The LCLS injector is required to provide a 1-nC, 10-ps bunch with a normalized rms transverse projected emittance of less than 1 micron. The LCLS beam is generated and accelerated in a 1.6-cell S-band RF gun at 120 MV/m up to 6 MeV. The gun is followed by two SLAC 3-m S-band accelerator structures to further accelerate the beam to 135 MeV which moves the beam out of the space-charge dominated regime. In the SLAC S-band structures, the RF power feed is through a single coupling-hole (single-feed coupler) which results in a field asymmetry. The time dependent multipole fields in the coupler induce a transverse kick along the bunch and cause the emittance to increase above the LCLS specification. To meet the stringent emittance requirements for the injector, the single-feed couplers will be replaced by a dual-feed racetrack design to minimize the multipole field effects. We will present detailed studies of the multipole fields in the SLAC linac RF coupler and the improvements with the dual-feed ractrack design using the parallel finite element S-parameter solver S3P.

An international team comprising SLAC, KEK, FNAL, JLAB and DESY is collaborating on the design, fabrication and test of a low loss, 1.3 GHz 9-cell SRF structure as a potential improvement for the ILC main linac. The advantages of this structure over the TESLA structure include lower cryogenic loss, shorter rise time, and less stored energy. Among the issues to be addressed in this design are HOM damping, Lorentz force detuning and multipacting. We will report on HOM damping calculations using the parallel finite element eigenmode solver Omega3P and the progress made towards an optimized design. Studies on multipacting and estimates of the Lorentz force detuning will also be presented.

Galactosylceramide (GalCer), a glycosphingolipid, is believed to exist in the extracellular leaflet of cell membranes in nanometer sized domains or rafts. The local clustering of GalCer within rafts is thought to facilitate the initial adhesion of certain viruses, including HIV-1 and bacteria to cells through multivalent interactions between receptor proteins (gp120 for HIV-1) and GalCer. Here we use atomic force microscopy (AFM) to study the effects of cholesterol on solid-phase GalCer domain microstructure and miscibility with a fluid lipid 1,2-Dilauroyl-sn-Glycero-3-Phosphocholine (DLPC), in supported lipid bilayers. Using ''slow cooled vesicle fusion'' to prepare the supported lipid bilayers, we were able to overcome the nonequilibrium effects of the substrate (verified by comparison to results for giant unilamellar vesicles, GUVs) and accurately quantify the dramatic effect of cholesterol on the GalCer domain surface area to perimeter ratio (AD/P) and DLPC-GalCer miscibility. We compare these results to a supported lipid bilayer system in which the bilayer is rapidly cooled (nonequilibrium conditions), ''quenched vesicle fusion'' and find that the microstructures are remarkably similar above a cholesterol mole fraction of approximately 0.06. We determined that GalCer domains were contained in one leaflet distal to the mica substrate through qualitative binding experiments with Trichosanthes kirilowii agglutinin (TKA), …

This document describes the implementation of the topological vertex finding algorithm ZVTOP within the org.lcsim reconstruction and analysis framework. At the present date, Java vertexing tools allow users to perform topological vertexing on tracks that have been obtained from a Fast MC simulation. An implementation that will be able to handle fully reconstructed events is being designed from the ground up for longevity and maintainability.

Design of the first generation LCLS injector is nearing completion. Fabrication has begun and component installation is planned for 2006. We discuss the last modifications made on both the 1.6 cell S-Band RF gun and the SLAC S-Band accelerating structures to minimize irreversible emittance growth. The mode separation between the 0 and {pi} modes was increased from 3.4 MHz to 15 MHz. Dual feed and racetrack shapes have been incorporated in the full cell of the new gun. The linac sections were also modified to accommodate dual feeds and racetrack shapes in their input cells. PARMELA simulations indicating the need for these modifications are presented.

Parameters are being studied for a high luminosity e{sup +}e{sup -} collider operating at the Upsilon 4S that would deliver a luminosity in the range of 7 to 10 x 10{sup 35}/cm{sup 2}/s. Particle physics studies dictate that a much higher luminosity collider than the present B-Factory accelerators will be needed to answer future new key physics questions. The success of the present B-Factories, PEP-II and KEKB, in producing unprecedented luminosity with very short commissioning times has taught us about the accelerator physics of asymmetric e{sup +}e{sup -} colliders in a new parameter regime. Such a collider could produce an integrated luminosity of 10,000 fb{sup -1} (10 ab{sup -1}) in a running year. A Super-B-Factory [1-8] with 30 to 50 times the performance of the present PEP-II accelerator would incorporate a higher frequency RF system, lower impedance vacuum chambers, higher power synchrotron radiation absorbers, and stronger bunch-by-bunch feedback systems. The present injector based on the SLAC linac needs no improvements and is ready for the Super-B-Factory.

PEP-II is an e{sup +}e{sup -} asymmetric B-Factory Collider located at SLAC operating at the Upsilon 4S resonance (3.1 GeV x 9 GeV). It has reached a luminosity of 9.21 x 10{sup 33}/cm{sup 2}/s and has delivered an integrated luminosity of 710 pb{sup -1} in one day. PEP-II has delivered, over the past six years, an integrated luminosity to the BaBar detector of over 262 fb{sup -1}. PEP-II operates in continuous injection mode for both beams boosting the integrated luminosity. The peak positron current has reached 2.45 A in 1588 bunches. Steady progress is being made in reaching higher luminosity. The goal over the next several years is to reach a luminosity of 2.1 x 10{sup 34}/cm{sup 2}/s. The accelerator physics issues being addressed in PEP-II to reach this goal include the electron cloud instability, beam-beam effects, parasitic beam-beam effects, high RF beam loading, shorter bunches, lower {beta}*{sub y} interaction region operation, and coupling control. Figure 1 shows the PEP-II tunnel.

It has been empirically observed in both experiments and particle-in-cell simulations that space-charge-dominated beams suffer strong growth in statistical phase-space area (degraded quality) and particle losses in alternating gradient quadrupole transport channels when the undepressed phase advance {sigma}{sub 0} increases beyond about 85{sup o} per lattice period. Although this criterion has been used extensively in practical designs of strong focusing intense beam transport lattices, the origin of the limit has not been understood.We propose a mechanism for the transport limit resulting from classes of halo particle resonances near the core of the beam that allow near-edge particles to rapidly increase in oscillation amplitude when the space-charge intensity and the utter of the matched beam envelope are both sufficiently large. When coupled with a diffuse beam edge and/or perturbations internal to the beam core that can drive particles outside the edge, this mechanism can result in large and rapid halo-driven increases in the statistical phase-space area of the beam, lost particles, and degraded transport. A core-particle model is applied to parametrically analyze his process. Extensive self-consistent particle in cell simulations are employed to better quantify space-charge limit and verify core-particle model predictions.

Forty-three subjects worked in a private office with switchable electrochromic windows, manually-operated Venetian blinds, and dimmable fluorescent lights. The electrochromic window had a visible transmittance range of approximately 3-60%. Analysis of subject responses and physical data collected during the work sessions showed that the electrochromic windows reduced the incidence of glare compared to working under a fixed transmittance (60%) condition. Subjects used the Venetian blinds less often and preferred the variable transmittance condition, but used slightly more electric lighting with it than they did when window transmittance was fixed.