| Paper |
Title |
Page |
| THPMN005 |
Technical Challenges for Head-On Collisions and Extraction at the ILC
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2716 |
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- O. Napoly, O. Delferriere, M. Durante, J. Payet, C. Rippon, D. Uriot
CEA, Gif-sur-Yvette
- M. Alabau, P. Bambade, J. Brossard, O. Dadoun, C. Rimbault
LAL, Orsay
- D. A.-K. Angal-Kalinin, F. Jackson, S. I. Tzenov
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
- R. Appleby
UMAN, Manchester
- B. Balhan, J. Borburgh, B. Goddard
CERN, Geneva
- Y. Iwashita
Kyoto ICR, Uji, Kyoto
- L. Keller
SLAC, Menlo Park, California
- S. Kuroda
KEK, Ibaraki
- G. L. Sabbi
LBNL, Berkeley, California
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Funding: EUROTeV Project Contract no.011899 RIDS
An interaction region with head-on collisions is considered as an alternative to the baseline ILC configuration. Progress in the final focus optics design includes engineered large bore superconducting final doublet magnets and their 3D magnetic integration in the detector solenoids. Progress on the beam separation optics is based on technical designs of electrostatic separator and special extraction quadripoles. The spent beam extraction is realized by a staged collimation scheme relying on realistic collimators. The impact on the detector background is estimated. The possibility of technical tests of the most challenging components is investigated.
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| THPMN008 |
Evaluation of Luminosity Reduction in the ILC Head-on Scheme from Parasitic Collisions
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2722 |
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- J. Brossard, P. Bambade, T. Derrien
LAL, Orsay
- M. Alabau
IFIC, Valencia
- D. A.-K. Angal-Kalinin
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
- O. Napoly, J. Payet
CEA, Gif-sur-Yvette
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An interaction region with head-on collisions is being developed for the ILC as an alternative to the base line 14 mrad crossing angle design, motivated by simpler beam manipulations upstream of the interaction point and a more favourable configuration for the detector and physics analysis. The design of the post-collision beam line in this scheme involves however a number of technological challenges, one of which is the strength requirement for the electrostatic separators placed immediately after the final doublet to extract the spent beam. In this paper, we examine in detail the main mechanism behind this requirement, the multi-beam kink instability, which results from the long-range beam-beam forces at the parasitic crossings after the bunches have been extracted. Our analysis uses realistic bunch distributions, the Guinea-Pig program to treat beam-beam effects at the interaction point and the DIMAD program to track the disrupted beam distributions in the post-collision beam line. A version of the beam-beam deflection based interaction point feedback system with an improved filtering algorithm is also studied to mitigate the luminosity deterioration from the instability.
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| THPMN009 |
Backscattering of Secondary Particles into the ILC Detectors from Beam Losses Along the Extraction Lines
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2725 |
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- O. Dadoun, P. Bambade
LAL, Orsay
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At the International Linear Collider (ILC) the beams will be focused to extremely small spot sizes in order to achieve the desired luminosity. After the collision the beams must be brought to the dump with minimal losses. In spite of all the attention put into the design of the extraction line, the loss of some disrupted beam particles, beamstrahlung or synchrotron radiation photons is unavoidable. These losses will generate low-energy secondary particles, such as photons, electrons and neutron, a fraction of which can be back-scattered towards the interaction point and generate backgrounds into the detector. In this paper we present an evaluation of such backgrounds, using the BDSIM and Mokka simulations, for several presently considered ILC extraction lines and detectors.
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| THPMN010 |
GUINEA-PIG++ : An Upgraded Version of the Linear Collider Beam-Beam Interaction Simulation Code GUINEA-PIG
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2728 |
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- C. Rimbault, P. Bambade, O. Dadoun, G. Le Meur, F. Touze
LAL, Orsay
- M. Alabau
IFIC, Valencia
- D. Schulte
CERN, Geneva
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GUINEA-PIG++ is a newly developed object-oriented version of the Linear Collider beam-beam simulation program GUINEA-PIG. The main goals of this project are to provide a reliable, modular, documented and versatile framework enabling convenient implementation of new features and functionalities. Examples of improvements described in this paper are an easy interface to study the impact of electromagnetic effects on Bhabha event selections, a treatment of spin depolarization effects, automatic consistency checks and adjustments of internal computational parameters, upgraded input/output and user interface, an optimised setup for massive production on distributed computing GRIDs. A possible setup to perform fast parallelised computations is also discussed.
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| THPMN056 |
Comparison of ILC Fast Beam-Beam Feedback Performance in the e-e- and e+e- Modes of Operation
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2832 |
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- M. Alabau, A. Faus-Golfe
IFIC, Valencia
- P. Bambade
LAL, Orsay
- A. Latina, D. Schulte
CERN, Geneva
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Several feedback loops are required in the Beam Delivery System (BDS) of the International Linear Collider (ILC) to preserve the luminosity in the presence of dynamic imperfections. Realistic simulations have been carried out to study the performance of the beam-beam deflection based fast feedback system, for both e+e- and e-e- modes of operation. The beam-beam effects in the e-e- collisions make both the luminosity and the deflections more sensitive to offsets at the IP than in the case of the e+e- collisions. This reduces the performance of the feedback system in comparison to the standard e+e- collisions, and may require a different beam parameter optimization.
