Question

Describe the construction and working theory of cyclotron.

Answer 1

Construction: It consists of a hollow metal cylinder that is divided into two sections D1 and D2. These sections are called Dees. They are enclosed in an evacuated chamber. The Dees are kept separated from each other and a source of ions is placed at the center. They are placed between the two poles of a strong electromagnet. The dees are connected to a high-frequency oscillator.

Principle: It works on a principle that a charged particle moving perpendicular to magnetic field experiences a magnetic force (Lorentz). This force makes the particle to move in a circular path.

Working: Cyclotron involves the use of an electric field that is used to accelerate charged particles across the gap between two D shaped magnetic field regions. The magnetic field used in a cyclotron is perpendicular to the paths of the charged particles. When a positive ion of charge q and mass m is emitted from the source it is accelerated towards the Dee having a negative potential. Due to the perpendicular magnetic field the ion experience magnetic Lorentz force and moves in a circular path. When the ion arrives at the gap between the gap the polarity of Dees gets reversed. It again accelerate the particle and due to which it moves into the other Dee having greater velocity. The particle now moves in a spiral path that has an increased radius. When it comes near the edge it can be taken out with the help of deflector plate. The particle now having high energy is now allowed to hit the target.

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