Hologic DISCOVERY A, Technical Manual

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Discovery QDR Series Technical Manual
3-47
Note: The PosLimitOffset and NegLimitOffset entries in the [ArMotor] section of the
SQDRIVER.INI file determine the motion limits relative to the mechanical stops. If
these entries are not present, or are zero, the motion limits are set to the mechanical
limits, as in the above example.
Note: The last calibration scan data is saved in the file MOTOR_AR.DAT. You can re
analyze the data–e.g., after editing SQDRIVER.INI–by typing the command
CALIBRATE @MOTOR_AR.DAT<Enter> at the MOTOR$AR> prompt in
SQDRIVER.
3.4.5 X-Ray Beam Alignment
It is crucial that the X-ray beam be precisely aligned with the detector array because
improper alignment will directly affect the repeatability (coefficient of variation, or CV)
of the Discovery. Therefore, this alignment must be verified at the time of installation or
whenever any work is performed that may affect it.
To check beam alignment:
Insert the alignment fixture (see the following three figures) into the detector opening.
Figure 3-21. X-Ray Alignment Fixture (TLS-00080)
WARNING: X-rays are generated during this procedure. Keep hands, head and other body parts out
of beam.
Alignment Pins
Holding Clamps