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Gain and Filter Optimization

SciMeasure cameras are typically provided with 3 or 4 gain settings, which are optimized to cover the dynamic range of the sensor. The highest gain is nominally chosen to yield 0.5 e- per ADU and the lowest gain is nominally chosen to span the well depth of the sensor. Additionally, SciMeasure cameras are typically provided with 4 filters on each analog input in order to optimize readnoise over the selected frequency range of the camera. These filters can be bypassed by SciMeasure's patented Turbo technology to allow faster settling after CCD reset. This means that there is relatively more time to read the CCD signal and a slower, quieter filter can be used.

 

Minimizing power consumption and Dark Current

SciMeasure AO and Astronomy cameras typically use sensors with integrated thermo-electric coolers to minimize power consumption and signal noise. Most SciMeasure cameras operate the sensors at 30 to 40 degrees C below ambient, which is sufficient to suppress dark current at high frame rates. Autonomous, programmable sensor temperature control is available for dark level signal stabilization.

 

Keeping heat away from where it is not wanted

SciMeasure AO and Astronomy cameras typically use remote camera heads, which are separated from the camera controller by 3m cables to keep excess heat and electrical noise away from the focal plane. Although SciMeasure camera controllers are not large and are relatively low power (about as much power as a 100W light bulb), SciMeasure cameras are used in the world's most demanding applications where any heat or noise is too much.

 

Wavefront sensor cameras

SciMeasure wavefront sensor cameras are based upon 4-port 80x80, 16-port 128x128 and 20-port160x160 pixel back-illuminated CCDs. Subject to the constraints of symmetry between segments, many creative readout formats are available. These include skipping guard rows and columns, reading different numbers of pixels in different rows as well as the usual range of windowing and binning modes.

 

[chart of operating points, coming soon]

 

Tracking Cameras

SciMeasure wavefront sensor cameras are based upon 4-port 80x80, 16-port 128x128 and 20-port160x160 pixel back-illuminated CCDs. Subject to the constraints of symmetry between segments, many creative readout formats are available. For tracking, these are typically windowing and binning modes.

 

[chart of operating points, coming soon]

 

Guider Cameras

SciMeasure Guider cameras are based on the 1024x1024 13-micron pixel e2v CCD47.

 

[chart of operating points, coming soon]

ADAPTIVE OPTICS and ASTRONOMY

SciMeasure cameras are designed to give the best performance possible in real world situations. Focusing on multi-port traditional CCDs means that our cameras yield better signal-to-noise at real world signal levels than CCDs that rely on electron multiplication. Focusing on back-illuminated CCDs means that our cameras have much better QE, MTF and cosmetics than all front-illuminated sensors, including CMOS sensors. Focusing on deeper-well CCDs with large pixels means that our cameras have a higher real dynamic range and higher signal-to-noise than small pixel CCDs and CMOS sensors. Large pixels also make it much easier to couple the target to the sensor.

NIRSPEC/MAGIQ guide camera image
Credit: Diane Wooden, NASA Ames/Mike DiSanti, NASA GSFC/Eliot Young SwRI/Al Conrad, Jim Lyke and Terry Stickel, WMKO