IPAC2015 - List of Keywords (collimation)

Paper	Title	Other Keywords	Page
MOPJE069	General Functionality for Turn-Dependent Element Properties in SixTrack	simulation, cavity, HOM, optics	468
	K.N. Sjobak, H. Burkhardt, R. De Maria, A. Mereghetti, A. Santamaría García CERN, Geneva, Switzerland
	In order to facilitate studies of how dynamically changing element attributes affect the dynamics of the beam and beam losses, the functionality for dynamic kicks (DYNK) of SixTrack has been significantly extended. This functionality can be used for the simulation of dynamic scenarios, such as when crab cavities are switched on, orbit bumps are applied, optics are changed, or failures occur. The functionality has been extended with a more general and flexible implementation, such that arbitrary time-dependent functions can be defined and applied to different attributes of families or individual elements, directly from the user input files. This removes the need for source code manipulation, and it is compatible with LHC@Home which offers substantial computing resources from volunteers. In this paper, the functionality and implementation of DYNK is discussed, along with examples of application to the HL-LHC crab cavities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE069
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMA019	Simulations of the Fermilab Recycler for Losses and Collimation	simulation, space-charge, proton, target	582
	E.G. Stern, R. Ainsworth, J.F. Amundson, B.C. Brown Fermilab, Batavia, Illinois, USA
	Fermilab has recently completed an upgrade to the com- plex with the goal of delivering 700 kW of beam power as 120 GeV protons to the NuMI target. A major part of boost- ing beam power is to shorten the beam cycle by accumulating up to 12 bunches of 0.5 × 10 11 protons in the Recycler ring through slip-stacking during the Main Injector ramp. This introduces much higher intensities into the Recycler than it has had before. Meeting radiation safety requirements with high intensity operations requires understanding the ef- fects of space charge induced tune spreads and resulting halo formation, and aperture restrictions in the real machine to de- velop a collimation strategy. We report on initial simulations of slip-stacking in the Recycler performed with Synergia.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUAC1	Beam Instrumentation and Diagnostics for High Luminosity LHC	synchrotron, radiation, diagnostics, pick-up	1349
	O.R. Jones, E. Bravin, B. Dehning, T. Lefèvre, H. Schmickler CERN, Geneva, Switzerland
	The extensive array of beam instrumentation with which the LHC is equipped, has played a major role in its commissioning, rapid intensity ramp-up and safe and reliable operation. High Luminosity LHC (HL-LHC) brings with it a number of new challenges in terms of instrumentation that will be discussed in this contribution. The beam loss system will need significant upgrades in order to be able to cope with the demands of HL-LHC, with cryogenic beam loss monitors under investigation for deployment in the new inner triplet magnets to distinguish between primary beam losses and collision debris. Radiation tolerant integrated circuits are also being developed to allow the front-end electronics to sit much closer to the detector. Upgrades to other existing systems are also envisaged; including the beam position measurement system in the interaction regions and the addition of a halo measurement capability to synchrotron light diagnostics. Additionally, several new diagnostic systems are under investigation, such as very high bandwidth pick-ups and a streak camera installation, both able to perform intra-bunch measurements of transverse position on a turn by turn basis.
	Slides TUAC1 [4.490 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUAC1
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPWA017	Collimation scheme for the ESRF Upgrade	lattice, radiation, shielding, beam-losses	1434
	R. Versteegen, P. Berkvens, N. Carmignani, L. Farvacque, S.M. Liuzzo, B. Nash, T.P. Perron, P. Raimondi, S.M. White ESRF, Grenoble, France
	The ultra low emittance foreseen for the ESRF Upgrade will translate into a limited Touschek lifetime, increasing substantially the loss rate around the ring compared to the present machine. Consequently it becomes crucial to know the distribution of electron beam losses to optimize the radiation shielding and to protect the insertion devices from radiation damage. Such loss maps of the storage ring can be produced thanks to the simulation of the Touschek scattering process along the lattice. It is shown that about 80 % of the beam losses can be collimated in a few chosen locations only, keeping the resulting lifetime reduction smaller than 10 %.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA017
