Summary of the Workshop on Beam-Beam effects in Large Hadron Colliders (LHC99)

The beam-beam interaction can limit the performance of hadron colliders such as the LHC and has to be taken into account during the design of the accelerator. A workshop was held at CERN from 12 to 16 April 1999 to review the current knowledge and experience and to discuss ongoing and future studies. The contributions and details of the discussion and the summaries are compiled in the proceedings of the workshop [1]. While these proceedings are a working document for further studies, this report intends to give an overview of the main problems and provides the interested but non-specialised reader with a survey of the critical issues, together with the proposed solutions and studies

Using SDDS data sets with MAD-X

The MAD-X program, which is used for the design of the LHC optics and other accelerators, is presently modified to be used as an on-line simulation tool. In this note we describe additional features developped for MAD-X to read and write the data structures used in the LHC Application Software project

Special Masters in State Court Complex Litigation: An Available and Underused Case Management Tool

This article examines the role masters have played in litigation and explores the benefits that might be obtained from the greater use of masters in the future. The FJC survey of federal judges appointing special masters concluded that special masters were “extremely or very effective.” The FJC study is an empirical survey of the effectiveness of special masters, and it includes commentary from judges regarding their experience after appointing special masters. These benefits include better, faster, and fairer resolution of litigation in the cases in which masters are used, as well as an easing of the burdens these cases place on the judiciary. This article also analyzes the barriers to the use of masters and how they might be removed

Self-Consistent parallel multi bunch beam-beam simulation using a grid-multipole method

The simulation code COMBI has been developed to enable the study of coherent beam-beam effects in the full collision scenario of the LHC, with multiple bunches interacting at multiple crossing points over many turns. The parallel version of COMBI was first implemented using a soft-Gaussian collision model which entails minimal communication between worker processes. Recently we have extended the code to a fully self-consistent collision model using a Grid-Multipole method, which allows worker processes to exchange charge and field information in a compact form which minimizes communication overhead. In this paper we describe the Grid-Multipole technique and its adaptation to the parallel environment through pre- and post-processing of charge and grid data. Performance measurements in a Myrinet cluster environment will be given