the three-dimensional set of Maxwell equations and the Vlasov-Liouville equation for the distribution function of beam particles in 6-dimensional phase space. The code allows performing numerical experiments with an arbitrary density distribution, beam crossing angle and relative offset. From the mathematical point of view the main problem of the three-dimensional modeling is the presence of the high relativistic factor values (the field gradients are high), the convergence conditions for PIC method and the necessary number of particles in 3D cell. Thus the parallel algorithm is based on the mixed Euler-Lagrangian decomposition in order to achieve good load balancing, and demonstrates the high scalability. With the advances of the code it will be possible to apply it for one-passage beam-beam simulations in linear colliders with supercritical parameters. We present the results of numerical simulations of colliding beams using dummy parameters and parameters close to the ones of the newest ILC project.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME027
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MOPME067	Kicker Development at the ELBE Facility	kicker, gun, SRF, electron	520
	G.S. Staats FZD, Dresden, Germany A. Arnold, H. Büttig, T. Kirschke, M. Kuntzsch, P. Michel, J. Teichert, H. Vennekate, A. Wagner, R. Xiang HZDR, Dresden, Germany R. Krause-Rehberg, A. Müller Martin-Luther-Universität, Naturwissenschaftliche Fakultät II, Halle (Saale), Germany
	Kicker-devices, also known as choppers, are of great interest for a multi-purpose electron accelerator like the ELBE at HZDR. They serve the following three main tasks: Firstly, they can be used to improve the time resolution for the positron beam line by removing certain parts of the bunch. As a second advantage they enable the machine to run two independent experiments at the same, as a chopper may split the beam into two separate parts. Lastly, a well-positioned kicker can reduce the dark current emitted by the SRF injector of the accelerator. Different designs for structures, deflecting the bunch in the beam line, have been simulated using CST Particle Studio. Here, no big difference to well-known strip line structures do exist. The next step is to design the supply electronics driving the kickers. As the ELBE accelerator runs at a high bunch repetition rate, the kicker has to keep up to this frequencies of up to 13 MHz. Hence, the high power levels needed for the operation may cause additional problems for the driver electronics. The poster is going to present the state of our development for all three tasks and our approaches to solve the corresponding challenges.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME067
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MOPME073	Status of Injection Complex VEPP-5: Machine Commissioning and First Experience of Positron Storage	injection, electron, dumping, damping	538
	A.A. Starostenko, F.A. Emanov, E.S. Kazantseva, P.V. Logatchov BINP SB RAS, Novosibirsk, Russia
	The Injection complex VEPP-5 consist of S-band linear accelerators (270 and 420 MeV), positron convertor (at 270 MeV) and damping ring. The injection complex is in commission. Positron rate production about 6·10⁸ positrons/pulse and conversion yield 0.14/GeV was achieved. Storage ring positron beam current is 70mA was achieved.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME073
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MOPRI002	Design, Manufacture and Operation of the Beam Spoiler for Positron Target Protection	target, electron, alignment, linac	573
	L. Zang, K. Kakihara, T. Kamitani, K. Mikawa, F. Miyahara, T. Suwada KEK, Ibaraki, Japan
	In order to produce positrons, intensive pulsed electron beam is used to strike on a tungsten target. The energy deposition is distributed non-uniformly over the target, leading to a mechanical stress. As a result of large thermal gradient, the target could be potentially damaged. To avoid the target destruction, the peak energy deposition density (PEDD) in the target should be well below the critical limit (35J/g) based on the SLAC operational experience. With an expected primary electron spot size on the target of the SuperKEKB positron source, the PEDD will exceeds the limit. We will introduce a beam spoiler to enlarge the spot size by multiple scattering in thin beam screen and aluminum plate. It reduces the PEDD down to half of the limit. This paper describes the design of the spoiler and the beam screen system used in the positron beam commissioning of the SuperKEKB positron source started in 2014.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI002
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MOPRI003	Positron Yield Optimization by Adjusting the Components Offset and Orientation	target, electron, injection, simulation	576
	L. Zang, M. Akemoto, S. Fukuda, K. Furukawa, T. Higo, N. Iida, K. Kakihara, T. Kamitani, T. Miura, F. Miyahara, Y. Ogawa, H. Someya, T. Takatomi, K. Yokoyama KEK, Ibaraki, Japan S. Ushimoto Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
	In order to keep high luminosity beam collision condition at SuperKEKB, low emittance electron/positron injection and flexible pulse-to-pulse switching of these beam modes are essential requirements. While a primary electron beam strikes on a target to generate positrons, an injection electron beam passes through a small hole besides the target. Since the injection electron orbit should be on axis to avoid emittance growth, the target and the flux concentrator for positron focusing have a few millimeters offset from the axis. This offset positron generation gives significant degradation in the positron yield. In this paper, we will discuss positron yield improvement by proper orientation of the cut-in slit of the flux concentrator which yields un-symmetric field distribution and primary electron incident point. With particle tracking simulation taking three dimensional field distribution into account, an ideal positron trajectory giving optimum yield was found.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI003
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MOPRI004	SuperKEKB Positron Source Construction Status	electron, target, solenoid, operation	579
	T. Kamitani, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, Y. Funakoshi, K. Furukawa, T. Higo, H. Honma, N. Iida, M. Ikeda, E. Kadokura, H. Kaji, K. Kakihara, H. Katagiri, M. Kikuchi, H. Koiso, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Mimashi, T. Miura, F. Miyahara, T. Mori, A. Morita, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, Y. Ohnishi, S. Ohsawa, M. Sato, T. Shidara, A. Shirakawa, M. Suetake, H. Sugimoto, T. Suwada, T. Takatomi, T. Takenaka, M. Tanaka, M. Tawada, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou KEK, Ibaraki, Japan D. Satoh TIT, Tokyo, Japan
	The KEKB positron source is under the upgrade for SuperKEKB. The previous positron production target and capture section have been removed and the new system is constructed at a location forty meters upstream to have sufficient energy margin for beam injection to the newly introduced damping ring. A flux concentrator is introduced in the new capture section to make an adiabatic matching system. Large aperture (30mm in diameter) S-band accelerating structures are introduced in the capture section and in the subsequent accelerator module to enlarge the transverse phase space acceptance. The beam focusing system of quadrupoles is also upgraded for a comparable beam acceptance to that of the capture section. This paper reports on the status of the SuperKEKB positron source construction and the preliminary positron beam commissioning.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI004
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MOPRI006	Possible Uses of Gamma-rays at Future Intense Positron Sources	undulator, synchrotron, software, electron	586
	A.O. Alrashdi, I.R. Bailey Lancaster University, Lancaster, United Kingdom A.O. Alrashdi, I.R. Bailey, D. Newton Cockcroft Institute, Warrington, Cheshire, United Kingdom A.O. Alrashdi KACST, Riyadh, Kingdom of Saudi Arabia D. Newton The University of Liverpool, Liverpool, United Kingdom
	Funding: This research is funded in part by STFC grant ST/G008248/1 The baseline design of the ILC (International Linear Collider) positron source requires the production of an intense flux of gamma rays. In this paper we present an investigation of using the gamma ray beam of the ILC for additional applications, including nuclear physics. As a result of changing the collimator shape, as well as the parameters of the undulator magnets, we obtained spectra from numerical simulations using the HUSR/GSR software package. We present results from simulations and a discussion of possible future investigations in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI006
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TUOBA03	Recent Beam-beam Effects and Luminosity at VEPP-2000	luminosity, collider, electron, detector	924
	D.B. Shwartz, D.E. Berkaev, A.S. Kasaev, I. Koop, A.N. Kyrpotin, A.P. Lysenko, E. Perevedentsev, V.P. Prosvetov, Yu. A. Rogovsky, A.L. Romanov, A.I. Senchenko, P.Yu. Shatunov, Y.M. Shatunov, I.M. Zemlyansky, Yu.M. Zharinov BINP SB RAS, Novosibirsk, Russia
	Funding: Work is supported by the Ministry of Education and Science of the Russian Federation, grant N 14.518.11.7003 VEPP-2000's last season was dedicated to the energy range of 160-520 MeV per beam. The application of round colliding beams concept along with the accurate orbit and lattice correction yielded the high peak luminosity of 1.210³¹ cm^-2s⁻¹ at 500 MeV with average luminosity of 0.910³¹ cm^-2s⁻¹ per run. The total beam-beam tune shift up to 0.174 was achieved in the runs at 392.5 MeV. This corresponds to beam-beam parameter ksi = 0.125 per one interaction point. The injection system is currently being upgraded to allow for the injection at the top energy of VEPP-2000 collider and to eliminate the present lack of positrons.
	Slides TUOBA03 [4.475 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOBA03
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TUPME001	Heat Load, Stress and Reaction Force Studies of a Polarized Positron Production Target for the Future International Linear Collider	target, photon, vacuum, undulator	1331
	F. Staufenbiel, S. Riemann DESY Zeuthen, Zeuthen, Germany G.A. Moortgat-Pick, A. Ushakov University of Hamburg, Hamburg, Germany