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY024	Updated Simulation Studies of Damage Limit of LHC Tertiary Collimators	proton, simulation, optics, kicker	2053
	E. Quaranta, A. Bertarelli, R. Bruce, 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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY024
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY025	Betatron Cleaning for Heavy Ion Beams with IR7 Dispersion Suppressor Collimators	ion, proton, heavy-ion, simulation	2057
	P.D. Hermes, R. Bruce, 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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY025
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY027	SixTrack Simulations of Beam Cleaning During High-beta Operation in the LHC	simulation, background, proton, experiment	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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY027
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY028	Collimator Layouts for HL-LHC in the Experimental Insertions	ion, luminosity, proton, heavy-ion	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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY028
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY029	Collimation Cleaning at the LHC with Advanced Secondary Collimator Materials	simulation, scattering, impedance, proton	2068
	E. Quaranta, R. Bruce, 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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY029
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY032	Study of Muon Backgrounds in the CLIC Beam Delivery System	shielding, hadron, background, betatron	2075
	F.B. Pilicer, E. Pilicer, I. Tapan UU, Bursa, Turkey H. Burkhardt, 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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY032
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY046	Impact of Beam Losses in the LHC Collimation Regions	simulation, proton, dipole, coupling	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
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY048	Changes to the Transfer Line Collimation System for the High-Luminosity LHC Beams	optics, injection, luminosity, brightness	2124
	V. Kain, O. Aberle, C. Bracco, M.A. Fraser, F. Galleazzi, A. Kosmicki, F.L. Maciariello, M. Meddahi, F.-X. Nuiry, G.E. Steele, 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
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY052	New Method for Validation of Aperture Margins in the LHC Triplet	optics, kicker, vacuum, dumping	2140
	V. Chetvertkova, R. Schmidt, F.M. Velotti, D. Wollmann CERN, Geneva, Switzerland F.M. Velotti 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
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY052
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY066	Beam Cleaning in Experimental IRs in HL-LHC for Incoming Beam	optics, betatron, quadrupole, background	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
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY067	Beam Induced Background Simulation Studies at IR1 with New High Luminosity LHC Layout	optics, background, simulation, luminosity	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
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTY069	Simulation of Hollow Electron Lenses as LHC Beam Halo Reducers using Merlin	electron, proton, betatron, simulation	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
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEBB1	Plans for Deployment of Hollow Electron Lenses at the LHC for Enhanced Beam Collimation	electron, solenoid, operation, gun	2462
	S. Redaelli, A. Bertarelli, R. Bruce, D. Perini, A. Rossi, B. Salvachua CERN, Geneva, Switzerland G. Stancari, A. Valishev Fermilab, Batavia, Illinois, USA
	Hollow electron lenses are considered as a possible mean to improve the LHC beam collimation system, providing an active control of halo diffusion rates and suppressing the population of transverse halos. After a very successful experience at the Tevatron, a conceptual design of a hollow e-lens optimized for the LHC was produced. Recent further studies have led to a mature preliminary technical design. In this paper, possible scenarios for the deployment of this technology at the LHC are elaborated in the context of the scheduled LHC long shutdowns until the full implementation of the HL-LHC upgrade in 2023. Possible setups of electron beam test stands at CERN and synergies with other relevant electron beam programmes outside CERN are also discussed.
	Slides WEBB1 [3.216 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEBB1
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMN003	The Magnetic Measurement for Low Magnetic Field Stability of Dipole Magnet for CEPC	positron, dipole, collider, electron	2917
