Paper |
Title |
Page |
MOPFI060 |
Beam Transfer to LHC with the Low Gamma-transition SPS Optics |
419 |
|
- G. Vanbavinckhove, W. Bartmann, H. Bartosik, C. Bracco, L.N. Drøsdal, B. Goddard, V. Kain, M. Meddahi, V. Mertens, Y. Papaphilippou, J.A. Uythoven, J. Wenninger
CERN, Geneva, Switzerland
- E. Gianfelice-Wendt
Fermilab, Batavia, USA
|
|
|
A new low gamma-transition optics with a lower integer tune, was introduced in the SPS to improve beam stability at high intensity. For transferring the beam to the LHC, the extraction bumps, extraction kickers and transfer lines needed to be adapted to the new optics. In particular, the transfer lines were re-matched and re-commissioned with the new optics. The first operational results are discussed for the SPS extraction, the transfer lines and the LHC injection. A detailed comparison is presented between the old and the new optics of the trajectories, dispersion, losses and other performance aspects.
|
|
|
MOPFI061 |
Concept for Elena Extraction and Beam Transfer Elements |
422 |
|
- J. Borburgh, B. Balhan, W. Bartmann, T. Fowler, L. Sermeus, G. Vanbavinckhove
CERN, Geneva, Switzerland
- R.A. Baartman
TRIUMF, Vancouver, Canada
- D. Barna
University of Tokyo, Tokyo, Japan
- V. Pricop
Transilvania University of Brasov, Brasov, Romania
|
|
|
In 2011 the ELENA decelerator was approved as a CERN project. Initially one extraction was foreseen, which should use a kicker and a magnetic septum which can be recuperated from an earlier installation. Since then a second extraction has been approved and a new solution was studied using only electric fields to extract the beam. This will be achieved by fast pulsing a separator, allowing single-bunch but also a full single-turn extraction from ELENA towards the experiments. The extraction and transfer requirements of ELENA are described, followed by the principal differences between the magnetic and electric field concepts. The design of electrostatic focussing and bending devices for the transfer lines will be presented. Finally the field quality which can be achieved with the separator and the concept of its power supply will be discussed.
|
|
|
MOPWO033 |
Analysis of LHC Transfer Line Trajectory Drifts |
960 |
|
- L.N. Drøsdal, W. Bartmann, H. Bartosik, C. Bracco, B. Goddard, V. Kain, Y. Papaphilippou, J.A. Uythoven, G. Vanbavinckhove, J. Wenninger
CERN, Geneva, Switzerland
- E. Gianfelice-Wendt
Fermilab, Batavia, USA
|
|
|
The LHC is filled from the SPS via two 3km long transfer lines. In the first years of LHC operation large trajectory variations were discovered. The sources of bunch-by-bunch and shot-by-shot trajectory variations had been identified and improved by the 2012 LHC run. The origins of the longer term drifts were however still unclear and significant time was spent correcting the trajectories. In the last part of the 2012 run the optics in the SPS was changed to lower transition energy. Trajectory stability and correction frequency will be compared between before and after the optics change in the SPS. The sources of the variations have now been identified and will be discussed in this paper. Remedies for operation after the long shutdown will be proposed.
|
|
|
TUPFI039 |
Optics Performance of the LHC During the 2012 Run |
1433 |
|
- P. Skowroński, T. Bach, M. Giovannozzi, A. Langner, Y.I. Levinsen, E.H. Maclean, T. Persson, S. Redaelli, T. Risselada, M. Solfaroli Camillocci, R. Tomás, G. Vanbavinckhove
CERN, Geneva, Switzerland
- M.J. McAteer
The University of Texas at Austin, Austin, USA
- R. Miyamoto
ESS, Lund, Sweden
- T. Persson
Chalmers University of Technology, Chalmers Tekniska Högskola, Gothenburg, Sweden
|
|
|
During 2012 the LHC was operating at 4TeV with beta star at ATLAS and CMS interaction points of 0.6m. During dedicated machine studies the nominal LHC optics was also setup with beta star of 0.4m. A huge effort was put into the optics commissioning leading to a record low peak beta-beating of around 7%. We describe the correction procedures and discuss the measurement results.
