Fluke Biomedical 35080B - Manual (Page 43)

Mobile Filter Pack Plus Option (37946)
Linearity Corrections
8
8-3
8.4 Linearity Corrections
Corrections for linearity of the Mobile Filter Pack Plus (37946) can be made by taking the measured
output of the Model 35080B kVp Divider and adding the value in kVp shown on the curve in Figure 8-2.
The curve shown by the solid line in Figure 8-2 is normally used for x-ray generators with an observed
ripple amplitude and frequency of approximately 20% at 2 kHz. For best accuracy, filtration corrections
should be made prior to the linearity corrections. However, if the difference in total filtration from the
calibration standard of 2.5 mm Al is small, linearity corrections alone may be sufficient. See Section 9.3
for information regarding filtration corrections.
Example
The Model 35080B kVp Divider with a Mobile Filter Pack Plus (37946) has a reading of 83 kVp. From
the chart, a kVp Correction value of -0.9 kVp is obtained. Assuming filtration corrections are not
required for this x-ray system, the actual kVp is 83 + (-0.9) = 82.1 kVp.
Figure 8-2. Mobile Filter Pack Plus (37946) Linearity Correction Curve. The kVp Correction Value
read from the vertical scale should be added to the Model 35080B kVp Divider reading to
obtain the corrected kVp result.
Mobile Filter Pack Plus (37946)
Linearity Correction Curves
-4
-3.5
-3
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
40 50 60 70 80 90 100 110 120 130 140
Model 35080B kVp Reading
kVp Correction
DC to 720 Hz Ripple 20% Ripple @ 2 kHz