	Z. Zhang, F.S. Chen, H. Geng, B. Yin IHEP, Beijing, People's Republic of China
	The CEPC (China Electron-Positron Collider) project is in the pre-research stage. When the beam energy of booster is 120 GeV, the magnetic field of deflection magnet is 640 G. In order to save funds for scientific research, we are ready to select the injection energy for 6 GeV, this corresponds to a magnetic field about 32 G. In such a low magnetic field, the effects of earth's magnetic field and ambient temperature variations cannot be ignored. In this paper, first written the collection procedures for magnetic field value and ambient temperature values by Labview software, then used a one-dimensional probe to measure the background magnetic field for three directions (Bx, By, Bz) and the value of the ambient temperature values, the time of data collection for each direction are more than 24 hours (every minute collecting a set of values). Finally, plus the different currents (3A, 6A.. 15A) to the dipole magnet, the time of measured and the data collected by over 24 hours. Based on the results of the analysis of large amounts of data, summarized and analyzed the effect of Earth's magnetic field and ambient temperature for dipole magnet in a low magnetic field.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN003
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPMN059	Design Study and Construction of a Transverse Beam Halo Collimation System for ATF2	wakefield, simulation, dipole, background	3062
	N. Fuster-Martínez, A. Faus-Golfe IFIC, Valencia, Spain P. Bambade, S. Liu, S. Wallon LAL, Orsay, France K. Kubo, T. Okugi, T. Tauchi, N. Terunuma KEK, Ibaraki, Japan I. Podadera, F. Toral CIEMAT, Madrid, Spain
	Funding: Work supported by IDC-20121074, FPA2013-47883-C2-1-P and ANR-11-IDEX-0003-02 The feasibility and efficiency of a transverse beam halo collimation system for reducing the background in the ATF2 beamline has been studied in simulations. In this paper the design and construction of a retractable transverse beam halo collimator device is presented. The wakefield induced-impact of a realistic mechanical prototype has been studied with CST PS, as well as the wakefield beam dynamics impact by using the tracking code PLACET.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN059
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPTY040	Quench Performance of the First Twin-aperture 11 T Dipole for LHC upgrades	dipole, magnet-design, status, detector	3361
	A.V. Zlobin, N. Andreev, G. Apollinari, E.Z. Barzi, G. Chlachidze, A. Nobrega, I. Novitski, S. Stoynev, D. Turrioni Fermilab, Batavia, Illinois, USA B. Auchmann, S. Izquierdo Bermudez, M. Karppinen, L. Rossi, F. Savary, D. Smekens CERN, Geneva, Switzerland
	Funding: *Work is supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy and European Commission under FP7 project HiLumi LHC, GA no.284404 The LHC luminosity upgrade plan foresees installation of additional collimators in Dispersion Suppressor areas around point 7 and interaction regions 1, 2 and 5. The required space for these collimators could be provided by replacing some 15-m long 8.33 T NbTi LHC main dipoles (MB) with shorter 11 T Nb3Sn dipoles (MBH) compatible with the LHC lattice and main systems. FNAL and CERN magnet groups are developing a 5.5-m long twin-aperture dipole prototype with the nominal field of 11 T at the LHC nominal current of 11.85 kA suitable for installation in the LHC. Two of these magnets with a collimator in between will replace one MB dipole. The single-aperture 2-m long dipole demonstrator and two 1-m long dipole models have been assembled and tested at FNAL in 2012-2014. The 1 m long collared coils were then assembled into the first twin-aperture Nb3Sn demonstrator dipole and tested. This paper reports test results of the first twin-aperture Nb3Sn dipole model focusing on magnet training, ramp rate sensitivity and temperature dependence of the magnet quench current. The twin-aperture dipole quench performance is compared with the data for the single-aperture models.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY040
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPWI042	A Table-Top Alpha-Magnet	operation, vacuum, power-supply, experiment	3584
	A.V. Smirnov, R.B. Agustsson, T.J. Campese, Y.C. Chen, J.J. Hartzell, F.H. O'Shea, E. Spranza RadiaBeam, Santa Monica, California, USA
