TUPTY —  Tuesday Posters (Tyler)   (05-May-15   16:00—18:00)

Paper	Title	Page
TUPTY001	Interaction Region for a 100 TeV Proton-Proton Collider	1996
	R. Martin, R. Tomás CERN, Geneva, Switzerland B. Dalenapresenter CEA/IRFU, Gif-sur-Yvette, France
	As part of its post-LHC high energy physics program, CERN is conducting a study for a new proton-proton collider, FCC-hh, running at center-of-mass energies of up to 100 TeV, pushing the energy frontier of fundamental physics to a new limit. At a circumference of 80-100 km, this machine is planned to use the same tunnel as FCC-ee, a proposed 90-350 GeV high luminosity electron-positron collider. This paper presents the design progress and technical challenges for the interaction region of FCC-hh.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY001
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TUPTY003	Study of the Dynamic Response of CLIC Accelerating Structures	2000
	E. Daskalaki NTUA, Athens, Greece S. Döbert, M. Duquenne, H. Mainaud Durand, A.L. Vamvakas CERN, Geneva, Switzerland V. Rude ESGT-CNAM, Le Mans, France
	CLIC is a linear electron-positron collider, 48 km long, consisting of more than 20000 repetitive modules. The target beam size of 1 nm dictates very tight alignment tolerances for the accelerating structures (AS). In order to assess the effect of short-term RF power interruptions (breakdowns or failure modes) on the alignment, the dynamic behaviour of the AS was investigated on the prototype two-beam module. On a dedicated experimental setup, the thermal and mechanical time constant (TC) was monitored as a function of ambient temperature, water flow and power. The experimental results showed that the thermal TC ranged between 4 and 11 minutes and presented strong correlation with the cooling water flow. These results were in very good agreement with the theoretical expectations. The displacement dynamics were found to be comparable with the thermal ones. The study indicates that temperature measurement, which is a fast and easy process, can be used as an indicator of the AS displacement. Moreover, it is shown than the transient response can be efficiently controlled through appropriate regulation of the cooling water flow.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY003
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TUPTY004	Tracking Simulation for Beam Loss Studies with Application to FCC	2004
	M. Boscolo INFN/LNF, Frascati (Roma), Italy H. Burkhardt CERN, Geneva, Switzerland
	We present an implementation of a tracking simulation tool used to evaluate the main particle loss effects for Flavor Factories with the aim of applying these studies also to FCC. We describe the interface of the Monte Carlo tracking code with MAD-X, showing first simulations of the Touschek effect for the FCC-ee at the Z. We plan to use this approach also for multi-turn simulations of particles scattered by radiative Bhabha, beam-gas and eventually Beamstrahlung effects.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY004
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TUPTY006	Study of Electron Cloud Instabilities in FCC-hh	2007
	K. Ohmi KEK, Ibaraki, Japan L. Mether, D. Schulte, F. Zimmermann CERN, Geneva, Switzerland
	Electron cloud effects are serious issue for LHC and future hadron colliders, FCC-hh. Electron cloud causes coherent instabilities due to collective motion between beam and electrons. Electron cloud also causes incoherent emittance growth due to nonlinear force of beam-cloud electron force. We discuss the fast head-tail instability and the emittance growth in FCC-hh.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY006
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TUPTY007	Study of Beam-beam Effects in FCC-he	2010
	K. Ohmi KEK, Ibaraki, Japan F. Zimmermann CERN, Geneva, Switzerland
	Beam-beam effects of the ring-ring scheme of FCC-he and LHeC are being studied using weak-strong simulations. The beam-beam tune shift of the electron beam is one order larger than that of proton beam. The study of the electron motion under the beam-beam interaction is the main subject. Luminosity and equilibrium beam size and beam lifetime are analysed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY007
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TUPTY008	Commissioning Status and Plan of SuperKEKB Injector Linac	2013
	M. Satoh, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, Y. Enomoto, S. Fukuda, Y. Funakoshi, K. Furukawa, T. Higo, H. Honma, N. Iida, M. Ikeda, H. Iwase, H. Kaji, K. Kakihara, T. Kamitani, H. Katagiri, S. Kazama, 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, Y. Seimiya, T. Shidara, A. Shirakawa, M. Suetake, H. Sugimoto, T. Suwada, T. Takenaka, M. Tanaka, M. Tawada, Y. Yano, K. Yokoyama, M. Yoshida, R. Zhang, X. Zhou KEK, Ibaraki, Japan D. Satoh TIT, Tokyo, Japan
	Toward SuperKEKB project, the injector linac upgrade is ongoing at KEK in order to deliver the low emittance electron/positron beams with the high intensity and small emittance. In the September of 2013, the injector linac commissioning has started. In this presentation, we will describe the commissioning status and plan of SuperKEKB injector linac.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY008
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TUPTY010	The Luminosity Reduction with Hourglass Effect and Crossing Angle in an e-p Collider	2016
	Y.M. Peng IHEP, Beijing, People's Republic of China Y. Zhang JLab, Newport News, Virginia, USA
	This paper derived the luminosity reduction caused by crossing angle and hourglass effect in an asymmetric collision. Here, we gave the general expressions of the geometrical reduction factor of luminosity for the asymmetric case caused by crossing angle and hourglass effect, for tri-Gaussian bunches colliding. We also gave it simple expression in some special cases to recover the earlier results, such as the formulas for only hour-glass effect exist and only crossing angle exist. The expressions used in e-p collider are also analysed in detail.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY010
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TUPTY011	A Preliminary Design of the CEPC Interaction Region	2019
	Y. Wang, S. Bai, T.J. Bian, X. Cui, J. Gao, H. Gengpresenter, D. Wang, Y.S. Zhu IHEP, Beijing, People's Republic of China
	CEPC (Circular Electron and Positron Collider) is a circular Higgs Factory with optimized energy 240 GeV. In order to achieve luminosity as high as 2×1034/cm2/s, CEPC calls for a small vertical beta function at IP (betay∗=1.2 mm) which was provided by the final focus of the interaction region. In this paper, a preliminary design of the CEPC interaction region was presented. The optimization of dynamic aperture with interaction region insertion and the machine detector interface was discussed as well.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY011
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TUPTY012	Orbit Correction in CEPC	2022
	S. Bai, J. Gao, H. Geng IHEP, Beijing, People's Republic of China
	With the discovery of the higgs boson at around 125GeV, a circular higgs factory design with high luminosity (L ~ 1034 cm-2s-1) is becoming more popular in the accelerator world. The CEPC project in China is one of them. To reduce the cost, pretzel scheme was considered in CEPC orbit design. The presence of every kind of errors and misalignments will destroy the pretzel orbit. In this paper, we correct the distorted pretzel orbit in the CEPC main ring using the dipole correctors and beam position monitors. The pretzel orbit was recovered and the maximum corrector strengths are got.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY012
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TUPTY015	Study on the transverse painting during the injection process for CSNS/RCS	2025
	M.Y. Huang, L. Huang, N. Huang, J. Qiu, S. Wang, S.Y. Xu IHEP, Beijing, People's Republic of China
	Funding: Work supported by National Natural Science Foundation of China (11205185, 11175020, 11175193 ) For the China Spallation Neutron Source (CSNS), a combination of the H− stripping and phase space painting method is used to accumulate a high intensity beam in the Rapid Cycling Synchrotron (RCS). In this paper, firstly, the injection processes with different painting ranges and different painting methods were studied. With the codes ORBIT and MATLAB, the particle distribution and painting image were obtained. Then, the reasonable painting range which is suitable for the aperture size and magnet gap can be selected. Since the real field uniformity of BH3 and BV3 is not completely in conformity with the design requirement, the painting method and painting range also need to be selected to reduce the effects of bad field uniformity.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY015
