Service Delivery 4

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Service Delivery 4

• Radiation

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Aim

• To give students the basic theory of
  radioactivity and promote an awareness of the
  hazards posed by radiation.

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Learning Outcomes
At the end of the session students will be able
to

• State how radiation occurs
• List the different types of radiation
• State the precautions to be taken during
  radiation incidents.

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The atom

• Name given to the smallest particles of which
  all matter is composed
• Greek- Atomos, meaning indivisible

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Atoms consist of

• A nucleus, surrounded by electrons (negative
  charge)

.
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The nucleus

• Consists of
• Protons, equal in number to electrons but
  positively charged
• Neutrons (no charge).

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Atomic number Atomic weight

• Equal to the number of protons within a nucleus
  

• Equal to the number of protons and neutrons
  within a nucleus.

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Instability
Due to

• Too many neutrons in nucleus
• Too few neutrons in nucleus
• More than 83 protons.

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Radiation

• The process through which matter gains atomic
  stability by the emission of particles
• Can contaminate materials which may then be
  ingested or inhaled
  e.g. dusts, smoke, liquids etc.

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Alpha radiation
Alpha particles
Nucleus

• The emission of
• two neutrons and
• two protons.

Alpha particles
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Beta radiation
Beta particles

• Neutron emission (negatron)
• Proton emission (positron).

Nuclei
Antineutrino
Beta particle
Beta particle
Neutrino
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Gamma radiation
Gamma rays

• Very high frequency
• Electro - magnetic radiation
• Emitted by the nuclei during decay.

Nucleus
Gamma rays
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Particles and rays

• Alpha particles
  9,000 miles/second - up to 50 mm
• Beta particles
  16,000 miles/second - up to 1-2 metres
• Gamma rays
  186,000 miles/second - unlimited distance.
  
  

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Protection

• Exposure time
• Distance
• Shielding.

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Exposure time

• Limiting the time exposed to a radiation
  source to reduce absorption levels.

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Distance

• The intensity of radiation is proportional to the
  inverse square of the distance travelled
• If the distance is doubled the received dose is
  one quarter.

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Distance.
Max Dose
¼ Dose
1/16 Dose
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Shielding

• Radiation will penetrate different materials to
  varying extents

• Use of shielding will reduce absorption levels.

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Radiation is reduced tohalf original strength

• By thickness of
• Lead 12 mm
• Concrete 55 mm
• Earth 85 mm
• Steel 16 mm
• Brick 75 mm.

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Protection
Alpha

• Will not penetrate unbroken skin
• Prevent ingestion / inhalation
• Breathing Apparatus to be worn.

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Protection
Beta

• Personal protective clothing
• Breathing Apparatus to be worn for protection to
  eyes and against inhalation.

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Protection
Gamma

• No form of clothing provides protection
• Utilise distance and shielding.

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Radiation incidents

• Survey meters
• Restrict number of personnel
• Dosimeters
• Decontamination
• Contamination meters
• Specialist advice
• Medical treatment.

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Dose rates
Males

• Max 30 mSv (millisieverts) at incident
• Max 50 mSv in any 12 month period.

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Dose rates
Females

• Max 13 mSv (millisieverts) at incident
• Max 50 mSv in any 12 month period.

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How harmful is radiation

• 800mSv No apparent short term effects
• 1200mSv 1 in 10 suffer mild symptoms
• 2000mSv Lymphatic system affected
• 2500mSv 50 suffer radiation sickness
• 3000mSv Potential sterility or genetic
  mutation.

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How harmful is radiation

• 6000mSv 50 die within a month
• 8000mSv 75 die within a week
• 10000mSv 100 fatal.

• 4000mSv 1 in 4 die in six weeks

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N.A.I.R. scheme

• National
• Arrangements for dealing with
• Incidents involving
• Radiation
• Invoked by the Police.

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Confirmation
Assessments will be based on this lesson and the
corresponding study note

• Learning Outcomes
• State how radiation occurs
• List the different types of radiation
• State the precautions to be taken during
  radiation incidents.

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THE END