	The International Linear Collider requires an intense polarized positron beam with yields of about 10¹⁴ positrons per second. A polarized positron beam can be produced with a helical undulator passed by the accelerated electron beam to create a high power polarized photon beam. The photon beam penetrates a thin titanium-alloy rotating target wheel of 1m diameter with 500 to 2000 rpm rotation speed and produces polarized positrons. The system should run for 1-2 years without failure. A break down can occur due to the huge heat load in a short time (<1ms). The target design must keep the resulting thermo-mechanical stress below the yield strength and the fatigue limit of the material. FEM ANSYS simulations are used to evaluate the thermo-mechanical stress as well as the vibrations at the bearings of the rotating system. Results are presented with the goal to optimize the target wheel design parameters for a long lifetime.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME001
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TUPME002	An Optimization of Positron Injector of ILC	target, electron, booster, linac	1334
	M. Kuriki, Y. Seimiya HU/AdSM, Higashi-Hiroshima, Japan S. Kashiwagi Tohoku University, Research Center for Electron Photon Science, Sendai, Japan T. Okugi, M. Satoh, J. Urakawa KEK, Ibaraki, Japan
	Funding: This work is supported by Photon and Quantum Basic Research Coordinated Development Program of MEXT. ILC (International Linear Collider) is a future project of high energy physics. In the current baseline design, positron generation by gamma rays from undulator radiation is assumed. However, this approach is totally new and it is very difficult to demonstrate the system prior to the construction because it requires more than 100 GeV beam as the driver. A conventional positron generation (e-driven) has been proposed as a technical backup option. In this method, the technology is well established, but the issue is to obtain an enough amount of positron with a manageable energy deposition on target. We present a result of a systematic study of capture efficiency defined by DR (Damping Ring) acceptance where the beam emittance is reduced by radiation damping. We performed a start-to-end simulation of the positron source of ILC and found that an enough amount of the positron per bunch is obtained with a manageable energy deposition on the production target.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME002
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TUPRI034	Numerical Modeling for CesrTA Measurements of Electron Cloud Buildup in a Quadrupole Magnet	electron, detector, vacuum, quadrupole	1632
	J.A. Crittenden, M.G. Billing, W. Hartung, C. Shill, J.P. Sikora, K.G. Sonnad Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: Work supported by the U.S. National Science Foundation contracts PHY-0734867, PHY-1002467, and the U.S. Department of Energy contract DE-FC02-08ER41538 We describe a numerical model for measurements of the formation of long-lived electron clouds in a quadrupole magnet in the CESR storage ring. The shielded stripline detector measures the electron flux incident on the vacuum chamber wall directly in front of one of the poles of the magnet. The model includes photo-electron production by synchrotron radiation, electrostatic forces from the bunched positron beam and the cloud, macroparticle tracking in the field of the quadrupole, secondary electron emission from the 9.5-cm-diameter cylindrical stainless steel beam-pipe and an analytic calculation of the transmission function of the holes in the vacuum chamber which allow cloud electrons to reach the stripline collector. These modeling studies provide a quantitative understanding of the trapping mechanism which results in cloud electrons surviving the 2.3-microsecond time interval prior to the return of a train of positron bunches. These studies have been performed in the context of the CESR Test Accelerator program, which aims to quantify and mitigate performance limitations on future low-emittance storage and damping rings.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI034
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TUPRI067	Recent Results for the Dependence of Beam Instabilities caused by Electron Clouds at CesrTA due to Variations in Bunch Spacing and Chromaticity	electron, damping, feedback, controls	1721
	M.G. Billing, K.R. Butler, G. Dugan, M.J. Forster, G. Ramirez, N.T. Rider, K.G. Sonnad, H.A. Williams Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA J.W. Flanagan KEK, Ibaraki, Japan R. Holtzapple, K.E. McArdle, M.I. Miller, M.M. Totten CalPoly, San Luis Obispo, California, USA
	Funding: Work supported by DOE Award DE-FC02-08ER41538, NSF Award PHY-0734867, PHY-1068662 and the Lepton Collider R&D, Coop Agreement: NSF Award PHY-1002467 At the Cornell Electron-Positron Storage Ring Test Accelerator (CesrTA) experiments have been studying the interaction of the electron cloud (EC) with 2.1 GeV stored electron and positron beams. These experiments are intended to characterize the dependence of beam–EC interactions on various beam parameters, such as bunch spacing and vertical chromaticity. Most experiments were performed with 30 or 45-bunch trains, at a fixed current of 0.75 mA/bunch. Earlier experiments with positrons had varied the bunch spacing between 4 and 56 ns at three different vertical chromaticity settings. More recent measurements have included electron-bunch trains to contrast the build up of EC between electron and positron beams. The dynamics of the stored beam was quantified using: a gated Beam Position Monitor (BPM) and spectrum analyzer to measure the frequency spectrum of bunches in the trains; an x-ray beam size monitor to record the bunch-by-bunch, turn-by-turn vertical size of each bunch within the trains. We report on recent ob-servations from these experiments and additional studies, using witness bunches trailing 30 or 45-bunch positron trains, which were used for the generation of the ECs.
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TUPRI089	Numerical Technique for Nonlinear Beam-based Alignment	quadrupole, alignment, simulation, damping	1778
	F. Guatieri, C. Milardi INFN/LNF, Frascati (Roma), Italy D. Orsucci UNIPI, Pisa, Italy
	Two techniques to perform Beam-Based Alignment are presented. These techniques are intended for the difficult case arising in circular accelerators characterized by a nonlinear dependence of the Response Matrix on misalignments of the magnetic sources, where the standard approach fails. The developed algorithms have been successfully used to reconstruct misalignments in the transverse position of the quadrupoles installed in the main rings of the DAΦNE collider.
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TUPRI090	Linac Alignment for SuperKEKB Injector	alignment, laser, linac, emittance	1781
	T. Higo, K. Kakihara, T. Kamitani, M. Satoh, R. Sugahara, T. Suwada, M. Tanaka KEK, Ibaraki, Japan
	The misalignment of the linac beamline components amounted to be a millimeter level during the operation of KEKB, though the requirement of 0.1mm in mind. The limited effort toward improving such big misalignments has long been pursued but could not finish especially after the earthquake in March 2011. This linac is now under upgrade to the SuperKEKB, where the required alignment is 0.1mm in σ for the short distance in 100m span, while 0.3mm through the whole linac for the emittance preservation. The straight line as a reference for the alignment was defined by laser beam over 500m. The actual hardwares are set with respect to this reference line by using a laser tracker. The alignment present status is reported in this paper. On the other hand, we noticed, through the alignment measurements over months, that the tunnel floor moved in the range of 0.1mm or maybe more. The evaluation of this movement is on-going to discuss about how to achieve the required emittance and how to keep the situation. Various measurements to evaluate the movement are presented also in the paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI090
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TUPRI109	Construction and Commissioning of Event Timing System at SuperKEKB	timing, linac, injection, software	1829
	H. Kaji, K. Furukawa, M. Iwasaki, E. Kikutani, T. Kobayashi, F. Miyahara, T.T. Nakamura, M. Satoh, M. Suetake, M. Tobiyama KEK, Ibaraki, Japan T. Kudo, S. Kusano Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan T. Okazaki EJIT, Hitachi, Ibaraki, Japan
	The Event Timing System of Injector Linac at KEK is upgraded to satisfy the new requirements for the SuperKEKB project. After finishing the design and feasibility studies, we have constructed the new system at Main Trigger Station of Linac. The new functions are developed in this system to perform the injection control of positrons with the newly constructed damping ring. Besides, we integrate the capability to adjust the trigger timing just 20 ms before injection so that the injection RF-bucket of the ring can be decided at the last minute. Now, both the new system and the current working system are operational at Main Trigger Station. This is important for the smooth taking over of Event Timing System. Even during the construction period, Linac must be operated to provide beams into the two light source rings. In this situation, we can carry out enough tests with the actual condition. These tests do not disturb the regular operation and brush up the Event Timing System to enable the quick startup of the SuperKEKB operation. We report about the detailed configuration of the new system and its commissioning performed in the 2014 spring run period. H. Kaji et al., "Upgrade of Event Timing System at SuperKEKB", proceedings of ICALEPCS13, San Francisco, USA, October 6-11, 2013.
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TUPRI116	Engineering Data Management for the ILC Site Specific Design Phase	site, lattice, linear-collider, collider	1839
	B. List, L. Hagge, J. Kreutzkamp, N.J. Walker DESY, Hamburg, Germany
