[en] In this note we shall review, at times with a sense of history, the measured and computed saturation induced harmonics in the cross section of all long and short 80 mm aperture RHIC dipole magnets built so far. With the help of several iterations in the yoke cross section, we have been able to reduce the saturation induced b₂ and b₄ harmonics by more than an order of magnitude. We shall briefly describe those iterations. The calculations described in this note have generally been done with the computer program POISSON. However, while comparing the calculations and measurements, we have included the results of field calculations with the code PE2D and MDP as well. The measurements are the average of up and down ramps. A small difference between the calculations and measurements has been observed consistently in the saturation induced b₂ and b₄ harmonics in all magnets DRA001 through DRA009. More work is still needed to explain the current dependence of skew quadrupole harmonic (α₁). We refer to current dependence of harmonics loosely as the saturation induced harmonics; but in an actual magnet it includes other effects like the harmonics induced by the coil deformation due to lorentz forces, etc

[en] In the RHIC arc dipoles, the center of the cold mass lies above the center of the cryostat. At the maximum design field, the magnetic flux lines leak through the yoke to the asymmetrically located cryostat, which provides an additional return path. This introduces a systematic top-bottom asymmetry leading to a skew quadrupole term at high fields. A similar asymmetry is also created by any difference in weights of the upper and the lower yoke halves. Data from measurements of several RHIC dipoles are presented to study this effect. In the current production series of the RHIC dipoles, an attempt is made to compensate the effect of the cryostat by an asymmetry in the iron yoke. Seven dipoles with this type of yoke have been cold tested, and show a reduced saturation in the skew quadrupole term, as expected

[en] The random multipole errors of superconducting quadrupoles are studied. For analyzing the multipoles which arise due to random variations in the size and locations of the current blocks, a model is outlined which gives the fractional field coefficients from the current distributions. With this approach, based on the symmetries of the quadrupole magnet, estimates are obtained of the random multipole errors for the arc quadrupoles envisioned for the Relativistic Heavy Ion Collider and for a single-layer quadrupole proposed for the Superconducting Super Collider

[en] In the RHIC are dipoles, the center of the cold mass lies above the center of the cryostat. At the maximum design field, the magnetic flux lines leak through the yoke to the asymmetrically located cryostat, which provides an additional return path. This introduces a systematic top-bottom asymmetry leading to a skew quadrupole term at high fields. A similar asymmetry is also created by any difference in weights of the upper and the lower yoke halves. Data from measurements of several RHIC dipoles are presented to study this effect. In the current production series of the RHIC dipoles, an attempt is made to compensate the effect of the cryostat by an asymmetry in the iron yoke. Seven dipoles with this type of yoke have been cold tested, and show a reduced saturation in the skew quadrupole term, as expected

[en] A number of techniques have been developed-and tested to improve the field quality in the superconducting dipole and quadrupole magnets to be used in the Relativistic Heavy Ion Collider (RHIC). These include adjustment in the coil midplane gap to compensate for the allowed and non-allowed harmonics, inclusion of holes and cutouts in the iron yoke to reduce the so harmonics, and magnetic tuning shims to correct for the residual errors. We compare the measurements with the calculations to test the validity of these concepts

[en] The physics that will be possible at Brookhaven National Laboratory ISABELLE is reviewed in basic terms. Among the topics discussed are gluons, intermediate vector bosons, jets, and total cross sections

[en] The authors have studied the random errors in the multipole coefficients of superconducting dipole magnets that result from asymmetries in their construction. In this paper they consider, in a similar way, the random multipole errors of superconducting quadrupoles. Perfect symmetry of construction in such a magnet allows only higher normal multipoles of 12 pole, 20 pole, etc. to be present in the magnetic field. However, when the conductors are not perfectly positioned, this ideal symmetry is broken and the non-allowed multipoles, normal and skew, appear in the magnetic field. In analyzing the multipoles which arise due to random variations in the sizes and locations of the current blocks, the authors adopt a model analogous to that used for their analysis of the superconducting dipole

[en] For the HERA luminosity upgrade two types of compact multifunction superconducting magnets, denoted GO and GG, are needed for installation inside the existing ZEUS and Hl experimental detectors in the year 2000. These magnets contain multiple concentric coil layers organized into independently powered quadrupole, dipole, skew quadrupole and skew dipole coil windings. Production of the first of three GO magnets using a newly constructed coil winding machine is currently in progress at BNL. The GG design is being completed and parallel production at BNL of three GG units will start soon. In this paper we highlight HERA upgrade magnet design challenges, present our production solutions and relate experience and results gained from warm and cold testing of short model magnets

[en] The Superconducting Super Collider uses ∼9600 dipole magnets. The magnets have been carefully designed to exhibit minimal magnetic field harmonics. However, because of superconductor magnetization effects, iron saturation and conductor/coil positioning errors, certain harmonic errors are possible and must be corrected by use of multipole correctors called trim coils. For the most efficient use of axial space in the magnet, and lowest possible current, a distributed internal correction coil design is planned. The trim coil assembly is secured to the beam tube, a UHV tube with special strength, size, conductivity and vacuum. This report details the SSC trim coil/beam tube assembly specifications, history, and ongoing development

[en] The Relativistic Heavy Ion Collider (RHIC) under construction at Brookhaven National Laboratory (BNL) 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 tesla. In this paper we discuss the magnetic design of the coil and iron cross section for these magnets. The first part will describe the quadrupoles and the second part the dipoles. 4 refs., 3 figs., 4 tabs