OHS026
Safe work procedure
1. Completed by:
Peter Reece
Staff/Student number:
2173999
The Writing Safe Work Procedures Guideline (OHS027) should be consulted to assist in the completion of this form
Faculty/Division: SCIENCE
Document number
SWP45 01.doc
School/Unit: PHYSICS / OPTOELECTRONICS
Initial Issue date
1 Nov 2011
Current version
1.0
Current Version
Issue date: 1 Nov 2011
Next review date
1 Nov 2012
2.Safe work procedure title and basic description of activity
Title: Alignment procedure for visible lasers (CLASS 3R, 3B & 4)
Lasers can be hazardous for a number of reasons, the most important of which is the danger associated with radiation
damaging the eye or the skin. Other non-beam related hazards include electrical, chemical and other concerns that are
also important but will not be discussed here. Here we shall only discuss safety issues related to radiation from the
laser. The degree of possible damage to the eye and skin is a function of the wavelength of emission, the power in the
beam, energy density and duration of the laser radiation.
WARNING: Always complete a risk assessment and seek approval from the academic-in-charge before starting a new
optical experiment involving Class 3R, 3B or 4 lasers.
Description of activity:General procedures associated with incorporating a visible laser with safety classification (CLASS 3R, 3B & 4) into an
experimental optical arrangement. These procedures cover a number of situations routinely performed within a
research lab conducting optical and spectroscopic measurements. Specific tasks include:
1. CASE 1: Establishing a beam line where no existing optical components are present
2. CASE 2: Redirection of an established beam path or gross alignment where the beam may deviate from any
optical component within the optical train.
3. CASE 3: Fine alignment where the beam will not deviate from any one component, but where the beam spot at
the end of the beam path will be modified.
4. CASE 4: Optical alignment where the beam is not directly manipulated, but the scattered light is modified.
The safe work practices described here are designed with Class VI visible lasers, which afford the greatest risk in terms
of laser related eye damage, burns and skin damage and fire hazard, however they may also considered as general
good practices to adopted for handling all types of laser classes.
Lasers that are relevant to this SWP:
Coherent Innova 70, Coherent Innova 90, Quantronix OEM, Coherent Cube 440, Coherent Cube 405.
3.List Hazards and risk controls as per risk assessment
Associated risk
assessment
number and
location:
Hazards
Controls
Electrical Hazard
Laser Eye Damage
Burns
Damage to optical
equipment
4.List resources required including personal protective clothing, chemicals and equipment needed
Laser safety goggles: L
Anodized black metal baffles
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Beam stop – a beam stop is
Viewing card
5.List step by step instructions or order for undertaking the task
General safe-handling protocols:The following practices apply to all visible lasers (UV and IR lasers have additional constraints):
1. Lasers cannot be handled without proper training from the Area Supervisor (Peter Reece).
2. Never view the laser beam directly along the beam path with your naked eye or any kind of optical viewing
apparatus.
3. Never place your hand or other part of your body or clothing into the direct beam path when laser is running at
high powers.
4. Where possible, maintain the laser beam path to a plane parallel to the optical bench and well below the viewing
height of the operator.
5. Periscope arrangements are only appropriate to change the height of the beam with respect to optical bench or
when passing the beam through a microscope column. Laser beams should never be directed out of the plane
towards the ceiling in an uncontrolled manner.
6. Always keep your head above the height of the beam path at all times.
7. Never allow the laser beam or any associated specular reflections to stray from the optical bench in an
uncontrolled manner; this represents a hazard to your work colleagues.
8. Always terminate the laser beam or strong collimated stray reflections using a beam-dump, beam-stop or metal
baffle. Black curtains do not block stray reflections.
9. Never perform any gross alignment of a laser beam under high power; attenuate the beam to a level that is
equivalent to a class II laser for the wavelength and temporal mode of operation for the laser.
10. Always visually check the intended beam path for obstructions and termination conditions before turning setting
the laser to high power operation.
11. For lasers with cooling water and three-phase power, always turn off the cooling water after the cool-down
procedure has been completed.
12. Laser safety goggles are only appropriate for procedures where minor adjustments to the beam path are required
and shouldn’t be used for gross alignment.
13. Complete Risk Assessments for all new optical experimental set-ups.
Task-specific protocols:-
1. PROCEDURE FOR ESTABLISHING A NEW BEAM LINE (CASE 1)
1. Ensuring that the laser aperture is closed or blocked with a beam-dump, start the laser as per the
model specific instructions – given below.
2. Plan the beam path on paper and identify all of the optical components that are necessary to complete
the optical train.
3. Clear the space on the optical bench where the beam will
4. Starting at the fi
2. PROCEDURE FOR OPTICAL FINE ALIGNMENT (CASE 3)
1. The laser start up procedure is unique to the particular laser system in use. The start-up procedure for
each of the lasers used in the Optoelectronics Lab is detailed at the end of this section.
