A stable black-refractive-index-matching liquid for optical CT scanning of hydrogels

摘要

The calibration of optical CT scanners often involves referencing of transmission values to surrounding refractive index matching liquid. Often these liquids suffer from wavelength dependencies or can degrade during the course of a scan. In this paper, we describe a black liquid that serves as a stable reference for attenuation measurements. An optically stable, refractive index matching liquid for optical CT scanning of hydrogels was developed. The solution contains: water, glycerol, surfactant and carbon black. Sequential transmission measurements demonstrated less than 5percent variation in transmission during a two week storage period at room temperature. Black solutions are expected to minimize spectral beam hardening artefacts associated with polychromatic light sources.