	Funding: Department of Energy, contract# DE- SC-FOA-0000760 A compact electromagnetic alpha-magnet design, engineering, and operation are presented. Initially the magnet has been designed for a low-energy, laser-free, coherent Cherenkov THz-sub-THz source. The source is designed and engineered in RadiaBeam in collaboration with ANL and integrated into the Injector Test Stand (ITS) of the Advanced Photon Source. The magnet having 15 cm depth, 14” height, and up to 4 T/m gradient features a rectangular yoke, two on-axis coils, and substantially truncated, partially non-hyperbolic poles. The tapered vacuum chamber for the magnet includes a motorized scraper and means of optical control. The novel and inexpensive design can be applied in relatively small, a few MeV facilities, where weight and dimensions are limited including free electron lasers, far infrared sources, inverse Compton sources of ultra-bright hard X-rays, as well as beam instrumentation for microbunching and phase-space manipulation (e.g., magnetic compression combined with round-to-flat beam transformation).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI042
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPF024	LEBT Dynamics and RFQ Injection	solenoid, rfq, ion, injection	3739
	P.P. Schneider, M. Droba, O. Meusel, H. Niebuhr, D. Noll, O. Payir, H. Podlech, A. Schempp, C. Wiesner IAP, Frankfurt am Main, Germany
	The Low Energy Beam Transport (LEBT) section at the accelerator-driven neutron source FRANZ* consists of four solenoids, two of which match the primary proton beam into the chopper. The remaining two solenoids are intended to prepare the beam for injection into the RFQ. In the first commissioning phase, the LEBT successfully transported a 14 keV He beam at low intensities*. In the current commissioning phase, the beam energy is increased to the RFQ injection energy of 120 keV. In the upcoming step, the intensity will be increased from 2 mA to 50 mA. Beam dynamics calculations include effects of different source emittances, position and angle offsets and the effects of space charge compensation levels. In addition, the behavior of the undesired hydrogen fractions, H²⁺ and H³⁺, and their influence on the performance within the RFQ is simulated. Meusel, O., et al. "FRANZ–Accelerator Test Bench And Neutron Source", MO3A03, LINAC 2012. ** Wiesner, C., et al. "Chopping High-Intensity Ion Beams at FRANZ", WEIOB01, LINAC 2014.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF024
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPF095	Limits on Failure Scenarios for Crab Cavities in the HL-LHC	simulation, luminosity, optics, beam-losses	3923
	A. Santamaría García, H. Burkhardt, A. Macpherson, K.N. Sjobak, D. Wollmann, B. Yee-Rendón CERN, Geneva, Switzerland K. Hernandez-Chahin DCI-UG, León, Mexico B. Yee-Rendón CINVESTAV, Mexico City, Mexico
	The High Luminosity (HL) LHC upgrade aims for a tenfold increase in integrated luminosity compared to the nominal LHC, and for operation at a levelled luminosity of 5 10³⁴ cm^-2.s^-1, which is five times higher than the nominal LHC peak luminosity. Crab Cavities (CCs) are planned to compensate the geometric luminosity loss created by the increased crossing angle by rotating the bunch, allowing quasi head-on collisions at the Interaction Points (IP). The CCs work by creating transverse kicks, and their failure may have short time constants comparable to the reaction time of the Machine Protection System (MPS), producing significant coherent betatron oscillations and fast emittance growth. Simulations of CC failure modes have been carried out with the tracking code SIXTRACK, using the newly added functionality called DYNK, which allows to dynamically change the attributes of the CCs. We describe these simulations and discuss early, preliminary results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF095
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPF098	SPS-to-LHC Transfer Lines Loss Map Generation Using PyCollimate	scattering, simulation, proton, injection	3934
	F.M. Velotti EPFL, Lausanne, Switzerland W. Bartmann, C. Bracco, M.A. Fraser, B. Goddard, V. Kain, M. Meddahi, F.M. Velotti CERN, Geneva, Switzerland
	The Transfer Lines (TL) linking the Super Proton Synchrotron (SPS) to the Large Hadron Collider (LHC) are both equipped with a complete collimation system to protect the LHC against mis-steered beams. During the setting up of these collimators, their gaps are positioned to nominal values and the phase-space coverage of the whole system is checked using a manual validation procedure. In order to perform this setting-up more efficiently and more reliably, the simulated loss maps of the TLs will be used to validate the collimator positions and settings. In this paper, the simulation procedure for the generation of TL loss maps is described, and a detailed overview of the new scattering routine (pycollimate) is given. Finally, the results of simulations benchmark with another scattering routine are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF098
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOPJE069

