Nobelium-titanium alloy foil and pure niobium tube - Working together to create the heart of cutting-edge technology - superconductivity

At the cutting-edge of technological research that strives for the physical limits, pure niobium tubes (and the cavities they form) and niobium-titanium alloy foils may seem ordinary, but they are actually the key materials that determine success or failure. When considered individually, they are already excellent engineering materials, but when precisely combined, they jointly form the "superconducting heart" of human exploration of the microscopic world and development of frontier applications.

The pure niobium tubes used for superconducting cavities usually require extremely high purity (RRR > 300), with very few impurities. The purity of the niobium tubes is crucial. Because niobium tubes possess outstanding superconducting properties. Pure niobium has the highest superconducting transition temperature (9.2K) and extremely high critical magnetic field among all elements, enabling it to withstand extremely high acceleration gradients. It is an ideal material for manufacturing radio frequency superconducting cavities. The resonant cavities fabricated from pure niobium tubes can conduct microwave currents almost without resistance at extremely low temperatures, generating a powerful electric field to accelerate particles.

Nitinol alloy foil is a "heat dissipation expert" at extremely low temperatures. Although nitinol alloy itself is also a superconductor, its critical magnetic field is higher, and it is usually used to manufacture superconducting wires (for magnets) rather than radio frequency cavities. In the liquid helium temperature range (approximately 2K), nitinol alloy exhibits an astonishing thermal conductivity, much higher than pure niobium. This property makes it an indispensable heat sink material in extremely low-temperature environments. When the superconducting cavity is in operation, any minor disturbance, such as stray magnetic fields, resistance losses at microscopic defects, or cosmic rays, can cause local temperature increases. Once the local temperature exceeds the superconducting transition temperature of niobium, the area will instantly regain resistance, generating Joule heat. This process spreads rapidly like an avalanche, causing the entire cavity to lose its superconductivity, which is known as "superconducting transition failure" (or "superconducting quench").

To prevent "overheating", it is necessary to quickly remove any potential "hot spots" of heat and disperse them into the surrounding liquid helium. This is when the niobium-titanium alloy foil comes into play.

How to produce standard superconducting cavities? First, a pure niobium tube is precisely processed, shaped and undergoes a series of surface treatments (such as electro-polishing and annealing) to form a radio frequency superconducting cavity. Then, a thin and uniform niobium-titanium alloy foil is tightly wrapped or adhered to the outer wall of the pure niobium cavity. Finally, a copper outer shell is encapsulated on the outside of the niobium-titanium alloy foil, and liquid helium is circulated inside.

In this way, a "sandwich" structure is formed: pure niobium (superconducting layer) - niobium-titanium alloy foil (heat sink layer) - copper (structural support and helium flow channel).

When a local hot spot occurs in the pure niobium cavity, heat is generated. The heat rapidly spreads to the adjacent niobium-titanium alloy foil. Thanks to its extremely high low-temperature thermal conductivity, the heat is instantly diffused laterally. The diffused heat is transferred through the niobium-titanium alloy foil to the liquid helium. The heat is efficiently removed, and the local temperature drops. Thus, the hot spot is eliminated in its infancy, maintaining the superconducting state, and the cavity operates stably. Without this layer of niobium-titanium alloy foil, the pure niobium cavity has insufficient heat dissipation ability, and its resistance to "superconducting failure" will be greatly reduced. It cannot be applied to high-performance accelerators.

The radio frequency superconducting cavities, which are manufactured using pure niobium tubes and niobium-titanium alloy foils, are the core components in the following fields: Particle colliders: Examples include the upgrade of the Large Hadron Collider at the European Organization for Nuclear Research, and the project of the Circular Electron-Positron Collider in China, which are used to explore the fundamental composition of matter.

Free electron laser: Produces extremely bright and short-pulsed X-rays, which are used in materials science, structural biology and chemical research.

Synchrotron radiation source: As a "super microscope", it provides advanced light sources for multidisciplinary research.

Medical isotope production and cancer treatment equipment: Developing more advanced and precise radiation therapy technologies.

The perfect combination of pure niobium tubes and niobium-titanium alloy foils is the result of the wisdom of materials science and engineering. It has solved the core problem of the stable operation of high-performance superconducting cavities in extreme environments. Understanding the relationship between these two materials is equivalent to having the key to opening the doors to modern particle accelerator technology and many cutting-edge applications. As the requirements for the energy and efficiency of accelerators become increasingly higher in the future, this precise material combination process will continue to play an indispensable role.

Fortu Tech supplies NbTi alloys foil products to multiple countries and regions around the world. Its service coverage includes the United States, Canada, Russia, Germany, France, the United Kingdom, Italy, Sweden, Austria, the Netherlands, Belgium, Switzerland, Spain, Czech Republic, Poland, Japan, South Korea, as well as Chile, Brazil, Argentina, Colombia and other places in Latin America.

Fortu Tech can produce and process niobium foil, niobium Capillary Tube, niobium billet, niobium sheet & plate, niobium rod, niobium wire, niobium tubes, niobium target, niobium ingot.