Hologic DISCOVERY A, Technical Manual

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Discovery QDR Series Technical Manual
4-8
Note: The last direction turned should be clockwise to eliminate backlash when
the jam nuts are tightened. The plot should show peak amplitude.
10. Tighten the jam nuts on both Filter Drum alignment screws.
Note: The X-rays should still show peak amplitude.
11. Turn off the X-rays using the
<F2>
key.
12. Remove the alignment test fixture.
Figure 4-7. Array Assembly - Top View, Partial
The next six steps adjust the beam front to back.
13. At the Array assembly, loosen the four X-alignment nuts (see Figure 4-7 above).
14. Turn on the X-rays with the
<F1>
key.
15. For a Discovery A only, adjust the array X-alignment screw in one direction until
the trace drops off (the signal on the end detectors of the array will drop off).
Then, count the turns while moving it in the other direction until the trace falls
off on the detector on the other end of the array. Set the adjustment in the middle
by turning the screw back half the number of turns counted.
16. For Discovery C, Ci, W, Wi, and SL models, detectors 44 through 171 will be
turned on. You will have to exit this routine, remove the alignment pin, run the
Aperture Calibration procedure (Aperture Calibration cannot be run on Ci and
Wi), and then return to X-Ray Survey. When you enter X-Ray Survey do not
change this Aperture setting (set to 7), the Hi gain setting (set to 2), the Lo gain
setting (set to 1) or the X-ray mode setting (set to 3).
17. For Display, click Graph.
18. Click X-ray (F2) to turn x-rays on.
X -A lig n m e n t N u t (4 x )
A lig n m e n t S c r e w