M. Rehak

About the mechanics of SSC dipole magnet prototypes

During the last two years, nine 4‐cm aperture, 17‐m‐long dipole magnet prototypes were produced by Brookhaven National Laboratory (BNL) under contact with the Superconducting Super Collider (SSC) Laboratory. These prototypes are the last phase of a half‐decade‐long R&D program, carried out in collaboration with Fermi National Accelerator Laboratory and Lawrence Berkeley Laboratory, and aimed at demonstrating the feasibility of the SSC main‐ring dipole magnets. They also lay the groundwork for the 5‐cm‐aperture dipole magnet program now underway. After reviewing the design features of the BNL 4‐cm‐aperture, 17‐m‐long dipole magnets, we describe in detail the various steps of their fabrication. For each step, we discuss the paramaters that need to be mastered, and we compare the values that were achieved for the nine most recent prototypes. The data appear coherent and reproducible, demonstrating that the assembly process is under control. We then analyze the mechanical behavior of these magnets during cool...

Construction and testing of arc dipoles and quadrupoles for the Relativistic Heavy Ion Collider (RHIC) at BNL

The production run of superconducting magnets for the Relativistic Heavy Ion Collider (RHIC) project at Brookhaven National Laboratory (BNL) is well underway. Of the 288 arc dipoles needed for the collider, more than 120 have been delivered. More than 150 arc quadrupoles have been delivered. All of these magnets have been accepted for RHIC. This paper reports the construction and performance of these magnets. Novel features of design and test, introduced to enhance technical performance and control costs, are also discussed.

Large aperture quadrupoles for RHIC interaction regions

The ultimate luminosity performance of the Relativistic Heavy Ion Collider (RHIC) depends on the field quality in the large aperture (130 mm) superconducting quadrupoles in the interaction regions. In this paper we discuss the design features that are incorporated to obtain a good field quality. Coil midplane gap and pole shims may be adjusted to remove certain field harmonics due to systematic errors in construction. Iron tuning shims will be inserted at eight strategic locations in the assembled magnets to correct the measured values of harmonics in each magnet. The performance of two prototype magnets and upgrades under consideration will be discussed.<<ETX>>

Status of 4-cm Aperture, 17-m-Long SSC Dipole Magnet R&D Program at BNL Part I: Magnet Assembly

Over the last year-and-a-half, several 4-cm-aperture, 17-m-long dipole magnet prototypes were built by Brookhaven National Laboratory (BNL) under contract with the Superconducting Super Collider (SSC) Laboratory. These prototypes are the last phase of a half-decade-long R D program, carried out in collaboration with Fermi National Accelerator Laboratory and Lawrence Berkeley Laboratory, and aimed at demonstrating the feasibility of the SSC main ring dipole magnets. They also prepare the way of the 5-cm-aperture dipole magnet program to be started soon. In this paper, we analyze the mechanical behavior of the BNL prototypes during cool-down and excitation, and we attempt to relate this behavior to the magnet features. The data reveal that the mechanical behavior is sensitive to the vertical collar-yoke interference, and that the magnets exhibited somewhat erratic changes in coil end-loading during cool-down. 9 refs., 6 figs.

Quench propagation study for full-length RHIC dipole magnets

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. >

Results of magnetic field measurements of 40 mm aperture 17-m long SSC model collider dipole magnets

Magnetic field measurements have been made on twelve 17-m-long, 40-mm-aperture R&D superconducting dipoles. Data on dipole field strength, multipole coefficients, and alignment have been obtained. The data indicate that the magnets as built are generally within the expectations for this design. >

Test results of BNL built 40-mm aperture, 17-m-long SSC collider dipole magnets

Eleven 17-m-long, 40-mm-aperture SSC (Superconducting Super Collider) R&D superconducting collider dipole magnets, built at BNL (Brookhaven National Laboratory), have been extensively tested at BNL and Fermilab during 1990-1. Quench performance of these magnets and details of their mechanical behavior are presented. Although the quench performance of the most recent magnets shows slightly more quenches than expected, there is now a better understanding of the mechanical behavior of these magnets. The baseline design leads to reasonable quench performance. The quench performance of the DC series magnets seems to indicate a strong sensitivity to change in design parameters, key among them being the collar-yoke interference and the coil end loading. >

RHIC insertion magnets

The Relativistic Heavy Ion Collider (RHIC) has six interaction regions for the colliding beam. Each interaction region is part of an insertion region consisting of several magnets. The required aperture of some of the quadrupoles and dipoles in the insertion regions is much larger than the nominal 80-mm aperture of the other magnets in the accelerator. There will be 82 quadrupole magnets having an aperture of 130 mm and a maximum operating field gradient of 59 T/m, and 12 dipole magnets having an aperture of 200 mm and an operating central field of 4.3 T. The authors discuss the magnetic design of the coil and iron cross section for these magnets.<<ETX>>

B series RHIC arc quadrupoles

A series of pre-production superconducting quadrupoles has been constructed at Brookhaven National Laboratory. These magnets have an operating gradient of 71 Tesla/meter with a coil bore of 80 mm. The eight magnets are exact prototypes of the quadrupoles which will be used in the arcs. These magnets were tested and measured and met the accelerator specifications.<<ETX>>

Test of eight superconducting arc quadrupoles for RHIC

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. >