Chapter 7 Glossary of Basic Nuclear and Radiation Terms

Flashcards covering key vocabulary and definitions from Chapter 7 on nuclear and radiation terminology.

atomic mass unit (amu)

A unit of mass equal to one-twelfth the mass of a neutral atom of Carbon-12.

atomic number (Z)

The number of protons in the nucleus of an atom.

electron volt (eV)

A unit of energy equal to the energy gained by an electron passing through a potential difference of 1 volt.

ion

An atomic particle or chemical radical with an electrical charge, either negative or positive.

isotopes

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

mass number (A)

The total number of protons and neutrons in the nucleus of an atom.

nuclide

An atom characterized by its mass number and atomic number.

ionizing radiation

Radiation that has enough energy to remove tightly bound electrons from atoms, causing ionization.

non-ionizing radiation

Radiation that lacks sufficient energy to ionize atoms; examples include microwaves and visible light.

health physics

An interdisciplinary science focused on radiation protection for humans and the environment.

radiation

Energy in transit in the form of high-speed particles and electromagnetic waves.

radioactive contamination

Radioactive materials distributed over an area or object that require decontamination.

radioactive half-life

The time required for a radioactive substance to lose 50% of its activity.

radioactive material

Any material that contains radioactive atoms.

radioactivity

The spontaneous transformation of an unstable atom, often resulting in the emission of radiation.

specific activity

Total activity of a radionuclide per unit mass or volume.

alpha particle (α)

A particle made of two protons and two neutrons, emitted from the nucleus of an atom.

beta particle (β)

A high-speed particle emitted from the nucleus of an atom that is similar to an electron.

bremsstrahlung

X-rays produced by the deceleration of charged particles, such as a beta particle near an atomic nucleus.

electron capture

Radioactive decay process where an orbital electron is captured by the nucleus, converting a proton into a neutron.

gamma rays (γ)

Electromagnetic waves emitted from the nucleus of an atom.

internal conversion

Radioactive decay where energy from an excited nucleus is transferred to an orbital electron, ejecting it instead of emitting a gamma ray.

neutrino (ν)

A particle with zero mass and charge emitted from the nucleus during certain types of radioactive decay.

positron (e+)

A particle identical to an electron but with a positive charge.

X-rays

Photons emitted due to energy changes in electrons, often during transitions between orbital shells.

curie (Ci)

A unit of radioactivity equal to 37 billion disintegrations per second.

rad (radiation absorbed dose)

A unit measuring the amount of energy absorbed in a material, equivalent to 100 ergs per gram.

rem (roentgen equivalent mammal)

A unit measuring biological damage from radiation, derived from absorbed dose.

roentgen (R)

A measure of exposure to gamma and X-rays in air, equivalent to 2.58 × 10−4 coulombs per kg of dry air.

becquerel (Bq)

A unit of radioactivity equivalent to one disintegration per second.

gray (Gy)

A unit measuring absorbed dose, equal to one joule of energy deposited in one kilogram of material.

sievert (Sv)

A unit measuring equivalent dose relating to the biological effect of radiation.

attenuation

The process by which radiation intensity is reduced when passing through material.

background radiation

Ionizing radiation from sources other than the primary source of concern.

efficiency

The ratio of detected count rate to the actual disintegration rate of radioactive material.

Geiger-Mueller (GM) counter

A device used for detecting and measuring radiation.

half value layer

The thickness of a specified material needed to reduce radiation intensity by half.

ionization chamber (IC)

A radiation measurement device useful for measuring dose rates.

scintillation counter

A device that produces light flashes from ionizing radiation and converts them to electrical pulses.

thermoluminescent dosimeter (TLD)

A device that stores energy when hit by radiation and releases it as visible light when heated.

optically stimulated luminescence dosimeter (OSL)

A device that stores energy when exposed to radiation and releases it as visible light when stimulated by laser light.

acute dose

A radiation dose received over a short period of time.

ALARA

An acronym for 'As Low As Reasonably Achievable,' a principle for minimizing radiation doses.

annual limit on intake (ALI)

The maximum radioactive material intake allowed for an adult worker per year.

biological half-life

The time required for the body to eliminate half of a substance through biological processes.

chronic dose

A radiation dose received over a long period.

committed dose equivalent (CDE)

The dose equivalent to organs from ingesting radioactive material over 50 years.

committed effective dose equivalent (CEDE)

The weighted sum of radiation exposure effects to different organs over a certain period.

deep-dose equivalent (DDE)

The dose equivalent at a tissue depth of 1 cm from external radiation.

deterministic effect

Non-stochastic effects that increase in severity with dose and have a threshold.

dose

A term denoting the amount of radiation or energy absorbed in a specified mass.

dose equivalent

A product of absorbed dose in tissue and quality factor.

effective half-life

The time for a radioactive nuclide to decrease by 50% due to decay and elimination.

eye dose

The dose equivalent measured at a depth of 0.3 cm to the lens of the eye.

genetic effects

Effects from radiation observed in the offspring of the individual exposed.

linear energy transfer (LET)

The average amount of energy lost by particles or photons as they traverse an absorbing substance.

quality factor (Q)

A factor used to calculate dose equivalent from absorbed dose, dependent on radiation type.

shallow-dose equivalent

The dose equivalent at a tissue depth of 0.007 cm from external exposure to skin.

somatic effects

Effects seen in individuals who have received radiation exposure.

stochastic effects

Random effects of radiation, typically with no threshold related to dose level.

teratogenic effects

Effects seen in the offspring from maternal exposure to agents during pregnancy.

total effective dose equivalent (TEDE)

The sum of deep-dose equivalent and committed effective dose equivalent.

weighting factor

The risk proportion for stochastic effects of an organ relative to total body risk.