laser safety l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
LASER SAFETY PowerPoint Presentation
Download Presentation
LASER SAFETY

Loading in 2 Seconds...

play fullscreen
1 / 59

LASER SAFETY - PowerPoint PPT Presentation


  • 514 Views
  • Uploaded on

LASER SAFETY. Texas State University | San Marcos. Objectives. IDENTIFY what the acronym LASER means and briefly DESCRIBE how a laser performs it function. (LST.OBJ.001) LIST the characteristics of a laser beam. (LST.OBJ.002)

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

LASER SAFETY


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
laser safety

LASER SAFETY

Texas State University | San Marcos

objectives
Objectives
  • IDENTIFY what the acronym LASER means and briefly DESCRIBE how a laser performs it function. (LST.OBJ.001)
  • LIST the characteristics of a laser beam. (LST.OBJ.002)
  • DIFFERENTIATE between a Continuous Wave Laser and a Pulsed Laser. (LST.OBJ.003)
objectives continued
Objectives (continued)
  • LIST the five types of lasers and briefly DESCRIBE their attributes. (LST.OBJ.004)
  • LIST several types of laser excitation sources. (LST.OBJ.005)
  • IDENTIFY the American National Standards Institute Laser Classifications. LST.OBJ.006
objectives continued4
Objectives (continued)
  • LIST three areas in which lasers have been used. (LST.OBJ.007)
  • Describe the two common types of laser pointers. (LST.OBJ.008)
  • List the criteria used by the FDA to determine laser pointer classification and the required labeling on each class of laser pointer. (LST.OBJ.009)
objectives continued5
Objectives (continued)
  • IDENTIFY the three primary mechanisms of tissue injury associated with laser radiation exposure. LST.OBJ.010
  • MATCH the specified laser wavelength to the part of the eye that is most affected. LST.OBJ.011
objectives continued6
Objectives (continued)
  • IDENTIFY the two mechanisms by which laser radiation may potentially cause skin injury. LST.OBJ.012
  • IDENTIFY the three basic categories of controls used in laser environments to provide a degree of protection from possible laser radiation injury and GIVE several examples of each type of control. LST.OBJ.013
objectives continued7
Objectives (continued)
  • IDENTIFY other non-beam hazards that are possible in laser environment and GIVE an example of each. LST.OBJ.014
  • MATCH the following laser related terms to their corresponding meaning:
    • Accessible Exposure Limit - Nominal Hazard Zone
    • -iffuse Reflection - Specular Reflection
    • Intrabeam Exposure - Radiant Exposure
    • Irradiance - Peak Power
    • Maximum Permissible Exposure

