Maximizing Frame Rate Performance in EMCCDs
The iXon Ultra is capable of market leading frame rate performance, achieved from ‘overclocking’ the horizontal and vertical shifts during readout while maintaining quantitative stability. Furthermore, fastest possible continuous Region of Interest (ROI) frame rates can be attained using ‘Crop Mode’.
Part 1. Overclocking horizontal and vertical shifts for fastest speeds
Maximum frame rate performance in EMCCDs is a function of two parameters; (1) Pixel Readout Speed (horizontal); (2) Vertical Clock Speed. The former dictates how rapidly charge is pushed horizontally through the EM gain register and the remaining readout electronics, while the latter dictates the speed at which charge is vertically shifted down through both the exposed sensor area and masked frame transfer area of the chip. Significant advantages are gained through optimizing the camera electronics to enable both horizontal and vertical shifts to be speeded up through overclocking.
iXon offers industry fastest vertical shift speeds, resulting in faster frame rates and reduced smearing, significantly faster under commonly employed conditions of sub-array/binning. Notably, the iXon Ultra markedly overclocks the pixel readout speed to up to as fast as 30 MHz, compared to the standard 10MHz speed, further boosting the frame rate by 3x, in the case of the iXon Ultra 888.
- iXon Ultra 888 overclocked to 30MHz pixel readout speed: 3x faster full frame rate
- Fastest vertical shift speeds yield further speed gains with ROI / binning
- Minimized smearing through faster vertical shifts
Part 2. Boosting ROI Frame Rates with Crop Mode
The iXon family offer Crop Mode, which carries the following advantages:
- Specialized readout mode for achieving very fast ROI frame rates (sub-millisecond exposures) from ‘standard’ cameras.
- Continuous rapid spooling of images/spectra to hard disk
- User selectable cropped sensor size – highly intuitive software definition.
- The iXon Ultra is equipped with ‘Optically Centred Crop Mode’ – ROIs can be selected from the centre of the image.
- Ideal for super-resolution microscopy, ion signalling, voltage sensitive dyes and adaptive optics.
- The iXon is now available with the complementary OptoMask accessory, which can be used to shield the region of the sensor outside of the cropped area.
