| Paper | Title | Page |
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| TUPEB004 | Super-B Lattice Studies | 1521 |
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The Super-B asymmetric e+e- collider is designed for 1036 cm-2sec-1 luminosity and beam energies of 6.7 and 4.18 GeV for e+ and e-, respectively. The machine will have the High and Low Energy Rings (HER and LER), and one Interaction Point (IP) with 60 mrad crossing angle. The INFN-LNF at Frascati is one of the proposed sites, and a lattice for short 1.3 km rings fitting to this site has been designed. The two rings are radially separated by 2 m except near the IP and in the dogleg on the opposite side of the rings. The injection sections and RF cavities are included. The lattice is optimized for a low emittance required for the desired high luminosity. Final Focus chromaticity correction is optimized for large transverse and energy acceptance. The "crab waist" sextupoles are included for suppression of betatron resonances induced at the IP collisions with large Piwinski angle. The LER spin rotator sections provide longitudinal polarization for the electron beam at IP. The lattice is flexible for tuning the design parameters and compatible with reusing the PEP-II magnets, RF cavities and other components. Design criteria and details on the lattice implementation are presented. |
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| TUPEB025 | Polarimetery for SuperB | 1575 |
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We present a conceptual design for a polarimeter based on Compton scattering of laser light on the electron beam for the Super-B accelerator proposed for Frascati, Italy. The accelerator design has polarized electrons in the low-energy ring (4.18 GeV). We want to measure the polarization of every bunch every few seconds using a laser with 119 Mhz repetition rate. The spin rotator section has a second point between the solenoids and interaction point where the polarization is nearly longitudinal with helicity opposite to that found at the interaction point. We plan to use this point to measure the polarization as the possible location near the interaction point has too much background from the collision. We show the area in the accelerator where the polarimeter would be installed and describe the laser as well as the detectors for the Compton scattered electrons and photons. |
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| TUPEB029 | Polarization in SuperB | 1587 |
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The availability of longitudinally polarized electrons is an important aspect of the design of the proposed SuperB project at LNF Frascati. Spin rotators are an integral part of the design of the Interaction Region (IR). We have chosen a solenoid-dipole design; at the 4.18 GeV nominal energy this is more compact that a design purely based on dipole magnets. Integration with the local chromaticity correction of the ultra-low beta* IR has been achieved. The spin rotators are symmetric about the Interaction Point, this design saves a significant amount of length as the dipoles become a part of the overall 360 deg. bend. The layout leaves limited opportunity to setup the optics for minimum depolarization; this is acceptable since beam life time in SuperB at high luminosity is only about 5 min and up-to 90% polarized electrons will be injected continuously. In this way an average beam polarization of about 70% is maintained. Simulations and analytic estimates with the DESY code SLICKTRACK and other codes indicate such operation is feasible from a spin-dynamics point of view. The paper will discuss the overall spin-rotator design as well as the spin dynamics in the ring. |
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| WEPEA073 | Lattice Development for PEP-X High Brightness Light Source | 2654 |
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Design of PEP-X high brightness light source machine is under development at SLAC. The PEP-X is a proposed replacement of the PEP-II in the existing 2.2 km tunnel. Two of the PEP-X six arcs contain DBA type lattice providing 30 dispersion free straights suitable for 3.5 m long undulators. The lattice contains TME cells in the other four arcs and a 90 m wiggler in a long straight section yielding an ultra low horizontal emittance of ~0.1 nm-rad at 4.5 GeV for a high brightness. The recent lattice modifications further increase the predicted brightness and improve beam dynamic properties. The standard DBA cells are modified into supercells for providing low beta undulator straights. The DBA and TME lattice parameters are better optimized. Harmonic sextupoles are added into the DBA arcs to minimize the sextupole driven resonance effects and amplitude dependent tune shift. Finally, the injection scheme is changed from vertical to horizontal plane in order to avoid large vertical amplitudes of injected beam within small vertical aperture of undulators. |
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| WEPEA074 | A Baseline Design for PEP-X: an Ultra-low Emittance Storage Ring | 2657 |
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Over the past year, we have worked out a baseline design for PEP-X, as an ultra-low emittance storage ring that could reside in the existing 2.2-km PEP-II tunnel. The design features a hybrid lattice with double bend achromat cells in two arcs and theoretical minimum emittance cells in the remaining four arcs. Damping wigglers reduce the horizontal emittance to 86 pm-rad at zero current for a 4.5 GeV electron beam. At a design current of 1.5 A, the horizontal emittance increases, due to intra-beam scattering, to 164 pm-rad when the vertical emittance is maintained at a diffraction limited 8 pm-rad. The baseline design will produce photon beams achieving a brightness of 1022 (ph/s/mm2/mrad2/0.1% BW) at 10 keV in a 3.5-m conventional planar undulator. Our study shows that an optimized lattice has adequate dynamic aperture, while accommodating a conventional off-axis injection system. In this paper, we will present the study of the lattice properties, nonlinear dynamics, intra-beam scattering and Touschek lifetime, and collective instabilities. Finally, we discuss the possibility of partial lasing at soft X-ray wavelengths using a long undulator in a straight section. |
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| TUPEB003 | The SuperB Project Accelerator Status | 1518 |
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The SuperB project is an international effort aiming at building in Italy a very high luminosity e+e- (1036 cm-2 sec-1) asymmetric collider at the B mesons cm energy. The accelerator design has been extensively studied and changed during the past year. The present design, - based on the new collision scheme, with large Piwinski angle and the use of 'crab' sextupoles, which has been successfully tested at the DAPHNE Phi-Factory at LNF Frascati, - provides larger flexibility, better dynamic aperture and in the Low Energy Ring spin manipulation sections, needed for having longitudinal polarization of the electron beam at the Interaction Point. The Interaction Region has been further optimized in terms of apertures and reduced backgrounds in the detector. The injector complex design has been also updated. A summary of the design status, including details on lattice and spin manipulation will be presented in this paper. |
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| WEPE037 | Optimization of Dynamic Aperture of PEP-X Baseline Design | 3437 |
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SLAC is developing a long-range plan to transfer the evolving scientific programs at SSRL from the SPEAR3 light source to a much higher performing photon source that would be housed in the 2.2-km PEP-II tunnel*,**. The proposed PEP-X storage ring is one of the possibilities. The goal of the PEP-X design is to develop an optimal light source design with horizontal emittance less than 100 pm at 4.5 GeV and vertical emittance of 8 pm corresponding to the diffraction limit of 1-Å X-ray. The low emittance design requires a lattice with strong focusing leading to high natural chromaticity and therefore to strong sextupoles. The latter cause reduction of dynamic aperture. The horizontal dynamic aperture required at PEP-X injection point is about 10 mm. In order to achieve the desired dynamic aperture, transverse non-linearities of PEP-X are studied. The program LEGO*** is used for particle tracking simulations. The technique of frequency map is used to analyze the nonlinear behavior. The effects of the non-linearities are tried to minimize. The details and results of dynamic aperture optimization are discussed in this paper. *,** R. Hettel et al., 'IDEAS FOR A FUTURE PEP-X LIGHT SOURCE', EPAC08, 'CONCEPTS FOR THE PEP-X LIGHT SOURCE', PAC09. |