Hello, A yearly allocation for the LCRC cluster has been requested with the following updated information: Submitter/PI: Michael Borland Project Name: ApsRenewalLattice Division: ASD Project title: Development of accelerator lattices for the APS Renewal Associated funding: Other Systems: ASD "weed" cluster, operated by ASD/AOP group. weed has 56 Nehelem processors with a lustre filesystem and infiniband network. I typically have access to about 50% of the cluster full time. I was also granted an allocation of 32M core hours on intrepid. Science: As part of the APS Renewal, the accelerator lattice (the location and powering of the magnets) will be modified to incorporate a number of long straight sections for insertion devices and other purposes, such as Short-Pulse X-rays (SPX). This involves breaking the symmetry of the ring, which has serious implications for particle stability. Using simulation-based techniques developed at APS, we can tune the nonlinear elements to improve the dynamic and momentum aperture. Rapid turn-around is essential in order to respond to requests from the APS user community for evaluation of new options. In addition, simulations related to SPX beam dynamics will be performed. Project description: Because of an allocation of 32 M hours received on intrepid, we will make use of fusion primarily for simulation of the SPX system, which is a related aspect of the APS upgrade. Simulations include on-going analysis of sensitivity to static and dynamic errors. We will also begin modeling of the impact of collective effects in the presence of a chirped beam. The computational methods for the SPX sensitivity are relatively simple, involving tracking a large (e.g, 10k) number of simulation particles to find the perturbed equilibrium. These simulations are to a large degree "embarrassingly parallel," as very little communication is required between processors. The simulations essentially consist of perturbing some aspect of the accelerator (e.g., a cavity phase or voltage) and tracking to find an equilibrium response. We also perform analysis of the response to time-dependent modulations. Simulations with single-bunch collective effects are similar, but involve more interprocess communication, although it is still quite limited. In these simulations, we track with various levels of beam intensity under various conditions to determine single-bunch instability limits. In addition to the single-bunch limits, we will use multi-bunch tracking simulation to find coupled-bunch instability limits. The parameters of these simulations need to be determined by some initial runs, but are about an order of magnitude more intensive than the single-bunch simulations. Project URL: Current FY Hours Used: undetermined amount New FY Requested allocation: 400000 Justification: Thank You, The LCRC Accounts System