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Breaking Matter Down
Accelerating Charged Particles
An electric field is a region in which a charged object experiences a force. The electric field
strength is defined as the force pet unit positive charge. Electric forces may be either
attractive or repulsive due to positive and negative charges.
F =…

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There are two heating methods; direct heating (current is passed through the filament) or
indirect heating (cathode is heated by a separate filament close to it).

The emitted electrons produce an electric field. The electrons repel other electrons and
disperse whilst forming a cloud around the filament or cathode ­…

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Deflection by a Uniform Electric Field:
Electric fields can be used to deflect the path of a beam of charged particles when the field
is applied at right angles to the path of the beam. This is the similar to projectile motion in a
gravitational field

A particle of charge…

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force of the particle of charge Q, travelling at velocity V in a magnetic field of strength B is
given by

F = BQv

This force, when at a right angle to the magnetic field, provides a centripetal force, keeping
the particle in circular motion. The diagram below shows a…

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electron, making them into a positive ion. Mass spectrometer separate ions according to
the ratio of their mass to their charge. As most of the ions have a charge of +1 it can be
considered that the mass spectrometer separates ions with different masses.

Velocity selector: From the ion chamber…

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entering the linac. The beam passed through several hollow metallic cylindrical electrodes
called drift tubes. They are connected to a radio frequency alternating supply. The ions are
accelerated by the electric field that exists between each pair of drift tubes. In order to use a
constant frequency supply each drift…

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For particles travelling close to speed of light if the half-life was measured from earth it
would be found to be much longer than that of similar stationary particles. The time is
dilated or prolonged as a result of travelling at such high speeds. The half-life of the moving

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they spiral around. As they travel faster, they trace a larger arc meaning they always take the
same time to travel each semi-circle. This allows the voltage applied to the dees to be of a
constant frequency
2r 2( QB ) 2m
T= V = V V = QB…

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alternating voltage is applied between the electrodes positioned around the ring. This
accelerates the charged particles to high energies. The particles are initially injected into the
ring with relatively high energy before having their energy boosted as they are accelerated by
the electrodes.

Synchrotron Radiation

A property of any accelerated…

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magnets which are cooled to 2K, along with 1232 dipole magnets to bend the protons and
392 quadrupole magnets to focus the beams

Way Forward

The production of synchrotron radiation is a limiting factor when accelerating electrons in a
circular accelerator. The low rest mass and availability of the electron…


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