Incoherent scattering of gamma photons for non-destructive tomographic inspection of pipeline

Simulation of defect detection for the buried petroleum pipe by the X-ray backscatter imaging

Ensuring the integrity, safety, and compliance of oil pipelines is crucial for operators. Two significant factors affecting pipeline integrity are metal loss due to corrosion or air gouging and the presence of cracks. This paper introduces an X-ray backscatter nondestructive testing model on a smart pig(an intelligent robot) for internal inspection of petroleum pipelines. The paper investigates the X-ray source and detection system, essential components of the backscatter imaging technology, to provide technical guidance for model design. The imaging system's layout is modeled using GEANT4, and its performance in detecting defects of various formats on pipe walls is studied. The research demonstrates the feasibility of using X-ray backscatter imaging for pipeline inspection and provides insights into different defect detection. The findings contribute to designing and optimizing the robot's scanning head for effective pipeline inspection.

Modeling and quantitative analysis of X-ray transmission and backscatter imaging aimed at security inspection

X-ray transmittance and backscatter imaging are important methods for detecting drugs and plastic explosives in the security-inspection field. In this study, we developed an analytical model based on Geant4 toolkit and verified it by measuring the energy spectrum and backscatter images. According to the model, we analyzed the imaging contrasts to detect concealed contrabands. The results show that the backscatter contrasts are significantly better than those of the transmission, especially in thinner organic materials. However, for shelters with strong absorption and scattering, the gaps become smaller. In addition, the variations in the contrasts with thickness appear to linearly increase in the transmittance imaging and nonlinearly grow until saturation in the backscatter imaging. Compared with traditional methods, our model, which is more accurate and complete, employs energetically distributed X-rays, instead of monochromatic X-rays, and involves multiple scattering effects. By using this method, we cannot only calculate and analyze the image characteristics of large amounts of contrabands in various system structures but also design and optimize instruments specially used to detect drugs and explosives.

A novel lobster-eye imaging system based on Schmidt-type objective for X-ray-backscattering inspection

This paper presents a novel lobster-eye imaging system for X-ray-backscattering inspection. The system was designed by modifying the Schmidt geometry into a treble-lens structure in order to reduce the resolution difference between the vertical and horizontal directions, as indicated by ray-tracing simulations. The lobster-eye X-ray imaging system is capable of operating over a wide range of photon energies up to 100 keV. In addition, the optics of the lobster-eye X-ray imaging system was tested to verify that they meet the requirements. X-ray-backscattering imaging experiments were performed in which T-shaped polymethyl-methacrylate objects were imaged by the lobster-eye X-ray imaging system based on both the double-lens and treble-lens Schmidt objectives. The results show similar resolution of the treble-lens Schmidt objective in both the vertical and horizontal directions. Moreover, imaging experiments were performed using a second treble-lens Schmidt objective with higher resolution. The results show that for a field of view of over 200 mm and with a 500 mm object distance, this lobster-eye X-ray imaging system based on a treble-lens Schmidt objective offers a spatial resolution of approximately 3 mm.

A method for determination mass absorption coefficient of gamma rays by Compton scattering

A method was proposed for determination mass absorption coefficient of gamma rays for compounds, alloys and mixtures. It is based on simulating interaction processes of gamma rays with target elements having atomic numbers from Z=1 to Z=92 using the MCSHAPE software. Intensities of Compton scattered gamma rays at saturation thicknesses and at a scattering angle of 90° were calculated for incident gamma rays of different energies. The obtained results showed that the intensity of Compton scattered gamma rays at saturations and mass absorption coefficients can be described by mathematical formulas. These were used to determine mass absorption coefficients for compound, alloys and mixtures with the knowledge of their Compton scattered intensities. The method was tested by calculating mass absorption coefficients for some compounds, alloys and mixtures. There is a good agreement between obtained results and calculated ones using WinXom software. The advantages and limitations of the method were discussed.