Radiation, Half Life Flashcards
What are the 5 biggest national radiation sources in the uk
48% radioactive radon gas from the ground
16% medical radiation
13% terrestrial gamma radiation
12% cosmic radiation
11% intakes of radionuclides excluding radon
What is ionisation and when does it occur
Occurs when electrons are removed from atoms or molecules to produce positive ions. All forms of radioactive decay produce radiation that can cause ionisation
What is excitation and when does it occur
occurs when radiation transfers energy to atoms or molecules so they increase their energy level but it is retained in the atom. If enough energy is transferred to the electron, it will be removed from the atom and ionisation will have occurred. Gamma radiation can cause excitation.
What is non ionising radiation
does not have enough energy to remove electrons from atoms and molecules. Non-ionising radiation is longer wavelength/lower frequency lower energy but can cause heat damage to tissues.
What is ionising radiation
has sufficient energy to produce ions in matter at the molecular level so ionising radiations can cause dermatitis, burns, cell damage, cataracts, damage to DNA. While ionising radiation is short wavelength/high frequency higher energy. The change occurs in the UV part of the spectrum.
What is the 1st step in ionisation and cellular mutation
Energy transferred by ionising radiation removes electrons from atoms to form ions
What is the 2nd step in ionisation and cellular mutation
Ions are reactive and can cause mutations to the dna in cells
What is the 3rd step in ionisation and cellular mutation
Damaged dna can lead to cancer if into corrected by the body’s natural repair mechanisms
What are 2 broad safety measures for radiation
-keep exposure as low as reasonable practical and not exceed specific dose limits
-restriction of exposure should achieved first by means of engineering control and design features
What does the ionising radiation regulations 2017 state and what does it protect the public from
Set out the minimum legal duties and the approval code of practice gives advice on how to comply with those regulations
Protected from- radiation’s arising from work, radioactive substances, any other forms of ionising radiation
What are 3 applications of radioactivity in health care
-radioactive tracers
-medical dianostic and imaging applications
-radiotherapy
What are the 3 types of radiation
Alpha particle, beta particle, gamma ray
Which of the 3 types of radiation are the most harmful
Alpha- most ionising, least penetrating type
Beta- moderately ionising, moderately penetrating
Gamma- least ionising, used in health more often
Define half life
The time it takes for half of the unstable nuclei in a sample to decay off for the activity of the sample to halve or for the count rate to half
Define count rate
The number of decays recorded each second by a detector, such as the Geiger-muller tube