General Functionality for Turn-Dependent Element Properties in SixTrack

simulation, cavity, HOM, optics

468

K.N. Sjobak, H. Burkhardt, R. De Maria, A. Mereghetti, A. Santamaría García
CERN, Geneva, Switzerland

In order to facilitate studies of how dynamically changing element attributes affect the dynamics of the beam and beam losses, the functionality for dynamic kicks (DYNK) of SixTrack has been significantly extended. This functionality can be used for the simulation of dynamic scenarios, such as when crab cavities are switched on, orbit bumps are applied, optics are changed, or failures occur. The functionality has been extended with a more general and flexible implementation, such that arbitrary time-dependent functions can be defined and applied to different attributes of families or individual elements, directly from the user input files. This removes the need for source code manipulation, and it is compatible with LHC@Home which offers substantial computing resources from volunteers. In this paper, the functionality and implementation of DYNK is discussed, along with examples of application to the HL-LHC crab cavities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE069

Export •

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

MOPMA019

Simulations of the Fermilab Recycler for Losses and Collimation

simulation, space-charge, proton, target

582

E.G. Stern, R. Ainsworth, J.F. Amundson, B.C. Brown
Fermilab, Batavia, Illinois, USA

Fermilab has recently completed an upgrade to the com- plex with the goal of delivering 700 kW of beam power as 120 GeV protons to the NuMI target. A major part of boost- ing beam power is to shorten the beam cycle by accumulating up to 12 bunches of 0.5 × 10 11 protons in the Recycler ring through slip-stacking during the Main Injector ramp. This introduces much higher intensities into the Recycler than it has had before. Meeting radiation safety requirements with high intensity operations requires understanding the ef- fects of space charge induced tune spreads and resulting halo formation, and aperture restrictions in the real machine to de- velop a collimation strategy. We report on initial simulations of slip-stacking in the Recycler performed with Synergia.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA019

Export •

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

TUAC1

Beam Instrumentation and Diagnostics for High Luminosity LHC

synchrotron, radiation, diagnostics, pick-up

1349

O.R. Jones, E. Bravin, B. Dehning, T. Lefèvre, H. Schmickler
CERN, Geneva, Switzerland

The extensive array of beam instrumentation with which the LHC is equipped, has played a major role in its commissioning, rapid intensity ramp-up and safe and reliable operation. High Luminosity LHC (HL-LHC) brings with it a number of new challenges in terms of instrumentation that will be discussed in this contribution. The beam loss system will need significant upgrades in order to be able to cope with the demands of HL-LHC, with cryogenic beam loss monitors under investigation for deployment in the new inner triplet magnets to distinguish between primary beam losses and collision debris. Radiation tolerant integrated circuits are also being developed to allow the front-end electronics to sit much closer to the detector. Upgrades to other existing systems are also envisaged; including the beam position measurement system in the interaction regions and the addition of a halo measurement capability to synchrotron light diagnostics. Additionally, several new diagnostic systems are under investigation, such as very high bandwidth pick-ups and a streak camera installation, both able to perform intra-bunch measurements of transverse position on a turn by turn basis.

Slides TUAC1 [4.490 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUAC1

Export •

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

TUPWA017

Collimation scheme for the ESRF Upgrade

lattice, radiation, shielding, beam-losses

1434

R. Versteegen, P. Berkvens, N. Carmignani, L. Farvacque, S.M. Liuzzo, B. Nash, T.P. Perron, P. Raimondi, S.M. White
ESRF, Grenoble, France

The ultra low emittance foreseen for the ESRF Upgrade will translate into a limited Touschek lifetime, increasing substantially the loss rate around the ring compared to the present machine. Consequently it becomes crucial to know the distribution of electron beam losses to optimize the radiation shielding and to protect the insertion devices from radiation damage. Such loss maps of the storage ring can be produced thanks to the simulation of the Touschek scattering process along the lattice. It is shown that about 80 % of the beam losses can be collimated in a few chosen locations only, keeping the resulting lifetime reduction smaller than 10 %.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA017

Export •

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

TUPTY024

Updated Simulation Studies of Damage Limit of LHC Tertiary Collimators

proton, simulation, optics, kicker

2053

E. Quaranta, A. Bertarelli, R. Bruce, 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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY024

