Acceleration in the CERN SPS Present Status and Future Developments

Boussard, D.; Dome, G.; Linnecar, T.

doi:10.1109/tns.1979.4329993

Cited by 6 publications

(4 citation statements)

References 4 publications

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“…Transverse deflecting modes have also been identified in the structure and additional loops were installed to damp them. 6 iBecause of the wide bandwidth of the cavities, there is ; significant impedance at frequencies ± nf 0 from the driving frequency hf Q where n « 1,2 20. Longitudinal coupled bunch instablities driven by this impedance with mode numbers of 1 to 17 have been observed and damped with feedback.…”

Section: Travelling Wave Systemmentioning

confidence: 99%

“…Longitudinal coupled bunch instablities driven by this impedance with mode numbers of 1 to 17 have been observed and damped with feedback. 6 Now the beam induced voltage Is zero at the drive end of the cavity, so the power source does not see the beam. The beam power is subtracted from the power incident on the terminating load at the upstream end and It Is only necessary to supply additional power as a function of beam current to maintain the same total cavity voltage.…”

Section: Travelling Wave Systemmentioning

confidence: 99%

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Radio Frequency Systems for Present and Future Accelerators

Raka

1989

New Techniques for Future Accelerators II

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Section: Travelling Wave Systemmentioning

confidence: 99%

Section: Travelling Wave Systemmentioning

confidence: 99%

Radio Frequency Systems for Present and Future Accelerators

Raka

1989

New Techniques for Future Accelerators II

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“…The dipole mode instabilities can be monitored using the set-up described in reference (3). They disappear completely with RF feedback ON.…”

Section: The Digital Filtermentioning

confidence: 99%

Reduction of the Apparent Impedance of Wide Band Accelerating Cavities by RF Feedback

Boussard

Lambert

1983

IEEE Trans. Nucl. Sci.

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“…The impedance of the main RF system around the fundamental (200 MHz) frequency had long been recognized to be a serious problem not only for beam loading but also for coupled-bunch instability [3]. The One-Turn-Delay Feedback (1tFB) in operation since the early eighties [4] and acting on the 4 cavities in parallel did not provide sufficient impedance reduction for the LHC beam.…”

Section: Impedance Reductionmentioning

confidence: 99%

Nominal longitudinal parameters for the LHC beam in the CERN SPS

Baudrenghien

Bohl

Linnecar

et al.

Proceedings of the 2003 Bipolar/BiCMOS Circuits and Technology Meeting (IEEE Cat. No.03CH37440)

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A proton beam with the basic structure defined by the the LHC requirements, was first available for injection into the SPS in 1998. At the end of 2002, following a significant beam-studies and RF hardware upgrade programme, a beam having both the nominal LHC intensity and the correct longitudinal parameters was obtained at top energy for the first time. This beam, characterised by high local density, must satisfy strict requirements on bunch length, longitudinal emittance and bunch to bunch phase modulation for extraction to the LHC, where only very limited particle losses are acceptable. The problems to be solved came mainly from the high beam loading and microwave and coupled bunch instabilities which led both to beam losses and to unacceptably large longitudinal emittance on the flat top. In this paper the steps taken to arrive at these nominal beam parameters are presented. Large Hadron Collider Project NOMINAL LONGITUDINAL PARAMETERS FOR THE LHC BEAM IN THE CERN SPSP. Baudrenghien, T. Bohl, T. Linnecar, E. Shaposhnikova and J. Tuckmantel, CERN, Geneva, Switzerland Abstract A proton beam with the basic structure defined by the the LHC requirements, was first available for injection into the SPS in 1998. At the end of 2002, following a significant beam-studies and RF hardware upgrade programme, a beam having both the nominal LHC intensity and the correct longitudinal parameters was obtained at top energy for the first time. This beam, characterised by high local density, must satisfy strict requirements on bunch length, longitudinal emittance and bunch to bunch phase modulation for extraction to the LHC, where only very limited particle losses are acceptable. The problems to be solved came mainly from the high beam loading and microwave and coupled bunch instabilities which led both to beam losses and to unacceptably large longitudinal emittance on the flat top. In this paper the steps taken to arrive at these nominal beam parameters are presented.

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Acceleration in the CERN SPS Present Status and Future Developments

Cited by 6 publications

References 4 publications

Radio Frequency Systems for Present and Future Accelerators

Radio Frequency Systems for Present and Future Accelerators

Reduction of the Apparent Impedance of Wide Band Accelerating Cavities by RF Feedback

Nominal longitudinal parameters for the LHC beam in the CERN SPS

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