Method of Use for Spectra Physics 2017 laser
in Hydraulics Lab Laser Enclosure
Nature of Laser and purpose
The Spectra Physics 2017 laser is a constant wave laser producing a continuous
laser beam at 492nm wavelength, which is in the visible spectrum.
The laser is rated at 5W but the output is continuously variable from about 1 - 6W.
The emissions are strong enough to damage eyes and burn skin in less than a
second.
The laser is used primarily for PIV on transparent models but also can be used for
other tests requiring a coherent or monochromatic light source.
Features of the installation
The laser is permanently mounted on a table below eye level and requires a three
phase power supply, a key, cooling water and an auxiliary interlock to activate.
 The three phase power supply can be switched on without any special
requirements. Switching it on also illuminates a lamp above the main door to the
enclosure.
 The key may only be removed from the switch in the off position.
 Cooling water must be supplied at a minimum rate above which the water
interlock light goes out
 The auxiliary interlock requires two pins in a plug to be shorted which can only
happen when a normally open reed switch on both doors close (the doors are
closed) or a momentary action switch inside the room is depressed. This allows
one operator to allow another into or out of the enclosure.
Both doors require a key to open them and have a sign on them warning of the laser
hazard.
A lamp above the main door comes on when the laser power supply is switched on,
whether the laser is armed or not.
Operating the laser
Two pairs of goggles are provided for operators. Be aware the beam is invisible when
wearing the goggles and they are best used for setting up with the laser at its lowest
power.
Before the laser is switched on checks must be made:
 At the control panel
 the three knobs below the meter - current, meter and power - should be as far
anticlockwise as they will go
 the four switches to the right of the meter should be set to mode - 'current',
range - '2W', head - 'A', control - 'remote'
 Visually check the optical path to ensure all mirrors and lenses look to be in the
correct orientation and won't produce unexpected reflections.
The laser is operated by switching on the isolator for the three phase power supply,
turning on the water until the lamp goes out and turning the key in its lock with the
doors to the enclosure shut. The lights should be on.
Look away from the beam path until the laser is active - up to 10 seconds after the
key is turned and denoted by a change in sound emitting from the laser head.
Carefully inspect the beam (if you can't see it the shutter on top of the laser head
may be closed) to ensure it is properly contained and going where expected.
Now turn the meter knob to 'watts', the mode switch to 'power' and the range switch
to '10W'. Adjust the power knob to the required level when ready.
Switching off is a reverse of starting. The control panel knobs and switches and head
controls should be in their normal starting positions when you have finished. Leave
the water running for twenty minutes before turning it off.
Rules for operating
 Only authorised people may be in the room while the laser is operating. All such
people must have had an eye test and be registered as users. Undergraduates
are authorised if they are registered as users, have had an eye test and the work
is part of their course.
 Visitors who have had eye tests as part of their employer's H&S arrangements
may be classed as authorised but must have a member of staff who normally
operates the laser with them.
 Undergraduates are not allowed to operate the laser unsupervised.
 Only one of the two keys used to activate the laser is available for issue and will
only be issued by a member of the laboratory staff to authorised people. The
other key is for emergency use - loss of the first key, absence of the key holder
etc.
 The key must not be left in the laser when the laser is unattended. To remove the
key the laser must be switched off.
 The momentary action switch which allows workers to leave and enter the room
must not be defeated.
Good working practice
 Experiments are usually conducted in the dark with a lot of equipment in a
cramped space. Know where everything is and devise tests so there is as little
need to move around with the lights out as possible.
 Set up optics with the lights on and the laser on low power. Insert optics with the
laser beam off and when in place tilt them so the beam is away from operators
eyes, preferably downward. Make final adjustments with the beam on and the
beam after the optic blocked.
 Remain standing while the laser is on. Sitting puts your eyes at the beam level.
 Keep the test apparatus low so that the laser beam doesn't have to rise to eye
level to get to it.
 Block all unrequired emissions appropriately. Do not let them pass to the walls.
 Try and design in a safe area for operators where the beam cannot go even if the
optics move.
 Do not make adjustments to optics 'on the fly'.
 Keep the numbers of operators to a minimum - three should be the maximum.
Method of Use for Spectra Physics 2017 laser.doc - Paul Williams V1 21 December 2005