Export •

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

TUPTY025

Betatron Cleaning for Heavy Ion Beams with IR7 Dispersion Suppressor Collimators

ion, proton, heavy-ion, simulation

2057

P.D. Hermes, R. Bruce, 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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY025

Export •

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

TUPTY027

SixTrack Simulations of Beam Cleaning During High-beta Operation in the LHC

simulation, background, proton, experiment

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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY027

Export •

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

TUPTY028

Collimator Layouts for HL-LHC in the Experimental Insertions

ion, luminosity, proton, heavy-ion

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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY028

Export •

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

TUPTY029

Collimation Cleaning at the LHC with Advanced Secondary Collimator Materials

simulation, scattering, impedance, proton

2068

E. Quaranta, R. Bruce, 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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY029

Export •

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

TUPTY032

Study of Muon Backgrounds in the CLIC Beam Delivery System

shielding, hadron, background, betatron

2075

F.B. Pilicer, E. Pilicer, I. Tapan
UU, Bursa, Turkey
H. Burkhardt, 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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY032

Export •

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

TUPTY046

Impact of Beam Losses in the LHC Collimation Regions

simulation, proton, dipole, coupling

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

Export •

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

TUPTY048

Changes to the Transfer Line Collimation System for the High-Luminosity LHC Beams

optics, injection, luminosity, brightness

2124

V. Kain, O. Aberle, C. Bracco, M.A. Fraser, F. Galleazzi, A. Kosmicki, F.L. Maciariello, M. Meddahi, F.-X. Nuiry, G.E. Steele, 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

Export •

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

TUPTY052

New Method for Validation of Aperture Margins in the LHC Triplet

optics, kicker, vacuum, dumping

2140

V. Chetvertkova, R. Schmidt, F.M. Velotti, D. Wollmann
CERN, Geneva, Switzerland
F.M. Velotti
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

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY052

Export •

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

TUPTY066

Beam Cleaning in Experimental IRs in HL-LHC for Incoming Beam

optics, betatron, quadrupole, background

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

Export •

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

TUPTY067

Beam Induced Background Simulation Studies at IR1 with New High Luminosity LHC Layout

optics, background, simulation, luminosity

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

Export •

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

TUPTY069

Simulation of Hollow Electron Lenses as LHC Beam Halo Reducers using Merlin

electron, proton, betatron, simulation

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

Export •

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

WEBB1

Plans for Deployment of Hollow Electron Lenses at the LHC for Enhanced Beam Collimation

electron, solenoid, operation, gun

2462

S. Redaelli, A. Bertarelli, R. Bruce, D. Perini, A. Rossi, B. Salvachua
CERN, Geneva, Switzerland
G. Stancari, A. Valishev
Fermilab, Batavia, Illinois, USA

Hollow electron lenses are considered as a possible mean to improve the LHC beam collimation system, providing an active control of halo diffusion rates and suppressing the population of transverse halos. After a very successful experience at the Tevatron, a conceptual design of a hollow e-lens optimized for the LHC was produced. Recent further studies have led to a mature preliminary technical design. In this paper, possible scenarios for the deployment of this technology at the LHC are elaborated in the context of the scheduled LHC long shutdowns until the full implementation of the HL-LHC upgrade in 2023. Possible setups of electron beam test stands at CERN and synergies with other relevant electron beam programmes outside CERN are also discussed.

Slides WEBB1 [3.216 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEBB1

Export •

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

WEPMN003

The Magnetic Measurement for Low Magnetic Field Stability of Dipole Magnet for CEPC

positron, dipole, collider, electron

2917

Z. Zhang, F.S. Chen, H. Geng, B. Yin
IHEP, Beijing, People's Republic of China

The CEPC (China Electron-Positron Collider) project is in the pre-research stage. When the beam energy of booster is 120 GeV, the magnetic field of deflection magnet is 640 G. In order to save funds for scientific research, we are ready to select the injection energy for 6 GeV, this corresponds to a magnetic field about 32 G. In such a low magnetic field, the effects of earth's magnetic field and ambient temperature variations cannot be ignored. In this paper, first written the collection procedures for magnetic field value and ambient temperature values by Labview software, then used a one-dimensional probe to measure the background magnetic field for three directions (Bx, By, Bz) and the value of the ambient temperature values, the time of data collection for each direction are more than 24 hours (every minute collecting a set of values). Finally, plus the different currents (3A, 6A.. 15A) to the dipole magnet, the time of measured and the data collected by over 24 hours. Based on the results of the analysis of large amounts of data, summarized and analyzed the effect of Earth's magnetic field and ambient temperature for dipole magnet in a low magnetic field.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN003

