Kinetics Readout; Figure 50. Two Examples Illustrating Partial Illumination Of Ccd For Kinetics Mode In - Princeton Instruments ProEM+ EMCCD User Manual

Chapter 6 Advanced Topics 87

Kinetics Readout

Kinetics readout allows a burst of subframes to be captured with μs resolution. This is
accomplished by shifting each subframe exposure under the mask before reading it out.
Since there is no overhead of readout time between each exposure, faster time resolution
is achieved. At the end of a series "exposure-shift" cycles, the entire frame is typically
read out at a slower readout speed, which does not affect the time resolution. The use of
multiplication gain {EM Gain} in ProEM+ further improves the SNR when the signal is
below the read noise.
In kinetics mode, a portion of the CCD image is optically masked in order to minimize
the cross-talk between subframes. Typically, in imaging applications, this is
accomplished by placing a "knife edge" or an optical mask in the collimated beam path.
Whereas, in spectroscopy, this is best achieved by limiting the height of the entrance slit
of the spectrograph. In most of the applications, the ability to mask as few rows as
possible sets the ultimate limit on the temporal resolution. The operation is illustrated
with examples in Figure 50 using an optical test target image.
Figure 50. Two Examples illustrating Partial Illumination of CCD
for Kinetics Mode in ProEM+:512B
Note: The illuminated area is the furthest from the serial register. The left image shows
an illuminated area of 60 rows. Window Size is 60 rows high. The right image shows an
illuminated area of 12 rows. Window Size is 12 rows high.
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