Weaving Superconducting Magnets

Magnets are neverendingly awesome, and superconductors may be the ultimate in cool—they are, after all, literally extremely cold. And not just anyone has the tools to weave superconducting magnets with compressed metallic thread. It's a more essential skill than you might think.

Ultra-cold superconducting magnets steer high-speed particles inside colliders, keeping the beams tight and guiding them smoothly through the curves of circular racetracks. But those magnets generally rely on iron, an intrinsically magnetic metal, for key structures. That works beautifully for the particle acceleration, but what about when the beams collide?

Physicists actually track and identify many different bits of subatomic debris based on their paths through precisely defined magnetic fields—iron and other magnetic pipes would seriously throw off any sensitive detector. The challenge, then: Build a superconducting pipe without using those pesky magnetic metals.

Superconducting Magnet Assembly The first pass in winding a final focus magnet for the International Linear Collider.

We stitch superconducting wires (niobium titanium with thin copper jacket) onto non-magnetic stainless steel and fiberglass tubes—that’s the process unfolding above. Just before charged particles such as electrons or protons smash together inside a collider, these superconducting magnets must squeeze them into a tight beam as they enter the hearts of the detectors. The tighter the squeeze, the more fruitful the collision.

The magnet seen here is actually a prototype for the proposed International Linear Collider, which will push particle physics beyond the capabilities of our Relativistic Heavy Ion Collider or CERN’s Large Hadron Collider.

Beyond that, the same techniques are crucial to one of the great challenges in fundamental physics: trapping antimatter. Our magnet team built the magnetic bottle insert that the ALPHA project at CERN used to hold antihydrogen inside a near-perfect vacuum for 1,000 seconds.

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