First 302 words of the document:
... consist of particles which are Helium nucleii. They are charged positive and
can be deflected by electric and magnetic fields. Their exit speed is about
... consist of electrons of different speed between 108m/s and 0.999c0. Because
of their negative charge, they are deflected contrarily to alpha particles in
electric and magnetic fields.
... are electromagnetic waves with a wavelength of about 1012m (frequency of
~1020Hz). There is no deflection in electric or magnetic fields.
When an unstable nucleus decays, there are three ways that it can do so.
It may give out:
an alpha particle (we use the symbol )
a beta particle (symbol )
a gamma ray (symbol )
Gamma rays are waves, not particles.
This means that they have no mass and no charge. So
we sometimes write .
Gamma rays have a high penetrating power it takes a
thick sheet of metal such as lead, or concrete to
reduce them significantly.
Gamma rays do not directly ionise other atoms, although
they may cause atoms to emit other particles which will
then cause ionisation.
We don't find pure gamma sources gamma rays are
emitted alongside alpha or beta particles. Strictly
speaking, gamma emission isn't 'radioactive decay'
because it doesn't change the state of the nucleus, it
just carries away some energy.
Beta particles have a charge of minus 1, and a mass of about 1/2000th of
a proton. This means that beta particles are the same as an electron.
We can write them as or, because they're the same as an electron,
They are fast, and light.
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Beta particles have a medium penetrating power they are stopped by a
sheet of aluminium or plastics such as perspex.
Beta particles ionise atoms that they pass, but not as strongly as alpha
Alpha particles are made of 2 protons and 2 neutrons.…read more