The Large Hadron Collider Project

The Large Hadron Collider (LHC), approved by the CERN Council in December 1994, will be the premiere research tool at the energy frontier of particle physics. It will provide proton-proton collisions with a centre-of-mass energy of 14 TeV and an unprecedented luminosity of 1034 cm-2 s-1. The most critical technologies of the LHC are the superconducting magnet system, with a dipole field above 8 Tesla, and the huge cryogenic system operating at below 2 K needed to achieve such high fields. A brief overview of the project is presented and the main technological challenges are discussed

LHC accelerator physics and technology challenges

The Large Hadron Collider (LHC) incorporates many technological innovations in order to achieve its design objectives at the lowest cost. The two-in-one magnet design, with the two magnetic channels i ntegrated into a common yoke, has proved to be an economical alternative to two separate rings and allows enough free space in the existing (LEP) tunnel for a possible future re-installation of a lept on ring for e-p physics. In order to achieve the design energy of 7 TeV per beam, with a dipole field of 8.3 T, the superconducting magnet system must operate in superfluid helium at 1.9 K. The LHC wi ll be the first hadron machine to produce appreciable synchrotron radiation which, together with the heat load due to image currents, has to be absorbed at cryogenic temperatures. A brief review of th e machine design is given and some of the main technological and accelerator physics issues are discussed

The Large Hadron Collider: Present Status and Prospects

The Large Hadron Collider (LHC), due to be commissioned in 2005, will provide particle physics with the first laboratory tool to access the energy frontier above 1 TeV. In order to achieve this , protons must be accelerated and stored at 7 TeV, colliding with an unprecedented luminosity of 1034 cm-2 s-1. The 8.3 Tesla guide field is obtained using conventional NbTi technology cooled to below the lambda point of helium. Considerable modification of the infrastructure around the existing LEP tunnel is needed to house the LHC machine and detectors. The project is advancing according to schedule with most of the major hardware systems including cryogenics and magnets under construction. A brief status report is given and future prospects are discussed

LHC Status and Plans

The Large Hadron Collider project (LHC) was approved by the CERN Council in December 1994 as a two-stage project, the first stage at two thirds of the final centre-of-mass energy of 14 TeV to become operational in 2004 and the final stage to be completed in 2008. The CERN management was also requested to solicit contributions to the machine construction from Non-member States involved in the experimental programme in order to allow construction of the machine in a single stage. Taking into consideration the strong support for the project from a number of countries outside the Member States, the CERN Council decided in December 1996 that the machine should be constructed in a single stage with first physics in 2005. Although global participation in detector construction has been well established for many years, this is the first large CERN project in which Non-member States have been involved in the construction of a machine. A brief status report is given and future plans are discussed

Progress in construction of the LHC

The Large Hadron Collider (LHC) project, approved by the CERN Council in December 1994, has now fully entered its construction phase, with the detailed technical definition of the major systems, and the adjudication of a number of large procurement contracts. We first recall the main features and characteristics of the LHC, report on the advances in definition of the layout and optics as well as on preparation of the injector complex, and review recent progress in the key technical systems of the main ring: magnets, cryogenics and vacuum, as well as civil construction, which has started following acceptance by authorities in the Host States

Shape computations without compositions

Parametric CAD supports design explorations through generative methods which compose and transform geometric elements. This paper argues that elementary shape computations do not always correspond to valid compositional shape structures. In many design cases generative rules correspond to compositional structures, but for relatively simple shapes and rules it is not always possible to assign a corresponding compositional structure of parts which account for all operations of the computation. This problem is brought into strong relief when design processes generate multiple compositions according to purpose, such as product structure, assembly, manufacture, etc. Is it possible to specify shape computations which generate just these compositions of parts or are there additional emergent shapes and features? In parallel, combining two compositions would require the associated combined computations to yield a valid composition. Simple examples are presented which throw light on the issues in integrating different product descriptions (i.e. compositions) within parametric CAD

Vibrations of a Columnar Vortex in a Trapped Bose-Einstein Condensate

We derive a governing equation for a Kelvin wave supported on a vortex line in a Bose-Einstein condensate, in a rotating cylindrically symmetric parabolic trap. From this solution the Kelvin wave dispersion relation is determined. In the limit of an oblate trap and in the absence of longitudinal trapping our results are consistent with previous work. We show that the derived Kelvin wave dispersion in the general case is in quantitative agreement with numerical calculations of the Bogoliubov spectrum and offer a significant improvement upon previous analytical work.Comment: 5 pages with 1 figur