RADIATIONS

1
RADIATIONS
INFRARED
ULTRAVIOLET
VISIBLE
FREQUENCY ( Hz )
1024
1016
1014
1012
1010
108
106
1020
104
102
1022
1018
1
COSMIC
GAMMA RAYS
BROADCAST
HARD-XRAYS-SOFT
VUV
UV
RADAR
INFRARED
FM
TV
SW
POWERTRANS
1 X-UNIT
1KM
1CM
1 M
1UM
1 ANG
10-16
10-8
10-6
10-4
10-2
108
106
10-12
104
102
10-14
10-10
1
WAVE LENGTH IN METRE
2
IONIZING RADIATION

• Electromagnetic or particulate radiation capable
  of producing ions, by interaction with matter.

3
IONIZING RADIATION

• COMMON TYPES
• Alpha particles
• Beta particles
• Neutrons
• Gamma radiation
• X-radiation

4
IONIZING RADIATION

• Alpha
• Originate from disintegration of radioactive
  atoms
• Positively charges ( 2 protons 2 neutrons )
• High Density ( Heavy ) Ionization
• Energy transfer - Short Distance
• Readily Shielded by piece paper / dead skin.
• Internal Radiation Hazards
• Beta
• Negatively charge
• Light High speed
• Penetrate tissues up to 1.5 cm
• Stopped by 12mm aluminium

5
IONIZING RADIATION

• X-rays
• Highly penetrating electromagnetic waves
• Electron bombardment of target materials.
• Gamma Rays
• Highly penetrating and present and external
  radiation exposure hazards

6
SOURCE OF RADIATION

• Radioactive materials - emit one or more forms
  of radiation
• All radiation except x-rays originate from
  radioactive materials. ( Cobalt-60 Radium 226
  Cesium137 ).
• X-ray is produce by x-ray machine
• High speed electrons suddenly slowed down on
  striking target and losing energy in form of x-
  radiation.

7
HEALTH EFFECTS

• ALPHA PARTICLES
• Interact electrically with human tissues and
  other matter. Range 10 cm in air.
• Hazardous when taking into the body.
• Tend to accumulate in kidney, lung, liver and
  spleen.
• No effect when outside the body.

8
HEALTH EFFECTS

• BETA PARTICLES
• Ejected from nuclei by disintegration of
  Radioactive atoms.
• Maximum range wood 4 cm
• Human body penetration 0.2 to 2.3 cm.
• High excessive dose may cause skin burns.

9
HEALTH EFFECTS

• NEUTRONS
• Release by nuclei disintegration of Radioactive
  atoms. ( Fissionable isotopes ).
• The range and extend of damage to human depend on
  the characteristic of material they pass
  through.
• Human body penetration 0.6 cm approx.
  depending on the neutron energy.
• Emit secondary radiations ( alpha, beta, gamma.
  etc) on collision with atoms.

10
HEALTH EFFECTS

• GAMMA RADIATION
• Similar to x-radiation
• Penetration depend on the wavelength
• The shorter wave length have greater penetrating
  power and will penetrate several centimeters of
  steel.
• They are capable of penetrating deep into tissues
  and cause ionizing.

11
HEALTH EFFECTS

• COMMON EFFECTS-
• Skin redness, Dermatitis, Skin Cancer, hair loss,
  eyes inflammation.
• Damage to the bone marrow resulting a blood
  disease.
• Damage the digestive systems
• Radiation Sickness
• Mutagenesis Carcinogenesis Teratogenesis

12
APPLICATION / USES

• X-rays Medicine Dentistry NDT
• Gamma- X-rays Medicine Sterilisations of
  medical supplies.
• Laboratories and Instrumentations
• Nuclear Power Generation
• Atomic weapons manufacturer.

13
UNITS

• Gray - 1 joule of absorbed energy/kg ( dose )
• Roentgen - amount of x or gamma which produce 1
  electrostatic unit of charge in 1 cm3 air
• Roentgen Equivalent Man ( REM ) - unit absorbed
  energy x quality factor as compared with gamma
  radiation.
• Seivert ( SV ) - modern unit of absorbed dose. (
  1 rem 10 mSV )

14
NCRP recommended limits

• Occupational exposure
• Annual 5 rem or 50 mSv
• Cumulative 1 rem x age or 10mSv x age
• Fetus exposure ( monthly )
• Equivalent dose limit 50 mrem or 0.5 mSv

15
CONTROL MEASURES

• Basic Protection Measures are associated with
  
• (1) Time - exposure by 1/2 Dose by half
• (2) Distance - 2x ( distance) 1/4 amount
• (3) Shielding - Thickness Radiation

16
RADIATION PROTECTION PROGRAMME

• Highly Specialised
• Includes following
• Controlled Area
• Tracking of source
• Monitoring of area
• Personal Monitoring
• Biological Monitoring

17
NON IONIZING RADIATION

• The electromagnetic rays that do not have
  sufficient energy to dislodge electrons in the
  body.
• It does transmit energy to the atoms which give
  rise to health effect.
• The shorter wavelength have higher energies than
  larger wave length.

18
ULTRAVIOLET

• Divided into three regions
• Near 400 - 300 nm ( UV-A )
• Far 300 - 200 nm ( UV-B )
• Vacuum 200 -100 nm (UV-C )
• Health Effects
• UV-A Pigmentation of skin
• UV-B Biological active Potentially harmful
• UV-C Bactericidal Germicidal

19
INFRARED

• IR region Visible red light ( 750nm ) to 0.3-cm
  wavelength of microwaves.
• Health Effects
• Increase tissue temperature upon exposure depend
  on w/length.
• IR - A 780 - 1400nm absorbed through
  skin/cornea
• IR - B 1400 -3000nm Absorbed all in
  cornea/cataract
• IR - C 3000 - 1mm Damage to skin/eyes

20
INFRARED

• HEALTH EFFECTS
• Short w/length Injured cornea, iris, retina and
  lens.
• Exposure to visible IR radiation from furnace -
  Glass blower cataract / Heat Cataract.

21
MICROWAVES/RADIOWAVES

• Within broadspectrum of Radio frequencies (
  approx 10-300,000 MHz )
• HEALTH EFFECTS
• Thermal effects
• lt 3000 MHz can penetrate skin and absorb by
  underlying tissues.
• Serious damage can occur when underlying tissues
  such as eyes are exposed.

22
LASER

• Light Amplification by the Stimulated Emission of
  Radiation.
• Coherent Highly direction low divergence
• HEALTH EFFECTS
• Permanent eye damage and skin bruises can result
  from exposure to powerful lasers.

23
RADIATION MONITORING

• To check - installation is safe
• To suggest ways to improve
• To enable safe working procedure
• To check amount of radiation received
• To monitor consequence of changes

24
PERSONAL MONITORING

• PURPOSE
• Radiation dose received
• Contamination and ingestion
• Film Badge - chest
• Gas ionisation Device - pocket
• Scintillation Counter - ingested / surface

25
ENVIRONMENT MONITORING

• Ionisation Chamber
• Scintillation Phosphors
• Geiger Counter
• Wipe test