Akhdiyor Sattarov

On the Feasibility of a Tripler Upgrade for LHC

The design of high-field dipoles has been optimized using a block coil geometry. The optimization includes stress management and flux plate suppression of multi-poles from snap-back. The design has been extended to higher field by devising a hybrid coil geometry containing inner windings of Bi-2212 and outer windings of Nb3Sn. A 24 Tesla dual dipole using this design offers the possibility of an LHC tripler. Issues of fabrication technology and synchrotron radiation control are discussed. There is no obvious upper limit to the field that could be attained for the dipoles of future hadron colliders.

A superconducting isochronous cyclotron stack as a driver for a thorium-cycle power reactor

Designs for thorium-cycle power reactors require a proton driver capable of 1 GeV energy and 10 MW total power. For this purpose we have prepared a preliminary design for the magnetic structure for a stack of 5 super-conducting isochronous cyclotrons, each delivering 2 MW beam power. By achieving the required power with multiple independent apertures rather than pushing beyond currently achieved limits, we hope to arrive at a design that is cost-minimum and reliable. Each sector magnet consists of a flux-coupled stack of cold-iron inserts supported within a single warm-iron, in a fashion inspired by the new Riken heavy-ion cyclotron. We have developed a preliminary field design in which in-plane fields are cancelled in all 5 apertures and the field-map is appropriate for the focusing optics of the sector cyclotron.

Optimization of block-coil dipoles for hadron colliders

A first model dipole is being built for a 16 Tesla block-coil dipole for future hadron colliders. The design uses stress management: a support matrix that intercepts Lorentz stress between successive sections of the coil and bypasses it to prevent strain degradation of the superconductors and insulation. The block-coil methodology has also been used to design dipoles for 12 Tesla and 15 Tesla, in which the amount of superconductor is minimized by cabling copper stabilizer strands with superconductor strands. The 12 Tesla block-coil dipole requires only one-fifth as much superconductor as does a 12 Tesla cos /spl theta/ dipole that is being developed elsewhere.

Optimized block-coil dipoles for future hadron colliders

We are developing an improved technology for high-field dipoles, aimed at making a robust, affordable Nb/sub 3/Sn dipole for future hadron colliders and other accelerator applications. The technology incorporates five elements that depart from conventional dipole design. The coil is arranged in rectangular blocks, rather than the usual cos /spl theta/ geometry. The coil contains a structural support matrix that provides stress management. The superconducting cables in the coil contain an admixture of superconducting and pure copper strands, with the ratio chosen in each coil region to optimize the use of superconductor. Multipoles are controlled over a large dynamic range by current programming a trim winding. Finally, persistent-current multipoles are suppressed at low field by a close-coupled planar steel boundary. We show that these five design elements enable the design of conductor-optimized dipoles up to at least 16 Tesla. We describe a particular design for a 12 Tesla dipole that could triple the energy of the Fermilab Tevatron and support a new generation of hadron collider physics at the existing facility. Progress is reported on the construction and testing of model dipoles.

Bi-2212 Structured Cable for High-Field Solenoid Inserts

A structured cable has been developed and tested for use in insert windings for high-field solenoids. The cable utilizes a design developed earlier, in which six strands of multi-filament Bi-2212/Ag round wire are cabled around a thin-wall spring tube and jacketed in a high-strength Inconel sheath. The cable provides stress management within each winding so that coil stress cannot degrade the fragile superconducting filaments. The cable-based coil accommodates inward pre-load, giving the potential for twice the achievable field increment per shell. Prototype lengths of cable have been prepared and a heat treatment schedule has been optimized. Test results are presented for the performance of small test windings.

Accelerator-driven subcritical fission in molten salt core: Closing the nuclear fuel cycle for green nuclear energy

A technology for accelerator-driven subcritical fission in a molten salt core (ADSMS) is being developed as a basis for the destruction of the transuranics in used nuclear fuel. The molten salt fuel is a eutectic mixture of NaCl and the chlorides of the transuranics and fission products. The core is driven by proton beams from a strong-focusing cyclotron stack. This approach uniquely provides an intrinsically safe means to drive a core fueled only with transuranics, thereby eliminating competing breeding terms.

Test Results of a

A second phase of a high field dipole technology development has been tested. A Nb3Sn block-coil model dipole was fabricated, using magnetic mirror geometry and wind/react coil technology. The primary objective of this phase was to make a first experimental test of the stress-management strategy pioneered at Texas A&M. In this strategy a high-strength support matrix is integrated with the windings to intercept Lorentz stress from the inner winding so that it does not accumulate in the outer winding. The magnet attained a field that was consistent with short sample limit on the first quench; there was no training. The decoupling of Lorentz stress between inner and outer windings was validated. In ramp rate studies the magnet exhibited a remarkable robustness in rapid ramping operation. It reached 85% of short sample(ss) current even while ramping 2-3 T/s. This robustness is attributed to the orientation of the Rutherford cables parallel to the field in the windings, instead of the transverse orientation that characterizes common dipole designs. Test results are presented and the next development phase plans are discussed.

{\rm Nb}_{3}{\rm Sn}

The second phase of development of a new high-field dipole technology has been completed. A model dipole employing wind/react Nb 3Sn cable and stress-managed block coil geometry was fabricated and will soon be tested at LBNL. The dipole features stress-strain management in its internal windings and metal-filled bladder preload. Pending validation of performance of these new features, the new technology should result in improved cost-effective fabrication of dipoles for 16 T and beyond. Construction experience and plans for the next phase of development are presented

Wind/React “Stress-Managed” Block Dipole

The design of a 1.5-T superconducting magnet for open MRI for breast imaging is described. The homogeneous field region is designed to lie above the surface of the unit, so that it includes both breasts for a woman lying prone upon the surface. The magnet was designed using a novel approach to optimizing the field, and the coil structure utilizes a novel structured coil strategy that makes it possible to produce the patterns of current required in the design.

Construction of a Mirror-Configuration Stress-Managed

The current status of the Texas A&M superconducting magnet R&D program is reported. The program is implementing a design philosophy in which Lorentz stress is managed within the coils of a block-coil geometry, isostatic preload is delivered using an arrangement of pressurized Woods metal filled bladders, insulation utilizes fine-filament Silane-sized S-glass, and low-field multipoles are constrained by a flux plate integrated with the coil package. Construction progress on TAMU3 is reported and plans for a full-aperture dipole TAMU5 are discussed.