LST.OBJ.015

txstate laser safety program
TxState Laser Safety Program
  • Laser Safety Training Manual
  • Laser Safety Manual
  • Texas Department of State Health Services Bureau Radiation Control
    • 25 TAC §289.301
laser
LASER
  • Acronym for:
    • Light
    • Amplification by the
    • Stimulated
    • Emission of
    • Radiation.
laser10
Laser
  • Emits non-ionizing electromagnetic radiation that is ultraviolet, visible, or infrared light.
  • Lasers now capable of emission in X-ray frequency.
laser light
Laser Light
  • Monochromatic
    • One wavelength or color
  • Directional
    • Does not expand as quickly as ordinary light
  • Coherent
    • Waves of light generated in phase with each other.
basic operating concept
Basic Operating Concept
  • Electrons moved from ground state to higher energy state.
  • When electrons descend to ground state, photons emitted of specific wavelength.
  • Photons oscillate in mirrored resonator
  • Increases intensity by stimulating emission of additional photons of same wavelength and phase.
  • Photons escape via output coupler
continuous wave lasers
Continuous Wave Lasers
  • Operated in a continuous mode for at least a period of .25 seconds.
  • Output expressed as the average power (watts).
irradiance power density
Irradiance (Power Density)
  • Expressed in W/cm2
  • Function of the beam power divided by beam area
  • Beam area a function of:
    • Beam size at aperture
    • Beam divergence
    • Distance from aperture
  • > irradiance > potential hazard
pulsed lasers
Pulsed Lasers
  • Delivers energy in the form of a:
    • single pulse
    • train of pulses
  • Delivered in less than .25 seconds.
  • Output expressed as the total energy per pulse (joules).
radiant exposure energy density
Radiant Exposure (Energy Density)
  • Normally expressed in Joules/cm2
  • Function of:
    • Pulse Density
    • Pulse duration
    • Pulse frequency
  • > radiant exposure > potential hazard
laser types
Laser Types
  • Solid state
    • Ruby crystals and neodymium-doped glasses and crystals most common solid laser media.
  • Gas
    • A pure gas or mixture of gases (i.e. Helium-Neon or Carbon dioxide)
  • Liquid
    • Inorganic dyes contained in glass vessels most common.
laser types18
Laser Types
  • Excimer
    • Uses reactive gas with inert gas. Dimer produced which when lased produce UV
  • Semi-conductor (most common laser)
    • Gallium arsenide most common semiconductor material
excitation sources
Excitation Sources
  • Types
    • Flash lamps
    • Plasma discharge tubes
    • High voltage current
    • Radio frequency
    • Some lasers used to “pump” other lasers.
  • Excitation device can present serious non-beam hazard
ansi classification
ANSI Classification
  • ANSI (and LIA) - ANSI 2000 has developed four categories of hazard potential.
  • Based on the ability of optical emissions from a laser system to produce injury to personnel.
  • The higher the classification number, the greater the hazard potential.
class i
Class I
  • May produce visible or invisible laser radiation.
  • Do NOT pose a hazard under normal operating conditions.
class ii
Class II
  • Low-power visible light lasers or laser systems that:
    • Do NOT normally present a hazard because of the normal human aversion response
      • Blinking
      • eye movement, etc.
    • Potential for hazard if viewed directly for extended period of time
      • similar to many conventional light sources
class iiia
Class IIIa
  • Normally not injure the eye if viewed for momentary period (within the aversion response period) with the unaided eye
  • May present a greater hazard if viewed using collection optics.
  • Must carry a caution label.
class iiia25
Class IIIa
  • Another group of Class IIIA lasers have DANGER labels
  • Capable of exceeding permissible exposure levels for the eye in 0.25 seconds.
  • Still poses a low risk of injury.
class iiib
Class IIIb
  • Produce eye damage if viewed directly.
  • Includes intrabeam viewing of specular reflections.
  • Normally do not produce a hazardous diffuse reflection.
class iv
Class IV
  • Produce retinal damage from direct or specular reflections.
  • May also produce hazardous diffuse reflections.
  • May produce significant eye and skin radiation hazards as well as fire hazards.
laser applications
Laser Applications
  • Industry
    • Can be used to melt, vaporize, drill material in precise manner
    • Many other
  • Scientific Research
    • Used to study molecular structure
    • Selectively induce chemical reactions
  • Medicine
    • Cut and cauterize without damaging healthy tissue
    • Eye surgery
laser applications31
Laser Applications
  • Military
    • Guidance systems for missles, aircraft, and satellites
  • Communication
    • Laser light can carry 1000 times number television channels now carried by microwave
    • Play audio compact discs and videodiscs
laser pointers
Laser Pointers
  • Not dangerous when used properly.
  • Looking directly into beam for > 1 ½ minutes can result in eye injury.
  • Flashblindness
    • Split second look
    • Similar to effect in flash photography
    • Vision returns to normal after few moments
    • No long term effect
red laser pointers
Red Laser Pointers
  • 670 nm
    • 1000’ range
    • Rarely sold today
  • 650 nm
    • 2000’ range
    • Adequate most purposes
  • 635 nm
    • 4000’ range
    • Usefule outdoors unless sun brightly shining
green laser pointers
Green Laser Pointers
  • 532 nm
    • Eye more sensitive to green light
    • Reason for exceptionally brilliant visibility
  • Frequency doubled diode
    • Uses infrared diode (2 x 1064)
    • Low efficiency
      • 500 mW into diode
      • Few mW out of diode
fda regulation
FDA Regulation
  • Laser pointers are regulated according to their power output.
  • Class II laser Pointers
    • < 1 mW
    • CAUTION Label required
  • Class IIIb Laser Pointers
    • 1 to 5 mW
    • WARNING Label required
biological effects
Biological Effects
  • Tissues at risk are:
    • Eyes
    • Skin
  • Three mechanisms of injury
    • Thermal effects
    • Photochemical effects
    • Acoustical transient effects
eye injury potential
Eye Injury Potential
  • Related to laser wavelength
    • < 300 nm & > 1400 nm
      • Cornea
    • > 300 < 400 nm
      • Aqueous Humor
      • Iris
      • Lens
      • Vitreous humor
    • > 400 < 1400 nm
      • Retina
eye injury potential38
Eye Injury Potential
  • Retinal Injury
    • May be severe due to focal magnification
    • Optical gain ~ 105
    • Example
      • 1 mW/cm2 into eye ≈100 W/cm2 on retina
  • Lesions
    • Caused when choroids blood flow cannot regulate retina heat loading
skin injury potential
Skin Injury Potential
  • Thermal Injury
    • Acute exposures to high power lasers beams
    • Direct contact with beam or specular reflection
    • Not usually serious
  • Photochemically induced
    • Chronic exposure to scattered UV radiation
    • Direct contact with UV beam, specular reflection, or diffuse reflection
    • Can cause minor or severe sunburn
    • May promote formation of cancer
laser safety43
Laser Safety
  • Responsibility of each individual
  • Three categories of controls
    • Engineering
    • Administrative and Procedural
    • Personal Protective Equipment
  • Work better together than singly.
engineering controls
Engineering Controls
  • Normally designed and built into laser equipment
    • Protective housing
    • Master key switch
    • Beam stops/attenuators
    • Activation warning system
    • Interlocked doors
    • Airborne emissions controls
administrative procedural controls
Administrative & Procedural Controls
  • No physical barrier
  • Examples
    • Area postings
    • Standard Operating procedures
    • Maintenance procedures
    • Administrative procedures
    • Alignment procedures
personal protective equipment
Personal Protective Equipment
  • Eye protection
    • Essential for beam alignments
    • Must be marked with:
      • Optical Density
      • Laser Wavelength
    • Must be comfortable
  • Skin protection
    • Gloves
    • UV face shield
    • Lab coat
non beam hazards
Non-Beam Hazards
  • Industrial Hygiene
    • Associated with compressed gases, cryogenic materials, toxic & carcinogenic materials
    • Adequate ventilation to reduce fumes & vapors
  • Explosion Hazards
    • High pressure arc lamps, filament lamps, or laser welding equipment
    • Laser targets and elements of optical train
non beam hazards49
Non-Beam Hazards
  • Non-beam Optical Radiation Hazards
    • Laser discharge tubes, pumping lamps, and laser welding plasma
  • Electrical Hazards
    • Installation and connection
    • Conduit versus flexible cord
  • Noise Hazards
    • High noise levels during operation
non beam hazards physical
Non-Beam Hazards - Physical
  • Factors that contribute to injury are:
    • Fire
    • Explosions
    • electrocutions
  • From
    • arc and filament lamps
    • capacitors
    • wiring
    • power supplies
    • circuits
    • solvents
    • gases
non beam hazards chemical
Non-Beam Hazards - Chemical
  • Various chemical agents:
    • Dyes
    • Solvents
    • Gases
  • Laser-generated airborne contaminants
    • Dusts
    • Mists
    • Fumes
    • Smokes
slide53
Mastering Light:

An Introduction to Laser Safety and Hazards

objectives54
Objectives
  • IDENTIFY what the acronym LASER means and briefly DESCRIBE how a laser performs it function. (LST.OBJ.001)
  • LIST the characteristics of a laser beam. (LST.OBJ.002)
  • DIFFERENTIATE between a Continuous Wave Laser and a Pulsed Laser. (LST.OBJ.003)
objectives continued55
Objectives (continued)
  • LIST the five types of lasers and briefly DESCRIBE their attributes. (LST.OBJ.004)
  • LIST several types of laser excitation sources. (LST.OBJ.005)
  • IDENTIFY the American National Standards Institute Laser Classifications. LST.OBJ.006
objectives continued56
Objectives (continued)
  • LIST three areas in which lasers have been used. (LST.OBJ.007)
  • Describe the two common types of laser pointers. (LST.OBJ.008)
  • List the criteria used by the FDA to determine laser pointer classification and the required labeling on each class of laser pointer. (LST.OBJ.009)
objectives continued57
Objectives (continued)
  • IDENTIFY the three primary mechanisms of tissue injury associated with laser radiation exposure. LST.OBJ.010
  • MATCH the specified laser wavelength to the part of the eye that is most affected. LST.OBJ.011
objectives continued58
Objectives (continued)
  • IDENTIFY the two mechanisms by which laser radiation may potentially cause skin injury. LST.OBJ.012
  • IDENTIFY the three basic categories of controls used in laser environments to provide a degree of protection from possible laser radiation injury and GIVE several examples of each type of control. LST.OBJ.013
objectives continued59
Objectives (continued)
  • IDENTIFY other non-beam hazards that are possible in laser environment and GIVE an example of each. LST.OBJ.014
  • MATCH the following laser related terms to their corresponding meaning:
    • Accessible Exposure Limit - Nominal Hazard Zone
    • -iffuse Reflection - Specular Reflection
    • Intrabeam Exposure - Radiant Exposure
    • Irradiance - Peak Power
    • Maximum Permissible Exposure

LST.OBJ.015