Specifications

Version 1.1 rev Jan 2013
Page 59
iXon Ultra
, Features and Functionality
3.4.2 - Capture Sequence in Non-Frame Transfer Mode (NFT) with an FT
EMCCD
It is also possible to operate an FT EMCCD in a Non-Frame Transfer (NFT) mode. In this mode of operation, an FT
EMCCD acts much like a standard CCD. The capture sequence for this mode is illustrated here:
Figure 19: Capture sequence (NFT mode)
Step 1 Both Image and Storage areas of the EMCCD are fully cleared out.
Step 2
On receipt of a start acquisition command the EMCCD stops the Keep Clean Cycle and an acquisition
begins. The image builds up in the Image area of the EMCCD until the exposure time has elapsed, at which
point the readout process starts.
Step 3
The rst phase of this process is to quickly shift the charge built up in the Image area into the Storage area.
The time required to move the charge into the Storage area is the same as in Frame Transfer mode
Step 4
With the image now in the Storage area the captured image is read out. The time taken to read out the
image is again the same as in the Frame Transfer mode.
Step 5
On completion of the readout, the EMCCD is completely cleared, ready to acquire the next image. The
EMCCD will remain in the Keep Clean Cycle until the end of the accumulation or kinetic cycle time,
depending on the acquisition mode, i.e. back to Step 1. As at least one Keep Clean Cycle is performed
between each exposure, the minimum exposure time is no longer set by the time to read out the image.