Varex Imaging Azure 3131Z Manual page 37

Azure 3131Z - 4131Z Reference Manual
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Performing a Gain Calibration sequence is used to:
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To ensure the X-ray detector is properly calibrated, perform
gain calibration.
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It is critical for gain calibration to acquire the flat field image(s) within a range that is
large enough to be higher than the background noise created by the X-ray source and
readout electronics of the detector, but lower than the saturation point of the detector.
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Acquire flat field images with a median count of approximately 17000 – 27000.
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Using larger numbers of calibration frames to capture the flat field image will result in
more accurate calibration. Accumulating a minimum 32 frames for gain calibration
provides optimal image quality.
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Gain calibration should typically be performed:
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Every 6 months.
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Whenever the central beam of the X-ray source moves relative to the detector.
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After replacement of an X-ray tube.
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The detector should be at a normal operating temperature before a gain calibration is
performed.
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If pulsed X-ray is used, see
on detector X-ray synchronization
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Gain calibration should be performed in each operating mode.
Once offset and gain calibration are complete with your selected mode, the
Note
X-ray detector is ready to acquire images.
"Section 20.6, Acquisition Timing" on page 33
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an offset calibration prior to
for information
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