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What is a LASER? (PART ONE)

Have you ever seen a LASER? They're powerful beams of electromagnetic radiation.

Laser beams can be made from visible light, x-rays, ultraviolet light or infrared light.                        

            LASER pointers                                             LASERs for entertainment

                                           

 

Laser is a narrow beam of light of a single wavelength (monochromatic) in which each wave is in phase (coherent) with other near it.

Did you know? Laser stands for Light Amplification by Stimulated Emission of Radiation.

LASER is an unusual light source. It is quite different from a light bulb or a flash light. Lasers produce a very narrow beam of light.

The waves of laser light travel together with their peaks all lined up, or in phase. This is why laser beams are very narrow, very bright, and can be focused into a very tiny spot.

There are many types of lasers including gas lasers, fiber lasers, solid state lasers, dye lasers, diode lasers and excimer lasers. All of these laser types share a basic set of components when  produced.

Laser Components

  1. Gain medium capable of sustaining stimulated emission
  2. Energy source to pump the gain medium
  3. Total reflector to reflect energy
  4. Partial reflector
  5. Laser beam output

The gain medium and resonator determine the wavelength of the laser beam and the power of the laser

 

 

 

 

 

 

 

 

Properties of lasers are:

  1. Monochromatic
  2. Directional
  3. Coherent

Laser Classes: lasers are classified according to their relative hazards and then specify appropriate controls for each class. Classes include Class 1, Class 1M, Class 2, Class 2M, Class 3R, Class 3B and Class 4.

"Class 1 lasers" are considered to be incapable of producing damaging radiation levels, and are therefore exempt from most control measures or other forms of surveillance.

"Class 2 lasers" emit radiation in the visible portion of the spectrum, and protection is normally afforded by normal human aversion response (blink reflex) to bright radiant sources. In general, the human eye will blink within 0.25 seconds when exposed to Class 2 laser light. This blink reflex provides adequate protection. However Class 2 lasers emit laser light in the visible range and are capable of creating eye damage through chronic exposure.

Their power output is less than 1 mW. This class of lasers causes injury only when viewed directly for more than 1,000 seconds. The 1,000 seconds is spread over an 8-hour day, not continuous exposure.

Class 3 lasers

"Class 3a laser" are those that normally would not produce injury if viewed only momentarily with the unaided eye. These may present a hazard if viewed using collecting optics, e.g., telescopes, microscopes, or binoculars. Laser above 1 mill watt but not exceeding 5 mill watts radiant power

"Class 3b laser"light  is capable of causing eye or skin damage if the beam is viewed directly, will cause injury upon direct viewing of the beam and specular reflections. Laser above 5 mill watts but not exceeding 500 mill watts radiant power.

"Class 4 laser" is a laser that is capable of causing eye or skin damage during direct beam exposure or exposure to diffuse reflections or specular reflections. It includes all lasers with power levels greater than 500 milliWatts  radiant power.  They pose eye hazards, skin hazards, and fire hazards. Viewing of the beam and of specular reflections or exposure to diffuse reflections can cause eye and skin injuries.

Resources:

https://www.researchgate.net/publication/308337305_Basic_Concepts_of_Laser

http://www.planet-science.com/categories/over-11s/technology/2012/01/what-is-a-laser.aspx

https://spaceplace.nasa.gov/laser/en/

 

 

 


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Ethiopian Radiation Protection Authority and   Sudanese Nuclear and Radiological Regulatory  Authority has signed MOU to explore collaboration in a wide range of programs, projects and activities that are determined to be feasible and consistent with the guiding principles and organizational needs of the Parties.  In particular, the Parties mutually intend to cooperate in regulatory activities pertaining to the following areas: 
(i) Nuclear and radiological safety ; 
(ii) Transport safety
(iii) Radiation protection
(iv) Environmental impact of nuclear & radiological facilities and activities
(v Radioactive waste management and spent fuel management; 
(vi) Nuclear security
(vii) Emergency preparedness and response; 
(viii) Mining activities of radioactive materials 
(ix) Safeguards

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Workshop on Radiation Safety and Security conducted Workshop on Radiation Safety and Security conducted

A workshop organized by the National Nuclear Security Administration of U.S in cooperation with the Ethiopian Radiation Protection Authority was conducted at Hilton Hotel, Addis Ababa, from August 3 to 4, 2015. The workshop focused on the development of regulations that is a vital tool for the security of radioactive sources and nuclear facilities. Specific topics such as IAEA Code of conduct which basically provides guidance for developing policies laws and regulations to uphold the safety and security of radioactive sources, categorization of radioactive sources that helps maintain a high level of safety and security, IAEA Nuclear Security Series that serves as a guidance for establishing regulating requirements, regulatory development process that introduces a systematic process which helps make development of new security regulations more effective and efficient and principles that highlight effective regulation drafting were critically addressed in the workshop.

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