OptAcquire – Flexibility need not be complicated
OptAcquire is a unique control interface, whereby a user can conveniently choose from
a pre-determined list of set-up configurations, each designed to optimize the camera for
different experimental acquisition types, thus removing complexity from the extremely
adaptable control architecture of the iXon3.
The control architecture of the iXon3 is extremely tunable, meaning
the camera can be adapted and optimized for a wide variety of
quantitative experimental requirements. The range from fast
single photon counting through to slower scan, 16-bit dynamic
range measurements. However, successfully optimizing EMCCD
technology is not a trivial exercise, with various set-up parameters
directly influencing different camera performance characteristics.
OptAcquire has been designed as a unique interface whereby a
user can choose from a pre-determined list of nine camera set-up
configurations. A variety of set-up parameters are balanced behind the
scenes through the OptAcquire menu. Furthermore, advanced users
may wish to create their own additional OptAcquire modes to aid
future set-up convenience.
iXon3 control parameters include:
- EM gain – this parameter has a direct bearing on both sensitivity
and dynamic range.
- Vertical clock speed – flexibility in this parameter is critical to
optimizing the camera for lowest noise, fastest speed, minimal
frame transfer smear or maximum pixel well depth.
- Vertical Clock Amplitude – can be employed to help
‘over-clock’ the sensor to achieve faster frame rates and can
also be used to reduce charge leakage into the image area when
there is saturated signal in the frame transfer storage area (e.g.
when combining very short exposure with a slow readout speed).
- Horizontal readout speed – ranging between faster frame rates
and best dynamic range.
- Pre-amplifier gain – trading off reduced digitization noise versus
accessing full pixel well depth.
- EM / Conventional amplifier – to choose between ultrasensitive
EMCCD operation or traditional high dynamic range CCD
operation, the latter recommended for relatively ‘brighter’ signals
or when it is possible to apply long exposures to overcome read
- Frame Transfer (overlap) – overlap readout is used to achieve
100% duty cycle, ideal for fastest frame rate measurements
without switching exposure time between frames. This mode
should be deselected for time-lapse experiments.
Pre-defined OptAcquire modes include:
- Sensitivity & Speed (EM Amplifier) - Optimized for capturing weak signal at fast frame rates, with single
photon sensitivity. Suited to the majority of EMCCD applications.
- Dynamic Range & Speed (EM Amplifier) - Configured to deliver optimal dynamic range at fast frame rates.
Moderate EM gain applied.
- Fastest Frame Rate (EM Amplifier) - For when it’s all about speed. Optimized for absolute fastest frame
rates of the camera. Especially effective when combined with
Time Lapse (EM Amplifier) - Configured to capture low light images with time intervals between
exposures. Overlap ('frame transfer') readout is deactivated.
- Time Lapse & Short Exposures (EM Amplifier) - Configured to minimize vertical smear when using exposure
times < 3 ms.
- EMCCD Highest Dynamic Range (EM Amplifier) - Combines EMCCD low light detection with the absolute highest
dynamic range that the camera can deliver. Since this requires slower
readout, frame rate is sacrificed.
CCD Highest Dynamic Range (Conventional Amplifier) - Optimized for slow scan CCD detection with highest available
dynamic range. Recommended for brighter signals or when it is
possible to apply long exposures to overcome noise floor.
- Photon Counting - Configuration recommended for photon counting with individual
exposures < 10 sec.
- Photon Counting with Long Exposures (> 10 sec) - Configuration recommended for photon counting with individual
exposures > 10 sec.