Further Research
TYPICAL WAVELENGTH - 10-12m (a million millionth of a metre) i.e. 10,000,000,000 waves per cm
SOURCES - Radioactive materials
HAZARD - Extreme: damage to cells
DETECTOR - Radiation monitor
USES - Sterilisation of food. Medical - reduction of tumours. Detecting flaws in metals
Typical wavelength of gamma rays
Gamma rays are to be found at the very high frequency, or very short wavelength, part of the spectrum. They are emitted from some radioactive isotopes and are unaffected by electric and magnetic fields. The gamma rays of highest energies are very penetrating and only approach complete absorption after passing through several centimetres of lead. They arise from changes in the nuclei of atoms as a result of alpha or beta decay.
Sources of gamma rays
The isotope cobalt 60 is the usual source of high energy gamma rays.
Hazards of gamma rays
Long exposure to gamma rays is a very serious health hazard. It can produce burning of the skin and will penetrate into the body, leading to irreparable damage to tissue and organs. Cells are damaged and chromosomes affected. Extreme exposure levels can be fatal.
Uses of gamma rays
It is often used as an alternative to x-ray machines used to produce radiographs for the examination of forgings, casting and welded seams in engines, boilers and pressure apparatus. In aeroengines, for example, this technique will quickly identify very fine cracks without the need to dismantle the engine, which would take many hours. Moreover, carefully controlled, well-focused doses of gamma rays are used to kill cancer cells in a procedure called radiotherapy but some healthy cells may also be affected at the same time.
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