| Paper |
Title |
Page |
| MOPLS052 |
Luminosity Improvement at PEP-II Based on Optics Model and Beam-beam Simulation
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661 |
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- Y. Cai, W.S. Colocho, F.-J. Decker, Y. Nosochkov, P. Raimondi, J. Seeman, K.G. Sonnad, M.K. Sullivan, J.L. Turner, M. Weaver, U. Wienands, W. Wittmer, M. Woodley, Y.T. Yan, G. Yocky
SLAC, Menlo Park, California
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The model independent analysis (MIA) has been successfully used at PEP-II to understand machine optics and improve the luminosity. However, the rate of success was limited because the improvement of optics does not necessarily lead to increase of luminosity. Recently, we were able to reconstruct MIA model in a full optics code, LEGO, and used it to calculate complete lattice and beam parameters. These parameters were fed to the beam-beam code, BBI, to understand the luminosity histories at PEP-II over the past year. Using these tools, we optimized the luminosity by varying the beam parameters such as emittance. Finally, we implemented an optimized solution with a set of asymmetric horizontal orbit bumps into the machines during a delivery shift with a few percentage gain in luminosity. The solution was retained at PEP-II machines along with the luminosity. Later, these asymmetric bumps also played a vital role in reaching 1x1034cm-2s-1 as the beam currents increased.
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| MOPLS077 |
The 2mrad Crossing Angle Interaction Region and Extraction Line
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730 |
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- R. Appleby
UMAN, Manchester
- D.A.-K. Angal-Kalinin
CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
- P. Bambade, O. Dadoun
LAL, Orsay
- J. Carter
Royal Holloway, University of London, Surrey
- L. Keller, K. C. Moffeit, Y. Nosochkov, A. Seryi, C.M. Spencer
SLAC, Menlo Park, California
- O. Napoly
CEA, Gif-sur-Yvette
- B. Parker
BNL, Upton, Long Island, New York
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A complete optics design for the 2mrad crossing angle interaction region and extraction line was presented at Snowmass 2005. Since this time, the design task force has been working on developing and improving the performance of the extraction line. The work has focused on optimising the final doublet parameters and on reducing the power losses resulting from the disrupted beam transport. In this paper, the most recent status of the 2mrad layout and the corresponding performance are presented.
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| MOPLS082 |
Simulation of the ILC Collimation System Using BDSIM, MARS15 and STRUCT
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744 |
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- J. Carter, I.V. Agapov, G.A. Blair, L. Deacon
Royal Holloway, University of London, Surrey
- A.I. Drozhdin, N.V. Mokhov
Fermilab, Batavia, Illinois
- Y. Nosochkov, A. Seryi
SLAC, Menlo Park, California
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The simulation codes STRUCT, MARS15 and BDSIM are used to simulate in detail the collimation section of the ILC. A comparative study of the collimation system performance is performed, and the key radiation loads are calculated. Results for the latest ILC designs are presented together with their implications for future design iterations.
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| WEPCH061 |
SABER Optical Design
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2062 |
| |
- R.A. Erickson, K.L.F. Bane, P. Emma, Y. Nosochkov
SLAC, Menlo Park, California
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SABER, the South Arc Beam Experimental Region, is a proposed new beam line facility designed to replace the Final Focus Test Beam at SLAC. In this paper, we outline the optical design features and beam parameters now envisioned for SABER. A magnetic chicane to compress positron bunches for SABER and a bypass line that could transport electrons or positrons from the two-thirds point of the linac to SABER, bypassing the LCLS systems, are also discussed.
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| MOPLS060 |
Design of an Interaction Region with Head-on Collisions for the ILC
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682 |
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- J. Payet, O. Napoly, C. Rippon, D. Uriot
CEA, Gif-sur-Yvette
- M. Alabau Pons, P. Bambade, J. Brossard, O. Dadoun, C. Rimbault
LAL, Orsay
- D.A.-K. Angal-Kalinin, F. Jackson
CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
- R. Appleby
UMAN, Manchester
- L. Keller, Y. Nosochkov, A. Seryi
SLAC, Menlo Park, California
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An interaction region with head-on collisions is considered an alternative to the baseline configuration of the International Linear Collider, including two interaction regions with finite crossing-angles (2 and 20 mrad). Although more challenging from the point of view of the beam extraction, the head-on scheme is favoured by the experiments because it allows a more convenient detector configuration, particularly in the forward region. The optics of the head-on extraction is revisited by separating the e+ and e- beams horizontally, first by electrostatic separators operated at their LEP nominal field and then using a defocusing quadrupole of the final focus beam line. In this way the septum magnet is protected from the beamstrahlung power. Newly optimized final focus and extraction optics are presented, including a first look at post-collision diagnostics. The influence of parasitic collisions is shown to lead to a region of stable collision parameters. Beam and beamstrahlung photon losses are calculated along the extraction elements. Issues concerning the design of the large bore superconducting final focus magnets, common to both incoming and outgoing beams, are considered.
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| THPLS083 |
Implementation of the Double-waist Chicane Optics in SPEAR 3
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3472 |
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- W.J. Corbett, M. Cornacchia, T. Dao, D. Dell'Orco, D. Harrington, R.O. Hettel, X. Huang, Y. Nosochkov, T. Rabedeau, F.S. Rafael, H. Rarback, A. Ringwall, J.A. Safranek, B. Scott, J.J. Sebek, J. Tanabe, A. Terebilo, C. Wermelskirchen, M. Widmeyer
SLAC, Menlo Park, California
- M. Yoon
POSTECH, Pohang, Kyungbuk
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The SPEAR 3 upgrade produced two new 7.6 m racetrack straight sections in the 18 cell, 234 m magnet lattice. One of these straights houses four PEP-II style mode-damped RF cavities. The other straight will accommodate two new small-gap insertion devices separated by 10mrad in a magnetic chicane configuration. A quadrupole triplet has been installed at the midpoint of the chicane and the vertical tune has been raised by an integer to create a 'double waist' optics with betay = 1.6m in the center of each ID. Furthermore, as part of the optics upgrade, betay in the four straights adjacent to the racetrack sections was reduced from 5m to 2.5m. In this paper, we describe the physical implementation of the double-waist chicane optics and initial operational results.
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