Teledyne Princeton Instruments PI-MAX 3, System Manual

Page: 173 / 250

Chapter 12 LightField and Dual Image Feature (DIF) 173
b. Use the hyperlinks at the top of the expanded panel to make any necessary
changes to the following parameter configurations:
•
Intensifier Settings;
• Trigger Settings;
• Phosphor Decay Delay Time;
• Number of Frames (i.e., a multiple of 2);
• Readout Mode (i.e., DIF or Full Frame).
c. When using PI-MAX3 generated internal triggers for DIF acquisition, configure
the desired Internal Trigger Frequency.
d. Configure the desired Gate Width and Delay Times for the first and second
images:
•
The Initial Gate Delay time will be
≥
85

s;
• The Second Gate Delay time will be
≥
0.441

s.
e. If required, configure the AUX Output trigger.
f.
To have trigger outputs from the SyncMASTER1 and SyncMASTER2 connectors
on the AUX I/O cable, click SyncMASTER ON.
By enabling SyncMASTER:
•
The output of the SyncMASTER1 connector will be the Internal Trigger
Frequency.
• The SyncMASTER2 output will be at the same frequency but can be delayed
by between 0 ns and 999700 ns, in 100 ns increments.
5. Verify:
• The I.I.T. Power switch on the rear of the PI-MAX3 is turned ON;
• Enable Intensifier is checked on the Common Acquisition Settings expander.
6. When the experiment is ready, click Acquire.
12.5 Tips and Tricks
Experiments using the DIF feature of the PI-MAX3 can be complex, and timing of the
events is usually rather exacting. Here are several points to consider that may make the
experiment setup or troubleshooting much smoother and easier.
• The most important piece of equipment in a DIF experiment is an oscilloscope.
The PI-MAX3 has a MONITOR BNC on the back of the camera which is very
useful for seeing when the two image exposures occur during the course of the
experiment. The use of the MONITOR BNC and an oscilloscope is discussed in
more detail in
Chapter 15, Tips and Tricks , on page 183.
• The short time between the two images in DIF requires an intensifier with a fast
phosphor. P46 phosphor has a decay time of ~ 2

s which means it takes 2

s
for the phosphor emission to drop to 10% of its peak value. The decay is not a
simple single exponential. Even after 100

s there may be 1% or more of the first
image on the phosphor screen. It is usually possible to subtract a percentage of
the first image from the second image to remove the residual image. If this is
not possible, there are intensifiers with P47 phosphor, which is an order of
magnitude faster than P46.
• The software uses the Phosphor Decay Time to determine how long to wait
after the gate pulse to shift the image. This value can be adjusted on the
Advanced fly-out panel of the Common Acquisition Settings expander. If there is
some residual image from the first frame in the second frame, simply increase
the Phosphor Decay Time to allow the phosphor more time to decay before
shifting the image. If residual image is not an issue, then Phosphor Decay Time
can be shortened to decrease the time between the two DIF images.