	In August 2013, the Japanese ILC Site Evaluation Committee has recommended the Kitakami area in northern Japan as the technically preferred site for the International Linear Collider (ILC) in Japan. With this decision, the ILC planning has moved into a new stage where the Technical Design Report baseline design has to be adapted to the specific site, and refined in preparation for a possible construction project. Engineering data management provides the methods and supporting tools to create and maintain the design data throughout the entire life of the ILC project. The Management and integration of engineering data from the design teams around the globe that contribute to the ILC requires a carefully structured body of documentation, clearly defined processes including configuration control, and efficient vision sharing through 3D modelling.
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WEPRO107	Positron Annihilation Spectroscopy at the LEPTA Facility	electron, background, vacuum, scattering	2215
	P. Horodek JINR/DLNP, Dubna, Moscow region, Russia A.G. Kobets, I.N. Meshkov, O. Orlov, A.A. Sidorin JINR, Dubna, Moscow Region, Russia
	Since 2009 year the LEPTA facility at Joint Institute for Nuclear Research in Dubna is operated with positron beam. Today it is developed into two directions. The first one is getting orthopositronium flux in flight. Slow positrons from 22Na source are accumulated in Surko trap and then are injected into the ring where they should overlap with electrons from the single-pass electron beam. In this way the flux of orthopositronium atoms will appear and will be observed in the process of registration of gamma quanta from annihilation process. The second group of works focuses on using the positron injector for Positron Annihilation Spectroscopy (PAS) applications. This method is dedicated to detection of structural defects as vacancies in the solid body lattice. The latest progress of this technique is strictly connected with measurements of PAS characteristics using positron beams. The progress in the LEPTA development, the first results obtained in the PAS, idea and actual state of works concerning the construction of the pulsed positron beam will be presented. The creation of pulsed positron beams is the modern tendency in the PAS domain.
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THOAA01	Beam Trip Analysis by Bunch-by-bunch BPM System in BEPCⅡ	storage-ring, controls, electron, resonance	2779
	Q.Y. Deng, J.S. Cao, J. Yue IHEP, Beijing, People's Republic of China
	A new bunch-by-bunch beam position measurement prototype system has been designed and built to monitor and analysis beam trip in the BEPCⅡ(Beijing Electron-Positron ColliderⅡ) machine. The fast ADC and programmable FPGA can obtain the beam information bunch-by-bunch, so we can analyze base on both time domain and frequency domain. In this paper we will presentation the system architecture and discuss some beam trip analysis result, such as beam instability, tune drifting, RF breakdown, and so on.
	Slides THOAA01 [0.999 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THOAA01
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THPME090	Fast Luminosity Monitoring using Diamond Sensors for the Super Flavor Factory SuperKEKB	luminosity, scattering, photon, simulation	3442
	D. El Khechen, P. Bambade, D. Jehanno, C. Rimbault LAL, Orsay, France
	Super luminous flavor factories, as SuperKEKB in Japan, aim to achieve very high luminosity thanks to a newly employed concept, the nano-beam scheme, where ultra-low emittance beams collide at very large crossing angle . Luminosity optimisation and dynamic imperfections require fast luminosity measurements. The aimed precision, 10^-3 in 10 ms, can be achieved thanks to the very large cross-section of the radiative Bhabha process at zero-photon scattering angle. As a result of huge particle fluxes, diamond sensors are chosen to be placed just outside the beam-pipe, downstream of the interaction point, at locations with event rates consistent with the aimed precision and small enough contamination by backgrounds from single-beam particle losses . We will present the results concerning the investigation of the optimal positioning of our diamond sensors, taking into account the rate of Bhabha particles, their interactions with the beam pipe material.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME090
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THPME129	Application of Libera Brilliance⁺ to Special Purpose BPMs in SuperKEKB	brilliance, instrumentation, luminosity, betatron	3544
	S. Kanaeda, H. Fukuma, H. Ishii, K. Mori, M. Tobiyama KEK, Ibaraki, Japan
	The KEKB accelerator at KEK is being upgraded to SuperKEKB, and will be starting operation in 2015. SuperKEKB will have 444 Beam Position Monitors (BPMs) in the positron ring (LER), and 466 in the electron ring (HER). Two BPMs in each ring will be newly introduced for measuring fast beam orbit oscillations, and another two BPMs in each ring will be introduced for the fast beam orbit interlock at SuperKEKB. The required resolution is below several μm for fast beam orbit oscillation monitoring, and the requirement for the response time is less than 100 μs for the fast beam orbit interlock. We plan to use the Libera Brilliance⁺ from Instrumentation Technologies as signal processors for these special purpose BPMs. This paper discusses the application of the Libera Brilliance⁺ to these special purpose BPMs.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME129
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THPME153	The New Optical Device for Turn-to-turn Beam Profile Measurement	electron, storage-ring, synchrotron, collider	3617
	O.I. Meshkov, V.L. Dorohov, A.A. Ivanova, A.D. Khilchenko, A.I. Kotelnikov, A.N. Kvashnin, P.V. Zubarev BINP SB RAS, Novosibirsk, Russia S.V. Ivanenko, E.A. Puryga Budker Institute of Nuclear Physics, Novosibirsk, Russia V. Korchuganov RRC, Moscow, Russia Stirin, A.I. Stirin NRC, Moscow, Russia
	The linear avalanche photodiodes array is applied for turn-to-turn beam profile measurement at Siberia-2 synchrotron light source. The apparatus is able to record a transversal profile of selected bunch and analyze the dynamics of beam during 2²⁰ turns. The first experience with application of new diagnostics for routine use at the installation is described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME153
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THPME155	Beam Phase Space Reconstruction for Monitoring the Luminosity in the VEPP-2000 Collider	electron, luminosity, lattice, collider	3623
	A.L. Romanov, I. Koop, E. Perevedentsev, D.B. Shwartz BINP SB RAS, Novosibirsk, Russia
	16 synchrotron light imaging monitors available in VEPP-2000 can be used for evaluation of dynamic betas and emittances at collision. Tomographic techniques are useful for reconstruction of non-gaussian beam phase space at the IPs at high intensities of colliding bunches. The output is applied for prompt luminosity monitoring.
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THPRI013	A Beam Driven Plasma-wakefield Linear Collider from Higgs Factory to Multi-TeV	plasma, acceleration, electron, linear-collider	3791
	J.-P. Delahaye, E. Adli, S.J. Gessner, M.J. Hogan, T.O. Raubenheimer SLAC, Menlo Park, California, USA W. An, C. Joshi, W.B. Mori UCLA, Los Angeles, California, USA
	An updated design of a beam-driven Plasma Wake-Field Acceleration Linear Collider (PWFA-LC) covering a wide range of beam collision energy from Higgs factory to multi-TeV is presented. The large effective accelerating field on the order of 1 GV/m and high wall-plug to beam power transfer efficiency of the beam driven plasma technology in a continuous operation mode allows to extend linear colliders to unprecedented beam collision energies up to 10 TeV with reasonable facility extension and power consumption. An attractive scheme of an ILC energy upgrade using the PWFA technology in a pulsed mode is discussed. The major critical issues and the R&D to address their feasibility in dedicated test facilities like FACET and FACET2 are outlined, especially the beam quality preservation during acceleration and the positron acceleration. Finally, a tentative scenario of a series of staged facilities with increasing complexity starting with short term application at low energy is developed.
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THPRI047	Large-aperture Travelling-wave Accelerator Structure for Positron Capture of SuperKEKB Injector Linac	operation, acceleration, linac, solenoid	3872
	S. Matsumoto, T. Higo, K. Kakihara, T. Kamitani, M. Tanaka KEK, Ibaraki, Japan
	Comparing to the previous KEKB, the four-times higher charge of 4 nC per bunch is required for the injector linac of SuperKEKB. Not only a flux concentrator will be introduced but also the physical aperture of the downstream six 2m-long accelerator structures was increased as large as 30mm in diameter. We call these structures as LAS, “Large Aperture S-band” structure. The resultant higher RF group velocity of about 3% makes the acceleration gradient lower. In the nominal acceleration system, a 40MW klystron with SLED feeds four 2m-long accelerator structures producing 20MV/m acceleration field. The acceleration gradient higher than 14 MV/m is required for the very first two LAS structures to suppress the satellite bunches. This gradient is obtained by feeding only two LAS structures. Initially, ten LAS structures were installed and the RF processing has partly started. In the present paper, we firstly describe the acceleration system design and then present the processing characteristics through the RF processing without beam and with beam.
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THPRI060	Conceptual Design of an Electromagnetic Driven Undulator Based Positron Target System for ILC	target, gun, vacuum, photon	3908
	W. Gai, W. Liu ANL, Argonne, Illinois, USA
	There have been intense activities on development of the fast spinning Ti wheel positron target for ILC in the last few years. As in many high power target design, it requires solutions for many technical challenges, such as vacuum, thermal stress and radiation damage control, just to name a few. Due to the unique beam timing structure, in this paper, we present a target system based on a electromagnetic mechanical system that drives a bullet type Ti slug (~ 1.4x1.4x10 cm, weigh ~ 50 g) as the target system. The mechanism is similar to a reloadable EM rail gun driven projectiles. The system can be compact, vacuum isolated, and ease of cooling. Conceptual design layout and parameter estimations are presented.
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Paper

