Daniel Balonek: “Mechanical Characterization of Cryogenic Targets”
Target vibration can degrade the implosion performance of an ICF capsule. Cryogenic targets are particularly sensitive to vibration because the capsules are suspended on spider silk. The goal of the target resonance characterization fixture (TRCF) is to obtain quantitative information that will help isolate and correct design and manufacturing problems associated with these (Fig. 1) delicate target assemblies.
The TRCF evaluates the mechanical integrity of a cryogenic target assembly at room temperature, prior to filling and cooling. A target assembly is excited with a known vibration input, and its vibratory response is measured optically. Initially, this system will be used to measure characteristics of targets in a consistent manner. Subsequent performance of these targets will be evaluated on OMEGA during cryo system testing using high-speed video imaging and during target shots using the cryogenic target characterization diagnostic. Once a correlation is established between performance on OMEGA and the characteristics measured using the TRCF, this system will be used to exclude suboptimal targets prior to the fill process. Other potential uses of this fixture include the evaluation of alternative target assembly methods and materials.
Daniel worked with Dr. Douglas Jacobs-Perkins on the TRCF. Daniel built the optical modules for the TRCF and packaged electronics used for signal conditioning. He also developed procedures for assembly and calibration of this hardware, as well as implementing several design ideas throughout the project.