OPHIR BeamSquared, User Manual

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External Attenuation of the Beam 2.4
Avoid eye or skin exposure to direct or scattered radiation!
Before allowing laser energy to enter the instrument, it is important to limit the beam intensity.
Excessive laser energy may cause damage to the camera or the internal components of the
BeamSquared hardware.
A CCD camera imager is subject to damage at energy levels in excess of 1μJ/cm
2
or at average power levels
greater than .15mW/cm
2
.
Beam splitters and/or filters may be used to attenuate the beam, but care must be used to prevent the
introduction of distortions.
The peak energy density that reaches the camera changes, potentially over several orders of magnitude,
during a measurement cycle. This is a result of the camera effectively moving from a large unfocused spot
near the lens, into and through the focus at the waist then out again to an unfocused spot (see diagram
below). During a regular run, the optical train automatically adjusts to accommodate these changes in beam
intensity, so long as the user has prudently selected the intensity of the input beam.
It is the user’s
responsibility to properly attenuate the laser to operate within the safe dynamic range of the
BeamSquared system.
The internal attenuation is intended to compensate for changes in energy density as the beam is
focused. Use caution to attenuate the beam sufficiently before presenting it to the BeamSquared
device.