X-ray computed tomography of the periodically moving object

Abstract

X-ray computed tomography is a standard method of non-destructive testing of a wide range of static objects. In recent years, time-dependent tomography has been on the rise, for which it is necessary to acquire a series of tomographic data covering the event of interest. For slower processes, conventional laboratory X-ray computed tomography (CT) scanners can be used, while when events are faster, a very intense X-ray source is usually required. For high resolution requirements, the need for an intense X-ray source leads to the use of a synchrotron. An exception is tomographic tracking of periodic events. As will be shown, for these, a good quality reconstruction can be achieved even in the case of a relatively low-intensity X-ray source. To avoid blurring of the individual X-ray images by the motion of the object, the exposure time must be reasonably short. At motion rates of units of Hz, this time cannot be longer than tens of ms, this requirement naturally leads to low data statistics. Sufficient statistics is achieved by integrating images taken at an identical position of the moving object. A key requirement of such an approach is the precise synchronization of all active components of the system. The imaging detector must be capable of taking images on demand by hardware triggering with the capability of adequately short exposures. The ability of the CT system to investigate periodically moving objects will be demonstrated on the object oscillating harmonically at 3.81 Hz.