Deep defect density imaging

Contour and surface plots of S and T parameters were generated for a 2D slice of four 304L steel specimens inserted in a 5 cm × 5 cm plastic holder. This was achieved by performing Doppler broadening spectroscopy (DOBS) coupled with in situ pair-production using a 1 kHz repetition rate linear accelerator (LINAC) at the physics department of Idaho State University. The results confirmed the imaging potential of this technique and also revealed its limitations.