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The LHC inner triplets at Fermilab were investigated with regard to quench behavior of quadrupole model magnets.

The development of the superconducting quadrupole magnets for the interaction areas of the Large Hadron Collider is examined.

The Large Hadron Collider Inner Triple Quadrupole Development Program at Fermilab is discussed.

Four prototype superconducting magnets that can be used in replacing several of the existing 36 conventional 1.5 T, 1-meter-long magnets used the Advanced Light Source at Lawrence Berkeley National Laboratory have been designed and tested. The four magnets attained the required field for bending 1.9 GeV electrons 10 degrees but the three had excessive training. The fourth, Superbend 4, attained short-sample current with no training.

A superconducting 3X3 quadrupole magnet array for increasing the beam intensity and reducing space charge effects in a Heavy Ion Fusion Driver has been designed and constructed. A single array unit made up of several quadrupole magnets will be installed within a ferromagnetic accelerating core. The operating quadrupole field is 50 T/m across a 78 mm warm bore and the magnetic length is 0.32 m. The overall array size is 900 mm in diameter and 700 mm long including the cryostat.

Results of magnetic field measurements for three short models of the MQXB quadrupole magnet built at the Fermilab is presented. Results indicate good agreement between the measured and calculated geometric harmonics, magnetization and Lorentz force effects. Measurement of the field along the magnet length and in the magnet end region also agree with the calculated values. It has also been confirmed that the straight section harmonics are within the uncertainty specified in the reference harmonics table.

The design, production experience and experimental results of the initial 2 m quadrupole magnet models are presented. The quadrupole magnets are being designed and tested by the Lawrence Berkeley National Laboratory and the Fermi National Accelerator Laboratory for the LHC Interaction Region inner triplets. The magnets have a nominal gradient of 205 T/m in a 70 mm bore and are designed to operate in a superfluid helium environment at a temperature of 1.9 degrees Kelvin.

The Brookhaven National Laboratory, Lawrence Berkeley National Laboratory and Fermilab are jointly developing a high gradient quadrupole for the LHC interaction regions. The design involves a two-layer, cos(2theta) coil geometry incorporated in a 70 mm aperture operating in superfluid helium conditions. Magnetic, thermal and mechanical design developments for cooling, high field quality and maximum gradient exceeding 250 T/m are described.

An Nb3Sn conductor-based cosine theta type dipole magnet was developed and tested. The D19H features a two-layer dipole magnet with a recycled NbTi outer layer and a Nb3Sn inner layer. Test results reveal that the magnet's splice resistances and ramp-rate sensitivity were low and that 4.4 K training was rapid. A 90% training ceiling of the outer-layer limit was observed at 1.8 K.

A study was conducted on the development of a two-layer superconducting magnet with a NbTi outer layer and a Nb3Sn inner layer. The Nb3Sn coil was used to replace the NbTi dipole magnet's 50 mm bore inner layer. The Nb3Sn coil was fully epoxy impregnated and reacted at 660-degrees celsius for 240 hours using a glass insulated cable with end spacers and aluminum-bronze poles.

In the design of superconducting magnet elements, such as may be required to guide and focus ions in a particle accelerator, one frequently premises some particular current distribution and then proceeds to compute the consequent magnetic field through use of the laws of Blot and Savart or of Ampere. When working in this manner one of course may need to revise frequently the postulated current distribution before arriving at a resulting magnetic field of acceptable field quality. It therefore is of interest to consider an alternative ('inverse') procedure in which one specifies a desired character for the field required in the region interior to the winding and undertakes then to evaluate the current distribution on the specified winding surface that would provide this desired field. By evaluating the specified potential in the region interior to the winding along the interface, we have determined that a relaxation solution to the potential in the region outside the winding can be converged and used to calculate wire location. We have demonstrated this method by applying a slightly modified version of the program POISSON to a periodic alternating sinusoidal quadrupole field.

Wax prototypes of bronze end spacers designed for use in a 13-T superconducting dipole magnets have been fabricated using rapid prototyping processes and a five-axis milling machine. The prototypes enabled different designs to be implemented, physically inspected and optimized to obtain a good fit between magnet coils and spacers. Around 75 spacers are required at the magnet's end to minimize the stored strain energy and field harmonics.

The optimization of an a superconducting dipole magnet composed of niobium titanium conductors is discussed. The optimization, which led to the implementation of a 13-T dipole, involved cable design, cable insulation, Nb3Sn heat treatment conditions, end spacer and pole development, joint design and coil impregnation. The 50-mm-bore prototype demonstrated that the wind-and-react process and soldered joints result in low-resistance joints as well as Nb3Sn and niobium titanium cables.

A superconducting magnet has been designed as one of two candidates for the quadrupoles in the interaction region of the PEP II B-factory collider under construction at SLAC. The iron-free quadrupole, which consists of four nested magnets, has a length of 1.1 m. and high current density in the windings to meet the requirements for a uniform field. Compact in design, it is cooled by helium flow.

Motivated by the need for new means for specification and determination of 3-D fields that are produced by electromagnetic lens elements in the region interior to coil windings and seeking to obtain techniques that will be convenient for accurate conductor placement and dynamical study of particle motion, we have generalized the representation of a 2-D magnetic field to 3-D. We have shown that the 3-D magnetic field components of a multipole magnet in the curl-free divergence-free region near the axis r=0 can be derived from one dimensional functions [A.sub.n](z) and their derivatives.

Test runs were conducted to validate the design of a thin collar and an elliptical yoke for a 1-m long prototype of an accelerator magnet. The 50-mm bore superconducting dipole, known as D19, was fabricated to operate with a magnetic field of 6.6 T at 4.35 K and 5800 A. During the experiment, which was conducted in a horizontal cryostat at 4.35 K and 1.8 K, it proved the viability of using an aluminum spacer for regulating the iron yoke gap and holding the coil prestress a constant.