Fluke Biomedical 35080B - Manual (Page 21)

Test Filter Pack Option (32863)
Introduction
4
4-1
Section 4
Test Filter Pack Option (32863)
4.1 Introduction
The Test Filter Pack (32863) provides a means for a complete system check of the Model 35080B kVp
Divider’s calibration. The CAL position on the kVp divider provides a check of the electronics only. The
Test Filter Pack (32863) verifies the calibration of the kVp divider from radiation input through to the
output signal under actual operating conditions.
4.2 SPECIFICATIONS
Output
3.00 V ± 1%
Cal
0.750 V ± 1%
X-ray Generator kV Setting
100 kV is recommended
X-ray Generator mA Setting
200 mA at 22 inches focal spot to kVp divider is recommended
4.3 Theory of Operation
Section 3 describes the theory of operation of the Model 35080B kVp divider. With the Test Filter Pack
(32863) installed, the output voltage of the kVp divider is equal to three times the x-ray intensity striking
the heavily filtered detector divided by the x-ray intensity striking the lightly filtered detector. The Test
Filter Pack (32863) has equal thickness of copper filters for both detectors. When this filter pack is
inserted into the kVp Divider, the ratio seen by the instrument (for adequately high intensities) is 1.0. The
Model 35080B kVp Divider is factory-calibrated to produce 3.0 volts for a ratio of 1.0. In theory, the 3-volt
value is not a function of tube current, distance or kV; in order to have a standardized test, however, the
3-volt check should be run at 22 inches focal spot to kVp divider, at 200 mA and 100 kVp. Typical
waveforms from single-phase and three-phase exposures using the Test Filter Pack (32863) are shown in
Figure 4-1.