Quick Shot

Quantifying submicron contaminants on cryogenic fusion targets can be challenging. An ongoing project is underway with its main objective being to quantify submicron contaminants that are theorized to be picked up on the outside of the shell during the filling and transfer process. Such submicron particulates could act to degrade implosion performance by seeding surface perturbations that would grow as a result of hydrodynamic instabilities. A light microscope is  implemented into the cold confines of a Fill and Transfer Station to view a cryogenic DT target at a distance of 3 mm. This process employs two novel concepts including a complementary metal oxide semiconductor (CMOS) camera in a warm vacuum space and an off-the-shelf microscope objective which is  modified for vacuum conditions cooled to 40 K (–387.7°F). This new microscope can resolve features down to ~0.5 µm, which is far superior to the  3-µm resolution of  the current characterization stations. Shown at the imager’s objective is Jun Zou, mechanical engineer on the project. Additional primary team members include Dave Weiner, Sal Scarantino, Jason Bender, Mark Wittman, Mike Koch, and Dean Bredesen. Roger Janezic is the principal investigator.