Export •

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

WEPMN059

Design Study and Construction of a Transverse Beam Halo Collimation System for ATF2

wakefield, simulation, dipole, background

3062

N. Fuster-Martínez, A. Faus-Golfe
IFIC, Valencia, Spain
P. Bambade, S. Liu, S. Wallon
LAL, Orsay, France
K. Kubo, T. Okugi, T. Tauchi, N. Terunuma
KEK, Ibaraki, Japan
I. Podadera, F. Toral
CIEMAT, Madrid, Spain

Funding: Work supported by IDC-20121074, FPA2013-47883-C2-1-P and ANR-11-IDEX-0003-02
The feasibility and efficiency of a transverse beam halo collimation system for reducing the background in the ATF2 beamline has been studied in simulations. In this paper the design and construction of a retractable transverse beam halo collimator device is presented. The wakefield induced-impact of a realistic mechanical prototype has been studied with CST PS, as well as the wakefield beam dynamics impact by using the tracking code PLACET.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN059

Export •

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

WEPTY040

Quench Performance of the First Twin-aperture 11 T Dipole for LHC upgrades

dipole, magnet-design, status, detector

3361

A.V. Zlobin, N. Andreev, G. Apollinari, E.Z. Barzi, G. Chlachidze, A. Nobrega, I. Novitski, S. Stoynev, D. Turrioni
Fermilab, Batavia, Illinois, USA
B. Auchmann, S. Izquierdo Bermudez, M. Karppinen, L. Rossi, F. Savary, D. Smekens
CERN, Geneva, Switzerland

Funding: *Work is supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy and European Commission under FP7 project HiLumi LHC, GA no.284404
The LHC luminosity upgrade plan foresees installation of additional collimators in Dispersion Suppressor areas around point 7 and interaction regions 1, 2 and 5. The required space for these collimators could be provided by replacing some 15-m long 8.33 T NbTi LHC main dipoles (MB) with shorter 11 T Nb3Sn dipoles (MBH) compatible with the LHC lattice and main systems. FNAL and CERN magnet groups are developing a 5.5-m long twin-aperture dipole prototype with the nominal field of 11 T at the LHC nominal current of 11.85 kA suitable for installation in the LHC. Two of these magnets with a collimator in between will replace one MB dipole. The single-aperture 2-m long dipole demonstrator and two 1-m long dipole models have been assembled and tested at FNAL in 2012-2014. The 1 m long collared coils were then assembled into the first twin-aperture Nb3Sn demonstrator dipole and tested. This paper reports test results of the first twin-aperture Nb3Sn dipole model focusing on magnet training, ramp rate sensitivity and temperature dependence of the magnet quench current. The twin-aperture dipole quench performance is compared with the data for the single-aperture models.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY040

Export •

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

WEPWI042

A Table-Top Alpha-Magnet

operation, vacuum, power-supply, experiment

3584

A.V. Smirnov, R.B. Agustsson, T.J. Campese, Y.C. Chen, J.J. Hartzell, F.H. O'Shea, E. Spranza
RadiaBeam, Santa Monica, California, USA

Funding: Department of Energy, contract# DE- SC-FOA-0000760
A compact electromagnetic alpha-magnet design, engineering, and operation are presented. Initially the magnet has been designed for a low-energy, laser-free, coherent Cherenkov THz-sub-THz source. The source is designed and engineered in RadiaBeam in collaboration with ANL and integrated into the Injector Test Stand (ITS) of the Advanced Photon Source. The magnet having 15 cm depth, 14” height, and up to 4 T/m gradient features a rectangular yoke, two on-axis coils, and substantially truncated, partially non-hyperbolic poles. The tapered vacuum chamber for the magnet includes a motorized scraper and means of optical control. The novel and inexpensive design can be applied in relatively small, a few MeV facilities, where weight and dimensions are limited including free electron lasers, far infrared sources, inverse Compton sources of ultra-bright hard X-rays, as well as beam instrumentation for microbunching and phase-space manipulation (e.g., magnetic compression combined with round-to-flat beam transformation).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI042