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TUPTY016	Study of Background and MDI Design for CEPC	2028
	Y. Yue, Q. Qin IHEP, Beijing, People's Republic of China
	CEPC is a project designed to obtain a large number of Higgs events by keeping e+e− collisions at the center-of-mass energy of 240 GeV and deliver peak luminosity above 1034 cm-2 s-1 for each interaction point. The super high energy and the pretty high luminosity will bring some special background problems, which will exert difficulty on the MDI design and the detectors protection. In this article, I will show the simulation result of the main background sources at CEPC and give some suggestions on the MDI design and detectors protection.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY016
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TUPTY017	Ion Polarization Control in the MPD and SPD Detectors of the NICA Collider	2031
	A.D. Kovalenko, A.V. Butenko, V.D. Kekelidze, V.A. Mikhaylov JINR, Dubna, Moscow Region, Russia Y. Filatov MIPT, Dolgoprudniy, Moscow Region, Russia A.M. Kondratenkopresenter, M.A. Kondratenko Science and Technique Laboratory Zaryad, Novosibirsk, Russia
	Two solenoid Siberian snakes are placed in the opposite collider’s straight sections are used to control deuteron’s and proton’s polarization in the NICA collider. Solenoid snakes substantially reconstruct beam’s orbital motion. The change of the polarization direction in the vertical plane of MPD and SPD detectors occurs due to insertion of polarization control (PC) solenoids in the magnetic lattice of the collider. The solenoids rotating particle’s spin by small angels practically do not influence on the beam’s orbital motion parameters. The dynamic of the polarization vector as function of the orbit length for cases of longitudinal and vertical polarization in the MPD and SPD detectors are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY017
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TUPTY018	Interaction region for crab waist scheme of the Future Electron-Positron Collider (CERN)	2034
	A.V. Bogomyagkov, E.B. Levichev BINP SB RAS, Novosibirsk, Russia
	Funding: Work is supported by the Ministry of Education and Science of the Russian Federation Design study of the accelerator that would fit 80-100~km tunnel called Future Circular Colliders (FCC) includes high-luminosity e+e- collider (FCC-ee) with center-of-mass energy from 90 to 350~GeV to study Higgs boson properties and perform precise measurements at the electroweak scale. Crab waist interaction region provides collisions with luminosity higher than 2×1036~cm-2sec-1 at beam energy of 45~GeV. The small values of the beta functions at the interaction point and distant final focus lenses are the reasons for high nonlinear chromaticity limiting energy acceptance of the whole ring. The paper describes interaction region for crab waist collision scheme in the FCC-ee, principles of tuning the chromaticity correction section in order to provide large energy acceptance.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY018
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TUPTY019	Realistic Beam Halo Model study in the Extraction Line of ATF2	2038
	N. Fuster-Martínez, A. Faus-Golfepresenter IFIC, Valencia, Spain P. Bambade, S. Liu, S. Wallon LAL, Orsay, France K. Kubo, T. Okugi, T. Tauchi, N. Terunuma KEK, Ibaraki, Japan E. Marín, G.R. White SLAC, Menlo Park, California, USA
	Funding: Work supported by IDC-20101074, FPA2013-47883-C2-1-P and ANR-11-IDEX-0003-02 The understanding and control of the transverse beam halo distributions is an important issue to reduce sources of background noise in Future Linear Colliders (FLC) and specifically at ATF2. A realistic model of the beam halo in the old extraction line of the ATF damping ring was obtained in 2005, based on wire scanner measurements. Recently, new measurements were done in the new extraction line of ATF2, using both wire scanners, in 2013, and Optical Transition Radiation monitors (OTR), in 2014. The beam halo propagation through the ATF2 beamline by means of tracking simulations has been investigated using as input a purely Gaussian and uniform beam halo model.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY019
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TUPTY020	Building a Luminosity Model for the LHC and HL-LHC	2042
	F. Antoniou, G. Arduini, Y. Papaphilippou, G. Papotti CERN, Geneva, Switzerland
	One key objective of the High Luminosity LHC Upgrade is to determine a set of beam parameters and the hardware configuration that will enable the LHC to reach a peak luminosity of 5×1034 cm-2 s-1 and ultimately 7.5x1034 cm-2 s-1 with levelling, allowing an integrated luminosity of 250-300 fb-1 per year. In order to determine the integrated performance it is important to develop a realistic model of the luminosity evolution during a physics fill. In this paper, the different mechanisms affecting luminosity lifetime in the LHC are discussed and a luminosity model is presented. The model is benchmarked with data from LHC Run I.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY020
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TUPTY022	Alternative Optics Design of the CLIC Damping Rings with Variable Dipole Bends and High-field Wigglers	2046
	P.S. Papadopoulou, F. Antonioupresenter, Y. Papaphilippou CERN, Geneva, Switzerland
	The CLIC Damping Rings baseline design aims to reach an ultra-low horizontal normalised emittance of 500nm-rad at 2.86GeV, based on the combined effect of TME arc cells and high-field super-conducting damping wigglers, while keeping the ring as compact as possible. In this paper, an alternative design is described, based on TME cells with longitudinally variable bends and an optimized Nb3Sn high-field wiggler. The impact of these changes on ring optics parameters and the associated optimisation steps are detailed taking account the dominant effect of intrabeam scattering.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY022
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TUPTY023	Lessons Learned From the First Long Shutdown of the Lhc and Its Injector Chain	2050
	K. Foraz, M.B.M. Barberan Marin, M. Bernardinipresenter, J. Coupard, N. Gilbert, D. Hay, S. Mataguez, D.J. Mcfarlane, E. Vergara Fernandez CERN, Geneva, Switzerland
	The First Long Shutdown (LS1) of the LHC and its Injector chain, which started in February 2013, was completed by the first quarter 2015. A huge number of activities have been performed; this paper reviews the process of the coordination of LS1 from the preparatory phase to the testing phase. The preparatory phase is a very important process: an accurate view of what is to be done, and what can be done is essential. But reality is always different, the differences between what was planned and what was done will be described. The paper will recall the coordination, reporting and decisional processes, highlighting points of success and points to be improved in terms of general coordination, in-situ coordination, safety coordination, logistics and resource management.
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TUPTY024	Updated Simulation Studies of Damage Limit of LHC Tertiary Collimators	2053
	E. Quaranta, A. Bertarelli, R. Brucepresenter, F. Carra, F. Cerutti, P. Gradassi, A. Lechner, S. Redaelli, E. Skordis CERN, Geneva, Switzerland
	The tertiary collimators (TCTs) in the LHC, installed in front of the experiments, in standard operation intercept fractions of 103 halo particles. However, they risk to be hit by high-intensity primary beams in case of asynchronous beam dump. TCT damage thresholds were initially inferred from results of destructive tests on a TCT jaw, supported by numerical simulations, assuming simplified impact scenarios with one single bunch hitting the jaw with a given impact parameter. In this paper, more realistic failure conditions, including a train of bunches and taking into account the full collimation hierarchy, are used to derive updated damage limits. The results are used to update the margins in the collimation hierarchy and could thus potentially have an influence on the LHC performance.
