Particle Accelerators: Accelerating Our Knowledge of Fundamental Units of Matter
For the past eighty years, scientists have used the particle accelerator to find out more about these units of matter. The basic mechanism of the accelerator has not changed over its history. A charged particle travels through an electric potential difference, using the energy of the electric field to gain energy and travel at increasing speeds. Thus, the particle is accelerated. Particle accelerators are tools not only for studying matter at its fundamental level, but are also used in X-ray generators and cathode ray tube (CRT) television sets. However, in these “low-energy” machines, a simple setup of a pair of electrodes and a direct current (DC) voltage is used.
In contrast, linear “high-energy” accelerators use a series of plates called “drift tubes” and an alternating current (AC) voltage. This allows the particles to accelerate through each drift tube and align with the sinusoidal voltage to reach high speeds.
The most widely used particle accelerators fall into two categories: linear and circular. As the name implies, a linear particle accelerator allows a particle to travel in a vacuum down a long, straight tube until it collides with a target.
- One key disadvantage,
- is their emission of a type of radiation called
- approach the speed of light.
Circular accelerators work via a similar principle, but instead use electromagnets; they have the primary advantage of creating continuous acceleration. Thus, circular accelerators tend to be smaller in size than linear accelerators of comparable power.
One key disadvantage, however, is their emission of a type of radiation called synchrotron radiation. This radiation creates some energy loss as “synchrotron light,” and thus the energy must be restored by the accelerating cavities (analogous to the differing voltage plates in a linear accelerator) to maintain the high energy beam. The effect is magnified as the particles in the beam approach the speed of light.