beam spreading in a direction perpendicular to a scan direction application_number US 201013148621 A description referring to fig1 a a suitable x ray source 1 is used to direct x rays via a scanning zone in the direction of three linear array detectors 3 a to 3 c in the embodiment the linear array detectors 3 a to 3 c comprise material capable of spectroscopic resolution of incident x rays and in the specific example comprise cadmium telluride although the skilled person will appreciate that other material selections may be appropriate to exploit this spectral resolution the x ray source emits x ray across a broad energy spectrum in the example a tungsten source is used although the skilled person would appreciate that other materials might be appropriate incident ray paths 5 a to 5 c are shown through the scanning zone between the x ray source 1 and respectively the detectors 3 a to 3 c a suitable scanning arm 2 on which the source 1 and detector arrays 3 a to 3 c are mounted causes the source and linear arrays to move together relative to an object to be scanned 9 so that the object is caused to intercept the ray paths 5 a to 5 c in the scanning zone a possible application of this embodiment of the invention is as a security scanner and object 9 can be considered typically to be a container that is expected to contain a variety of distinct objects which it would be useful and desirable to characterise compositionally and to view effectively in a third.