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TUPTY025	Betatron Cleaning for Heavy Ion Beams with IR7 Dispersion Suppressor Collimators	2057
	P.D. Hermes, R. Brucepresenter, J.M. Jowett, S. Redaelli CERN, Geneva, Switzerland
	The betatron collimators in IR7 constitute the backbone of the collimation system of the LHC. A fraction of the secondary halo protons or heavy-ion fragments, scattered out of the primary collimator, is not captured by the secondary collimators but hit cold magnets in the IR7 dispersion suppressor (DS) where the dispersion starts to increase. A possible approach to reduce these losses is based on the installation of additional collimators in the DS region. In this paper, simulations of the cleaning efficiency for Pb82+ ions are used to evaluate the effect of the additional collimators. The results indicate a significant improvement of the heavy-ion cleaning efficiency.
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TUPTY027	SixTrack Simulations of Beam Cleaning During High-beta Operation in the LHC	2060
	R. Bruce CERN, Geneva, Switzerland
	The 1000 m high-beta run in the LHC provided very clean conditions for observing experimental backgrounds. In ATLAS, a much higher background was observed for Beam 2 than for Beam 1, suspected to be caused by upstream showers from beam losses on collimators or aperture. However, no local beam losses were observed in the vicinity. This paper presents SixTrack simulations of the beam cleaning during the high-beta run. The results demonstrate that, for the special optics and collimator settings used, the highest loss location in IR1 is at the TAS absorber just in front of the ATLAS detector, where no beam loss monitor is installed. Furthermore, the highest losses are seen in Beam 2. The results could thus provide a possible explanation of the ATLAS observations, although detailed shower calculations would be needed for a quantitative comparison.
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TUPTY028	Collimator Layouts for HL-LHC in the Experimental Insertions	2064
	R. Bruce, F. Cerutti, L.S. Esposito, J.M. Jowett, A. Lechner, E. Quaranta, S. Redaelli, M. Schaumann, E. Skordis, G.E. Steele CERN, Geneva, Switzerland H. Garcia Morales, R. Kwee-Hinzmann JAI, Egham, Surrey, United Kingdom
	This paper presents the layout of collimators for HL-LHC in the experimental insertions. On the incoming beam, we propose to install additional tertiary collimators to protect potential new aperture bottlenecks in cells 4 and 5, which in addition reduce the experimental background. For the outgoing beam, the layout of the present LHC with three physics debris absorbers gives sufficient protection for high-luminosity proton operation. However, collisional processes for heavy ions cause localized beam losses with the potential to quench magnets. To alleviate these losses, an installation of dispersion suppressor collimators is proposed.
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TUPTY029	Collimation Cleaning at the LHC with Advanced Secondary Collimator Materials	2068
	E. Quaranta, R. Brucepresenter, A. Mereghetti, S. Redaelli, A. Rossi CERN, Geneva, Switzerland
	The LHC collimation system must ensure efficient beam halo cleaning in all machine conditions. The first run in 2010-2013 showed that the LHC performance may be limited by collimator material-related concerns, such as the contribution from the present carbon-based secondary collimators to the machine impedance and, consequently, to the beam instability. Novel materials based on composites are currently under development for the next generation of LHC collimators to address these limitations. Particle tracking simulations of collimation efficiency were performed using the Sixtrack code and a material database updated to model these composites. In this paper, the simulation results will be presented with the aim of studying the effect of the advanced collimators on the LHC beam cleaning.
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TUPTY031	Tools for Flexible Optimisation of IR Designs with Application to FCC	2072
	H. Burkhardt CERN, Geneva, Switzerland M. Boscolo INFN/LNF, Frascati (Roma), Italy
	The interaction regions of future high-luminosity colliders require well balanced designs, which provide both for a very high luminosity and at the same time keep backgrounds and radiation at tolerable levels. We describe a set of flexible tools, targeted at providing a first evaluation of losses in the interaction region as part of the design studies, and their application to FCC.
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TUPTY032	Study of Muon Backgrounds in the CLIC Beam Delivery System	2075
	F.B. Pilicer, E. Pilicer, İ. Tapan UU, Bursa, Turkey H. Burkhardtpresenter, L. Gatignon, A. Latina, D. Schulte, R. Tomás CERN, Geneva, Switzerland
	We describe the detailed modelling of muon background generation and absorption in the CLIC beam delivery system. The majority of the background muons originates in the first stages of halo collimation. We also discuss options to use magnetised cylindrical iron shields to reduce the muon background flux reaching the detector region.
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TUPTY033	Civil Engineering Optimisation Tool for the Study of CERN's Future Circular Colliders	2079
	C. Cook, B. Goddard, P. Lebrun, J.A. Osborne, Y. Robert CERN, Geneva, Switzerland
	Funding: CERN The feasibility of Future Circular Colliders (FCC), possible successors to the Large Hadron Collider (LHC), is currently under investigation at CERN. This paper describes how CERN’s civil engineering team are utilising an interactive tool containing a 3D geological model of the Geneva basin. This tool will be used to investigate the optimal position of the proposed 80km-100km tunnel. The benefits of using digital modelling during the feasibility stage are discussed and some early results of the process are presented.
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TUPTY035	Beam Dynamics Requirements for the Powering Scheme of the HL-LHC Triplet	2082
	M. Fitterer, R. De Maria, S.D. Fartoukh, M. Giovannozzi CERN, Geneva, Switzerland
	Funding: The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404. For the HL-LHC, β* values as small as 15 cm are envisaged as baseline scenario for the high luminosity insertions IR1 and IR5, thus leading to an increase of the maximum beta-functions in the inner triplet (IT). The larger beta-functions in the IT result in a higher sensitivity of the beam to any linear or non-linear, static or dynamic, field imperfections in the IT region. In this paper, we summarize accordingly the tolerances of the triplet power supplies in terms of current ripple, stability and reproducibility. Both the baseline IT powering scheme and other alternative schemes will be presented, the later reducing the tune shift caused by a current modulation and thus weakening its possible impact on the long term stability.
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TUPTY036	Crossing Scheme and Orbit Correction in IR1/5 for HL-LHC	2086
	M. Fitterer, R. De Maria, S.D. Fartoukh, M. Giovannozzi CERN, Geneva, Switzerland
	Funding: The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404. In this paper we review the orbit correction strategy and crossing scheme adjustment for the HL-LHC orbit correctors in IR1/5 in view of the new optics and layout version HLLHCV1.1. The main objectives are to optimize the crossing scheme, in particular to reduce the strength of the orbit correctors at D2, and to validate the strength specifications of the several orbit corrector magnets involved, including a budget reserved for the correction of the orbit distortions from various sources.
