A multigrid strategy for accelerating steady-state computations of waves propagating with curvature dependent speeds

A multigrid strategy is developed for accelerating the steady state computations of waves propagating with curvature dependent speeds. This will allow the rapid computation of a burn table. In a high explosive material, the creation of a burn table will allow the elimination of solving chemical reaction ODEs and feed in source terms to the reactive flow equations for solution of the system of ignition of the high explosive material. Standard iterative methods show a quick reduction of the residual followed by a slow final convergence to the solution at high iterations. Such systems are excellent choices for the use of multigrid methods to speed up convergence, even on a nonlinear system such as this. Numerical steady-state solutions to the eikonal equation on a rectangular grid are conducted. Results are presented for a square grid in 2D and a cubic grid in 3D using a Runge-Kutta time iteration for the smoothing operator until steady-state is reached

Status and Operation of the Linac4 Ion Source Prototypes

CERN’s Linac4 45 kV H- ion sources prototypes are installed at a dedicated ion source test stand and in the Linac4 tunnel. The operation of the pulsed hydrogen injection, RF sustained plasma and pulsed high voltages are described. The first experimental results of two prototypes relying on 2MHz RF- plasma heating are presented. The plasma is ignited via capacitive coupling, and sustained by inductive coupling. The light emitted from the plasma is collected by viewports pointing to the plasma chamber wall in the middle of the RF solenoid and to the plasma chamber axis. Preliminary measurements of optical emission spectroscopy and photometry of the plasma have been performed. The design of a cesiated ion source is presented. The volume source has produced a 45 keV H- beam of 16-22 mA which has successfully been used for the commissioning of the LEBT, RFQ and chopper of Linac4

The ATLAS DAQ and Event Filter prototype "-1" project

A project has been approved by the ATLAS Collaboration for the design and implementation of a Data Acquisition and Event Filter prototype, based on the functional architecture described in the ATLAS Technical Proposal. The prototype consists of a full "vertical" slice of the ATLAS Data Acquisition and Event Filter architecture, including all the hardware and software elements of the data flow, its control and monitoring as well as all the elements of a complete on-line system. This paper outlines the project, its goals, structure, schedule and current status and describes details of the system architecture and its components. (C) 1998 Elsevier Science B.V