Currently the specialists of «Scantronic systems» are carring out the development of a modern system of industrial tomography. The equipment structure of an industrial tomography system is similar to the structure of an interiscopic one, but investigation of the internal structure of an object is performed by angular scanning of various cross-sections of the object with subsequent mathematical processing of obtained scanned data. Compared with the interoscopic method the self-descriptiveness of the tomographic one is much higher, but it is more time consuming. At interoscopic scanning a shadow two-dimensional image of an object is received, which can be easily interpreted only in the case of simple internal structure of the object under test (without overlapping). In the real case interoscopic images, obtained even at different angles of scanning, do not allow one to determine and interpret the received data that can lead to missed defects. In the case of tomographic investigation of internal structure of an object the results are obtained by mathematical solution of inverse problem. This method is sensitive to errors in measurements; therefore, the tomographic system (compared with interoscopic) must meet higher requirements to the accuracy of alignment equipment, to the parameters of accelerator operation, which determine its stability, to the precision of a positioning system, which determines the rotational movement of the object, to the accuracy of a detection system and its characteristics.

At tomographic investigation each section of an object is scanned, when the object is rotated in the plane of fan beam that is generated by a radiation source (accelerator) and collimation system. Resulting data is digitized and stored in an array (sinogram), which is then processed by the methods of mathematical reconstruction, allowing defining the two-dimensional density distribution in the investigated section (see the result of the reconstruction). The use of computer tomography to the set of studied sections allows obtaining three-dimensional density distribution in the studied object.

The specialists of «Scantronic systems» together with specialists of the laboratory «LEA-MSU» performed a series of experiments on tomographic investigation of various objects to analyze abilities of the hardware-software tomographic system, designed in the frames of research work on future developments in the field of industrial non-destructive radiation testing.

Photo of accelerator circulator.

Interiscopic image of an accelerator circulator with material discrimination by effective atomic number with «Scantronic» software module.

Set of circulator sections obtained in the result of data reconstruction with «Scantronic» software module.

Technical and operating characteristics of an industrial tomograph are defined during the design on the base of an inspected object configuration and requirements for defects identification.

Example of the technical and operating characteristics of a tomograph is given below:

Structure of industrial tomography system:

• Linear electron accelerator;
• Detector line (arc-like) with unit of preliminary data processing;
• System of bremsstrahlung forming, including:

  a) preliminary slit collimator,

  b) special collimator in front of an object, reducing part of dissipated photons,

  c) arc-like collimator (in front of the detectior line).

• Control system;
• System of an object positioning;
• System of data processing, reconstruction and visualization, including:

  a) hardware part.

  b) software.