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TUPTY037	HLLHCV1.1 Optics Version for the HL-LHC Upgrade	2090
	R. De Maria, S.D. Fartoukh, M. Fittererpresenter CERN, Geneva, Switzerland
	Funding: The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404. The optics and layout of the HL-LHC are evolving as the new hardware is being studied and integrated, any additional requirements from the experiments detailed, and other constraints of different nature clarified. Here we present the changes of version 1.1 of the optics and layout with respect to the previous version 1.0, which include the current hardware choices and an outlook on the main resulting optics limitations and the possible future evolutions of the layout.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY037
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TUPTY038	BPM Tolerances for HL-LHC Orbit Correction in the Inner Triplet Area	2094
	M. Fitterer, R. De Maria CERN, Geneva, Switzerland
	Funding: The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404. For the HL-LHC beam spot sizes as small as 7 mum are considered for the high luminosity insertions IR1 and IR5. In addition, the luminosity has to be levelled over several hours by changing β* resulting in constant changes of the optics and thus orbit changes. The small beam size and the continuous optics changes in general make the alignment of the beams at the IP challenging. In order to avoid continuous luminosity scans for the alignment of the beams at the IP, the orbit correction has to rely on the readings of the BPMs in the IT region. In this paper we review the requirements on resolution and accuracy of the BPMs and compare different options for the placement of the BPMs in the IT region.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY038
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TUPTY039	LHC Transfer Lines and Injection Tests for Run 2	2098
	C. Bracco, J.L. Abelleira, R. Alemany-Fernández, M.J. Barnes, W. Bartmann, E. Carlier, L.N. Drøsdal, M.A. Fraserpresenter, K. Fuchsberger, B. Goddard, J. Jentzsch, V. Kain, N. Magnin, M. Meddahi, J.S. Schmidt, L.S. Stoel, J.A. Uythoven, F.M. Velotti, J. Wenninger CERN, Geneva, Switzerland
	The transfer lines for both rings of the LHC were successfully re-commissioned with beam in preparation for the start-up of Run 2. This paper presents an overview of the transfer line and sector tests performed to bring the LHC back into operation after a two-year period of shutdown for consolidation and upgrade. The tests enabled the debugging of critical software and hardware systems and validated changes made to the transfer and injection systems. The beam-based measurements carried out to validate the optics and machine configuration are summarised along with the performance of the hardware systems.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY039
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TUPTY040	Comparison of Beam Sizes at the Collimator Locations from Measured Optics and Beam-based Collimator Alignment at the LHC	2101
	G. Valentino, R. Bruce, A. Langnerpresenter, S. Redaelli, R. Tomás CERN, Geneva, Switzerland
	At the LHC, the collimation hierarchy is defined in units of the betatron beam size using the sizes at each collimator location. The beam size at a given collimator can be inferred from the gap measurement during beam-based alignment campaigns, when the collimator touches a reference beam halo defined with the primary collimators. On the other hand, the beta functions at each collimator are also measured as a part of the standard LHC optics validation. This paper presents a comparison of the beam size measurements at the collimator locations applying these two techniques for different machine configurations. This work aims at determining which is the most reliable method for setting the collimator gaps at the LHC.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY040
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TUPTY042	Non-linear Coupling Studies in the LHC	2105
	T. Persson, Y.I. Levinsen, E.H. Maclean, R. Tomás CERN, Geneva, Switzerland E.H. Maclean JAI, Oxford, United Kingdom
	The amplitude detuning has been observed to decrease significantly as the horizontal and vertical tunes are approaching each other. This effect is potentially harmful since it might cause a loss of Landau damping, hence giving rise to instabilities. The measured tune split (Qx-Qy) versus amplitude is several times bigger than what can be explained with linear coupling. In this paper we present studies performed to identify the dominant sources of the non-linear coupling observed in the LHC.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY042
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TUPTY043	Analysis of Intensity-dependent Effects on LHC Transverse Tunes at Injection Energy	2108
	R. De Maria, M. Giovannozzi, T. Perssonpresenter, R. Tomás CERN, Geneva, Switzerland Y. Wei IHEP, Beijing, People's Republic of China
	The LHC Run I has provided a huge amount of data that can be used to deepen the understanding of the beam behaviour. In this paper the focus is on the analysis of transverse tunes at injection energy to detect signs of intensity-dependent effects. BPM data, recording the injection oscillations of the operational beams during the ring-filling phase, have been analysed in detail to enable extracting useful information about the tune shift vs. injected beam intensity. The data processing and the results are discussed in detail, including also possible implications for future operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY043
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TUPTY045	Interactions between Macroparticles and High-Energy Proton Beams	2112
	S. Rowan, A. Apollonio, B. Auchmann, A. Lechner, O. Picha, W. Riegler, H. Schindler, R. Schmidt, F. Zimmermann CERN, Geneva, Switzerland
	A known threat to the availability of the LHC is the interaction of macroparticles (dust particles) with the LHC proton beam. At the foreseen beam energy of 6.5 TeV during Run 2, quench margins in the superconducting magnets will be 2-3 times lower, and beam losses due such interactions may result in magnet quenches. The study introduce an improved numerical model of such interactions, as well as Monte-Carlo simulations that give the probability that such events will result in a beam-dump during Run 2.
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TUPTY046	Impact of Beam Losses in the LHC Collimation Regions	2116
	E. Skordis, R. Bruce, F. Cerutti, A. Ferrari, P.D. Hermes, A. Lechner, A. Mereghetti, P.G. Ortega, S. Redaelli, V. Vlachoudis CERN, Geneva, Switzerland
	The upgrade of the LHC energy and brightness, from the 2015 restart at close to design energy until the HL-LHC era with considerable hardware development and layout renewal, poses tight challenges in terms of machine protection. The collimation insertions and especially the one dedicated to betatron cleaning (IR7), where most of the beam halo is intercepted to spare from losses the cold sectors of the ring, will be subject to a significant increase of radiation load, whose leakage to the nearby dispersion suppressors must be kept sustainable. The past LHC run, while displaying a remarkable performance of the collimation system, offered the opportunity for a demanding benchmarking of the complex simulation chain describing the beam losses and the macroscopic effects of the induced particle showers, this way strengthening the confidence in the reliability of its predictions. This paper discusses the adopted calculation strategy and its evolution options, showing the accuracy achieved with respect to Beam Loss Monitor measurements in controlled loss scenarios. Expectations at design energy, including lifetime considerations concerning critical elements, will also be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY046
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TUPTY047	ERL with Non-Scaling Fixed Field Alternating Gradient Lattice for eRHIC	2120
	D. Trbojevic, J.S. Berg, S.J. Brooks, Y. Hao, V. Litvinenko, C. Liu, F. Méot, M.G. Minty, V. Ptitsyn, T. Roser, P. Thieberger, N. Tsoupas BNL, Upton, Long Island, New York, USA
	Funding: Work performed under Contract Number DE-AC02-98CH10886 with the auspices of the US Department of Energy. The proposed eRHIC electron-hadron collider uses a "non-scaling FFAG" lattice to recirculate 16 turns of different energy through just two beamlines located in the RHIC tunnel. This paper presents lattices for these two FFAGs that are optimised for low magnet field and to minimise total synchrotron radiation across the energy range. The higher number of recirculations in the FFAG allows a shorter linac (1.322GeV) to be used, drastically reducing cost, while still achieving a 21.2GeV maximum energy to collide with one of the existing RHIC hadron rings at up to 250GeV. eRHIC uses many cost-saving measures in addition to the FFAG: the linac operates in energy recovery mode, so the beams also decelerate via the same FFAG loops and energy is recovered from the interacted beam. All magnets will constructed from NdFeB permanent magnet material, meaning chillers and large magnet power supplies are not needed. This paper also describes a smaller prototype ERL-FFAG accelerator that will test all of these technologies in combination to reduce technical risk for eRHIC.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY047
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TUPTY048	Changes to the Transfer Line Collimation System for the High-Luminosity LHC Beams	2124
