Pulsed radiography and tomography of transient and low-density objects using laser plasma sources of extreme ultraviolet (EUV)

We present a brief review of radiography technique (shadowgraphy) and its extension to tomography. We used both techniques to characterize i.e. multi-jet gas puff target for different gases with a variable number of jets for various applications. The characterization measurements have been performed with the use of EUV shadowgraphy at 13.5 nm wavelength. Pulses of the EUV radiation were produced with a laser plasma EUV source based on a double-stream gas puff target. The shadowgrams of the characterized gas puff targets were registered using a back-illuminated CCD camera, sensitive to the EUV radiation. The gas density maps were calculated based on 2D transmission map and an atomic photoabsorption cross-section. To obtain 3D tomography reconstruction of multi-jet gas puff target we acquired projections at different viewing angles and performed the reconstruction numerically. This unique technique based on a compact laser-produced plasma source allows imaging 2D and 3D objects having a density 3 orders of magnitude smaller than the density of water.