# Linear Accelerator

Before we discussing about linearaccelerator first we should know what is linearaccelerator? It is a one of the type of oscillatingaccelerators and its main function is that to accelerate or increasesthe velocity of a charged sub atomic particle by making the chargedparticles move through the various oscillating voltage sources. Itwas invented separately at the same time by the two scientistsPhysicist Rolf Wideroe's and Leo Szilard in 1928.

It is also termed as linear particleaccelerator or in short as Linac. The passage of particle is linearor the particles are accelerating in linear manner that is the reasonwhy it is called as linear-accelerator. Stanford linear-acceleratorcenter (SLAC) is the largest linear accelerator. It has a capable ofaccelerate the charged particles up to 25 Gev and is 3 km long.

These accelerators are cylindrical inshape and consist of several voltage plates. They have very simpleoperation. When a particles are pass through the voltage plate, thevoltage at the plate is set such a way that they attract theparticles. Then the particles are accelerated towards the platecavity. The voltage polarity of the voltage plate is switched suchthat they repel the particles towards the next plate. So this wholeprocess can accelerates the particles greatly. They can acceleratethe particle which is nearly equal to the speed of light.

If we ask question like whatis a Linear accelerator used for? The answer would be, it isused in various applications like used in circular accelerator as afeeder device, to generate x-rays, in microwave technology, inparticle physics to achieve high kinetic energy for light particles,and also used in radiotherapy or in radio surgery for curing thetumors in the human body and other medicinal purposes.

The linearaccelerator diagram consists of following given elements.

1. Particle source

It is used toproduce a particle which needs to be accelerated. The particle sourcedepends upon the type of the particle to be used, when the particleis electron then cathode sources or radio frequency ion sources areused and when the particle is proton then ion sources are sued.

1. High voltage source

It requiresinjecting the particle in to linear-accelerator.

1. Hollow pipe vacuum chamber

Its length variesfrom 0.5-10 meters which is depends upon the purpose of the uses oflinear-accelerator.

1. Electrodes

They are placed inhollow pipe vacuum chamber in such that the particle is accelerate atthe desired acceleration towards the target. Its length is dependsupon the type of the particle to be accelerated. Its length is verysmall at the particle source and very large at the target.