	V. Kain, O. Aberle, C. Bracco, M.A. Fraser, F. Galleazzi, A. Kosmicki, F.L. Maciariello, M. Meddahi, F.-X. Nuiry, G.E. Steelepresenter, F.M. Velotti CERN, Geneva, Switzerland E. Gianfelice-Wendt Fermilab, Batavia, Illinois, USA
	The current LHC transfer line collimation system will not be able to provide enough protection for the high brightness beams in the high-luminosity LHC era. The new collimation system will have to attenuate more and be more robust than its predecessor. The active jaw length of the new transfer line collimators will therefore be 2.1 m instead of currently 1.2 m. The transfer line optics will have to be adjusted for the new collimator locations and larger beta functions at the collimators for absorber robustness reasons. In this paper the new design of the transfer line collimation system will be presented with its implications on transfer line optics and powering, maintainability, protection of transfer line magnets in case of beam loss on a collimator and protection of the LHC aperture
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY048
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TUPTY049	Protection of Superconducting Magnets in Case of Accidental Beam Losses during HL-LHC Injection	2128
	A. Lechner, M.J. Barnes, C. Bracco, B. Goddard, F.L. Maciariello, A. Perillo Marcone, N.V. Shetty, G.E. Steelepresenter, J.A. Uythoven, F.M. Velotti CERN, Geneva, Switzerland F.M. Velotti EPFL, Lausanne, Switzerland
	Funding: Research supported by the High Luminosity LHC project. The LHC injection regions accommodate a system of beam-intercepting devices which protect superconducting magnets and other accelerator components in case of mis-steered injected beam or accidentally kicked stored beam, e.g. due to injection kicker or timing malfunctions. The brightness and intensity increase required by the High Luminosity (HL) upgrade of the LHC necessitates a redesign of some devices to improve their robustness and to reduce the leakage of secondary particle showers to downstream magnets. In this paper, we review possible failure scenarios and we quantify the energy deposition in superconducting coils by means of FLUKA shower calculations. Conceptual design studies for the new protection system are presented, with the main focus on the primary injection protection absorber (TDI) and the adjacent mask (TCDD).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY049
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TUPTY050	Considerations for the Beam Dump System of a 100 TeV Centre-of-mass FCC hh Collider	2132
	T. Kramer, M.G. Atanasov, M.J. Barnes, W. Bartmann, J. Borburgh, E. Carlier, F. Cerutti, L. Ducimetière, B. Goddard, A. Lechner, R. Losito, G.E. Steele, L.S. Stoel, J.A. Uythoven, F.M. Velottipresenter CERN, Geneva, Switzerland
	A 100 TeV centre-of-mass energy frontier proton collider in a new tunnel of 80–100 km circumference is a central part of CERN’s Future Circular Colliders (FCC) design study. One of the major challenges for such a machine will be the beam dump system, which for each ring will have to reliably abort proton beams with stored energies in the range of 8 Gigajoule, more than an order of magnitude higher than planned for HL-LHC. The transverse proton beam energy densities are even more extreme, a factor of 100 above that of the presently operating LHC. The requirements for the beam dump subsystems are outlined, and the present technological limitations are described. First concepts for the beam dump system are presented and the feasibility is discussed, highlighting in particular the areas in which major technological progress will be needed. The potential implications on the overall machine and other key subsystems are described, including constraints on filling patterns, interlocking, beam intercepting devices and insertion design.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY050
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TUPTY051	Injection Protection Upgrade for the HL-LHC	2136
	J.A. Uythoven, N. Biancacci, C. Bracco, L. Gentini, B. Goddard, A. Lechner, F.L. Maciariello, A. Perillo Marcone, B. Salvant, N.V. Shetty, G.E. Steele, F.M. Velottipresenter CERN, Geneva, Switzerland O. Frasciello, M. Zobov INFN/LNF, Frascati (Roma), Italy
	The injector complex of the LHC is undergoing important changes in the light of the LIU project to provide brighter beams to the LHC. For this reason and as part of the High Luminosity LHC project the injection protection system of the LHC will be upgraded in the Long Shutdown 2 (2018 - 2019) to be able to protect downstream elements against injection failures with the high brightness, high intensity HL-LHC beams. The upgraded LHC injection protection system will consist of a segmented injection protection absorber TDIS, and auxiliary collimators and masks. The layout modifications are described, and the machine element protection and absorber jaw robustness studies are presented for the new systems.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY051
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TUPTY052	New Method for Validation of Aperture Margins in the LHC Triplet	2140
	V. Chetvertkova, R. Schmidt, F.M. Velottipresenter, D. Wollmann CERN, Geneva, Switzerland F.M. Velottipresenter EPFL, Lausanne, Switzerland
	Funding: Work supported by COFUND grant PCOFUND-GA-2010-267194 Safety of LHC equipment including superconducting magnets depends not only on the proper functioning of the systems for machine protection, but also on the accurate adjustment of the protective devices such as collimators. In case of a failure of the extraction kicker magnets, which are part of the beam dumping system, it is important to ensure protection of the superconducting triplet magnets from missteered beam. The magnets are located to the right of Interaction Point 5 (IP5) and are protected by one set of collimators in the beam dumping insertion in IR6 and another set close to the triplet magnets. In this paper, a new method for verification of the correct collimator position with respect to the aperture is presented. It comprises the application of an extended orbit bump with identical trajectory as the beam trajectory after a deflection by the beam dump kickers. By further increasing the bump amplitude and successively moving in/out the collimators in the region of interest, the accurate positioning of the collimators can be validated. The effectiveness of the method for LHC IP5 and IP1 and both beams is discussed
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TUPTY053	Roadmap towards High Accelerator Availability for the CERN HL-LHC Era	2143
	A. Apollonio, M. Brugger, L. Rossi, R. Schmidt, B. Todd, D. Wollmann, M. Zerlauthpresenter CERN, Geneva, Switzerland
	High Luminosity-LHC is the future upgrade of the LHC that aims at delivering an integrated luminosity of 3000 fb-1 over about 10 years of operation, starting from 2025. Significant modifications [1] will be implemented to accelerator systems, including new superconducting magnets, crab cavities, superconducting links, new collimators and absorbers based on advanced materials and design and additional cryo-plants. Due to the limit imposed by the number of simultaneous events at the experiments (pile-up) on peak luminosity, the latter will be levelled to 5*1034 cm-2s−1. The target integrated luminosity can only be achieved with a significant increase of the total available time for beam collisions compared to the 2012 LHC run, despite a beam current that is planned to double the nominal 0.58 A. Therefore one of the key figures of merit to take into account for system upgrades and new designs is their impact on the accelerator availability. In this paper the main factors affecting LHC availability will be discussed and predictions on the impact of future system upgrades on integrated luminosity presented. Requirements in terms of the maximum allowed number of dumps for the main contributing systems to LHC unavailability will be derived.
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TUPTY054	RF Design of the CLIC Structure Prototype Optimized for Manufacturing from Two Halves	2147
	H. Zha, A. Grudiev CERN, Geneva, Switzerland V.A. Dolgashev SLAC, Menlo Park, California, USA
	We present the RF design of a 12GHz Compact Linear Collider (CLIC) main linac accelerating structure prototype. The structure is made from two longitudinally symmetric halves. The main manufacturing process of each half is precision milling. The structure uses the same iris dimensions as the CLIC-G structure but the cell shape is optimized for milling. The geometry is optimized to reduce the surface electric and magnetic fields and the modified Poynting vector. This design can potentially reduce fabrication cost.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY054
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TUPTY055	Optimization of the RF Design of the CLIC Main Linac Accelerating Structure	2150
	H. Zha, A. Grudiev CERN, Geneva, Switzerland
	We present a new optimized design of the accelerating structure for the main linac of CLIC (Compact Linear Collider). The new structure has lower surface magnetic fields and a significantly smaller transverse size compared to the baseline design described in the CLIC Concept Design Report (CDR). This new design should reach higher accelerating gradients and have a reduced manufacturing cost. The details of the RF design procedure and the obtained results are presented in this paper.