Title

Other Keywords

Page

MOPRO001

Upgrade Status of Injector LINAC for SuperKEKB

electron, linac, emittance, gun

59

T. Miura, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, Y. Funakoshi, K. Furukawa, T. Higo, H. Honma, R. Ichimiya, N. Iida, M. Ikeda, E. Kadokura, H. Kaji, K. Kakihara, T. Kamitani, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, F. Miyahara, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, Y. Ohnishi, S. Ohsawa, F. Qiu, M. Satoh, T. Shidara, A. Shirakawa, H. Sugimoto, T. Suwada, T. Takenaka, M. Tanaka, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou
KEK, Ibaraki, Japan
D. Satoh
TIT, Tokyo, Japan

The SuperKEKB collider is under construction to achieve 40-times higher luminosity than that of previous KEKB collider. The injector LINAC should provide high-intensity and low-emittance beams of 7-GeV electron and 4-GeV positron for SuperKEKB based on a nano-beam scheme. A photocathode RF-gun for low emittance electron beam has been already installed and the commissioning has started. The construction of positron capture section using a flux-concentrator and the dumping ring for low emittance positron beam is in progress. The simultaneous top-up injections to four storage-rings including photon factories is also required. In the upstream of dumping ring, the compatible optics between positron and electron has been designed. In the downstream of dumping ring, RF phase, focusing, and steering magnets will be switched by pulse to pulse against each beam-mode for optimising beam-transportation. This paper describes recent upgrade status toward the SuperKEKB.

