Compared with commercial X-ray tubes, Betatron can emit MeV-level X-rays and its penetration capability is better than that of keV-level X-rays, which can be used for non-destructive testing (NDT) of large workpieces.

This study aims to design and build a 2D/3D X-ray imaging platform for NDT of large workpieces by using a compact Betatron as the X-ray source.

Firstly, the hardware of the imaging platform was designed. It consisted of the compact Betatron with X-ray energy of 2.50/7.50 MeV, a high-energy X-ray line array detector with GGAG(Gd₃Ga₂Al₃O₁₂) scintillator and a two-axis mobile platform. Then, based on the principle and image correction algorithm of the 2D imaging system, the stripe noise characteristics in both the pixel direction and time direction were analyzed, and the blank pixel correction method was employed to correct the two-dimensional image. Its two-dimensional imaging performance test was conducted on a 6 cm square steel workpiece. Finally, three-dimensional image reconstruction of the workpiece was achieved by rotating the workpiece to obtain projection values at different angles, and the spatial resolution of 3D imaging was calculated using logistic function fitting method. Results of different tomographic reconstruction algorithms were compared and analyzed to obtain important 3D imaging system parameters.

Measurement results show that the thickness of the stainless-steel half-value layer of the system is 24.94 mm, the 2D imaging spatial resolution is 2.12 mm, and the tomographic reconstruction image spatial resolution is 1.00 mm.

Compared with the keV-level X-ray imaging system, this system can complete the non-destructive testing of larger workpieces.