Philips CARDIOMD, Service Manual

Page: 366 / 466

Detailed Description
12-18
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CardioMD Service Manual
1MAN0158-H11 04-2005 CSIP Level 1
Sensing the Position of the Line Source Housing
The line source compartment has a mechanism that detects when the line source is in the park
position. When the line source housing approaches the park position, it will push the indicator
arm, as you can see from Figure 12.14. The indicator arm pulls a plate mounted on a slide bearing
away from the optocoupler, enabling current through the optocoupler (shown in Figure 12.15),
and thereby signaling to the motion controller. The indicator arm is supplied with a spring (shown
in Figure 12.14 but not in Figure 12.15), which will pull it back in position when the line source
moves away from the park position again.
Figure 12.15 The mechanism sensing the position of the line source
Line Source Housing
The line source housing contains the Gd-153 line source. The line source housing is manufactured
from a lead-bronze alloy and has a 1.5 mm aperture. Thus, the line source housing serves as a
collimator, collimating the radiation from the line source in both the x (30 mm resolution) and y
directions (200 mm resolution).
Optocoupler detecting
line source position
Source in park
position
Line source position
indicator arm