Princeton Instruments PhotonMAX System, Manual, Page: 60 / 98

60 PhotonMAX System Manual Version 1.B
Kinetics Mode (Option)
Introduction
“Kinetics” refers to a special readout
mode in which a portion of the CCD is
illuminated while the rest of the active
area is used to store a series of frames.
At the end of the exposure-shift
sequence, the entire CCD is readout to
give a series of subframes (kinetic
frames) separated in time. In order to
support this special mode of operation, it
is essential that the camera architecture
be made flexible with special access to
underlying CCD control functions Aided
by the back illumination technology for
high QE and multiplication gain for sub-
electron read noise, the kinetics mode (as
implemented in WinView and WinSpec
software packages ver. 2.5.19.4 or later)
provides the powerful combination of
speed and sensitivity.
Kinetics Readout
Kinetics readout allows a burst of subframes be captured with
µ
sec 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 PhotonMAX 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, 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 49. Hardware Setup Dialog Box:
Kinetics Readout Mode
Enter "Window Size"
(number of rows per
subframe).
Select "Kinetics" as
the Readout Mode.