Possible approaches to fast quality control of IFE targets

In recent years, research into the development of reliable methods and techniques for characterization and quality control of ICF/IFE targets has been carried out very actively. This is motivated by the need to provide the means for precise and accurate knowledge of cryogenic target parameters. On the other hand, particular emphasis should be paid to the fact that fuelling of a commercial power plant requires ~6 targets each second. This indicates that the development of fast quality control techniques is of critical importance as well. Therefore, in this report we discuss the issues underlying the construction of different algorithms for characterization and quality control of ICF/IFE targets. Among them are: (a) algorithm banks and their structure, (b) algorithm testing, (c) target reconstruction experiments. The algorithm bank incorporates the algorithms for two stages of target production: the stage of fuel layering technique development (motionless target) and the stage of cryogenic target delivery (injected target). In the first case an inverse algorithm for individual target characterization (3D target reconstruction) and two threshold algorithms for fast control of target quality are presented. They are based on tomographic information processing methods. Experimentally, tomographic data acquisition is carried out by a hundred projections microtomograph. The spatial resolution of the optical system of the microtomograph is 1 µm for 490 nm wavelength, the accuracy of target angular positioning is ±1.5–2.5 min. In the second case we describe the algorithm based on Fourier transform holography for ultra fast target characterization during its injection. The performed computer experiments have demonstrated much promise of this approach in the following directions: recognition of the target imperfections in both low- and high- harmonics; quality control of both a single target and a target batch; simultaneous control of both an injected target quality and its velocity and trajectory.