Fluke Biomedical 07-611 - Manual (Page 12)

Nuclear Associates Radiographic and Mammographic Focal Spot Measurement Products
Operators Manual
2-6
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T = tube assembly tilt angle (Provided by the x-ray system manufacturer.)
For example, for a 0.80 mm measured focal spot length (F), an anode angle (A) of 20°, and a tube
assembly tilt angle of 8°, one obtains
Sin (20°) L = 0.80 mm
Sin (8° +
20°)
0.34
L = 0.80 mm
0.47
= 0.58
mm
14. Compare the dimensions to the focal spot size tolerance limits in Table 2-2. The manufacturer may
not accept screen-film slit image measurements for acceptance testing purposes. In this case, it
may be necessary to repeat the procedure using direct exposure x-ray film.
Table 2-2.
Focal Spot Size Tolerance Limits
(For Slit Camera Method)
Maximum Focal Spot
Dimensions in mm (F
eff
)
Nominal Focal Spot
Designation (F)
Width Length
0.05 0.075 0.075
0.1 0.15 0.15
0.15 0.23 0.23
0.2 0.30 0.30
0.25 0.40 0.40
0.3 0.45 0.65
0.4 0.60 0.85
0.5 0.75 1.1
0.6 0.90 1.3
0.7 1.1 1.5
0.8 1.2 1.6
0.9 1.3 1.8
1.0 1.4 2.0
1.1 1.5 2.2
1.2 1.7 2.4
1.3 1.8 2.6
1.4 1.9 2.8
1.5 2.0 3.0
1.6 2.1 3.1
1.7 2.2 3.2
1.8 2.3 3.3
1.9 2.4 3.5
2.0 2.6 3.7