| Paper |
Title |
Page |
| MOPP003 |
Study of Abnormal Vertical Emittance Growth in ATF Extraction Line
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553 |
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- 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 |
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- 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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