Teledyne PIXIS-XF, Системное руководство

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Chapter 5 Operation 53
5.5.4 Controller Gain
Controller Gain is software-selectable and is used to change the relationship between
the number of electrons acquired on the CCD and the Analog-to-Digital Units (ADUs or
counts) generated.
In WinX/32, gain selection is made on the Acquisition
►
Experiment Setup…
►
ADC tab.
The choices are
• 1 (Low)
Users who measure high-level signals may wish to select Low to allow
digitization of larger signals.
• 2 (Medium)
Medium is suitable for experiments within the mid-level intensity range.
• 3 (High)
Users who consistently measure low-level signals may wish to select High,
which requires fewer electrons to generate an ADU and reduces some sources
of noise.
The Certificate of Performance supplied with the camera lists the measured gain values
at all settings.
Example
The following descriptions assume the Low Noise Readout Port has been selected and
that the actual incoming light level is identical in all three instances.
NOTE:
The numbers used illustrate the effect of changing a
controller gain setting and may not reflect actual
performance: gain at the 1, 2, and 3 settings depends on the
CCD installed.
• 1 (Low) requires four electrons to generate one ADU. Strong signals can be
acquired without flooding the CCD array. If the gain is set to Low and the
images or spectra appear weak, you may want to change the gain setting to
Medium or High.
• 2 (Medium) requires two electrons to generate one ADU. If the gain is set to
Medium and the images or spectra do not appear to take up the full dynamic
range of the CCD array, you may want to change the gain setting to High. If the
CCD array appears to be flooded with light, you may want to change the setting
to Low.
• 3 (High) requires one electron to generate one ADU and some noise sources are
reduced. Because fewer electrons are needed to generate an ADU, weaker
signals can be more readily detected. Lower noise further enhances the ability
to acquire weak signals. If the CCD array appears to be flooded with light, you
may want to change the setting to Medium or Low.
Table 5-1: Typical Controller Gain {Analog Gain} vs. Readout Port
Readout Port
{Quality}
Controller Gain {Analog Gain} Selection
1 {Low} 2 {Medium} 3 {High}
Low Noise 4 e-/count 2 e-/count 1 e-/count
High Capacity 16 e-/count 8 e-/count 4 e-/count