Search

The Relativistic Heavy Ion Collider now under construction at Brookhaven National Laboratory (BNL) is a colliding ring accelerator to be completed in 1999. Through collisions of heavy ions it is hoped to observe the creation of matter at extremely high temperatures and densities, similar to what may have occurred in the original 'Big Bang'. The collider rings will consist of 1740 superconducting magnet elements. Some of these elements are being manufactured by industrial partners (Northrop Grumman and Everson Electric). Others are being constructed or assembled at BNL. A description is given of the magnet designs, the plan for manufacturing and test results. In the manufacturing of the magnets, emphasis has been placed on uniformity of their performance and on quality. Results so far indicate that this emphasis has been very successful.

Over a period of ten months, a 15 m-long, 50 mm-aperture superconducting SSC Collider dipole was taken through a series of thermal and power cycles to check for changes in performance. One quench below operating current was experienced during this period. Small changes in the coil preload and certain harmonics were observed.

Test results from a group of eight superconducting quadrupoles made at Brookhaven National Laboratory are presented. The magnets have been designed for use in the arc regions of the Relativistic Heavy Ion Collider now under construction at Brookhaven. Novel features of the design include a single-layer coil, the use of injection-molded phenolic for the pole spacers, and a yoke that also serves as a collar. This R&D series has been used to verify the magnet quench performance and field quality prior to the start of the production run in industry.

Four 8 cm aperture sextupoles have been built at BNL to verify the magnetic performance of this magnet in the RHIC installation. Two significantly different mechanical configurations have been designed, and two magnets of each design have been built, and successfully tested, and have exceeded the required minimum quench current by a substantial margin. This report describes the assembly details of the second configuration, which is the final production configuration. In addition the first industry built production sextupole has been delivered and tested. This report presents the results of quench tests on all 5 magnets and field measurements on the first production sextupole.

Quench propagation velocities and conductor hot spot temperatures have been studied during the testing of RHIC superconducting dipole magnets. These studies were facilitated by artificially inducing quenches with spot heaters. The results of these tests are presented here and are compared with adiabatic model calculations.

The testing of 90 cm long racetrack shaped coils at 77 K and 4.2 K in a common coil configuration is described and performance compared with shorter versions.

Studies of the Mesolithic-Neolithic transition in Europe have focused on plants and animals exploited for food. However, the exploitation of plants for fibres underwent a significant change with the addition of domestic flax as a fibre crop. While the technology of flax fibre processing is increasingly understood by archaeologists, its material value as a fibre crop in comparison to indigenous fibre is less well explored. We examine the mechanical properties of flax and two indigenous fibres (lime bast, willow bast), by testing fibre strips for tensile properties and discuss the results in the light of material choices in these periods. [ABSTRACT FROM AUTHOR]