IB7 - Radiation Flashcards
What is the electromagnetic spectrum?
The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies.
All types of non-ionising radiation are electromagnetic waves and can be broadly categorised as :
Optical Radiation (Ultraviolet, Visible light and Infrared) Radio Frequencies (Microwaves and radiowaves)
How is an atom with an unstable structure (unstable nucleus) called?
A radionuclide, when this atom undergoes radioactive decay, it will emit ionising radiation
How can Radiation of and Exposure to ionising materials be measured?
- Passive dosimeters, such as the thermo-luminescent dosimeters.
- Active dosimeters, such as personal alarm dosimeters.
Control of exposure to external ionizing radiation sources is achieved using:
- Time.
- Distance
- Shielding.
Control of exposure to internal ionizing radiation sources is achieved by preventing:
- Inhalation
- Ingestion
- Absorption
- Injection of the radioactive substance.
The word ‘LASER’ is an acronym for :
Light Amplification by the Stimulated Emission of Radiation.
Regarding Laser safety, what are the two important exposure limits?
- Maximum Permissible Exposure (MPE)
- Accessible Exposure Limit (AEL)
Regarding Laser safety, what is the Maximum Permissible Exposure (MPE)?
The MPE is the level of laser radiation that, under normal circumstances, persons may be exposed without suffering damage.
The MPE is the highest laser power that is considered safe for the eye
Regarding Laser safety, what is the Accessible Exposure Limit (AEL)?
The AEL is the maximum value of accessible laser radiation to which an individual could be exposed during the operation of a laser and is dependent on the laser class.
On which concept is the classification of Laser products based?
Classification is based on the Accessible Exposure Limit (AEL) concept.
Lasers have been classified according to the power of the Laser beam and the accessibility level to exposed people to produce damage, mainly on eyes and skin.
Which standard is related with the Laser equipment classification and requirements?
BS EN60825-1:2014
How are Laser products classified?
- Lasers have been classified by wavelength and power into four classes and a few subclasses (7) since the early 1970s.
- Class 1 being the lowest risk and Class 4 being the highest and 7 subclassifications.
- Class 1 (max 0.4mW), Class2 (max 1mW), Class3 (5-500mW) and class4 (500mW+)
How can Laser irradiation damage the eye?
Laser irradiation of the eye may cause damage to the cornea, lens, or retina, depending on the wavelength of the light and the energy absorption characteristics of the ocular tissues.
Laser retinal injury can be severe because of the focal magnification (optical gain) of the eye which is approximately 100,000 times. This means that an irradiance of 1 mW/cm2 entering the eye will be effectively increased to 100 W/cm2 when it reaches the retina.
List control measures that could be used to reduce the risks to the public on laser entartainment displays
- Using lasers that are within the maximum permissible exposures (MPE) set down in standards
- Consider using the lowest class of laser
- Directing the laser beams away from the public
- Removing of reflective surfaces
- Using competent operators
- Seeking advice from a laser safety officer
- Restricting access to the hazardous areas by displaying warning signs
- Develop and implement emergency procedures
