Particle Accelerator

A particle accelerator is a machine used to accelerate particles like protons and electrons with a very high speed and energy. The primary purpose of originating these particles is to form a well-defined beam. Ernest Lawrence invented this machine (circular particle accelerator) in 1929. The produced beams of accelerated particles like protons and electrons are used for research purposes such as analyzing the structure of nuclei, properties of nuclei, and studying characteristics of nuclear forces. Its other applications apart from the research are sterilization of materials(biological), radiocarbon dating, radiography, and radiation therapy. The alpha particle scattering experiment(Rutherford’s scattering experiment) can be quickly concluded using a particle accelerator. 

Working of Particle Accelerator: 

An electric field is applied to the beam of particles to increase their speed and energy, which travels in a vacuum pipe(dust-free pipe). The reason behind using the vacuum pipe is to remove the dust from the path of particles which can cause unwanted disturbances. A magnetic field is used for the path’s guidance and to steer up the beam of particles. The electric field in the accelerators keeps on switching its direction so that the particles can accelerate in bunches.

Types of Particle Accelerator: 

Particle accelerators are classified into two types based on the method used. These are: 

1. Electrostatic particle accelerator
2. Electrodynamics particle accelerator. 

1. Electrostatic particle accelerator: In these accelerators, particles are accelerated using a static high voltage difference. The initial accelerators were based on electrostatics only, in which a single high voltage was used to accelerate charged particles. These accelerated particles were passed through the vacuum tube with electrodes at both ends. Due to only one pair of electrodes, these particles gain minimal energy. Thus, they are mainly used in low energy required experiments and studies. 

Particles accelerate twice using the same potential in a tandem electrostatic particle accelerator. The movement of particles is done by reversing the polarity of particles while they are inside the evacuated tube. 

2. Electrodynamics particle accelerator: Electric discharge is used in an electrodynamics particle accelerator, which produces a very high potential for the particle to get the required speed and energy. This high speed is maintained by introducing the involvement of dynamic fields in place of the static fields. 

Electrodynamics particle accelerators can be of many types:

1. Circular structures in which a magnetic field is used to maintain the circular path of the beam
2. a straight line
3. Cyclotrons 
4. Synchrotrons 
5. Electron synchrotron
6. Betatron
7. Magnetic induction accelerator
8. Linear induction accelerator
9. Linear accelerator
10. Storage rings

Some standard accelerators are explained as follows: 

Magnetic induction accelerators: In this accelerator, the increase in the magnetic field causes the movement of particles. The particles behave as the secondary winding, as in the case of the transformer. The increase in the magnetic field causes the induction of the electric field, which forces and accelerates the particle. This type of accelerator can have linear or circular structures. 

Linear induction accelerators: This was invented by the scientist named Christofilos in the 1960s. These accelerators can have a very high value of beam current(more significant than 1000A)

Betatrons: It is made in a circular shape and was invented by a scientist named Donal Kerst in 1940.  

Circular or cyclic RF accelerators: In these, the particles are accelerated in a circular orbit to reach to have sufficient speed and energy. The main advantage of using a circular or RF accelerator is that they provide an indefinite path for the particle to accelerate without sudden direction changes. Also, it is smaller compared to the linear accelerators of equivalent power. 

Cyclotrons: are circular accelerators invented by Ernest Lawrence in 1929. It uses a hollow D-shaped plate and dipole magnet to accelerate and guide the particle on its path. 

Advantages of Particle Accelerator: 

These accelerators and generated beams are mainly used in fundamental research and experiments. Almost 80% of the accelerators are used for radiotherapy and ion implanters. A fraction(20%) of the total accelerators are used in industry, biomedical and energy research.

• The accelerated particles can be used in cancer treatment. 
• These can be used in studying the structure and behavior of nuclei. 
• These particle accelerators can be used in telescopes to study the universe’s origin and processes. This is widely used in the fields of cosmology and astrophysics. 
• Experiments like Rutherford’s scattering experiment were quickly completed by producing particles with much higher kinetic energy, which gave more accurate data compared to the conclusion from the alpha scattering experiment. 

Conclusion:

A particle accelerator is a machine used to generate a beam of accelerated particles like photons and electrons. These accelerators are widely used in scientific research, radiotherapy and ion implanters. A small proportion of these accelerators are also used for industrial and biomedical purposes. These are classified into two types based on their mechanism: Electrostatic particle accelerator and electrodynamics particle accelerator. In an electrostatic particle accelerator, particles are accelerated using a static high voltage difference across the electrode. In an electrodynamics particle accelerator, electric discharge is used, which causes a much higher potential difference in producing high speed accelerated particles.