The term “atom smasher” is the common name for a particle accelerator. This sophisticated technology generates highly focused beams of charged subatomic particles, such as electrons or protons, and propels them to extremely high speeds and energies. Accelerators serve a fundamental purpose in modern science by allowing researchers to investigate the smallest building blocks of matter and energy. They enable discoveries ranging from testing theories about the universe’s origins to developing new medical treatments.
How Particle Accelerators Work
Particle accelerators manipulate charged particles using electric and magnetic fields. The entire process occurs within a vacuum to prevent high-speed particles from colliding with air molecules, which would obstruct the beam. A particle source, such as hydrogen gas, provides the protons or electrons that are accelerated.
Acceleration is achieved using electric fields, which function like a series of precisely timed pushes or pulls on the charged particles. These fields are generated by radiofrequency cavities, which switch polarity at a specific frequency. Each time a particle passes through an active cavity, it receives an energy boost, increasing its speed toward the speed of light.
Magnetic fields, produced by electromagnets, guide the beam. Unlike electric fields, magnetic fields do not increase the particle’s energy. Strong dipole magnets bend the path of the beam, keeping it contained within the vacuum tube, especially in circular designs. Quadrupole magnets act like lenses, ensuring the high-energy beam remains tightly focused and prevents the particles from scattering.
Linear Versus Circular Designs
Particle accelerators are generally built in one of two fundamental configurations: linear or circular. Each design uses the same underlying principles of electric acceleration and magnetic guidance, but they apply them differently.
Linear accelerators, or linacs, propel particles in a straight line. Because the particles only pass through the accelerating electric fields once, higher energy requires increasing the machine’s length. The Stanford Linear Accelerator (SLAC), for example, is over three kilometers long. Particles in linacs do not lose energy from bending their path, a phenomenon known as synchrotron radiation.
Circular accelerators, such as synchrotrons and cyclotrons, guide particles around a closed loop using powerful magnets. This design allows the particles to pass through the same accelerating electric fields repeatedly, gaining energy with each revolution. As the particle energy increases, the magnetic fields must be continuously strengthened to keep the particles on their curved path.
Primary Uses in Science and Medicine
Particle accelerators are utilized from probing the fundamental nature of the universe to treating diseases. In fundamental research, the primary use is to create particle collisions. Scientists collide particles, either into a fixed target or head-on with another beam, to break them apart and observe the resulting debris.
Physicists gain insights into the subatomic forces and particles that govern all matter. Discoveries like the Higgs boson, a particle that helps explain why other fundamental particles have mass, are only possible using these powerful colliders. These experiments test the predictions of theoretical physics.
Beyond fundamental research, accelerators are used in medicine and industry. Linear accelerators are standard equipment for radiation therapy, generating high-energy X-rays or electron beams to destroy cancerous tumors. Proton therapy uses accelerated proton beams that deposit most of their energy precisely at the tumor site, minimizing damage to surrounding healthy tissue.
Accelerators are also essential for producing medical isotopes used in diagnostic imaging and treatment, such as Positron Emission Tomography (PET) scans. These machines generate short-lived radioactive materials used in pharmaceuticals. The beams are also employed in industrial applications, including manufacturing semiconductors and sterilizing medical equipment.