Fluke Biomedical 30-471 - Manual (Page 11)

Operation
Photon Detectors
2
2-3
5–11 MV Diodes
Similar results are shown in the following figures for 5-11 MV diodes, although the output changes by less
than 1% for a slightly smaller range of angles. That range being 35-40 degrees from 180 for both planes
of rotation.
Gantry angle (degree with 180 being vertical)
Diode (type 471 [1–4 MV rated]) output vs. incident angle;
asymmetric setup cable faces collimator when at 90 degrees
Diode out
p
ut (n
ormalized
to
180°)
Gantry angle (degree with 180 being vertical)
Diode (type 472 [5–11 MV rated]) output vs. incident angle;
symmetric setup in 6 MV phontons
Diode out
p
ut (n
ormalized
to
180°)