Enhanced Portability and Anti-Frosting Functionality of Cryostats for Synchrotron-Based X-ray Imaging

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Virginia Tech

The intensity of light produced from synchrotrons enables X-ray imaging down to the micron and submicron scale. This high degree of resolution is necessary to study metals in hydrated biological samples, where trace (metal) elements are found in the lowest concentration. Water within these aqueous samples will undergo radiolysis and produce various reactive oxygen species, which degrades the quality of information gathered from the sample during X-ray imaging. Studies have shown that the best way to counter the effects of radiolysis and preserve samples in their metabolic state during X-ray imaging is to keep them cryogenically frozen. We have developed affordable cryostats and novel protocol to not only improve cryo-imaging at current third-generation synchrotrons, but also enable cryo-imaging at existing synchrotrons that have limited accessibility. This dissertation will provide a detailed description of the tasks that were accomplished to contribute to the development cryo-imaging. The first task was the fabrication of a portable cryostage. The cryostage's discreet profile and unique design successfully enabled it to be effortlessly adapted into three beamlines across two different DOE facilities and facilitate multiple imaging modalities, i.e., correlative imaging. With the next task, we explored adding an ice frame about the stage to help reduce the accumulation of frost on the surface of a frozen sample that was explored. The addition of the ice frame significantly improved the imaging of frozen samples, nearly doubling the overall image clarity in comparison to when it was absent. The final task saw the application of a cryostream, in place of a cryostage, to provide a cooled convective flux across the sample for 2D and 3D visualization for cryo X-ray imaging.

hygroscopic, anti-frosting, cryo-microscopy