| Henryk Piekarz of Fermilab’s Accelerator Division controls the flow of cryogens in the high-temperature superconductor magnet prototype. Photo: Ryan Postel, Fermilab |
A small team of physicists, engineers and technicians at the U.S. Department of Energy’s Fermi National Particle Accelerator Laboratory, led by Henryk Piekarz, just demonstrated the world’s fastest magnetic ramping rates for particle accelerator magnets. Noteworthy, they achieved this record by using magnets made with energy-efficient, high-temperature superconducting material.
What is the best conductor?
Despite the many attractive features of superconducting wire, the fastest-ramping high-energy particle accelerators still use magnets with copper conductors operating at room temperature. Examples include the 3 GeV proton ring at JPARC in Japan, which features a magnetic field that changes at a rate of 70 tesla per second (T/s) and reaches a peak magnetic field of 1.1 tesla, and the 8 GeV Booster ring at Fermilab, which achieves a ramping rate of 30 T/s and a peak field of 0.7 tesla.
Most of the powerful superconducting magnets employed in modern-day particle accelerators are relatively slow when it comes to increasing the magnetic field. Their main goal is to ramp up to a high peak magnetic field to steer particles around a ring while electric fields propel the particles to higher and higher energy. The higher the energy, the stronger the magnetic field must be to keep the particles in their track as they go around the ring.