| Paper |
Title |
Page |
| MOPP003 |
Study of Abnormal Vertical Emittance Growth in ATF Extraction Line
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553 |
| |
- M. Alabau, A. Faus-Golfe
IFIC (CSIC-UV), Valencia
- M. Alabau, P. Bambade, J. Brossard, G. Le Meur, C. Rimbault, F. Touze
LAL, Orsay
- D. Angal-Kalinin, J. K. Jones
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
- R. Appleby, A. Scarfe
UMAN, Manchester
- S. Kuroda
KEK, Ibaraki
- G. R. White, M. Woodley
SLAC, Menlo Park, California
- F. Zimmermann
CERN, Geneva
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Since several years, the vertical emittance measured in the Extraction Line (EXT) of the Accelerator Test Facility (ATF) at KEK, that will transport the electron beam from the ATF Damping Ring (DR) to the future ATF2 Final Focus beam line, is significantly larger than the emittance measured in the DR itself, and there are indications that it grows rapidly with increasing beam intensity. This long-standing problem has motivated studies of possible sources of this anomalous emittance growth. One possible contribution is non-linear magnetic fields in the extraction region experienced by the beam while passing off-axis through magnets of the DR during the extraction process. In this paper, simulations of the emittance growth are presented and compared to observations. These simulations include the effects of predicted non-linear field errors in the shared DR magnets and orbit displacements from the reference orbit in the extraction region. Results of recent measurements using closed orbit bumps to probe the relation between the extraction trajectory and the anomalous emittance growth are also presented.
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| MOPP005 |
The 2 mrad Crossing Angle Scheme for the International Linear Collider
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556 |
| |
- R. Appleby
UMAN, Manchester
- D. Angal-Kalinin
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
- P. Bambade, S. Cavalier, G. Le Meur, F. Touze
LAL, Orsay
- Y. Iwashita
Kyoto ICR, Uji, Kyoto
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The present baseline configuration of the ILC has a 14 mrad crossing angle between the beams at the interaction point. This allows easier extraction of the beams after collisions, but imposes on the other hand more constraints on the control of the beams prior to colliding them. Moreover, some limitations to physics capabilities arise, in particular because of the degraded very forward electromagnetic detector hermeticity and because calibration procedures for (gaseous) tracking detectors become more complex. To mitigate these problems, alternative configurations with very small crossing angles are studied. A new version of the 2 mrad layout was designed last year, based on simpler concepts and assumptions. The emphasis of this new scheme was to satisfy specifications with as few and feasible magnets as possible, in order to reduce costs. Recent progress designing several of the magnets involved and the particular vacuum chamber needed in the shared part of the beam line is reported.
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| MOPP030 |
ATF2 Final Focus Orbit Correction and Tuning Optimisation
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613 |
| |
- A. Scarfe, R. Appleby
UMAN, Manchester
- D. Angal-Kalinin, J. K. Jones
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
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ATF2 is an upgrade to the ATF facility at KEK, Japan consisting of a replacement to the current ATF extraction line and the addition of a final focus section. The final focus system has been designed, and is aiming to test, the local chromaticity correction scheme as proposed for future linear colliders. The final focus system focuses the ultra-low emittance beams at the collision point in the linear collider. To provide the required small beam sizes and to maintain the beam sizes to nanometer level requires optimised orbit correction and tuning procedures. In this paper, the optimisation of the orbit correction using a global SVD method is discussed, along with the progress on final focus tuning knob analysis. The tuning algorithms used at ATF2 will provide an important feedback for future linear colliders (including the ILC and CLIC).
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| MOPP031 |
Challenges and Concepts for Design of an Interaction Region with Push-pull Arrangement of Detectors - an Interface Document
|
616 |
| |
- A. Seryi, T. W. Markiewicz, M. Oriunno, M. K. Sullivan
SLAC, Menlo Park, California
- D. Angal-Kalinin
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
- B. Ashmanskas, V. R. Kuchler, N. V. Mokhov
Fermilab, Batavia, Illinois
- K. Buesser
DESY, Hamburg
- P. Burrows
OXFORDphysics, Oxford, Oxon
- A. Enomoto, Y. Sugimoto, T. Tauchi, K. Tsuchiya
KEK, Ibaraki
- A. Herve, J. A. Osborne
CERN, Geneva
- A. A. Mikhailichenko
Cornell University, Department of Physics, Ithaca, New York
- B. Parker
BNL, Upton, Long Island, New York
- T. Sanuki
Tohoku University, School of Scinece, Sendai
- J. Weisend
NSF, Arlington
- H. Y. Yamamoto
Tohoku University, Sendai
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Two experimental detectors working in a push-pull mode has been considered for the Interaction Region of the International Linear Collider [1]. The push-pull mode of operation sets specific requirements and challenges for many systems of detector and machine, in particular for the IR magnets, for the cryogenics system, for alignment system, for beamline shielding, for detector design and overall integration, and so on. These challenges and the identified conceptual solutions discussed in the paper intend to form a draft of the Interface Document which will be developed further in the nearest future. The authors of the present paper include the organizers and conveners of working groups of the workshop on engineering design of interaction region IRENG07 [2], the leaders of the IR Integration within Global Design Effort Beam Delivery System, and the representatives from each detector concept submitting the Letters Of Intent.
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| WEPP167 |
Effect of Collimator Wakefields in the Beam Delivery System of the International Linear Collider
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2880 |
| |
- A. M. Toader, R. J. Barlow
UMAN, Manchester
- D. Angal-Kalinin, F. Jackson
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
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The collimators in the design of the International Linear Collider (ILC) Beam Delivery System (BDS) may be a significant source of wakefields and significantly degrade luminosity. New simulations are used to predict the effect of BDS collimator wakefields, and compared with previous analytical methods. BDS lattices optimised for improved collimation performance are also examined.
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| WEPP168 |
Mechanical Design of Collimators for the ILC
|
2883 |
| |
- B. D. Fell, D. Angal-Kalinin, S. C. Appleton, J.-L. Fernandez-Hernando, F. Jackson, O. B. Malyshev
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
- N. Bliss
STFC/DL, Daresbury, Warrington, Cheshire
- G. Ellwood, R. J.S. Greenhalgh
STFC/RAL, Chilton, Didcot, Oxon
- J. D.A. Smith
Cockcroft Institute, Warrington, Cheshire
- N. K. Watson
Birmingham University, Birmingham
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Much attention has been paid to the optimisation of the geometry and material of collimators in the ILC to mitigate the effects of both short-range transverse wakefields and errant beam impacts. We discuss the competing demands imposed by realistic engineering constraints and present a preliminary engineering design for adjustable jaw spoilers for the ILC.
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