The invention provides an apparatus for collecting ablated material generated by exposure of an imaging layer to a source of radiation, said apparatus comprising a vacuum supply means, and a vacuum head connected to, and in close proximity with, a centrifugal separator, said vacuum head being for direct attachment to a movable mounting means having guide means. More particularly, the present invention relates to a flaky \u03b1-alumina crystal comprising aluminum oxide and zinc oxide, which is prepared by hydrolyzing an aluminum precursor solution containing a water-soluble flux and a zinc precursor solution to obtain a gel mixture and aging, drying, calcining and crystallizing it under a specific reaction condition, and a preparation method thereof. The invention further concerns the use of said dry emulsions for making food compositions. A transmitter communicates a parameter associated with the tensor to the surgical navigation system. In the solid-state imaging device, substantially only a gate insulation film is formed on a substrate corresponding to an area under a gate electrode of at least one transistor in the pixel. A user may, for example, watch TV while viewing overlay information from the video game console.