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==Key Stage 4==
===Meaning===
'''Gamma-rays''' are a type of [[Ionising Radiation|ionising radiation]] [[emit]]ed from the [[Atomic Nucleus|nucleus]] of an [[Unstable Isotope|unstable isotope]] and are the highest [[frequency]] and shortest [[wavelength]] of [[Electromagnetic Wave|electromagnetic wave]].
===About Gamma-raysas Electromagnetic Waves===
: [[Gamma-ray]]s are [[Transverse Wave|transverse waves]].
: [[Gamma-ray]]s can travel through a [[vacuum]] as well as through [[gas]]es in the [[Earth's Atmosphere|Earth's atmosphere]].
: [[Gamma-ray]]s can cause cancer because [[gamma-ray]]s can [[penetrate]] soft [[tissue]] and can ionise and damage [[DNA]] [[molecule]]s in the body [[Cell (Biology)|cells]] leading to a [[mutation]].
: High intensity [[gamma-ray]]s can cause [[Radiation Sickness|radiation sickness]] because they can ionise and damage all parts of a [[Cell (Biology)|biology]] killing that [[Cell (Biology)|cell]].
===About Gamma Rays as Ionising Radiation===
: '''Gamma-rays''' may also be referred to as '''gamma radiation''' and is written with the symbol '''γ'''.
: '''Gamma-rays''' are a the highest [[frequency]] [[Electromagnetic Wave|electromagnetic wave]].
: '''Gamma-rays''' have a [[Relative Atomic Mass|relative atomic mass]] of 0 and [[Relative Atomic Charge|relative charge]] of 0.
: '''Gamma-rays''' are [[emit]]ted when a [[Atomic Nucleus|nucleus]] is has excess [[Vibrational Energy|vibrational energy]] after it has [[Radioactive Decay|decayed]] via [[Alpha Particle|alpha]] or [[Beta Particle|beta]] [[emission]].
====Charge====
{| class="wikitable"
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|[[File:GammaRayCharge.png|center|200px]]
| style="height:20px; width:400px; text-align:left;" |Scientist were able to determine the [[Electrical Charge|charge]] of a [[Gamma-ray|γ-ray]] by sending it between two [[Electrical Charge|electrically charged]] plates and observing its path.
The '''γ-ray''' continues in a straight line so it must be [[Neutral Charge|neutral]].
|}
====Penetration Depth====
{| class="wikitable"
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|[[File:GammaPenetrationAir.png|center|200px]]
| style="height:20px; width:400px; text-align:left;" |[[Gamma-ray|Gamma-rays]] can travel an infinite distance through [[air]] and the chances of [[colliding]] with an [[atom]] or [[molecule]] are almost non-existent.
|}
{| class="wikitable"
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|[[File:GammaPenetration.png|center|200px]]
| style="height:20px; width:400px; text-align:left;" |[[Gamma-ray|Gamma-rays]] can penetrate paper and sheets of [[metal]] foil but cannot penetrate more than a few 5cm of [[Lead]] or a [[metre]] of [[concrete]].
|}
====Ionising Potential====
: With no [[Electrical Charge|electrical charge]], '''γ-rays''' are the least [[Ionising Radiation|ionising]] of the three [[Ionising Radiation|ionising radiations]]. It is capable of knocking out one [[electron]] from an [[atom]] or [[molecule]] by being [[Absorb (Physics)|absorbed]] by an [[electron]] in the [[Outer Shell|outer shell].
{| class="wikitable"
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|[[File:GammaIonise.png|center|500px]]
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| style="height:20px; width:500px; text-align:center;" |When a [[Gamma-ray|gamma-ray]] interacts with an [[atom]] the [[Gamma-ray|gammarray]] is [[Absorb (Physics)|absorbed]] by an [[electron]] in the [[Outer Shell|outer shell]] causing the [[electron]] to escape '''ionising''' the [[atom]].
|}
===Precautions===
: [[Gamma-ray|Gamma radiation]] is the least [[Ionising Radiation|ionising]] but most [[Penetration Depth|penetrating]].
: [[Gamma-ray]] sources are kept inside a block of [[lead]] with a hole that only allows the [[Gamma-ray|gamma-rays]] out in one direction.
: Outside the body an [[organism]] cannot easily be protected from [[Gamma-ray|gamma radiation]] as it can pass through the [[air]] unobstructed and needs thick sheets of [[Lead]] to block it. [[Gamma-ray|Gamma radiation]] can pass through the [[skin]] and [[Ionising Radiation|ionise]] [[tissue]] deep within the body.
: When handling a source of [[Gamma-ray|gamma radiation]] the precautions which should be taken are:
:*Wear gloves - to prevent [[Radioactive Contamination|contamination]].
:*Use tongs to handle the source, never touch it - to prevent [[Radioactive Contamination|contamination]].
:*Stand behind a thick sheet of [[Lead]] when not using it - to prevent [[irradiation]].
:*Aim the source away from any living [[organism]] - to prevent [[irradiation]].
:*Store the source in a sealed [[Lead]] container - to prevent [[Radioactive Contamination|contamination]] and [[irradiation]].