In a cyclotron, the purpose of large electrodes is to what?

In a cyclotron, large electrodes are primarily utilized to accelerate particles. The cyclotron operates by using a combination of a magnetic field and an electric field to create a circular motion for charged particles, typically ions. The electrodes, often referred to as "dees" due to their D-shaped design, create an alternating electric field as the particles travel through them. Each time the particles cross the gap between the electrodes, they gain energy due to the electric field, which accelerates them. As the particles continue to spiral outward due to the magnetic field, they accumulate more energy until they can be directed toward a target for various applications, such as medical isotope production or scientific research.

While the other options refer to important functions or concepts, they do not accurately describe the primary role of large electrodes in a cyclotron. For example, enhancing magnetic fields, shielding against radiation, or extracting positive ions may occur in the context of a cyclotron, but they do not represent the fundamental purpose of the electrodes themselves.