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| THPMN077 |
Improved 2mrad crossing angle layout for the International Linear Collider
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2883 |
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- R. Appleby, D. Toprek
UMAN, Manchester
- D. A.-K. Angal-Kalinin
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
- P. Bambade, S. Cavalier, O. Dadoun
LAL, Orsay
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The 2mrad interaction region and extraction line provide several machine and physics advantages, but also involves a number of technological challenges. In this paper a minimal extraction line without beam energy and polarization diagnostics is presented, which considerably simplifies the design and reduces costs. The optimization of the interaction region sextupoles, using current and proposed technologies, and an estimation of photon backscattering from spent beam particle losses are described. Overall performance is evaluated and compared with previous designs. The upgrade to 1 TeV and the possibility of including diagnostics are considered.
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| WEOCAB01 |
Design of the Beam Delivery System for the International Linear Collider
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1985 |
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- A. Seryi, J. A. Amann, R. Arnold, F. Asiri, K. L.F. Bane, P. Bellomo, E. Doyle, A. F. Fasso, L. Keller, J. Kim, K. Ko, Z. Li, T. W. Markiewicz, T. V.M. Maruyama, K. C. Moffeit, S. Molloy, Y. Nosochkov, N. Phinney, T. O. Raubenheimer, S. Seletskiy, S. Smith, C. M. Spencer, P. Tenenbaum, D. R. Walz, G. R. White, M. Woodley, M. Woods, L. Xiao
SLAC, Menlo Park, California
- I. V. Agapov, G. A. Blair, S. T. Boogert, J. Carter
Royal Holloway, University of London, Surrey
- M. Alabau, P. Bambade, J. Brossard, O. Dadoun
LAL, Orsay
- M. Anerella, A. K. Jain, A. Marone, B. Parker
BNL, Upton, Long Island, New York
- D. A.-K. Angal-Kalinin, C. D. Beard, J.-L. Fernandez-Hernando, P. Goudket, F. Jackson, J. K. Jones, A. Kalinin, P. A. McIntosh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
- R. Appleby
UMAN, Manchester
- J. L. Baldy, D. Schulte
CERN, Geneva
- L. Bellantoni, A. I. Drozhdin, V. S. Kashikhin, V. Kuchler, T. Lackowski, N. V. Mokhov, N. Nakao, T. Peterson, M. C. Ross, S. I. Striganov, J. C. Tompkins, M. Wendt, X. Yang
Fermilab, Batavia, Illinois
- K. Buesser
DESY, Hamburg
- P. Burrows, G. B. Christian, C. I. Clarke, A. F. Hartin
OXFORDphysics, Oxford, Oxon
- G. Burt, A. C. Dexter
Cockcroft Institute, Warrington, Cheshire
- J. Carwardine, C. W. Saunders
ANL, Argonne, Illinois
- B. Constance, H. Dabiri Khah, C. Perry, C. Swinson
JAI, Oxford
- O. Delferriere, O. Napoly, J. Payet, D. Uriot
CEA, Gif-sur-Yvette
- C. J. Densham, R. J.S. Greenhalgh
STFC/RAL, Chilton, Didcot, Oxon
- A. Enomoto, S. Kuroda, T. Okugi, T. Sanami, Y. Suetsugu, T. Tauchi
KEK, Ibaraki
- A. Ferrari
UU/ISV, Uppsala
- J. Gronberg
LLNL, Livermore, California
- Y. Iwashita
Kyoto ICR, Uji, Kyoto
- W. Lohmann
DESY Zeuthen, Zeuthen
- L. Ma
STFC/DL, Daresbury, Warrington, Cheshire
- T. M. Mattison
UBC, Vancouver, B. C.
- T. S. Sanuki
University of Tokyo, Tokyo
- V. I. Telnov
BINP SB RAS, Novosibirsk
- E. T. Torrence
University of Oregon, Eugene, Oregon
- D. Warner
Colorado University at Boulder, Boulder, Colorado
- N. K. Watson
Birmingham University, Birmingham
- H. Y. Yamamoto
Tohoku University, Sendai
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The beam delivery system for the linear collider focuses beams to nanometer sizes at the interaction point, collimates the beam halo to provide acceptable background in the detector and has a provision for state-of-the art beam instrumentation in order to reach the physics goals. The beam delivery system of the International Linear Collider has undergone several configuration changes recently. This paper describes the design details and status of the baseline configuration considered for the reference design.
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Slides
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| FRPMN012 |
Bias on Absolute Luminosity Measurements at the ILC from Beam-Beam Space Charge Effects
|
3907 |
| |
- C. Rimbault, P. Bambade
LAL, Orsay
- K. Moenig
DESY Zeuthen, Zeuthen
- D. Schulte
CERN, Geneva
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A way to determine luminosity at the International Linear Collider (ILC) is to measure the Bhabha event rate in a finely segmented calorimeter (LumiCal) at very low polar angles in the very forward region of the detector. An absolute precision between 10-4 and 10-3 is needed for a number of key physics measurements. Besides theoretical uncertainties on the Bhabha cross section and experimental errors when identifying Bhabha events in the LumiCal, the very strong beam-beam space charge effects which characterise the ILC e+e- collisions lead to a major bias in the counting rate, which drastically limits the luminosity measurement if uncorrected. In this paper, Bhabha event samples produced with the BHLUMI generator are used in the context of the GUINEA-PIG beam-beam simulation to study how beamstrahlung radiation and electromagnetic deflections affect the proposed experimental selections. A corrective method based on determining the luminosity spectrum within the LumiCal is suggested to minimise the resulting errors. The expected residual uncertainty after correction is estimated based on simulations with realistic beam conditions.
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