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MOPRO018

Booster of Electrons and Positrons (BEP) Upgrade to 1 GeV

dipole, injection, booster, vacuum

102

D.B. Shwartz, D.E. Berkaev, D.V. Bochek, I. Koop, I.E. Korenev, A.A. Krasnov, I.K. Sedlyarov, P.Yu. Shatunov, Y.M. Shatunov, I.M. Zemlyansky
BINP SB RAS, Novosibirsk, Russia

At present new electron and positron injection complex in BINP is comissioned and ready to feed VEPP-2000 collider with intensive beams with energy of 450 MeV. To obtain peak luminosity limited only by beam-beam effects in whole energy range of 160-1000 MeV and to perform high average luminosity with small dead time the top-up injection is needed. Booster BEP upgrade to 1 GeV includes modification of all magnetic elements, including warm dipoles magnetic field increase up to 2.6 T, vacuum chamber, RF-system, injection-extraction system. BEP comissioning is scheduled to the end of 2014.

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MOPME027

Parallel Three-dimensional PIC Code for Beam-beam Simulation in Linear Colliders

simulation, collider, linear-collider, beam-beam-effects

439

M.A. Boronina, V.D. Korneev, V.A. Vshivkov
ICM&MG SB RAS, Novosibirsk, Russia

We present our parallel 3D3V particle-in-cell code for the numerical simulations of ultrarelativistic charged beams in supercolliders. In the algorithm we employ the three-dimensional set of Maxwell equations and the Vlasov-Liouville equation for the distribution function of beam particles in 6-dimensional phase space. The code allows performing numerical experiments with an arbitrary density distribution, beam crossing angle and relative offset. From the mathematical point of view the main problem of the three-dimensional modeling is the presence of the high relativistic factor values (the field gradients are high), the convergence conditions for PIC method and the necessary number of particles in 3D cell. Thus the parallel algorithm is based on the mixed Euler-Lagrangian decomposition in order to achieve good load balancing, and demonstrates the high scalability. With the advances of the code it will be possible to apply it for one-passage beam-beam simulations in linear colliders with supercritical parameters. We present the results of numerical simulations of colliding beams using dummy parameters and parameters close to the ones of the newest ILC project.

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MOPME067

Kicker Development at the ELBE Facility

kicker, gun, SRF, electron

520

G.S. Staats
FZD, Dresden, Germany
A. Arnold, H. Büttig, T. Kirschke, M. Kuntzsch, P. Michel, J. Teichert, H. Vennekate, A. Wagner, R. Xiang
HZDR, Dresden, Germany
R. Krause-Rehberg, A. Müller
Martin-Luther-Universität, Naturwissenschaftliche Fakultät II, Halle (Saale), Germany

Kicker-devices, also known as choppers, are of great interest for a multi-purpose electron accelerator like the ELBE at HZDR. They serve the following three main tasks: Firstly, they can be used to improve the time resolution for the positron beam line by removing certain parts of the bunch. As a second advantage they enable the machine to run two independent experiments at the same, as a chopper may split the beam into two separate parts. Lastly, a well-positioned kicker can reduce the dark current emitted by the SRF injector of the accelerator. Different designs for structures, deflecting the bunch in the beam line, have been simulated using CST Particle Studio. Here, no big difference to well-known strip line structures do exist. The next step is to design the supply electronics driving the kickers. As the ELBE accelerator runs at a high bunch repetition rate, the kicker has to keep up to this frequencies of up to 13 MHz. Hence, the high power levels needed for the operation may cause additional problems for the driver electronics. The poster is going to present the state of our development for all three tasks and our approaches to solve the corresponding challenges.

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MOPME073

Status of Injection Complex VEPP-5: Machine Commissioning and First Experience of Positron Storage

injection, electron, dumping, damping

538

A.A. Starostenko, F.A. Emanov, E.S. Kazantseva, P.V. Logatchov
BINP SB RAS, Novosibirsk, Russia

The Injection complex VEPP-5 consist of S-band linear accelerators (270 and 420 MeV), positron convertor (at 270 MeV) and damping ring. The injection complex is in commission. Positron rate production about 6·10⁸ positrons/pulse and conversion yield 0.14/GeV was achieved. Storage ring positron beam current is 70mA was achieved.

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MOPRI002

Design, Manufacture and Operation of the Beam Spoiler for Positron Target Protection

target, electron, alignment, linac

573

L. Zang, K. Kakihara, T. Kamitani, K. Mikawa, F. Miyahara, T. Suwada
KEK, Ibaraki, Japan

In order to produce positrons, intensive pulsed electron beam is used to strike on a tungsten target. The energy deposition is distributed non-uniformly over the target, leading to a mechanical stress. As a result of large thermal gradient, the target could be potentially damaged. To avoid the target destruction, the peak energy deposition density (PEDD) in the target should be well below the critical limit (35J/g) based on the SLAC operational experience. With an expected primary electron spot size on the target of the SuperKEKB positron source, the PEDD will exceeds the limit. We will introduce a beam spoiler to enlarge the spot size by multiple scattering in thin beam screen and aluminum plate. It reduces the PEDD down to half of the limit. This paper describes the design of the spoiler and the beam screen system used in the positron beam commissioning of the SuperKEKB positron source started in 2014.

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MOPRI003

Positron Yield Optimization by Adjusting the Components Offset and Orientation

target, electron, injection, simulation

576

L. Zang, M. Akemoto, S. Fukuda, K. Furukawa, T. Higo, N. Iida, K. Kakihara, T. Kamitani, T. Miura, F. Miyahara, Y. Ogawa, H. Someya, T. Takatomi, K. Yokoyama
KEK, Ibaraki, Japan
S. Ushimoto
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan

In order to keep high luminosity beam collision condition at SuperKEKB, low emittance electron/positron injection and flexible pulse-to-pulse switching of these beam modes are essential requirements. While a primary electron beam strikes on a target to generate positrons, an injection electron beam passes through a small hole besides the target. Since the injection electron orbit should be on axis to avoid emittance growth, the target and the flux concentrator for positron focusing have a few millimeters offset from the axis. This offset positron generation gives significant degradation in the positron yield. In this paper, we will discuss positron yield improvement by proper orientation of the cut-in slit of the flux concentrator which yields un-symmetric field distribution and primary electron incident point. With particle tracking simulation taking three dimensional field distribution into account, an ideal positron trajectory giving optimum yield was found.

