7.1 The nature and different types of ionising and non-ionising radiation

Question 1

Radiation is

Answer 1

energy in transit in the form of high speed particles and electromagnetic
waves

Question 2

Radiations are produced by

Answer 2

the acceleration or sudden movement of electrons,
which results in an interlocked pair of electric and magnetic fields oscillating at the
frequency of the electron current. The electric field is created by the charge on the
electrons. The magnetic field is produced whenever charges move and is
proportional to the size of the current.

Question 3

Electromagnetic energy can be described by

Answer 3

frequency, wavelength, or energy

Question 4

Frequency is

Answer 4

the number of cycles or waves per second, measured in Hertz
(Hz)

Question 5

Wavelength is

Answer 5

the distance between crests of the wave, measured in metres (m)

Question 6

Energy increases as

Answer 6

the wavelength shortens. An electron volt (eV) is the
amount of kinetic energy needed to move an electron through one volt potential.

Question 7

Radio and microwaves are usually described in terms of

Answer 7

frequency (Hz)

Question 8

Infrared and visible light are usually described in in terms of

Answer 8

wavelength (m)

Question 9

X-rays and gamma rays in terms of

Answer 9

energy (eV).

Question 10

Non-ionising radiation

Answer 10

has enough energy to move atoms in a molecule around or
cause them to vibrate, but not enough to remove electrons. Examples of non-ionising
radiation include visible light, and microwaves.

Question 11

Ionising radiation

Answer 11

has enough energy to remove tightly bound electrons from
atoms, thus creating ions. Ionisation is the process in which a charged portion of a
molecule (usually an electron) is given enough energy to break away from the atom.
This process results in the formation of two charged particles or ions: the molecule
with a net positive charge, and the free electron with a negative charge. Each
ionisation releases approximately 33eV of energy which is absorbed into the material
surrounding the atom. The 33eV from one ionisation is more than enough energy to
disrupt the chemical bond between two carbon atoms.

Question 12

The International Commission on Radiological Protection (ICRP)

Answer 12

Since 1928, the ICRP has developed, maintained, and elaborated the International
System of Radiological Protection used world-wide as the common basis for
radiological protection standards, legislation, guidelines, programmes, and practice.

Question 13

Health Protection Agency (HPA)

Answer 13

The HPA identifies and responds to health hazards and emergencies caused by
infectious disease, hazardous chemicals, poisons or radiation. It gives advice to the
public on how to stay healthy and avoid health hazards, provides data and
information to government to help inform its decision making, and advises people
working in healthcare. It also makes sure the nation is ready for future threats to
health that could happen naturally, accidentally or deliberately.

The HPA has a statutory responsibility for advising UK government departments,
and those with responsibility for using ionising and non-ionising radiation, on the
associated risks to human health (these were formerly the responsibilities of the
National Radiological Protection Board (NRPB) before it merged into the HPA in
2005).

Question 14

Environment Agency

Answer 14

The Environment Agency (EA) enforces the Radioactive Substances Act 1993
(RSA93) in England and Wales. The primary purpose of which is to control
radioactive substances and in particular radioactive waste. It requires:
 registration with the Environment Agency for the keeping and use of
radioactive materials and mobile radioactive apparatus
 authorisation by the Environment Agency for the accumulation and disposal of
radioactive waste.