ASTM E1165 Focal Spots of Industrial X-Ray Tubes

Focal spots of industrial X-Ray tubes are measured by pinhole imaging, using ASTM E1165 standard test method. This test method specifies the process to determine the size of standard and mini focal spots in industrial X-ray tubes with focal spot dimensions ranging from 100 m to several mm and a tube voltage of 600 kV. Values expressed in SI units are considered standard.

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Scope:

The standard test method ASTM E1165 permits the user to determine the X-ray source’s adequate focal size. The reference to the object and object-to-detector distances are calculated, which is appropriate for preserving the desired degree of geometric unsharpness, maximum magnification, or both for a specific radiographic imaging application. The test can also assess if there has been a change in the tube overloading and focal spot size owing to tube aging.

Procedure:

The ASTM E1165 test method uses a pinhole camera to produce a picture of the focal spot. The size of the focal point from this image is measured. The size of the focal point is estimated by using the X- and Y-dimensions of the edge unsharpness. The geometrical picture and the sharpness values at given magnifications correlate to the measured effective spot sizes.

Specimen size

The angle between the pinhole axis and the beam direction must be less than 61.5°.

Result

The result report in ASTM E1165 testing should include: The image name, machine model number and serial number, X-ray tube serial number, focal spot(s) measured, set-up and exposure parameters, date, organization name, and expected beam time hours.

Conclusion:

The standard test method ASTM E1165 permits the user to determine the X-ray source’s adequate focal size.