|
|
|
TUPWO049 |
Automatic Correction of Betatron Coupling in the LHC using Injection Oscillations |
1979 |
|
- T. Persson, T. Bach, D. Jacquet, V. Kain, Y.I. Levinsen, E.H. Maclean, M.J. McAteer, P. Skowroński, R. Tomás, G. Vanbavinckhove
CERN, Geneva, Switzerland
- R. Miyamoto
ESS, Lund, Sweden
|
|
|
The control of the betatron coupling at injection and during the energy ramp is critical for the safe operation of the tune feedback and for the dynamic aperture. In the LHC every fill is preceded by the injection of a pilot bunch with low intensity. Using the injection oscillations from the pilot bunch we are able to measure the coupling at each individual BPM. The measurement is used to calculate a global coupling correction. The correction is based on the use of two orthogonal knobs which correct the real and imaginary part of the difference resonance term f1001, respectively. This method to correct the betatron coupling has been proven successful during the normal operation of the LHC. This paper presents the method used to calculate the corrections and its performance.
|
|
|
TUPWO051 |
Geometry and Optics of the Electrostatic ELENA Transfer Lines |
1985 |
|
- G. Vanbavinckhove, W. Bartmann, F. Butin, O. Choisnet
CERN, Geneva, Switzerland
- R.A. Baartman
TRIUMF, Vancouver, Canada
- D. Barna, H. Yamada
University of Tokyo, Tokyo, Japan
|
|
|
The future ELENA ring at CERN will decelerate the AD antiproton beam further from 5.3 MeV to 100 keV kinetic energy, to increase the efficiency of antiproton trapping. At present there are four experimental areas in the AD hall which will be complemented with the installation of ELENA by additional three experiments and an additional source for commissioning. This paper describes the optimisation of the transfer line geometry, ring rotation and source position. The optics of the transfer lines and error studies to define field and alignment tolerances are shown, and the optics particularities of electrostatic elements and their optimisation highlighted.
|
|
|
WEPEA062 |
Progress in ELENA Design |
2651 |
|
- S. Maury, W. Bartmann, P. Belochitskii, H. Breuker, F. Butin, C. Carli, T. Eriksson, R. Kersevan, S. Pasinelli, G. Tranquille, G. Vanbavinckhove
CERN, Geneva, Switzerland
- W. Oelert
FZJ, Jülich, Germany
|
|
|
The Extra Low Energy Antiproton ring (ELENA) is a small ring at CERN which will be built to increase substantially the number of usable (or trappable) antiprotons delivered to experiments for studies with antihydrogen. The report shows the progress in the ELENA design. The choice of optics and ring layout inside of AD hall is given. The main limitations for beam parameters at extraction like intra beam scattering and tune shift due to space charge are discussed. The electron cooler plays key role in ELENA both for efficient deceleration as well as for preparing extracted beam with parameters defined by experiments. The other important systems like beam vacuum, beam instrumentations and others are reviewed as well.
|
|
|
THPWO080 |
Operational Performance of the LHC Proton Beams with the SPS Low Transition Energy Optics |
3945 |
|
- Y. Papaphilippou, G. Arduini, T. Argyropoulos, W. Bartmann, H. Bartosik, T. Bohl, C. Bracco, S. Cettour-Cave, K. Cornelis, L.N. Drøsdal, J.F. Esteban Müller, B. Goddard, A. Guerrero, W. Höfle, V. Kain, G. Rumolo, B. Salvant, E.N. Shaposhnikova, H. Timko, D. Valuch, G. Vanbavinckhove, J. Wenninger
CERN, Geneva, Switzerland
- E. Gianfelice-Wendt
Fermilab, Batavia, USA
|
|
|
An optics in the SPS with lower integer tunes (20 versus 26) was proposed and introduced in machine studies since 2010, as a measure for increasing transverse and longitudinal instability thresholds, especially at low energy, for the LHC proton beams. After two years of machine studies and careful optimisation, the new “Q20” optics became operational in September 2012 and steadily delivered beam to the LHC until the end of the run. This paper reviews the operational performance of the Q20 optics with respect to transverse and longitudinal beam characteristics in the SPS, enabling high brightness beams injected into the LHC. Aspects of longitudinal beam stability, transmission, high-energy orbit control and beam transfer are discussed.
|
|
|