just a test PowerPoint presentation

1. What is ionising radiation?
Radiation is a form of energy which moves through space or through a medium such as air. There are many types of radiation that
we come across in everyday life such as sunlight, heat, microwaves, radio waves and X-rays. These different types of radiation have
different energies.
Radiation that has sufficient energy to cause a process called ionisation is called ionisation radiation.
What is ionisation?
Ionisation is the process by which ionising radiation can remove electrons from atoms.
The Atom consists of a nucleus composed of protons and neutrons surrounded
by a cloud of electrons.
Types Source
Routes of
Exposure
Units Track Structure
Ionising Radiation

2. Types Source
Routes of
Exposure
Units Track Structure
Gamma Rays
X-Rays
bBeta Particles
aAlpha Particles
Proton
Neutron

3. Types Source
Routes of
Exposure
Units Track Structure

4. Types Source
Routes of
Exposure
Units Track Structure

5. Types Source
Routes of
Exposure
Units Track Structure

6. Types Source
Routes of
Exposure
Units Track Structure

7. b Beta Particles
Protons
 Gamma Rays
a Alpha Particles
X-Rays
Neutrons
Alpha particles are composed of two protons and two neutrons and have an atomic
mass of 4 Daltons and a positive electrical charge of +2.
Beta particles can either be electrons with a negative charge of -1 or positrons with a positive
charge of +1. A beta particle has an atomic mass of 1/2000 Daltons.
Gamma rays are composed of electromagnetic waves and do not have mass or electrical charge.
X-rays are composed of electromagnetic waves and do not have mass or electrical charge.
Neutrons have an atomic mass of 1 Dalton and no electrical charge.
Protons have an atomic mass of 1 Dalton and a positive electrical charge of +1.
The different types of ionising radiation include alpha particles, beta particles, gamma rays, X-rays, protons and neutrons.

8. The general public are exposed to both natural and artificial sources of radiation. In addition, people in certain occupations are
exposed to additional sources of radiation through their work.
Environmental
Medical
Occupational
Accidents
Atomic Bombing
Nuclear Weapons
Tests
The natural sources of radiation in the environment include radon gas, rocks and soil, cosmic rays and
food and drink. The average annual natural radiation dose in the UK is 2.3 mSv.
The main source of artificial radiation for the general public are diagnostic X-rays. The average annual
X-ray dose in the UK is 0.4 mSv. Radiotherapy patients receive much higher doses (several Gy).
Workers who have a greater risk of radiation exposure include healthcare professionals, workers in
the nuclear power and fossil fuel industries, aviation staff and defence and military personnel.
People have been exposed to radiation as a consequence of accidents in medical and industrial
workplaces including nuclear power plants, the most serious of which occurred at Chernobyl in 1986.
The inhabitants of Hiroshima and Nagasaki in Japan were exposed to radiation as a consequence of
the atomic bombings of their cities in 1945.
The annual average effective dose due to global fallout from atmospheric nuclear weapons tests is
0.005 mSv. There have been cases of higher local exposures.
Types Source
Routes of
Exposure
Units Track Structure

9. b Beta Particles
Protons
 Gamma Rays
a Alpha Particles
X-Rays
Neutrons
Beta particles can penetrate skin and light clothing. They can also be inhaled or digested,
though they are less harmful than alpha particles.
X-rays can only be stopped by steel, lead or concrete. In medicine X-rays are applied only
to selected parts of the body in order to minimise the risk of harm.
Neutrons can only be stopped by concrete or water. Neutron radiation primarily occurs
inside a nuclear reactor, where many feet of water provide shielding.
High energy protons can penetrate tissue and are used to treat cancer. Proton therapy
can generate neutrons and so concrete shielding is required in the medical facility.
The effects of different types of radiation depend upon the route of exposure.
Alpha particles can't penetrate skin or clothing, but if inhaled or digested they can
cause more damage than other forms of radiation.
Gamma rays can only be stopped by lead or concrete. During the atomic bombings of Japan some
residents received lower gamma ray doses by being indoors.
Types Source
Routes of
Exposure
Units Track Structure

10. What is Radioactivity?
Radioactivity refers to the process in which certain types of ionising radiation, called alpha
particles, beta particles and gamma rays, are produced by the spontaneous decay of atoms.
The rate of decay of a radioactive substance is measured in Becquerel (Bq). One Becquerel
represents one disintegration of a radioactive atom per second.
What is Dose?
The amount of energy deposited in living tissue is described in terms of a quantity called a
dose. The amount of radiation energy absorbed per kilogram of tissue is called the
absorbed dose and is expressed in units called Grays (Gy).
The potential for biological damage depends on the type of radiation as well as the dose.
To take this into account a weighted dose used (effective dose) which is expressed in units
called Sieverts (Sv).
Types Source
Routes of
Exposure
Units Track Structure

11. b Beta Particles
Protons
 Gamma Rays
a Alpha Particles
X-Rays
Neutrons
Beta
X-rays
Neutrons
Protons
Linear Energy Transfer describes the amount and the distribution of energy deposited by ionising radiation to a track when it passes
through a medium.
Alpha
Gamma
Types Source
Routes of
Exposure
Units Track Structure