Laser Safety Presentation David Baer Former Laser Safety

Laser Safety Presentation David Baer – Former Laser Safety Officer Centre for Lasers & Applications Macquarie University - April 2004

The First Step in Laser Safety Plan your experiment n Source correct optics and mounting hardware n Map out beam paths n Do the Laser Safety Calculations n

The Old Classification System Class 4 Approx. Power Limits for CW Visible Wavelengths Only 0. 5 W Class 3 B 5 m. W Class 3 A 1 m. W Class 2 Visible wavelengths only Unsafe for eyes Unsafe for skin Unsafe for eyes Generally safe for skin Safe with (0. 25 s. ) aversion response no viewing aids Safe with (0. 25 s. ) aversion response including viewing aids 220μW to 0. 4μW Class 1 No precautions required

The New Classification System Class 4 Unsafe for eyes Unsafe for skin Approx. Power Limits for CW Visible Wavelengths Only 500 m. W Class 3 B Unsafe for eyes Generally safe for skin 5 m. W Class 3 R Safe with (0. 25 s. ) aversion response no viewing aids 5 m. W Class 2 M Safe with no viewing aids Visible wavelengths only 1 m. W Class 2 Visible wavelengths only 1 m. W 39μW to 390μW (depending on λ) Safe with (0. 25 s. ) aversion response including viewing aids Class 1 M Safe with no viewing aids Class 1 No precautions required

Why Lasers Are Hazardous 2 Main Factors. § Collimation Effects : More light can be introduced into the eyes compared to other light sources. § Spot Size Effects : Radiation in the 400 – 1400 nm region is brought to a sharp focus on the retina. This can increase the radiant exposure (irradiance) by approx 100, 000 times.

To Determine the Laser Hazard 6 main factors need to be taken Consideration. § Wavelength § CW or Pulsed Operation § Power or Pulse Energy § Repetition Rate (PRF) § Beam Diameter & Profile § Beam Divergence

Eye Effects Video Segment § § Laser radiation effects on the eye. From Laser Safety Video from Uni. of Southampton.

Laser Safety Eye Effects Video Loading Video Presentation…………

Laser Effects on Eyes and Skin

Lasers Safety Precautions Class 1 & 1 M Lasers : - No Precautions Class 2 & 2 M Lasers : - No Staring Class 3 R Lasers : - No Staring (also old Class 3 A lasers) - No Magnifiers

Lasers Safety Precautions Class 3 B & - Avoid Exposure Class 4 Lasers : - Know the NOHD - Controlled Area - Use Beam Stops - Diffuse Reflections Hazardous - Use Eye Protection - Interlocks Required - Chemical / Electrical hazards

Laser Safety @ the Faculty of Science § Majority of lasers are High Power Class IV Lasers § Research lasers may have many wavelengths § Laser, Chemical and Electrical safety procedures § must be followed No Laser maintenance after hours

Laser Safety Video § Laser Safety Video presentation from the Laser Institute of America. § Visit the LIA websites – valuable information on lasers and safety is available here. § § www. lasersafety. org www. laserinstitute. org

Laser Safety Video Loading Video Presentation…………

General Laboratory Safety § Clothing: No watches & rings. Long sleeve clothing encouraged. Wear enclosed footwear in labs. § Tripping hazards: cables, equipment on floors. Use cable trays whenever possible. § Housekeeping: When finished with equipment, put it away. If equipment is broken, get it fixed (see your supervisor).

General Laser Lab Safety § Never directly view a laser beam. § Never remove covers from equipment without approval from supervisors – laser, high voltages and other hazards are present. § Although no deaths have been recorded from laser beam exposure, a number of people have been killed by Laser HV Excitation circuits. § Familiarise yourselves with the Australian laser safety standard (present in most labs) and the MSDS folders regarding chemicals and materials you use. If relevant MSDSs are missing inform your Supervisor.

Optical – Research Lasers § Research Lasers present additional dangers § Multiple wavelengths – complicates selection of laser eyewear § No Aperture stickers – be aware of beam paths

Optical – Table Hardware § Avoid the use of periscopes, keep laser beams in the one horizontal plane on optical tables. (A researcher at a university was permanently blinded aligning a periscope) § Never use horizontal beam posts. (if a mirror is knocked, it can deflect a beam off the horizontal plane)

Optical – Laser Monitoring § Use alignment jigs and attenuators during set up § Consider using remote monitoring (cameras, laser beam analysers, fluorescent crystals and cards)

Optical – Laser Labs No line of sight between optical tables and hallways. (use internal partitions and optical barriers on tables) STAGED

Optical – Laser Labs § A labyrinth style entryway into labs, giving a safe area to put on safety equipment (PPE). § A storage rack for laser safety eyewear (labeled with wavelengths etc).

Laser Generated Air Contaminants § Machining polymers can release acidic and carcinogenic byproducts § Familiarise yourself with any potential by-products § Consult MSDS, reference books and supervisors § Use adequate extraction

Other Lab Hazards - Chemical § § Laser dyes – most dyes are carcinogenic Insulation Materials – Dusts, Fibres (Wear Masks) Optical Fibers – Eye hazards Solvents – flammability

Other Lab Hazards - Electrical n High voltages – Always ensure covers are in place. n 240 v – No uninsulated connections permitted. n Use removable insulated covers on experimental circuits. Don’t leave live circuits unattended. n Safety Concerns - Contact Greg Yates from METS.

Other Lab Hazards - Gases § Vacuum system – implosion issues with glass vessels. Safety glasses must be worn. § Compressed gases – toxicity, flammability and asphyxiation hazards.

Other Lab Hazards - Cryogenic § Liquid nitrogen – burns and asphyxiation hazards. § Liquid N 2 can condense O 2 from the atmosphere and may cause an explosion. § Ensure you have been trained in the correct way to handle liquid N 2. § Do not accompany full Liquid N 2 Dewars in Lifts.

Other Lab Hazards - Combinations Toxic Gases Laser Beam 200 W Vacuum System High Voltage 40 k. V High Temp 800 C UV from Discharge Ionising Radiation from Thyratron Water Cooling Insulation Materials Oil Cooling (Hot Oil) n High Volts and Solvents/ Oils – Fire risk. n High Voltages and Water – Electric shock.

The First Step in Laser Safety Plan your experiment n Source correct optics and mounting hardware n Map out beam paths n Do the Laser Safety Calculations n

Conclusion § Always wear correct Laser Safety Glasses § Consider all the implications of your project. § Always think what your doing. § Report any lab problems or concerns to your supervisor and/or Susan Law (E 7 B-351, x 8126). Updated Jan 2010