Investigation of micro-focus X-ray tube for radiography

The radiography with micro focus x-ray tube is very promising for use in non-destructive industrial control, medical and biological x-ray imaging. We investigated a micro focus x-ray tube with hollow anode to find the smallest available focal spot sizes under the different values of the X-ray tube load. The electron beam focusing system of the x-ray tube was designed with the use of the deflection-coil assemblies and a short focusing lens. Under varying the tube power load from 20W to 70W we found that the X-ray focal spot size (fall width at half maximum-FWHM) is changed from 25 mu m to 54 mu m. The methods of focal spot size measurements are shortly described. Examples of radiographic images of the pair-line object target (phantom CIRS 11A) are presented. The phantom study showed the resolving power 18 pl/mm divided by 20 pl/mm. Practical applications of the developed X-ray apparatus are discussed in the report.