1,745 research outputs found
Orthogonality of final waist corrections at the IP of the SLC
No full textBecause the SLC final IP spot is produced by an aberration-dominated optical system, all components and couplings between dimensions of transverse phase-space must be controlled in the experimental tuning algorithm. For equal emittances epsilon/sub x/ = epsilon/sub y/, this amounts to ten linear optics adjustments. These adjustments are coupled and depend non-linearly on phase-space parameters. A ten-dimensional non-linear fitting program is therefore used to match the lattice in the Final Focus to the input beam. Local orthogonal ''knobs'' are also defined for fine-tweaking around the initial solution, although this is not always practical because of steering from the lenses. The three final waist corrections are however fully orthogonal to the other seven optical adjustments. This means that they do not cause any of the other seven optical distortions. We refer to this as external orthogonality. They can also be made internally orthogonal. This means that each one of the three orthogonalized controls can be applied independently of the two others. It also allows one to simultaneously correct and determine the phase-space at the IP
Beam-beam deflections to measure size spot and offset at SLC IP
No full textAs soon as two SLC beams make it to the intersection region, both transverse offsets, spot sizes and shapes can be extracted from the pattern of angular deflections produced by the electromagnetic interaction of the two beams, as one is scanned across the other. These deflections, measured in two high resolution Beam Position Monitors (BPM) mounted symmetrically on both sides of the intersection point, will produce detectable signals allowing spot sizes to be tuned, even with the very low luminosities expected at turn on. They will also furnish a good signal to monitor beam centering and will therefore become an important part of the FFS feedback system. This note summarizes the formulae which will allow us to correlate BPM offset readings with the properties of the two beams, and describes the range and limitations of the technique in the case of SLC
DELPHI results on the Z --> b partial width and on the average B hadrons semileptonic branching ratio
No full textImproved final doublet designs for the ILC baseline small crossing angle scheme
No full textThe ILC baseline consists of two interaction regions, one with a 20mrad crossing angle and the other with a 2mrad crossing angle. It is known that the outgoing beam losses in the final doublet and subsequent extraction line are larger in the 2mrad than in the 20mrad layout. In this work, we exploit NbTi and NbSn superconducting magnet technologies to redesign and optimise the final doublet, with the aim of providing satisfactory outgoing disrupted beam power losses in this region. We present three new final doublet layouts, specifically optimised for the 500 GeV and the 1 TeV machines
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