RADIATION Flashcards
PRELIM
Definition of atom
every substance is made up of atoms
Definition of proton
a particle found at the centre of an atom, has a positive charge
Definition of neutron
a particle found at the centre of an atom, has no charge
Definition of electron
a particle found orbiting the nucleus of an atom, negative charge
definition of nucleus
the centre of an atom, consists of protons and neutrons
definition of alpha radiation (α)
a type of ionising radiation, consists of 2 protons and 2 neutrons may be called a HELIUM NUCLEUS, highly ionising, positive charge
definition of beta radiation (β)
a type of ionising radiation, consists of an electron, FAST MOVING ELECTRON, negative charge
definition of gamma radiation
a type of penetrating radiation, it is a high energy electromagnetic wave, consist of no mass & no charge
definition of ionisation
when an atom gains or loses an electron the result is a charged ion
definition of penetration
the ability for radiation to go through materials
definition of activity
the number of nuclear decays per second, with the unit becquerel
definition of background radiation
radiation that is always present everywhere ,may come from natural sources or man made made sources
safety surrounding radiation
when handling radiation safety should be considered such as distance from source and using forceps and shielding
definition of absorbed dose
the quantity of energy absorbed per kg from radioactive decay, with unit gray (Gy)
definition of equivalent dose
the effect the absorbed does will have when considering the type of radioactive decay that accord, with the unit Sieverts (sv)
definition of equivalent dose rate
the equivalent dose absorbed over a certain time, this will have units such as Sieverts per year (Sv y^-1),Sievert per hour(Sv H^-1)
definition of radiation weighting factor
a quantity that the absorbed dose must be multiplied by to calculate the equivalent dose, all types of radiation have values of this (on sheet)
define medicine in radiation
nuclear radiation can be used in medicine, for example x ray imaging can be used to detect broken bones, can also be used to kill cancerous cells
definition of half life
the time taken for activity of a nuclear source to half
definition of fission
Nuclear fission is the process by which energy is released when a large atom is hit by a neutron, becomes unstable and splits into one or more smaller pieces
definition of fusion
Nuclear fusion is when one or more small, light nuclei join together to make one heavy nucleus
what is the average annual equivalent dose background radiation in uk
2.2mSv
what is the annual equivalent dose limit for people in the uk
1mSv
what is the annual equivalent dose limit for radiation workers in the uk
20mSv
A=N/T
activity = number of decays / time
N= AT
D=E/M
absorbed dose =energy /mass
E=DM
H= Dwr
equivalent dose = absorbed dose * radiation weighting factor
H^. =H/T
equivalent dose rate = equivalent dose / time
H=H^.T
Which type of radiation ionises the least
Gamma
What type of radiation ionises the most
Alpha
What is alpha radiation absorbed by
Paper
What is beta radiation absorbed by
Aluminium
What is gamma radiation absorbed by
10cm lead
What makes an atom uncharged
If the numbers of protons are equal to the number of electrons
Name a natural source of radiation
Cosmic Ray, animals, some rocks, soil and plants
How does radioactive decay happen
Spontaneously
Source of artificial radiation
Dental xray, xrays, screening mammography, adult abdominal ct, neonatal abdominal ct
What does fission mean
Splitting apart of atoms
What does fusion mean
Joining together
Define chain reaction
After a reaction this will trigger further reactions which
Advantage of nuclear energy
Nuclear power requires little fuel to create huge amounts of energy,
Unlike fossil fuels,nuclear fuel does not release huge amounts of greenhouse gases into the air
Fossil fuels are running out, so nuclear fuel provides a convenient way of producing electricity
Disadvantage of nuclear power
A serious accident in a nuclear power station is a major disaster and can cause major harm across the world,
Nuclear power stations produce radioactive waste, some of which is hard to deal with,
After a few decades nuclear power stations will have to be decommissioned
Cons of nuclear fusion
Requires extremely high temperatures
Requires high pressures
Very expensive
Pros of nuclear fusion
Release even more energy per kg of fuel,
Make less radioactive emissions
Uses “cleaner” fuel isotopes of hydrogen made from water and lithium
Define plasma
A hot electrically charged gas
What is the name for the project trying to create fusion on earth in europe
ITER (international thermonuclear experimental reactor) and the device is called TOKAMAK
Where does nuclear fusion naturally occur
Naturally in stars eg the sun
Use of nuclear energy
Medical diagnosis, cancer treatment, dating, sterilization
Unit of absorbed energy
Gy gray
Unit of equivalent dose
Sv sievert
Unit of energy absorbed
Joule j
Unit of mass
Kg
Unit of exposure dose rate
Sievert per sec (Sv s^-1)
Unit of activity
Bc becquerel