Export •

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

THPF024

LEBT Dynamics and RFQ Injection

solenoid, rfq, ion, injection

3739

P.P. Schneider, M. Droba, O. Meusel, H. Niebuhr, D. Noll, O. Payir, H. Podlech, A. Schempp, C. Wiesner
IAP, Frankfurt am Main, Germany

The Low Energy Beam Transport (LEBT) section at the accelerator-driven neutron source FRANZ* consists of four solenoids, two of which match the primary proton beam into the chopper. The remaining two solenoids are intended to prepare the beam for injection into the RFQ. In the first commissioning phase, the LEBT successfully transported a 14 keV He beam at low intensities**. In the current commissioning phase, the beam energy is increased to the RFQ injection energy of 120 keV. In the upcoming step, the intensity will be increased from 2 mA to 50 mA. Beam dynamics calculations include effects of different source emittances, position and angle offsets and the effects of space charge compensation levels. In addition, the behavior of the undesired hydrogen fractions, H²⁺ and H³⁺, and their influence on the performance within the RFQ is simulated.
* Meusel, O., et al. "FRANZ–Accelerator Test Bench And Neutron Source", MO3A03, LINAC 2012.
** Wiesner, C., et al. "Chopping High-Intensity Ion Beams at FRANZ", WEIOB01, LINAC 2014.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF024

Export •

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

THPF095

Limits on Failure Scenarios for Crab Cavities in the HL-LHC

simulation, luminosity, optics, beam-losses

3923

A. Santamaría García, H. Burkhardt, A. Macpherson, K.N. Sjobak, D. Wollmann, B. Yee-Rendón
CERN, Geneva, Switzerland
K. Hernandez-Chahin
DCI-UG, León, Mexico
B. Yee-Rendón
CINVESTAV, Mexico City, Mexico

The High Luminosity (HL) LHC upgrade aims for a tenfold increase in integrated luminosity compared to the nominal LHC, and for operation at a levelled luminosity of 5 10³⁴ cm^-2.s^-1, which is five times higher than the nominal LHC peak luminosity. Crab Cavities (CCs) are planned to compensate the geometric luminosity loss created by the increased crossing angle by rotating the bunch, allowing quasi head-on collisions at the Interaction Points (IP). The CCs work by creating transverse kicks, and their failure may have short time constants comparable to the reaction time of the Machine Protection System (MPS), producing significant coherent betatron oscillations and fast emittance growth. Simulations of CC failure modes have been carried out with the tracking code SIXTRACK, using the newly added functionality called DYNK, which allows to dynamically change the attributes of the CCs. We describe these simulations and discuss early, preliminary results.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF095

Export •

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

THPF098

SPS-to-LHC Transfer Lines Loss Map Generation Using PyCollimate

scattering, simulation, proton, injection

3934

F.M. Velotti
EPFL, Lausanne, Switzerland
W. Bartmann, C. Bracco, M.A. Fraser, B. Goddard, V. Kain, M. Meddahi, F.M. Velotti
CERN, Geneva, Switzerland

The Transfer Lines (TL) linking the Super Proton Synchrotron (SPS) to the Large Hadron Collider (LHC) are both equipped with a complete collimation system to protect the LHC against mis-steered beams. During the setting up of these collimators, their gaps are positioned to nominal values and the phase-space coverage of the whole system is checked using a manual validation procedure. In order to perform this setting-up more efficiently and more reliably, the simulated loss maps of the TLs will be used to validate the collimator positions and settings. In this paper, the simulation procedure for the generation of TL loss maps is described, and a detailed overview of the new scattering routine (pycollimate) is given. Finally, the results of simulations benchmark with another scattering routine are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF098

Export •

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