A tool for assessing a hole property of one or more holes in a component of a lithographic apparatus, the tool including: an assessment substrate; a fluid supply configured to supply a jet of fluid from each of the one or more holes to a first surface of the assessment substrate, wherein the fluid is supplied at a fluid temperature such that the one or more jets of fluid cause local temperature variations in at least part of the assessment substrate; and an infrared sensor configured to sense a temperature distribution of the assessment substrate in dependence on the local temperature variations.