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TUPTY056	Beam-Based Measurements of Long Range Transverse Wakefields in CLIC Main Linac Accelerating Structure	2153
	H. Zha, A. Grudiev, A. Latina, D. Schulte, A. Solodko, W. Wuensch CERN, Geneva, Switzerland E. Adli University of Oslo, Oslo, Norway G. De Michele EPFL, Lausanne, Switzerland G. De Michele PSI, Villigen PSI, Switzerland N. Lipkowitz, G. Yocky SLAC, Menlo Park, California, USA
	The baseline design of CLIC (Compact Linear Collider) uses X-band accelerating structures in the main linac. Every accelerating structure cell has four waveguides, terminated with individual RF loads, to damp the unwanted long-range transverse wakefields, in order to maintain beam stability in multi-bunch operation. In order to experimentally verify the calculated suppression of the wakefields, a prototype structure has been built and installed in FACET test facility at SLAC. The results of the measurements of the wakefields in the prototype structure by means of positron and electron bunches are presented.
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TUPTY057	Scenarios for Circular Gamma-Gamma Higgs Factories	2156
	F. Zimmermann, Y. Papaphilippou CERN, Geneva, Switzerland R. Aleksan CEA/DSM/IRFU, France A. Apyan NU, Evanston, Illinois, USA
	Funding: The research leading to these results has received partial funding from the European Commission under the FP7 Research Infrastructures project EuCARD-2, grant agreement no.312453. The Higgs boson can be produced directly in gamma-gamma collisions generated by laser Compton back scattering off 80-90 GeV electron or positron beams. We discuss options for realizing a gamma-gamma Higgs factory using a high-energy circular e+e− collider, such as FCC-ee or CEPC, and/or its top-up injector ring, and compare the parameters and advantages of such a facility, including the expected performance, with those for a Higgs factory based on a recirculating linac, such as SAPPHiRE.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY057
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TUPTY058	Mitigating Performance Limitations of Single Beam-pipe Circular e+e− Colliders	2160
	M. Koratzinos DPNC, Genève, Switzerland F. Zimmermannpresenter CERN, Geneva, Switzerland
	Renewed interest in circular e+e− colliders has spurred designs of single beam-pipe machines, like the CEPC in China, and double beam pipe ones, such as the FCC-ee effort at CERN. Single beam-pipe designs profit from lower costs but are limited by the number of bunches that can be accommodated in the machine. We analyse these performance limitations and propose a solution that can accommodate O(1000) bunches while keeping more than 90% of the ring with a single beam pipe.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY058
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TUPTY059	First Considerations on Beam Optics and Lattice Design for the Future Electron-Positron Collider FCC-ee	2162
	B. Härer, B.J. Holzer, F. Zimmermannpresenter CERN, Geneva, Switzerland A.V. Bogomyagkov BINP SB RAS, Novosibirsk, Russia
	The Future Circular Collider (FCC) study includes the design of a 100-km electron positron collider (FCC-ee) with collision energies between 90 GeV and 350 GeV. This paper describes first aspects of the design and the optics of the FCC-ee collider, optimised for four different beam energies. Special emphasis is put on the need for a highly flexible magnet lattice in order to achieve the required beam emittances in each case and on the layout of the interaction region that will have to combine an advanced mini-beta concept, an effective beam separation scheme and a local chromaticity control to optimise the momentum acceptance and dynamic aperture of the ring.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY059
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TUPTY060	The FCC-ee Study: Progress and Challenges	2165
	M. Koratzinos DPNC, Genève, Switzerland S. Aumon, C. Cook, A. Doblhammer, B. Härer, B.J. Holzer, R. Tomás, F. Zimmermannpresenter CERN, Geneva, Switzerland A.V. Bogomyagkov, E.B. Levichev, D.N. Shatilov BINP SB RAS, Novosibirsk, Russia M. Boscolo INFN/LNF, Frascati (Roma), Italy L.E. Medina Medrano UGTO, Leon, Mexico U. Wienands SLAC, Menlo Park, California, USA
	The FCC (future circular collider) study represents a vision for the next large project in high energy physics, comprising a 80-100 km tunnel that can house a future 100TeV hadron collider. The study also includes a high luminosity e+e− collider operating in the centre-of-mass energy range of 90-350 GeV as a possible intermediate step, the FCC-ee. The FCC-ee aims at definitive electro-weak precision measurements of the Z, W, H and top particles, and search for rare phenomena. Although FCC-ee is based on known technology, the goal performance in luminosity and energy calibration make it quite challenging. During 2014 the study went through an exploration phase and during the next three years a conceptual design report will be prepared.
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TUPTY061	Combined Operation and Staging Scenarios for the FCC-ee Lepton Collider	2169
	M. Benedikt, B.J. Holzer, E. Jensen, R. Tomás, J. Wenninger, F. Zimmermannpresenter CERN, Geneva, Switzerland A.V. Bogomyagkov, E.B. Levichev, D.N. Shatilov BINP SB RAS, Novosibirsk, Russia K. Ohmi, K. Oide KEK, Ibaraki, Japan U. Wienands SLAC, Menlo Park, California, USA
	FCC-ee is a proposed high-energy electron positron circular collider that would initially occupy the 100-km FCC tunnel that will eventually house the 100 TeV FCC-hh hadron collider. The parameter range for the e+/e− collider is large, operating at a cm energy from 90 GeV (Z-pole) to 350 GeV (t-tbar production) with the maximum beam current ranging from 1.5 A to 6 mA for each beam, corresponding to a synchrotron radiation power of 50 MW and a radiative energy loss varying from ~30 MeV/turn to ~7500 MeV/turn. This presents challenges for the rf system due to the varying rf voltage requirements and beam loading conditions. In this paper we present a possible gradual evolution of the FCC-ee complex by step-wise expansion, and possibly reconfiguration, of the superconducting RF system. The performance attainable at each step is discussed, along with the possible advantages and drawbacks.
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TUPTY062	FCC-hh Hadron Collider - Parameter Scenarios and Staging Options	2173
	M. Benedikt, B. Goddard, D. Schulte, F. Zimmermannpresenter CERN, Geneva, Switzerland M.J. Syphers NSCL, East Lansing, Michigan, USA M.J. Syphers Fermilab, Batavia, Illinois, USA
	FCC-hh is a proposed future energy-frontier hadron collider, based on dipole magnets with a field around 16 T installed in a new tunnel with a circumference of about 100 km, which would provide proton collisions at a centre-of-mass energy of 100 TeV, as well as heavy-ion collisions at the equivalent energy. The FCC-hh should deliver a high integrated proton-proton luminosity at the level of several 100 fb-1 per year, or more. The challenges for operating FCC-hh with high beam current and at high luminosity include the heat load from synchrotron radiation in a cold environment, the radiation from collision debris around the interaction region, and machine protection. In this paper, starting from the FCC-hh design baseline parameters we explore different approaches for increasing the integrated luminosity, and discuss the impact of key individual parameters, such as the turnaround time. We also present some injector considerations and options for early hadron-collider operation.
