Author: Bodenstein, R.M.
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WEPOR009 Intra-beam IP Feedback Studies for the 380 GeV CLIC Beam Delivery System 2683
 
  • R.M. Bodenstein, P. Burrows, J. Snuverink
    JAI, Egham, Surrey, United Kingdom
  • F. Plassard
    CERN, Geneva, Switzerland
 
  In its currently-envisaged initial stage, the Compact Linear Collider (CLIC) will collide beams with a 380 GeV center of mass energy. To maintain the luminosity within a few percent of the design value, beam stability at the interaction point (IP) must be controlled at the sub-nanometer level. To help achieve such control, use of an intra-pulse IP feedback system is planned. With CLIC's very short bunch spacing of 0.5 ns, and nominal pulse duration of 176 ns, this feedback system presents a significant technical challenge. Furthermore, as part of a study to optimize the design of the beam delivery system (BDS), several L* configurations have been studied. In this paper, we will review the IP feedback simulations for the 380 GeV machine for two L* configurations, and compare luminosity recovery performance with that of the original L* configuration in the 3 TeV machine.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR009  
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THPMR046 Advanced BBA Techniques for the Final Focuses of Future Linear Colliders 3504
 
  • J. Snuverink, A. Latina, D. Schulte, R. Tomás
    CERN, Geneva, Switzerland
  • R.M. Bodenstein
    JAI, Oxford, United Kingdom
 
  Tuning the Final-Focus System of future linear colliders is one of the open challenges the linear collider community is undertaking. Future colliders like ILC and CLIC will feature complex lattice design to focus the beams to nanometer level at the Interaction Point. Standard Beam-Based Alignment (BBA) techniques have proven to hardly meet the requirements in terms of acceptable emittance growth, in both machines. A set of new techniques, respectively called: nonlinear Dispersion-Free Steering (DFS), DFS-knobs scan, and hybrid DFS-knobs with beamsize measurements, have been put in place to cope with the challenge. This paper will reveal the key ideas behind the new techniques, and compare their effectiveness w.r.t. the conventional BBA tuning procedures.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR046  
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THPMR047 Two-beam Tuning in the CLIC BDS 3508
 
  • J. Snuverink, R.M. Bodenstein
    JAI, Oxford, United Kingdom
  • R. Tomás
    CERN, Geneva, Switzerland
 
  Beam tuning in the beam delivery system (BDS) is one of the major challenges for the future linear colliders. In those colliders, due to fast detuning of the final focus optics both beamlines will need to be tuned simultaneously. An initial two-beam tuning study for the Compact Linear Collider (CLIC) BDS had been performed, but was not fully satisfactory. In this paper a more extensive study is presented, as well as several improvements to the tuning algorithm. A comparative study between two competing CLIC final focus systems (FFS), the traditional and the compact FFS, will be discussed.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR047  
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THPOR034 Bunch-by-bunch Position and Angle Stabilisation at ATF based on Sub-micron Resolution Stripline Beam Position Monitors 3859
 
  • N. Blaskovic Kraljevic, R.M. Bodenstein, T. Bromwich, P. Burrows, G.B. Christian, M.R. Davis, C. Perry, R.L. Ramjiawan
    JAI, Oxford, United Kingdom
  • D.R. Bett
    CERN, Geneva, Switzerland
 
  A low-latency, sub-micron resolution stripline beam position monitoring (BPM) system has been developed and tested with beam at the KEK Accelerator Test Facility (ATF2), where it has been used to drive a beam stabilisation system. The fast analogue front-end signal processor is based on a single-stage radio-frequency down-mixer, with a measured latency of 16 ns and a demonstrated single-pass beam position resolution of below 300 nm using a beam with a bunch charge of approximately 1 nC. The BPM position data are digitised on a digital feedback board which is used to drive a pair of kickers local to the BPMs and nominally orthogonal in phase in closed-loop feedback mode, thus achieving both beam position and angle stabilisation. We report the reduction in jitter as measured at a witness stripline BPM located 30 metres downstream of the feedback system and its propagation to the ATF interaction point.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR034  
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THPOR035 Development of a Low-latency, Micrometre-level Precision, Intra-train Beam Feedback System based on Cavity Beam Position Monitors 3862
 
  • N. Blaskovic Kraljevic, R.M. Bodenstein, T. Bromwich, P. Burrows, G.B. Christian, M.R. Davis, C. Perry, R.L. Ramjiawan
    JAI, Oxford, United Kingdom
  • D.R. Bett
    CERN, Geneva, Switzerland
 
  A low-latency, intra-train, beam feedback system utilising a cavity beam position monitor (BPM) has been developed and tested at the final focus of the Accelerator Test Facility (ATF2) at KEK. A low-Q cavity BPM was utilised with custom signal processing electronics, designed for low latency and optimal position resolution, to provide an input beam position signal to the feedback system. A custom stripline kicker and power amplifier, and a digital feedback board, were used to provide beam correction and feedback control, respectively. The system was deployed in single-pass, multi-bunch mode with the aim of demonstrating intra-train beam stabilisation on electron bunches of charge ~1 nC separated in time by c. 220 ns. The system has been used to demonstrate beam stabilisation to below the 75 nm level. Results of the latest beam tests, aimed at even higher performance, will be presented.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR035  
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