Calibration and performance testing for reconfigurable computed tomography systems

Industrial CT systems used for NDT of manufactured objects are typically modular to allow for imaging of a wide variety of object shapes and sizes. This variability in the system geometry requires calibration each time the system is reconfigured, particularly if metrology is to be performed. In addition to calibration, performance measurement methods are needed to provide the user with a performance expectation for each new system configuration. Oak Ridge National Laboratory, BWXT Y-12, and the University of Tennessee have developed calibration and performance measurement tools for use in reconfigurable computed tomography systems. The calibration tool requires the operator to make a couple of rough measurements and perform a scan of a pin or set of pins to produce precision system geometry values. The performance measurement tool is based on a previous ASTM standard for performance, but has been modified to use a spherical object scan that allows monitoring of resolution in three dimensions.