Hologic DISCOVERY A, Technical Manual

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Discovery QDR Series Technical Manual
9-7
9.1.3.3.7 Aperture.
This is a spinner control with a range of 0 to 13. This controls the slit through which the
X-rays pass to limit the dimensions of the X-ray beam. This control allows the selection of
a specific aperture in the system and can be used to test aperture movement.
9.1.3.3.8 Average Voltage
This displays the average voltage across all detectors for the Hi Air segment
9.1.3.4 Controls starting with Display
Figure 9-7. Controls starting with
Display
9.1.3.4.1 Display
This has two buttons: GRAPH and TABLE. This controls what is seen on the Main
Display. In GRAPH the Main Display shows as a bar graph (see Figure 9-3) with scale
markings on the left side according to how Scale is set (see below). It shows the lo (brown
tinted) and the hi (green tinted) voltages. In TABLE the Main Display shows the data
from the detectors as numeric data.
9.1.3.4.2 Scale
This has three buttons: RAW, LOG and VOLTS. The Default is VOLTS. The Field
Engineer will not use RAW or LOG and the button should always remain the default
(VOLTS). This control sets up the scale markings on the Main Display when the Display
is set to GRAPH and changes the units for the numeric value when the TABLE is
displayed.
9.1.3.4.3 Segment
This has three buttons: BONE, TISSUE and AIR. The default is AIR. This controls the
data segment that are displayed in the GRASPH. The Field Engineer will not use either
BONE or TISSUE and the button should always remain the default (AIR).
9.1.3.4.4 Zoom In and Zoom Out.
By default, the GARAPH is displayed at minimum resolution When either function
reaches it maximum the button will be grayed out. Zoom In increases the resolution,
meaning that less of the total data range is displayed on the graph but differences in bar
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