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MOPRI004

SuperKEKB Positron Source Construction Status

electron, target, solenoid, operation

579

T. Kamitani, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, Y. Funakoshi, K. Furukawa, T. Higo, H. Honma, N. Iida, M. Ikeda, E. Kadokura, H. Kaji, K. Kakihara, H. Katagiri, M. Kikuchi, H. Koiso, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Mimashi, T. Miura, F. Miyahara, T. Mori, A. Morita, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, Y. Ohnishi, S. Ohsawa, M. Sato, T. Shidara, A. Shirakawa, M. Suetake, H. Sugimoto, T. Suwada, T. Takatomi, T. Takenaka, M. Tanaka, M. Tawada, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou
KEK, Ibaraki, Japan
D. Satoh
TIT, Tokyo, Japan

The KEKB positron source is under the upgrade for SuperKEKB. The previous positron production target and capture section have been removed and the new system is constructed at a location forty meters upstream to have sufficient energy margin for beam injection to the newly introduced damping ring. A flux concentrator is introduced in the new capture section to make an adiabatic matching system. Large aperture (30mm in diameter) S-band accelerating structures are introduced in the capture section and in the subsequent accelerator module to enlarge the transverse phase space acceptance. The beam focusing system of quadrupoles is also upgraded for a comparable beam acceptance to that of the capture section. This paper reports on the status of the SuperKEKB positron source construction and the preliminary positron beam commissioning.

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MOPRI006

Possible Uses of Gamma-rays at Future Intense Positron Sources

undulator, synchrotron, software, electron

586

A.O. Alrashdi, I.R. Bailey
Lancaster University, Lancaster, United Kingdom
A.O. Alrashdi, I.R. Bailey, D. Newton
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A.O. Alrashdi
KACST, Riyadh, Kingdom of Saudi Arabia
D. Newton
The University of Liverpool, Liverpool, United Kingdom

Funding: This research is funded in part by STFC grant ST/G008248/1
The baseline design of the ILC (International Linear Collider) positron source requires the production of an intense flux of gamma rays. In this paper we present an investigation of using the gamma ray beam of the ILC for additional applications, including nuclear physics. As a result of changing the collimator shape, as well as the parameters of the undulator magnets, we obtained spectra from numerical simulations using the HUSR/GSR software package. We present results from simulations and a discussion of possible future investigations in this paper.

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TUOBA03

Recent Beam-beam Effects and Luminosity at VEPP-2000

luminosity, collider, electron, detector

924

D.B. Shwartz, D.E. Berkaev, A.S. Kasaev, I. Koop, A.N. Kyrpotin, A.P. Lysenko, E. Perevedentsev, V.P. Prosvetov, Yu. A. Rogovsky, A.L. Romanov, A.I. Senchenko, P.Yu. Shatunov, Y.M. Shatunov, I.M. Zemlyansky, Yu.M. Zharinov
BINP SB RAS, Novosibirsk, Russia

Funding: Work is supported by the Ministry of Education and Science of the Russian Federation, grant N 14.518.11.7003
VEPP-2000's last season was dedicated to the energy range of 160-520 MeV per beam. The application of round colliding beams concept along with the accurate orbit and lattice correction yielded the high peak luminosity of 1.2*10³¹ cm^-2s⁻¹ at 500 MeV with average luminosity of 0.9*10³¹ cm^-2s⁻¹ per run. The total beam-beam tune shift up to 0.174 was achieved in the runs at 392.5 MeV. This corresponds to beam-beam parameter ksi = 0.125 per one interaction point. The injection system is currently being upgraded to allow for the injection at the top energy of VEPP-2000 collider and to eliminate the present lack of positrons.

Slides TUOBA03 [4.475 MB]

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TUPME001

Heat Load, Stress and Reaction Force Studies of a Polarized Positron Production Target for the Future International Linear Collider

target, photon, vacuum, undulator

1331

F. Staufenbiel, S. Riemann
DESY Zeuthen, Zeuthen, Germany
G.A. Moortgat-Pick, A. Ushakov
University of Hamburg, Hamburg, Germany

The International Linear Collider requires an intense polarized positron beam with yields of about 10¹⁴ positrons per second. A polarized positron beam can be produced with a helical undulator passed by the accelerated electron beam to create a high power polarized photon beam. The photon beam penetrates a thin titanium-alloy rotating target wheel of 1m diameter with 500 to 2000 rpm rotation speed and produces polarized positrons. The system should run for 1-2 years without failure. A break down can occur due to the huge heat load in a short time (<1ms). The target design must keep the resulting thermo-mechanical stress below the yield strength and the fatigue limit of the material. FEM ANSYS simulations are used to evaluate the thermo-mechanical stress as well as the vibrations at the bearings of the rotating system. Results are presented with the goal to optimize the target wheel design parameters for a long lifetime.

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TUPME002

An Optimization of Positron Injector of ILC

target, electron, booster, linac

1334

M. Kuriki, Y. Seimiya
HU/AdSM, Higashi-Hiroshima, Japan
S. Kashiwagi
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
T. Okugi, M. Satoh, J. Urakawa
KEK, Ibaraki, Japan

Funding: This work is supported by Photon and Quantum Basic Research Coordinated Development Program of MEXT.
ILC (International Linear Collider) is a future project of high energy physics. In the current baseline design, positron generation by gamma rays from undulator radiation is assumed. However, this approach is totally new and it is very difficult to demonstrate the system prior to the construction because it requires more than 100 GeV beam as the driver. A conventional positron generation (e-driven) has been proposed as a technical backup option. In this method, the technology is well established, but the issue is to obtain an enough amount of positron with a manageable energy deposition on target. We present a result of a systematic study of capture efficiency defined by DR (Damping Ring) acceptance where the beam emittance is reduced by radiation damping. We performed a start-to-end simulation of the positron source of ILC and found that an enough amount of the positron per bunch is obtained with a manageable energy deposition on the production target.

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TUPRI034

Numerical Modeling for CesrTA Measurements of Electron Cloud Buildup in a Quadrupole Magnet

electron, detector, vacuum, quadrupole

1632

J.A. Crittenden, M.G. Billing, W. Hartung, C. Shill, J.P. Sikora, K.G. Sonnad
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Work supported by the U.S. National Science Foundation contracts PHY-0734867, PHY-1002467, and the U.S. Department of Energy contract DE-FC02-08ER41538
We describe a numerical model for measurements of the formation of long-lived electron clouds in a quadrupole magnet in the CESR storage ring. The shielded stripline detector measures the electron flux incident on the vacuum chamber wall directly in front of one of the poles of the magnet. The model includes photo-electron production by synchrotron radiation, electrostatic forces from the bunched positron beam and the cloud, macroparticle tracking in the field of the quadrupole, secondary electron emission from the 9.5-cm-diameter cylindrical stainless steel beam-pipe and an analytic calculation of the transmission function of the holes in the vacuum chamber which allow cloud electrons to reach the stripline collector. These modeling studies provide a quantitative understanding of the trapping mechanism which results in cloud electrons surviving the 2.3-microsecond time interval prior to the return of a train of positron bunches. These studies have been performed in the context of the CESR Test Accelerator program, which aims to quantify and mitigate performance limitations on future low-emittance storage and damping rings.