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TUPTY063	FCC-ee: Energy Calibration	2177
	M. Koratzinos, A.P. Blondel DPNC, Genève, Switzerland E. Gianfelice-Wendt Fermilab, Batavia, Illinois, USA F. Zimmermannpresenter CERN, Geneva, Switzerland
	FCC-ee aims to improve on electroweak precision measurements, with goals of 100 keV on the Z mass and width, and a fraction of an MeV on the W mass. Compared to LEP, this implies a much improved knowledge of the centre-of-mass energy when operating at the Z peak and WW threshold. This contribution will describe how it is planned to achieve this, by making systematic use of resonant depolarization. A number of difficulties have been identified, due in particular to the long polarization time and amplified ground motion. However the smaller emittance and energy spread of FCC-ee with respect to LEP should help achieve a much improved performance.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY063
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TUPTY066	Beam Cleaning in Experimental IRs in HL-LHC for Incoming Beam	2181
	H. Garcia Morales Royal Holloway, University of London, Surrey, United Kingdom R. Bruce, S. Redaelli CERN, Geneva, Switzerland
	The HL-LHC will store 675 MJ of energy per beam, about 300 MJ more than the nominal LHC. Due to the increase in stored energy and a different interaction region (IR) optics design, the collimation system for the incoming beam must be revisited in order to avoid dangerous losses that could cause quenches and machine damage. This paper studies the ffectiveness of the current LHC collimation system in intercepting cleaning losses close to the experiments in the HL-LHC. The study reveals that additional tertiary collimators would be beneficial in order to protect not only the final focusing triplets but also the two quadrupoles further upstream.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY066
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TUPTY067	Beam Induced Background Simulation Studies at IR1 with New High Luminosity LHC Layout	2184
	R. Kwee-Hinzmann, S.M. Gibson JAI, Egham, Surrey, United Kingdom R. Bruce, F. Cerutti, L.S. Esposito, A. Lechner CERN, Geneva, Switzerland S.M. Gibson Royal Holloway, University of London, Surrey, United Kingdom
	Funding: Research supported by FP7 HiLumi LHC – Grant agreement 284404 In the High Luminosity LHC (HL-LHC), the collimation system will be upgraded in the high-luminosity experimental regions. Additional protection is planned for the Q4 and Q5 magnets that are located further upstream of the tertiary collimators that protect the inner triplet magnets. We evaluate the effect of this proposed collimation layout for the incoming beam 1 on machine-induced background in the experimental area of IR1 (ATLAS). The main scenario is the round optics with β∗ of 15 cm, but a flat scenario is also briefly discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY067
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TUPTY069	Simulation of Hollow Electron Lenses as LHC Beam Halo Reducers using Merlin	2188
	H. Rafique, R.J. Barlow University of Huddersfield, Huddersfield, United Kingdom R.B. Appleby, S.C. Tygier UMAN, Manchester, United Kingdom R. Bruce, S. Redaelli CERN, Geneva, Switzerland
	Funding: Research supported by FP7 HiLumi LHC (Grant agreement 284404) The Large Hadron Collider (LHC) and its High Luminosity (HL) upgrade foresee unprecedented stored beam energies of up to 700 MJ. The collimation system is responsible for cleaning the beam halo and is vital for successful machine operation. Hollow electron lenses (HEL) are being considered for the LHC, based on Tevatron designs and operational experience, for active halo control. HELs can be used as soft scraper devices, and can operate close to the beam core without undergoing damage. We use the Merlin C++ accelerator libraries to implement a HEL and examine the effect on the beam halo for various test scenarios.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY069
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TUPTY070	Strong-Strong Simulations of Beta star Levelling for Flat and Round Beams	2192
	M.P. Crouch, R.B. Appleby UMAN, Manchester, United Kingdom B.D. Muratori STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: STFC HL-LHC The HL-LHC project aims to reach larger peak luminosities, however this can lead to a high pile up in the detectors. To control the pile up, luminosity levelling has been suggested. One proposed method is β*-luminosity levelling, in which beams collide at a larger than nominal β*. The β* is then reduced in steps as the beam intensity decays. This allows the luminosity to be kept constant over part of a physics fill. The use of round or flat optics will change the beam-beam effect of the head on collisions as well as the long range interactions. Here simulations of β* levelling are presented for the case of flat and round beam optics and the difference in terms of the beam-beam effect is highlighted.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY070
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TUPTY072	A New ILC Positron Source Target System Using Sliding Contact Cooling	2196
	W. Gai, D.S. Doran, R.A. Erck, G.R. Fenske, V.J. Guarino, W. Liu ANL, Argonne, Illinois, USA
	The R&D of the baseline positron source target for ILC is still ongoing after TDR due to the uncertainty of rotating vacuum seal and water cooling system of the fast spinning target wheel. Different institutes around the globe have proposed different approaches to tackle this issue. A spinning target wheel system with sliding contact cooling has been proposed by ANL. The proposed system eliminated the needs of rotating vacuum seal by using magnet bearings and vacuum compatible motor driven solid spinning wheel target. The energy deposited from positron production process is taken away via sliding cooling pads sliding against the spinning wheel. Details about this new target system are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY072
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TUPTY073	An Alternative High Luminosity LHC with Flat Optics and Long-Range Beam-Beam Compensation	2199
	S.D. Fartoukh CERN, Geneva, Switzerland D.N. Shatilov BINP SB RAS, Novosibirsk, Russia A. Valishevpresenter Fermilab, Batavia, Illinois, USA
	Funding: Research supported by DOE via the US-LARP program and by EU FP7 HiLumi LHC - Grant Agreement 284404 In the baseline scenario of the High-Luminosity LHC (HL-LHC), the geometric loss of luminosity in the two high luminosity experiments due to collisions with a large crossing angle is recovered by tilting the bunches in the interaction region with the use of crab cavities. A possible backup scenario would rely on a reduced crossing angle together with flat optics (with different horizontal and vertical β* values) for the preservation of luminosity performance. However, the reduction of crossing angle coupled with the flat optics significantly enhances the strength of long-range beam-beam interactions. This paper discusses the possibility to mitigate the long-range beam-beam effects by current bearing wire compensators (or e-lens). We develop a new HL-LHC parameter list and analyse it in terms of integrated luminosity performance as compared to the baseline. Further, we evaluate the operational scenarios using numerical simulations of single-particle dynamics with beam-beam effects.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY073
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TUPTY074	Muon Beam Emittance Evolution in the Helical Ionization Cooling Channel for Bright Muon Sources	2203
	K. Yonehara, C.Y. Yoshikawa Fermilab, Batavia, Illinois, USA C.M. Ankenbrandt, R.P. Johnson, S.A. Kahn Muons, Inc, Illinois, USA M. Chung UNIST, Ulsan, Republic of Korea Y.S. Derbenev, A.V. Sy JLab, Newport News, Virginia, USA B.T. Freemire IIT, Chicago, Illinois, USA
	The six-dimensional ionization cooling is essential to design a bright muon source. A geometry constraint is a challenge issue in a compact helical cooling channel (HCC). Especially, the HCC requires a large bore helical magnet and a compact helical RF system to incorporate the RF into the magnet chamber. A new emittance evolution has been designed to mitigate the geometry constraint. The HCC was functionally separated into three parts sections. The lattice at the initial section provides a large transverse acceptance by using a strong helical focus magnet. Once the transverse beam size is small enough to get into the compact RF the HCC lattice in the middle section generates a large longitudinal beta tune to dominate the longitudinal cooling. Consequently, the longitudinal emittance becomes smaller than the transverse one at the end of middle section. In the final section, the magnetic field strength is gradually reduced to match out the helical channel to the straight solenoid. As a result, the emittance exchange takes place and the final transverse emittance becomes smaller than the longitudinal one. The new emittance evolution scenario will be discussed in this presentation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY074
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TUPTY076	Beam-Beam Simulation of Crab Cavity White Noise for LHC Upgrade	2206
