Precautionary Measures; Intensifier Modes And Safety; Alarm - Princeton Instruments PI-MAX 3 System Manual

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Precautionary Measures

Intensified CCD detectors, such as the PI-MAX3, when biased ON, can be irreparably
WARNING
damaged if continuously exposed to light levels higher than twice the A/D saturation
level. Thus it is critical that you not establish conditions that could result in damage to
the intensifier. Although intensified detectors are less prone to damage from background
light when operated gated, they are at significant risk of damage from high-intensity light
sources such as lasers. High intensity sources can damage the intensifier before the
protection circuits have time to respond, or even cause spot damage without the
protection circuits acting at all. If a sustained alarm indication occurs when the controller
is turned on, immediately switch the I.I.T. switch on the back of the PI-MAX3 to the
OFF position. Cover the detector window and only switch the I.I.T. switch to ON after
the illumination level has been lowered to safe operating conditions.

Intensifier Modes and Safety

The Experiment Setup Main screen allows selection of two modes, Gate Mode and Safe
Mode . In Gate Mode , the photocathode is biased ON only during the time each gate
*
pulse
the risk of damaging overload from intense light sources such as lasers remains. Intense
light sources in gated experiments can cause spot damage that would be undetected by
the alarm circuit. In Safe Mode , the photocathode is continuously biased OFF and the
intensifier is as safe as it can be.

Alarm

To reduce the risk of detector damage, the PI-MAX3 detector is equipped with an audible
alarm in the detector head, activated when the intensity of light falling on the image
intensifier exceeds a preset threshold. While the alarm is sounding, the photocathode is
disabled. Immediately toggle the I.I.T. switch (on the back of the PI-MAX) to the OFF
position. Cover the detector window and only switch the I.I.T. switch to ON after the
illumination level has been lowered. If the alarm sounds continuously even when the
illumination level is adequately low, shut the system down and contact the factory for
guidance.
Note: It is normal for the alarm to sound briefly when the system is turned on.
Caution
Discontinue operation and contact the factory at once if sporadic or continuous
unwarranted alarms occur. They may indicate intensifier damage or another situation that
requires immediate attention.
*
The Gate pulse is produced inside the PI-MAX3 from the Start and Stop signals supplied by the
internal timing generator.
PI-MAX
is applied. As a result, the tolerance to room light is higher in gated operation, but
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3 System Manual Version 1.A