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TUPRI067

Recent Results for the Dependence of Beam Instabilities caused by Electron Clouds at CesrTA due to Variations in Bunch Spacing and Chromaticity

electron, damping, feedback, controls

1721

M.G. Billing, K.R. Butler, G. Dugan, M.J. Forster, G. Ramirez, N.T. Rider, K.G. Sonnad, H.A. Williams
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J.W. Flanagan
KEK, Ibaraki, Japan
R. Holtzapple, K.E. McArdle, M.I. Miller, M.M. Totten
CalPoly, San Luis Obispo, California, USA

Funding: Work supported by DOE Award DE-FC02-08ER41538, NSF Award PHY-0734867, PHY-1068662 and the Lepton Collider R&D, Coop Agreement: NSF Award PHY-1002467
At the Cornell Electron-Positron Storage Ring Test Accelerator (CesrTA) experiments have been studying the interaction of the electron cloud (EC) with 2.1 GeV stored electron and positron beams. These experiments are intended to characterize the dependence of beam–EC interactions on various beam parameters, such as bunch spacing and vertical chromaticity. Most experiments were performed with 30 or 45-bunch trains, at a fixed current of 0.75 mA/bunch. Earlier experiments with positrons had varied the bunch spacing between 4 and 56 ns at three different vertical chromaticity settings. More recent measurements have included electron-bunch trains to contrast the build up of EC between electron and positron beams. The dynamics of the stored beam was quantified using: a gated Beam Position Monitor (BPM) and spectrum analyzer to measure the frequency spectrum of bunches in the trains; an x-ray beam size monitor to record the bunch-by-bunch, turn-by-turn vertical size of each bunch within the trains. We report on recent ob-servations from these experiments and additional studies, using witness bunches trailing 30 or 45-bunch positron trains, which were used for the generation of the ECs.

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TUPRI089

Numerical Technique for Nonlinear Beam-based Alignment

quadrupole, alignment, simulation, damping

1778

F. Guatieri, C. Milardi
INFN/LNF, Frascati (Roma), Italy
D. Orsucci
UNIPI, Pisa, Italy

Two techniques to perform Beam-Based Alignment are presented. These techniques are intended for the difficult case arising in circular accelerators characterized by a nonlinear dependence of the Response Matrix on misalignments of the magnetic sources, where the standard approach fails. The developed algorithms have been successfully used to reconstruct misalignments in the transverse position of the quadrupoles installed in the main rings of the DAΦNE collider.

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TUPRI090

Linac Alignment for SuperKEKB Injector

alignment, laser, linac, emittance

1781

T. Higo, K. Kakihara, T. Kamitani, M. Satoh, R. Sugahara, T. Suwada, M. Tanaka
KEK, Ibaraki, Japan

The misalignment of the linac beamline components amounted to be a millimeter level during the operation of KEKB, though the requirement of 0.1mm in mind. The limited effort toward improving such big misalignments has long been pursued but could not finish especially after the earthquake in March 2011. This linac is now under upgrade to the SuperKEKB, where the required alignment is 0.1mm in σ for the short distance in 100m span, while 0.3mm through the whole linac for the emittance preservation. The straight line as a reference for the alignment was defined by laser beam over 500m. The actual hardwares are set with respect to this reference line by using a laser tracker. The alignment present status is reported in this paper. On the other hand, we noticed, through the alignment measurements over months, that the tunnel floor moved in the range of 0.1mm or maybe more. The evaluation of this movement is on-going to discuss about how to achieve the required emittance and how to keep the situation. Various measurements to evaluate the movement are presented also in the paper.

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TUPRI109

Construction and Commissioning of Event Timing System at SuperKEKB

timing, linac, injection, software

1829

H. Kaji, K. Furukawa, M. Iwasaki, E. Kikutani, T. Kobayashi, F. Miyahara, T.T. Nakamura, M. Satoh, M. Suetake, M. Tobiyama
KEK, Ibaraki, Japan
T. Kudo, S. Kusano
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
T. Okazaki
EJIT, Hitachi, Ibaraki, Japan

The Event Timing System of Injector Linac at KEK is upgraded to satisfy the new requirements for the SuperKEKB project. After finishing the design and feasibility studies*, we have constructed the new system at Main Trigger Station of Linac. The new functions are developed in this system to perform the injection control of positrons with the newly constructed damping ring. Besides, we integrate the capability to adjust the trigger timing just 20 ms before injection so that the injection RF-bucket of the ring can be decided at the last minute. Now, both the new system and the current working system are operational at Main Trigger Station. This is important for the smooth taking over of Event Timing System. Even during the construction period, Linac must be operated to provide beams into the two light source rings. In this situation, we can carry out enough tests with the actual condition. These tests do not disturb the regular operation and brush up the Event Timing System to enable the quick startup of the SuperKEKB operation. We report about the detailed configuration of the new system and its commissioning performed in the 2014 spring run period.
* H. Kaji et al., "Upgrade of Event Timing System at SuperKEKB",
proceedings of ICALEPCS13, San Francisco, USA, October 6-11, 2013.

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TUPRI116

Engineering Data Management for the ILC Site Specific Design Phase

site, lattice, linear-collider, collider

1839

B. List, L. Hagge, J. Kreutzkamp, N.J. Walker
DESY, Hamburg, Germany

In August 2013, the Japanese ILC Site Evaluation Committee has recommended the Kitakami area in northern Japan as the technically preferred site for the International Linear Collider (ILC) in Japan. With this decision, the ILC planning has moved into a new stage where the Technical Design Report baseline design has to be adapted to the specific site, and refined in preparation for a possible construction project. Engineering data management provides the methods and supporting tools to create and maintain the design data throughout the entire life of the ILC project. The Management and integration of engineering data from the design teams around the globe that contribute to the ILC requires a carefully structured body of documentation, clearly defined processes including configuration control, and efficient vision sharing through 3D modelling.

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WEPRO107

Positron Annihilation Spectroscopy at the LEPTA Facility

electron, background, vacuum, scattering

2215

P. Horodek
JINR/DLNP, Dubna, Moscow region, Russia
A.G. Kobets, I.N. Meshkov, O. Orlov, A.A. Sidorin
JINR, Dubna, Moscow Region, Russia

Since 2009 year the LEPTA facility at Joint Institute for Nuclear Research in Dubna is operated with positron beam. Today it is developed into two directions. The first one is getting orthopositronium flux in flight. Slow positrons from 22Na source are accumulated in Surko trap and then are injected into the ring where they should overlap with electrons from the single-pass electron beam. In this way the flux of orthopositronium atoms will appear and will be observed in the process of registration of gamma quanta from annihilation process. The second group of works focuses on using the positron injector for Positron Annihilation Spectroscopy (PAS) applications. This method is dedicated to detection of structural defects as vacancies in the solid body lattice. The latest progress of this technique is strictly connected with measurements of PAS characteristics using positron beams. The progress in the LEPTA development, the first results obtained in the PAS, idea and actual state of works concerning the construction of the pulsed positron beam will be presented. The creation of pulsed positron beams is the modern tendency in the PAS domain.

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THOAA01

Beam Trip Analysis by Bunch-by-bunch BPM System in BEPCⅡ

storage-ring, controls, electron, resonance

2779

Q.Y. Deng, J.S. Cao, J. Yue
IHEP, Beijing, People's Republic of China

A new bunch-by-bunch beam position measurement prototype system has been designed and built to monitor and analysis beam trip in the BEPCⅡ(Beijing Electron-Positron ColliderⅡ) machine. The fast ADC and programmable FPGA can obtain the beam information bunch-by-bunch, so we can analyze base on both time domain and frequency domain. In this paper we will presentation the system architecture and discuss some beam trip analysis result, such as beam instability, tune drifting, RF breakdown, and so on.