	J. Qiang LBNL, Berkeley, California, USA J. Barranco García EPFL, Lausanne, Switzerland K. Ohmipresenter KEK, Ibaraki, Japan T. Pieloni CERN, Geneva, Switzerland
	High luminosity LHC upgrade will improve the luminosity of the current LHC operation by an order of magnitude. Crab cavity as a critical component for compensating luminosity loss from large crossing angle collision and also providing luminosity leveling for the LHC upgrade is being actively pursued. In this paper, we will report on the study of potential effects of the crab cavity noise on the beam luminosity lifetime based on strong-strong beam-beam simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY076
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TUPTY077	Strong-Strong Beam-Beam Simulation of Bunch Length Splitting at the LHC	2210
	J. Qiang, S. Paret LBNL, Berkeley, California, USA K. Ohmipresenter KEK, Ibaraki, Japan T. Pieloni CERN, Geneva, Switzerland
	Longitudinal bunch length splitting was observed for some LHC beams. In this paper, we will report on the study of the observation using strong-strong beam-beam simulations. We explore a variety of factors including initial momentum deviation, collision crossing angle, synchroton tune, chromaticity, working points and bunch intensity that contribute to the beam particle loss and the bunch length splitting, and try to understand the underlying mechanism of the observed phenomena.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY077
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TUPTY078	Fixed-energy Cooling and Stacking for an Electron Ion Collider	2214
	P.M. McIntyre, S. Assadi, J. Geritypresenter, A. Sattarov Texas A&M University, College Station, Texas, USA
	The proposed designs for polarized-beam electron-ion colliders require cooling of the ion beam to achieve and sustain high luminosity. One attractive approach is to make a fixed-energy storage ring in which ions are con-tinuously cooled and stacked during a collider store, then transferred to the collider and accelerated for a new store when the luminosity decreases. An example design is reported for a 6 GeV/u superferric storage ring, and for a d.c. electron cooling system in which electron space charge is fully neutralized so that high-current magnetized e-cooling can be used to best advantage.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY078
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TUPTY079	Initial Modeling of Electron Cloud Buildup in the Final-focus Quadrupole Magnets of the SuperKEKB Positron Ring	2218
	J.A. Crittenden Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: US National Science Foundation contracts PHY-0734867, PHY-1002467, and PHY-1068662, US Department of Energy contract DE-FC02-08ER41538 and the Japan/US Cooperation Program We present modeling results for electron cloud buildup in the final-focus quadrupole magnet nearest the interaction point in the SuperKEKB positron storage ring. The calculations employ as input recently obtained estimates of synchrotron radiation absorption rates on the vacuum chamber wall including the effect of photon scattering. While the effect both adds to and subtracts from photoelectron production at the points in the ring where unscattered photons strike the wall, it also produces cloud in the other regions. Results for beam-pipe-averaged and beam-averaged cloud densities are presented, as are estimates for the contribution to the fractional vertical coherent tune shift. The effect of the strong magnetic fields is studied and the dependence on the vacuum chamber surface secondary yield characteristics is considered. Cloud buildup is modeled with a 2D particle-in-cell macroparticle tracking code validated using recent measurements of electron trapping in a quadrupole magnet at the Cornell Electron Storage Ring Test Accelerator.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY079
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TUPTY080	Synchrotron Radiation Analysis of the SuperKEKB Positron Storage Ring	2222
	J.A. Crittenden, D. Sagan Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA T. Ishibashi, Y. Suetsugu KEK, Ibaraki, Japan
	Funding: US National Science Foundation contracts PHY-0734867, PHY-1002467, and PHY-1068662, US Department of Energy contract DE-FC02-08ER41538 and the Japan/US Cooperation Program. We report on modeling results for synchrotron radiation absorption in the SuperKEKB positron storage ring vacuum chamber including the effects of photon scattering on the interior walls. A detailed model of the geometry of the inner vacuum chamber profile has been developed and used as input to a photon tracking code. Particular emphasis is placed on the photon absorption rates in the electron-positron interaction region.
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TUPTY081	Design of a 6 TeV Muon Collider	2226
	M.-H. Wang, Y. Cai, Y. Nosochkovpresenter SLAC, Menlo Park, California, USA M.A. Palmer Fermilab, Batavia, Illinois, USA
	Funding: Work supported by the US Department of Energy contract DE-AC02-76SF00515 A design of a muon collider ring with the center of mass energy of 6 TeV is presented. The ring circumference is about 6.3 km, and the beta functions at collision point are 1 cm in both planes. The ring linear optics, the non-linear chromaticity correction scheme in the Interaction Region (IR), and the additional non-linear field orthogonal knobs are described in detail. The IR magnet specifications are based on the maximum pole tip field of 20 T in dipoles and 15 T in quadrupoles. The results of the beam dynamics optimization for maximum dynamic aperture are presented.
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TUPTY082	Scanning Synchronization of Colliding Bunches for MEIC Project	2229
	Y.S. Derbenev, V.P. Popov JLab, Newport News, Virginia, USA Y.D. Chernousov ICKC, Novosibirsk, Russia G.M. Kazakevich Euclid TechLabs, LLC, Solon, Ohio, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contracts No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Synchronization of colliding beams is one of the major issues of an electron-ion collider (EIC) design because of sensitivity of ion revolution frequency to beam energy. A conventional solution for this trouble is insertion of bent chicanes in the arcs space. In our report we consider a method to provide space coincidence of encountering bunches in the crab-crossing orbits Interaction Region (IR) while repetition rates of two beams do not coincide. The method utilizes pair of fast kickers realizing a bypass for the electron bunches as the way to equalize positions of the colliding bunches at the Interaction Point (IP). A dipole-mode warm or SRF cavities fed by the magnetron transmitters are used as fast kickers, allowing a broad-band phase and amplitude control. The proposed scanning synchronization method implies stabilization of luminosity at a maximum via a feedback loop. This synchronization method is evaluated as perspective for the Medium Energy Electron-Ion collider (MEIC) project of JLab with its very high bunch repetition rate.
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TUPTY083	Conceptual MEIC Electron Ring Injection Scheme using CEBAF as a Full Energy Injector	2232
	J. Guo, F. Lin, R.A. Rimmer, H. Wang, S. Wang, Y. Zhang JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 The Medium-energy Electron-Ion Collider (MEIC) proposed by Jefferson Lab is planning to use the newly upgraded 12 GeV CEBAF 1497 MHz SRF CW recirculating linac as a full-energy injector for the electron collider ring. The electron collider ring is proposed to reuse the 476MHz PEP-II RF system to achieve high installed voltage and high beam power. The MEIC electron injection requires 3-10 (or 12) GeV beam in 3-4μs long bunch trains with low duty factor and high peak current, resulting in strong transient beam loading for the CEBAF. In this paper, we propose an injection scheme that can match the two systems’ frequencies with acceptable injection time, and also address the transient beam loading issue in CEBAF. The scheme is compatible with future upgrade to 952.6 MHz SRF system in the electron ring.
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TUPTY084	Update on the MEIC Electron Collider Ring Design	2236
	F. Lin, Y.S. Derbenev, L. Harwood, A. Hutton, V.S. Morozov, F.C. Pilat, Y. Zhang JLab, Newport News, Virginia, USA Y. Cai, Y. Nosochkov, M.K. Sullivan, M.-H. Wang, U. Wienands SLAC, Menlo Park, California, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work also supported by the U.S. DOE Contract No. DE-AC02-76SF00515. The electron collider ring of the Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab is designed to accumulate and store a high-current polarized electron beam for collisions with an ion beam. We consider a design of the electron collider ring based on reusing PEP-II components, such as magnets, power supplies, vacuum system, etc. This has the potential to significantly reduce the cost and engineering effort needed to bring the project to fruition. This paper reports on an electron ring optics design considering the balance of PEP-II hardware parameters (such as dipole sagitta, magnet field strengths and acceptable synchrotron radiation power) and electron beam quality in terms of equilibrium emittances.
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