Fluke Biomedical 35080B - Manual (Page 42)

35080B
Operators Manual
8-2
8.2 Specifications
Range
50 to 135 kV
Sensitivity
0.1 V/10 kV
Cal
0.600 V
Zero
40 kV
Cal
100 kV
Calibration Filtration
2.5 mm Al
8.3 Filtration Effect Corrections
Corrections for filtration are made using the correction curve shown in Figure 8-1. The Mobile Filter Pack
Plus (37946) is calibrated at 2.5 mm Al total filtration, so measurements made at other filtration values
require correction of the measured reading. Corrections are made by subtracting the total filtration of the
x-ray machine being measured from 2.5 mm Al, multiplying the result by the value read off the chart for
the measured kVp, and adding this result to the measured kVp.
Example
The Model 35080B kVp Divider with a Mobile Filter Pack Plus (37946) inserted reads 80kVp. The x-ray
system has 3.3 mm Al total filtration. The filtration effect curve of Figure 8-1 indicates a filtration effect
of 1.05 kVp per mm Al at 80 kVp. The difference in filtration, 2.5 - 3.3 = -0.8 mm Al, is multiplied by the
correction value to yield -0.8 x 1.05 = -0.84 kVp. This number is then added to the apparent reading to
obtain the actual kVp, which is 80 kVp + (-0.84 kVp) = 79.16 kVp.
Figure 8-1. Mobile Filter Pack Plus (37946) Filtration Effect Correction Curve
Filtration Effect
kVp Per mm Al
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
1.4
1.5
1.6
40 50 60 70 80 90 100 110 120 130 140
Model 35080B Reading kVp
kV
p P
er
mm A
l