2. The laser beam (or associated specular reflections) should never deviate from the optical bench where
the experiment is being performed. Use a beam-stop to terminate strong optical reflections and
anodized metal baffles for all other stray reflections. Note that the material curtains surrounding the
optical benches are only for blocking background light in an experiment – they do not stop beam.
3.
4. All
3. PROCEDURE FOR OPTICAL GROSS ALIGNMENT (CASE 2)
Gross alignment procedures, where the laser beam deviates significantly from an existing optical beam path or
walks off any optical component within the optical train, should always be performed with the laser power at a
minimum operating power. Ideally the power will be smaller than the
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1. PROCEDURE FOR INSTRUMENT OPTIMISATION (CASE 4)
Once the laser beam is set with appropriate termination conditions, associated optical apparatus for measuring
sample properties may be aligned. An example such a procedure includes alignment of collection optics for
measuring photoluminescence from a semiconductor sample. This typically is achieved using the diffuse
scattering of the laser from the sample surface or the sample holder.
1. Under low excitation conditions, place a
LASER START UP PROCEDURES
Coherent INNOVA 70 argon ion lasers
1. Slowly open the outlet tap of the recirculating cooling water mounted on the wall adjacent to the Power
supply. The direction of flow is indicated on the pipes.
2. Slowly open the inlet tap of the recirculating cooling water and check there is no leaking at the input
and output connections.
3. Switch the aperture on the front of the laser to closed.
4. Switch the key on the power supply followed by the switch on the control panel – if the cooling water is
flowing correctly the flow interlock indicator will blink once.
5. Press the start button on the control panel and wait for the laser tube to fully ionize (approximately 30
seconds).
6. During the start up procedure the laser cycles through to maximum optical power and therefore it is
important to ensure that the beam is terminated using a beam stop or the aperture during this time.
7. With the aperture closed turn up the current to about 90% of its maximum operating current (~ 35A).
The argon ion lasers take about half an hour to an hour to warm to stable operation and it is important
to run it at close to full capacity during this period.
8. Once the warm up process is completed adjust the current to the desired output power.
Coherent INNOVA 90 argon ion laser
1. Slowly open the outlet tap of the recirculating cooling water mounted on the wall adjacent to the Power
supply. The direction of flow is indicated on the pipes.
2. Slowly open the inlet tap of the recirculating cooling water and check there is no leaking at the input
and output connections.
3. Switch the aperture on the front of the laser to closed.
4. Switch the key on the power supply followed by the switch on the control panel – if the cooling water is
flowing correctly the flow interlock indicator will blink once.
5. Press the start button on the control panel and wait for the laser tube to fully ionize (approximately 30
seconds).
6. During the start up procedure the laser cycles through to maximum optical power and therefore it is
important to ensure that the beam is terminated using a beam stop or the aperture during this time.
7. With the aperture closed turn up the current to 41.5A. The argon ion lasers take about an hour to an
hour to warm to stable operation and it is important to run it at close to full capacity during this period.
Quantronix - Frequency Doubled Q-switched YAG Laser
1. Place a beam-stop in front of the laser to block the
2. Slowly open the outlet tap of the recirculating cooling water mounted on the wall adjacent to the Power
supply. The direction of flow is indicated on the pipes.
3. Slowly open the inlet tap of the recirculating cooling water and check there is no leaking at the input
and output connections on the power supply or laser head.
4. Turn the key on the power control unit and press and hold the interlock button until the pump is running
continuously.
5. Set the triggering conditions – if no external trigger is used set the triggering mode to “int”
6. Adjust the current control to a minimum (counter-clockwise to the stop)
7. Switch the power button and wait for a few seconds until the flash lamp has ignited.
8. Increase the current until the laser light is observed to exit the aperture.
Coherent Cube Diode Lasers
6.List emergency shutdown procedures
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Argon ion lasers (Innova 70 and Innova 90 series)
7.List Emergency procedures for how to deal with fires, spills or exposure to hazardous substances
If an
8.List Clean up and waste disposal requirements
N/A
9.List legislation used in the development of this SWP
Laser Safety Standard
10.List competency required – qualifications, certificates, licensing, training - e.g. course or instruction:
UNSW Lab Induction
11.Supervisory approval, And review
Supervisor:
Peter Reece
Responsibility for SWP review:
Signature:
Peter Reece
Date of review: 1 Nov 2012
12.SWP Sign off sheet
SWP name and version:
In signing this section the assessor/ authorisor agrees that the following persons are competent in following this
SWP
Name
Signature
Date
Competent
Name of Assessor/Authoriser
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Assessor/Authoriser
signature
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OHS026 safe work procedure
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