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Luminosity of the Super -T au- C harm F actory with C rab W aist. D. Shatilov BINP, Novosibirsk. TAU’08 Workshop, Satellite Meeting “ On the Need for a Super -T au- C harm Factory ” 26-27 September 2008, BINP, Novosibirsk, Russia. Beam-Beam Studies (step by step).
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Luminosity of the Super-Tau-Charm Factory with Crab Waist D. Shatilov BINP, Novosibirsk TAU’08 Workshop, Satellite Meeting “On the Need for a Super-Tau-Charm Factory” 26-27 September 2008, BINP, Novosibirsk, Russia
Beam-Beam Studies (step by step) • Determine the main set of parameters (emittances, beta-functions, bunch current, damping decrements, crossing angle, etc.) • Wide range scan of betatron tunes for the simplified model: linear lattice and beam-beam. Two options: with and without Crab Waist. • Select a working point,taking into account the dynamic aperture Investigations. • More detailed simulations, including beam tails (linear lattice yet). Scan for bunch current. Two options: with and without Crab Waist. • Beam-Beam simulations for the actual (nonlinear) lattice: sextupoles and octupoles included.
4σx / σz·/2 z Set of parameters Piwinski angle: Basic relations for large Piwinski angle:
Betatron Tunes Scan Luminosity contour plots in the “geographical map” colors. Red – maximum, Blue - minimum Crab ON:Lmax=1.05·1035Crab OFF: Lmax=0.44·1035 Np=7·1010 Nb=380 Np=3·1010 Nb=890 Same total beam current
Simulations for the working point (0.533, 0.570) Crab OFF Crab ON Contour plots in the space of normalized betatron amplitudes. Scales (in sigmas): 20100.
Crab Scan for Np=7·1010 optimum Contour plots in the space of normalized betatron amplitudes. Scales (in sigmas): 1050.
Summary • Luminosity of 1035 can be achieved with the total beam current 1.6 A and rather small y (can be increased from 0.13 to 0.15÷0.17). • Crab Waist is a key feature, otherwise “mission impossible”. • More detailed simulations with the actual (nonlinear) lattice are required. This will be done as soon as the lattice is ready.