Uses of Radiation

Announcements Quiz on the atom tomorrow. Deadline for project ideas tomorrow also. Please give a brief explanation of your intended project on a piece of paper with your name on and hand it in.

Goal of the class To understand how the properties of radiation can be useful Question of the day: What is a use of alpha radiation? Previous answer: Alpha, beta or gamma particles Previous question: What is emitted from the nucleus during radioactive decay?

Radiation Treatment X-rays, gamma rays and beta particles are all used in medicine to treat internal organs. X-rays are produced by firing electrons at a metal target and gamma rays are emitted by the nucleus of radioactive atoms. Gamma rays are used to kill cancer cells, to sterilise medical equipment and in radioactive tracers.

Medical radioisotopes For example, technetium-99 is widely used in medical imaging. It is generated from molybdenum-99, which is produced when molybdenum-98 absorbs neutrons. Absorbing a neutron: Beta decay to produce technetium-99:

Sterilisation Gamma rays are high energy electromagnetic waves which are only stopped by thick lead. This means they can easily pass through medical equipment, such as syringes. As gamma rays pass through the packaging they will inactivate viruses and kill bacteria. As long as the equipment remains in a sealed plastic pack it will remain sterile. They do a similar thing with fruit

Radioactive Tracers This produces a picture showing where the tracer has accumulated. Leaks from a pipeline can be traced by adding a radioactive isotope into what ever it is carrying. The source must have a short half-life (a few hours) so that it can be detected as it passes through but not stay radioactive long enough to pose a health hazard

Treating Cancer Gamma rays damage cells whether they are normal or cancerous, so gamma rays must be focused on the tumour.. One way of doing this is to use a wide beam of gamma rays, but to rotate the beam around the patient, keeping the tumour at the centre. This concentrates the gamma rays on the cells that need to be killed.

Smoke Detectors It can detect particles of smoke that are too small to be visible. It includes a tiny mass of radioactive americium-241, which is a source of alpha radiation. Any smoke that enters the chamber absorbs the alpha particles, setting off the alarm.

Metal Thickness The amount of beta radiation detected adjusts the space between the rollers and changes the metal’s thickness. Emergency sign lighting for beta too

Carbon Dating Used to find the age of ancient materials. Living wood has a tiny proportion of radioactive carbon-14 The carbon -14 decays over time and we can calculate how long it has been decaying for.

Nuclear Power Nuclear energy is one of the safest and cleanest forms of energy production methods. Nuclear power is the use of nuclear reactors to release nuclear energy,[1] and thereby generate electricity. The term includes nuclear fission, nuclear decay and nuclear fusion. Presently, the nuclear fission of elements in the actinide series of the periodic table produce the vast majority of nuclear energy in the direct service of humankind, with nuclear decay processes, primarily in the form of geothermal energy, and radioisotope thermoelectric generators, in niche uses making up the rest. Nuclear (fission) power stations, excluding the contribution from naval nuclear fission reactors, provided 13% of the world's electricity in 2012. The share of the world's primary energy supply, which refers to the heat production without the conversion efficiency of about 33 %, was about 5.7%.[2] Its share of the global final energy consumption (actually useful energy, i.e. electric power) is below 2.5 %.[3] A lot of nuclear energy is used to power ships / submarines as well as space missions in RTG.

Vocabulary Tracer – substances that contain a radioactive atom to allow easier detection of illnesses.

Homework Please revise for tomorrow and think about your project ideas and submit them.