Laser-driven high-resolution MeV x-ray tomography
R. Hollinger, Shoujun Wang, S. Zahedpour, James King, Ping Zhang, G. Zeraouli, Alejandro Figueroa Bengoa, Matthew J. Sheats, Shannon Scott, Joel Heidemann, James Hunter, Yong Wang, Ray Edwards, Matthew Faulkner, Chris Aedy, J. J. Rocca, D. C. Gautier
Abstract
The need for high-resolution MeV x-ray tomography to observe the three-dimensional structure of dense, large-sized objects is rapidly increasing for the non-destructive evaluation of critical additively manufactured parts, national security, and other applications. We report a demonstration of high-resolution MeV computed tomography of a dense, large object with a laser-driven x-ray source. A record detector-limited MeV radiograph resolution of as determined with the Bennett approximation of the point spread function was achieved by irradiating millimeter-thick tungsten targets with 300 TW femtosecond laser pulses at a 0.5 Hz repetition rate. A tungsten alloy step wedge spectrometer indicates that the peak of the x-ray emission is between 1 and 2 MeV, with an endpoint energy of 19 MeV. To illustrate the radiographic imaging capability of the system, a tomographic reconstruction of a nickel superalloy turbine blade () with sub-millimeter resolution was performed using 2160 individual radiographs. The small x-ray source size opens the prospect of extremely high-resolution tomographs of large, dense objects. This laser-driven approach has major advantages for non-destructive evaluation.