Slides THOAA01 [0.999 MB]

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THPME090

Fast Luminosity Monitoring using Diamond Sensors for the Super Flavor Factory SuperKEKB

luminosity, scattering, photon, simulation

3442

D. El Khechen, P. Bambade, D. Jehanno, C. Rimbault
LAL, Orsay, France

Super luminous flavor factories, as SuperKEKB in Japan, aim to achieve very high luminosity thanks to a newly employed concept, the nano-beam scheme, where ultra-low emittance beams collide at very large crossing angle . Luminosity optimisation and dynamic imperfections require fast luminosity measurements. The aimed precision, 10^-3 in 10 ms, can be achieved thanks to the very large cross-section of the radiative Bhabha process at zero-photon scattering angle. As a result of huge particle fluxes, diamond sensors are chosen to be placed just outside the beam-pipe, downstream of the interaction point, at locations with event rates consistent with the aimed precision and small enough contamination by backgrounds from single-beam particle losses . We will present the results concerning the investigation of the optimal positioning of our diamond sensors, taking into account the rate of Bhabha particles, their interactions with the beam pipe material.

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THPME129

Application of Libera Brilliance⁺ to Special Purpose BPMs in SuperKEKB

brilliance, instrumentation, luminosity, betatron

3544

S. Kanaeda, H. Fukuma, H. Ishii, K. Mori, M. Tobiyama
KEK, Ibaraki, Japan

The KEKB accelerator at KEK is being upgraded to SuperKEKB, and will be starting operation in 2015. SuperKEKB will have 444 Beam Position Monitors (BPMs) in the positron ring (LER), and 466 in the electron ring (HER). Two BPMs in each ring will be newly introduced for measuring fast beam orbit oscillations, and another two BPMs in each ring will be introduced for the fast beam orbit interlock at SuperKEKB. The required resolution is below several μm for fast beam orbit oscillation monitoring, and the requirement for the response time is less than 100 μs for the fast beam orbit interlock. We plan to use the Libera Brilliance⁺ from Instrumentation Technologies as signal processors for these special purpose BPMs. This paper discusses the application of the Libera Brilliance⁺ to these special purpose BPMs.

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THPME153

The New Optical Device for Turn-to-turn Beam Profile Measurement

electron, storage-ring, synchrotron, collider

3617

O.I. Meshkov, V.L. Dorohov, A.A. Ivanova, A.D. Khilchenko, A.I. Kotelnikov, A.N. Kvashnin, P.V. Zubarev
BINP SB RAS, Novosibirsk, Russia
S.V. Ivanenko, E.A. Puryga
Budker Institute of Nuclear Physics, Novosibirsk, Russia
V. Korchuganov
RRC, Moscow, Russia
Stirin, A.I. Stirin
NRC, Moscow, Russia

The linear avalanche photodiodes array is applied for turn-to-turn beam profile measurement at Siberia-2 synchrotron light source. The apparatus is able to record a transversal profile of selected bunch and analyze the dynamics of beam during 2²⁰ turns. The first experience with application of new diagnostics for routine use at the installation is described.

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THPME155

Beam Phase Space Reconstruction for Monitoring the Luminosity in the VEPP-2000 Collider

electron, luminosity, lattice, collider

3623

A.L. Romanov, I. Koop, E. Perevedentsev, D.B. Shwartz
BINP SB RAS, Novosibirsk, Russia

16 synchrotron light imaging monitors available in VEPP-2000 can be used for evaluation of dynamic betas and emittances at collision. Tomographic techniques are useful for reconstruction of non-gaussian beam phase space at the IPs at high intensities of colliding bunches. The output is applied for prompt luminosity monitoring.

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THPRI013

A Beam Driven Plasma-wakefield Linear Collider from Higgs Factory to Multi-TeV

plasma, acceleration, electron, linear-collider

3791

J.-P. Delahaye, E. Adli, S.J. Gessner, M.J. Hogan, T.O. Raubenheimer
SLAC, Menlo Park, California, USA
W. An, C. Joshi, W.B. Mori
UCLA, Los Angeles, California, USA

An updated design of a beam-driven Plasma Wake-Field Acceleration Linear Collider (PWFA-LC) covering a wide range of beam collision energy from Higgs factory to multi-TeV is presented. The large effective accelerating field on the order of 1 GV/m and high wall-plug to beam power transfer efficiency of the beam driven plasma technology in a continuous operation mode allows to extend linear colliders to unprecedented beam collision energies up to 10 TeV with reasonable facility extension and power consumption. An attractive scheme of an ILC energy upgrade using the PWFA technology in a pulsed mode is discussed. The major critical issues and the R&D to address their feasibility in dedicated test facilities like FACET and FACET2 are outlined, especially the beam quality preservation during acceleration and the positron acceleration. Finally, a tentative scenario of a series of staged facilities with increasing complexity starting with short term application at low energy is developed.

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THPRI047

Large-aperture Travelling-wave Accelerator Structure for Positron Capture of SuperKEKB Injector Linac

operation, acceleration, linac, solenoid

3872

S. Matsumoto, T. Higo, K. Kakihara, T. Kamitani, M. Tanaka
KEK, Ibaraki, Japan

Comparing to the previous KEKB, the four-times higher charge of 4 nC per bunch is required for the injector linac of SuperKEKB. Not only a flux concentrator will be introduced but also the physical aperture of the downstream six 2m-long accelerator structures was increased as large as 30mm in diameter. We call these structures as LAS, “Large Aperture S-band” structure. The resultant higher RF group velocity of about 3% makes the acceleration gradient lower. In the nominal acceleration system, a 40MW klystron with SLED feeds four 2m-long accelerator structures producing 20MV/m acceleration field. The acceleration gradient higher than 14 MV/m is required for the very first two LAS structures to suppress the satellite bunches. This gradient is obtained by feeding only two LAS structures. Initially, ten LAS structures were installed and the RF processing has partly started. In the present paper, we firstly describe the acceleration system design and then present the processing characteristics through the RF processing without beam and with beam.

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THPRI060

Conceptual Design of an Electromagnetic Driven Undulator Based Positron Target System for ILC

target, gun, vacuum, photon

3908

W. Gai, W. Liu
ANL, Argonne, Illinois, USA

There have been intense activities on development of the fast spinning Ti wheel positron target for ILC in the last few years. As in many high power target design, it requires solutions for many technical challenges, such as vacuum, thermal stress and radiation damage control, just to name a few. Due to the unique beam timing structure, in this paper, we present a target system based on a electromagnetic mechanical system that drives a bullet type Ti slug (~ 1.4x1.4x10 cm, weigh ~ 50 g) as the target system. The mechanism is similar to a reloadable EM rail gun driven projectiles. The system can be compact, vacuum isolated, and ease of cooling. Conceptual design layout and parameter estimations are presented.

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