Apparatus and a method are described for investigating polymorphs of a material, isomers of a material which allow different isomeric forms to be resolved, different hydratessolvates andor different salts of a material. Compositions include, for example, an immunoglobulin constant region polypeptide linked to an imaging moiety or a bactericide. Each pixel sensor preferably includes a photosensitive element, a variable amplifier, and an analog-to-digital converter. In each of these sub picture element electrodes, formed are slits extending in directions respectively at angles of 45 degrees, 135 degrees, 225 degrees and 315 degrees to the X axis.