Radiation and Nuclear Processes

These flashcards cover key terms and definitions related to radiation and nuclear processes.

Photographic Film

A material that reacts to ionising radiation, allowing an image to be formed.

Positive Ions

Atoms that have lost electrons and so have a resultant positive charge.

Protons

A positively charged constituent of the nucleus.

Radioactive Contamination

The unwanted presence of radioactive atoms on other materials, hazardous due to the decay of the contaminating atoms.

Radioactive Decay

The random process involving unstable nuclei emitting radiation to become more stable.

Random Nature of Radioactive Decay

It is impossible to predict which nuclei in a radioactive sample will decay next or when the next decay will occur.

Shielding

A barrier used to prevent radioactive daughter products from leaving a nuclear reactor.

Uranium-235

The radioactive isotope used in nuclear reactors, often referred to as U-235.

Nuclear Fission

The splitting of a large and unstable nucleus into two smaller, more stable nuclei, producing energy.

Nuclear Fusion

The joining of two small, light nuclei to form a larger, heavier one, releasing energy.

PET Scanner

A medical imaging device that uses radioactive tracers and detectors to form internal body images.

Fission Products

Products of fission, including two smaller nuclei, two or three neutrons, and gamma rays.

Gamma Ray

Electromagnetic radiation emitted from a nucleus, having high penetrating power.

Geiger-Muller Tube

A device used to detect ionising radiation.

Half-Life

The time it takes for the number of unstable nuclei of an isotope in a sample to halve.

Ions

Atoms with a resultant charge due to the loss or gain of electrons.

Ionising Radiation

Radiation that can cause cell mutations and damage, potentially leading to cancers.

Irradiation

The process of an object being exposed to nuclear radiation without becoming radioactive.

Isotopes

Atoms with the same number of protons but different numbers of neutrons.

Mass Number

The number of protons and neutrons in an atom.

Mass-Energy Equivalence

The principle that all matter has an associated energy, allowing mass to be converted into energy.

Moderator

A substance in nuclear reactors that slows down neutrons to suitable speeds for inducing fission.

Negative Ions

Atoms that gained electrons and have a resultant negative charge.

Neutrons

A neutrally charged constituent of the nucleus.

Activity

The rate at which an unstable nucleus decays, which reduces over time.

Alpha Particle

A positively charged particle consisting of two protons and two neutrons, highly ionising but can be stopped by air.

Atomic Number

The number of protons found in an atom of a specific element.

Background Radiation

Radiation that exists in small quantities from natural and man-made sources.

Becquerel

The unit of radioactive activity.

Beta Particle

A high speed electron emitted when a neutron converts into a proton, ionising but stoppable by thin aluminium.

Chain Reaction

The process where neutrons released by fission induce further fission in other nuclei.

Control Rods

Devices in nuclear reactors that absorb neutrons to control the rate of fission.

Electrons

Negatively charged constituents of the atom located in different energy levels around the nucleus.

Energy Levels

Stable states of electrons around a nucleus, which can transition through absorption or emission of radiation.