Introduction

In a groundbreaking collaboration, researchers from the Berkeley Lab's Accelerator Technology & Applied Physics (ATAP) Division have joined forces with experts from Michigan State University's Facility for Rare Isotope Beams (FRIB) to innovate a pioneering superconducting magnet utilizing niobium-tin (Nb3Sn) technology. This magnet, a first in its class, has the potential to dramatically elevate the operational effectiveness and scientific capabilities of FRIB, the world’s most powerful heavy-ion accelerator.

Impact of the Research

Published in the esteemed journal IEEE Transactions on Applied Superconductivity, this exciting research could spark new advancements across various fields, including medicine, industrial applications, and fundamental scientific inquiry. At FRIB, the facility accelerates ionized atoms to speeds nearing half the speed of light, enabling groundbreaking collisions that produce short-lived isotopes. These isotopes are critical for advancing our understanding of atomic structures and cosmic evolution, offering insights into phenomena that remain largely shrouded in mystery.

Role of ECRIS

Tengming Shen, a leading scientist at ATAP, describes the integral role of the electron cyclotron resonance ion source (ECRIS) at FRIB. This state-of-the-art system uses a unique combination of magnets to confine electrons and ions in a plasma environment, subsequently heating them with high-frequency microwaves to produce highly charged ions. Current configurations utilize a sextupole magnet made with niobium-titanium (Nb-Ti), a material capable of producing magnetic fields of 6.7 tesla at ultra-cool temperatures. However, researchers are eyeing an upgrade to ensure higher magnetic fields, ideally over 10.8 T, to support microwave frequencies exceeding 45 GHz.

Transition to Nb3Sn Magnets

To meet this ambitious demand, the research team is transitioning to Nb3Sn magnets, which can handle much higher current densities and magnetic fields—potentially reaching up to 22 T. This leap in technology, however, isn’t without its challenges. Nb3Sn is known for its brittleness and susceptibility to strain, requiring a carefully managed fabrication process. Unlike Nb-Ti, the coils produced need a complex design involving hundreds of turns with small conductors, considerably increasing the difficulty in manufacturing.

Berkeley Lab's Expertise

Despite these challenges, Berkeley Lab has extensive experience with Nb3Sn magnets, having recently completed an important milestone by fabricating a set of quadrupole magnets utilizing superconducting cables made of this material. This progress is part of a larger initiative, contributing to the U.S. Accelerator Upgrade Project and aiming to enhance the capabilities of major particle physics experiments, including those at the Large Hadron Collider.

Expected Benefits

Soren Prestemon, Deputy Director of Technology at ATAP, emphasizes the dual benefits of this innovative magnet design, predicting it will not only advance accelerator technology but also reinforce FRIB's position at the forefront of scientific exploration.

Current Progress and Future Plans

Detailed magnetic and mechanical design calculations have already been conducted to tackle the unique challenges associated with Nb3Sn. Fabrication trials for the coils are underway, with a full-sized prototype set to be tested shortly. Success in these operations could pave the way for the implementation of a cutting-edge 28 GHz ECRIS system while laying the groundwork for future enhancements.

The Future of High-Energy Research

Jie Wei, the director of the Accelerator Systems Division at FRIB, articulates the magnet's potential to redefine high-energy research. The transition from Nb-Ti to Nb3Sn promises increased safety margins and the capability to operate at advanced frequencies, facilitating heightened plasma power and more efficient ion generation.

Conclusion

As these breakthroughs unfold, FRIB stands poised to remain at the cutting edge of fundamental science, allowing researchers to push the boundaries of our understanding of matter and the universe. The quest continues, and with it, the thrill of discovery awaits. Stay tuned for updates on this pivotal development in accelerator technology!