Measurement and optimisation of the PS-SPS transfer line optics

Arduini, G.; Giovannozzi, M.; Hanke, K.; Manglunki, D.; Martini, M.; Metral, G.

doi:10.1109/pac.1999.795522

Cited by 4 publications

(5 citation statements)

References 5 publications

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“…4. For the matched optics (∆β = 0), a vertical geometrical blow-up factor of 1.1 is found, which is in agreement with the result obtained from a multi-grid measurement in the line [3]. Detuning the β-function at the injection point in both directions leads to an increase of the mismatch fac- tor as expected.…”

Section: Resultssupporting

confidence: 89%

“…The geometry of the model was verified versus the official CERN survey data, while the correct magnetic behaviour was verified in a series of measurements. Based on the model, the line was successfully rematched [3] (and references therein). For the matched optics no blow-up due to mismatch could be detected except for the component due to dispersion in the horizontal plane.…”

Section: Introductionmentioning

confidence: 99%

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Tuning knobs for the PS-SPS transfer line

Arduini

Hanke

Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366)

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Transverse emittance preservation will be an important issue for the LHC injector chain. Minimization of the blowup at injection by tuning independently the Twiss parameters (α, β), the dispersion D and the dispersion derivative D is therefore mandatory. The optics of the transfer line between the PS and SPS machines was modeled and matched using the program package MAD. Tuning knobs were developed using a singular value decomposition (SVD) algorithm. Coupled to the measurement of the Twiss parameters at a given point downstream of the correction elements they provide a fast correction algorithm for the betatron mismatch.

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Section: Resultssupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Tuning knobs for the PS-SPS transfer line

Arduini

Hanke

Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366)

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“…These algorithms are usually devoted to the correction of the beam trajectory, via dedicated steering magnets, or to reducing the injection mismatch by using quadrupole magnets. An application of these concepts to the transfer line joining the PS and the SPS machines allowed a substantial improvement of the beam quality [5].Every correction procedure is based on a set of measured parameters to be compared with their theoretical values. Two different approaches are available.…”

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confidence: 99%

New methods to derive the optical and beam parameters in transport channels

Arduini

Giovannozzi

Hanke

et al. 2001

Nuclear Instruments and Methods in Physics Research Section A:

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The standard approach to compute the optical parameters and the beam emittance in a transport channel is based on the analysis of the profiles measured by three monitors. This requires the independent measurement of the dispersion function at the monitor locations and the knowledge of the value of the beam's momentum spread. In this paper different approaches based on the use of more than three beam profiles are presented. These techniques allow the determination of the complete set of four optical parameters, the betatron and dispersion functions and their derivatives, along with the beam emittance and the beam's momentum spread, simultaneously and without varying the physical parameters of the transport channel or the upstream machine. A detailed description of the different methods is carried out with a particular emphasis on their accuracy. Results of numerical simulations are presented. Accepted for publication in Nuclear Instr. and Methods in Physics Research A IntroductionThe complexity of the new generation of high-energy superconducting machines imposes tight constraints on the whole injector chain. In order to achieve the top performance in terms of luminosity of the planned CERN LHC [1], it is mandatory to preserve the value of the beam emittance through the whole chain of low-energy machines [2,3]. Although a crucial point is to avoid beam blow-up in the circular accelerators, which is obtained by carefully tuning the machines, the matching of the transfer lines to the phase space of the preceding and the subsequent machine also play a predominant role.In fact, even neglecting emittance blow-up due to the presence of possible non-linear fields, a transfer line generates transverse or longitudinal mismatch which will produce emittance increase after beam filamentation.Hence, as a consequence of the high performance required for the physics experiments, there has been a renewed interest in optics issues in transfer lines, with special emphasis on automated algorithms to measure optical parameters with the aim of computing mismatch factors, and, eventually, of applying corrections (see Ref. [4] for an overview of this field). These algorithms are usually devoted to the correction of the beam trajectory, via dedicated steering magnets, or to reducing the injection mismatch by using quadrupole magnets. An application of these concepts to the transfer line joining the PS and the SPS machines allowed a substantial improvement of the beam quality [5].Every correction procedure is based on a set of measured parameters to be compared with their theoretical values. Two different approaches are available. The first one deals with the measurement of the optical parameters by trajectory fit on Beam Position Monitor (BPM) data [6]. It allows the reconstruction of the transfer matrices between different BPMs and, in particular, the value of the dispersion function.The second technique allows to derive not only the optical parameters α, β, γ but also the beam characteristics, emittance and beam's momentum sp...

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“…N The betatron-and dispersion mismatch at injection were carefully measured and could be reduced to less than 10% [3].…”

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confidence: 99%

Acceleration of high intensity proton beams

Altuna

Arduini²,

Arimatea³

et al. 1999

Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366)

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In 1998 the CERN SPS accelerator finished a five years long program providing 450GeV proton beams for neutrino physics. These experiments required the highest possible beam intensity the SPS can deliver. During the last five years the maximum proton intensity in the SPS has steadily been increased to a maximum of 4.8 10 13 protons per cycle. In order to achieve these intensities a careful monitoring and improvement of the vertical aperture was necessary. Improved feedback systems on the different RF cavities were needed in order to avoid instabilities. Also the quality (emittance and extraction spill) of the injector, the CERN PS, had be optimised.

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Measurement and optimisation of the PS-SPS transfer line optics

Cited by 4 publications

References 5 publications

Tuning knobs for the PS-SPS transfer line

Tuning knobs for the PS-SPS transfer line

New methods to derive the optical and beam parameters in transport channels

Acceleration of high intensity proton beams

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