Security apparatus comprising an ion mobility spectrometer

An ion mobility spectrometer for analysing a gas is described which comprises a concentric arrangement of an inner ionisation region 110, an annular reaction region 112 which surrounds the ionization region 110 and through which a gas to be analysed is caused to flow continuously in the axial direction of the spectrometer, and an annular drift region 116 surrounding the reaction region through which ionized molecules of the gas to be analysed flow in a radial direction towards a cylindrical detector 124 forming the outer wall of the drift region 116. The ionization region 110 may be defined between corona discharge wires (18, Fig. 1) and a first grid (20), and the reaction region between the first grid (20) and an ion shutter 122 formed from an insulating layer sandwiched between two conductive layers perforated by a matrix of holes.

Apparatus for surface sterilisation

Surface Sterilisation

Sterilisation of a surface and/or low thickness materials is performed by exposing the surface to a large area X-ray beam having an energy less than 50 KeV and ideally 8KeV. An X-ray source capable of producing soft X-rays over a large area with a substantially uniform dosage over the area is described which comprises an evacuated envelope 10 containing an electron source 18 that is at least partially transparent to X-rays. Electrons 24 emitted by the source 18 bombard a target 12 to generate X-rays 26. The X-rays 26 pass through the electron source and leave the evacuated envelope through a window 16 arranged on the opposite side of the electron source 18 from the target 12. The arrangement is particularly applicable for sterilizing product packaging in sheet form via production line or conveyor means. Two sources can be used to irradiate both sides of the packaging material.