Embed Size (px)
Citation preview
Radiation hazards - eye damage - skin damage - fire
Non-Radiation hazards - electrical - toxic dyes - toxic gases
Majority of accidents
Risk of irriversible damage
EN-IEC 60825-1 → Safety of laser Products EN-208 → Protective Eyewear
Maximum Permissible Exposure (MPE) Skin and Eyes (W/cm2 or J/cm2)
Valid for wavelength range: 180 nm – 1 mm
Wavelength (nm)
Mode of operation (CW or pulsed)
Power (Watts or Joules/pulse)
Beam size (mm)
Exposure time (s)
Required to determine MPE!
532 nm: 390 µW for 10 sec. 830 nm: 710 µW for 10 sec. 1064 nm: 1.95 mW for 10 sec. 1310 nm: 96 mW for 10 sec.
Pulse energy = 1mJ/Pulse
τ=1 s Ppeak = 1×10-3 W = 1mW τ=1 ns Ppeak = 1×106 W = 1MW τ=1 fs Ppeak = 1×1012 W = 1 TW
800 nm Iceberg
λ= 632 nm Pavg= 2 mW HeNe Laser
λ= 800 nm Pavg= 2 W Ti-Saph Laser
Class 1= MPE not exceeded
Class 1M = May be unsafe when optical
instruments are used
Class 2= Blink reflex prevents retinal damage
(visible wavelengths)
Class 2M = May be unsafe when optical
instruments are used
≤1 mW for CW
Class 3B & 3R = MPE is exceeded,
dangerous to eyes. Safety goggles recommended (3B) /compulsory (3R)
≤5 mW (3B) ≤500 mW (3R) for CW
Class 4 = (Scattered) radiation is dangerous
to eyes and skin. Wear goggles and use beam blocks. ≥500 mW
Proper L-class (not OD!)
Whole eye must be covered
Goggles must sustain an exposure of 10 seconds or 100 pulses
Wavelength range D = CW operation I,R = Pulsed operation M = Ultrashort pulsed operation L = protection Level
PhD student was aligning set up in lab
He used goggles
Alignment of an optical isolator
Suddenly he smelt something burning
Holes burnt on shelf plate
Melted spots on laser goggles
1064 nm
3 Watt CW
Beam diameter = 4 mm
~ 24 W/cm2 = 2,4×105 W/m2
L scale 5 for 1064 nm operation mode D should be used
L scale 4 was used......
However, back reflected power was found to be 200 mW .... Was he lucky?
Goggles L class = 4
Beam dia < Entrance dia pupil
Exposure on retina = 20μW
MPE Eye = 1.95 mW for > 10 sec
Be aware of laser characteristics
Wear suitable goggles when laser class >3
Turn laser sign on
Close door
Close curtains
Laser beam should not leave set up
Use screens on edges of tables
Use beam dumps for highest powers
Do not change other people’s set up
Do not wear shiny jewelry
Align at low powers
Do not block lasers with your hand, especially short pulse lasers
Warn supervisor if you see unsafe behaviour
Secure and transport victim in a sitting position to prevent further eye damage!
Go to first aid employee (BHV-er)
Seek medical attention
Medication can not reverse retinal damage but reduce damage due to inflammatory response
Inform supervisor
Guide to Laser Safety (Laser Vision GmbH)
http://www.noirlaser.com/pdf/net_elements.pdf
http://www.laserlab.vu.nl/en/Images/SAFETY_eyes_tcm116-175360.ppt
