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Why do modern particle accelerators use repeated small electric-field pushes instead of one enormous voltage?

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Diagram of a linear proton resonance accelerator, or linac, showing protons entering from a source, passing through a series of labeled drift tubes powered by a radio-frequency source, and exiting as a beam through a cavity. — particle accelerator The accelerator is a large-diameter tube within which an electric field oscillates at a high radio frequency. Within the accelerator tube are smaller diameter metallic drift tubes, which are carefully sized and spaced to shield the protons from decelerating oscillations of the electric field. In the spaces between the drift tubes, the electric field is oriented properly to accelerate the protons in their direction of travel.

Modern particle accelerators utilize repeated small electric-field "pushes" rather than a single, enormous voltage because managing extremely high voltages is technically difficult and impractical. When electric potentials exceed one million volts, they frequently cause corona discharges and lightning-like sparks, which dissipate the energy intended for acceleration and can damage the equipment.12

By using multiple, weaker electric fields, modern linear accelerators and cyclic accelerators achieve high particle energies through a cumulative effect. In these systems, particles pass through a sequence of accelerating fields or are guided through the same fields multiple times. This approach relies on alternating voltages—often using radio-frequency electromagnetic waves—to ensure that particles receive a renewed "push" each time they pass through an accelerating region. This method is not only more stable and easier to control than generating a single, massive electrostatic potential but also allows for the creation of high-intensity beams necessary for advanced scientific research.13