Introduction
Superconductivity is a phenomenon of zero electrical resistance and perfect diamagnetism observed in certain materials at very low temperatures. Superconductors can be used to create unparalleled magnetic fields, and people use them in numerous ways. One of the most common applications is in high-field magnets. These superconducting magnets can be used in fields such as nuclear magnetic resonance (NMR) and high-energy physics. This article will explore the manufacturing process utilized in producing superconducting magnets.
Raw Materials
The ingredients required to make a superconducting magnet are the superconductors themselves. These are usually niobium-tin, niobium-titanium, or bismuth-strontium-calcium-copper-oxide, though other superconductors exist. Suppliers of superconductor materials usually provide the raw materials in coil form, consisting of strands of wire encapsulated in a copper sheath. This copper is important, as it serves as the electrical conductor for the magnet. Also needed are special plastics and epoxies, which are used in the wrap-coat process of creating the magnet.
Manufacturing Process
Assembly
The first step in creating a superconducting magnet is to assemble the raw materials. This includes the superconductor wire, the copper and the plastic wrap. The wire and the copper are wound in layers like a spring, with the plastic wrapping each layer. This wound package of material is typically about one inch in diameter and varies in length depending on the size of the magnet. The bundle is then crimped together to hold it together and to conduct electricity through the entirety of the coil.
Forming the Magnet
Once the material is wound and crimped, the magnet is formed into the desired shape. This shaping is done by pressing the coil into a metal mold. By doing this, the final shape of the magnet is achieved.
Cryostat Setup
Once the magnet is formed, it is placed in an enclosed vacuum chamber called a cryostat where cooling is done. This chamber is filled with special liquids that cool to extremely low temperatures. Very high vacuum levels are also needed, so a powerful vacuum pump is used to reduce the air pressure inside the cryostat.
Cryopumping
The next step is cryopumping, in which a long tube is attached to the vacuum chamber. This tube is then filled with liquids such as nitrogen, argon, or hydrogen. The addition of these liquids causes a reduction of pressure within the cryostat. This lowers the temperature, cooling the magnet down to the temperatures at which it operates as a superconductor.
Testing and Quality Assurance
Once the cryopumping is complete, the magnet must be tested for quality assurance. This is done by measuring inductance, which is the amount of electricity the magnet can produce. Measurements like this help to ensure that the magnet is meeting the required specifications for performance. Once these tests are done, the magnet is ready for use.
Conclusion
Superconducting magnets offer a wide range of applications in numerous fields. They can be used in particle accelerators, MRI machines and other high-field machinery. The process described in this article provides a thorough guide to the manufacturing process of these technologically advanced machines, helping ensure that the magnets are of the highest quality.
