Radiation

Question 1

Atom

Answer 1

An overall neutral particle consisting of a nucleus (protons and neutrons) and orbiting electrons.

All matter is made up of atoms.

Question 2

Nucleus

Answer 2

The small, dense region containing protons and neutrons at the centre of an atom.

Question 3

Proton

Answer 3

A positively charged particle in the nucleus of an atom.

Question 4

Neutron

Answer 4

A particle with neutral charge that exists in the nucleus of an atom.

Question 5

Electron

Answer 5

A negatively charged particle that orbits the nucleus of an atom.

Question 6

Radioactive Decay

Answer 6

When unstable nuclei emit nuclear radiation in the form of an alpha particle, beta particle or gamma ray in an attempt to become more stable.

Question 7

Alpha Particle

Answer 7

A particle made up of 2 protons and 2 neutrons.

It is also the nucleus of a helium atom.

Question 8

Beta Particle

Answer 8

A fast moving electron.

Question 9

Gamma Ray

Answer 9

An electromagnetic wave of very high frequency and energy.

Question 10

Ionisation

Answer 10

The addition or removal of an electron from a neutral atom.

Question 11

Geiger-Muller Tube

Answer 11

A radiation detector that uses the ionisation of gas in the tube to count the number of times radiation hits it.

Question 12

Scintillation Counter

Answer 12

A radiation detector that counts the flashes of light produced when radiation hits the scintillating material.

Question 13

Film Badge

Answer 13

A radiation detector often worn by people who work with radioactive materials to monitor the radiation dose that they are exposed to.

It uses different filters which blacken or ‘fog’ when radiation hits them.

Question 14

Activity

Answer 14

The number of nuclear decays (or disintegrations) per second.

Question 15

Background Radiation

Answer 15

Radiation that is all around us and is caused by both natural and artificial sources, e.g. radon gas.

Question 16

Absorbed Dose

Answer 16

The energy absorbed by a material per unit mass.

Question 17

Shielding

Answer 17

The act of placing a material between a person and a radioactive source to absorb radiation.

Question 18

Radiation Weighting Factor

Answer 18

An indicator of the relative biological effect of radiation on a material.

Question 19

Equivalent Dose

Answer 19

The absorbed dose multiplied by the radiation weighting factor.

Question 20

Equivalent Dose Rate

Answer 20

The equivalent dose per unit time.

Question 21

Half-life

Answer 21

The time taken for the activity of a radioactive source to decrease to half its original value.

Question 22

Nuclear Fission

Answer 22

The process in which an unstable, heavy atomic nucleus splits into two or more lighter nuclei (called fission fragments), with energy being released.

Question 23

Chain Reaction

Answer 23

When neutrons released in nuclear fission reactions go on to hit other nuclei, causing further fission reactions, and the cycle repeats.

The process may be controlled (nuclear reactors) or uncontrolled (nuclear bomb).

Question 24

Nuclear Fusion

Answer 24

The process of small nuclei joining together to form a larger nucleus, with energy being released.

Question 25

Plasma Containment

Answer 25

The use of powerful magnetic fields to prevent hydrogen plasma from physically touching any parts of a nuclear reactor.