Patent ID: 6437513
Filing Date: 2002-08-20
Classification: A61N,G01T,H01J

Abstract:
An ionisation chamber for ion beams (1) having a chamber housing (2), a beam inlet window (3), a chamber volume (5) filled with counting gas, a high-voltage anode (6) and a high-voltage cathode (7) wherein:the ionisation chamber (8) is constructed sandwich-like, from flat large-surface-area structures of the above-mentioned components, which are aligned orthogonally relative to the axis of the ion beam, wherein a centrally arranged large-surface-area orthogonally aligned flat counting anode (9) is surrounded on both sides by a large-surface-area flat high-voltage cathode (7) comprising two parallel cathode surfaces (10), and the chamber housing (2) comprises a housing frame (11) which frames a virtually square ionisation chamber volume (12); wherein a beam inlet window (3) and a beam outlet window (4) are mounted gas-impermeably and electrically conductively on the housing frame (11) in orthogonal alignment with the ion beam (1), the beam inlet window (3) and the beam outlet window (4) being metallised on the side facing the ionisation chamber volume (12) and the counting anode (9) and the high-voltage cathode (7) consisting of mesh comprising metal-coated plastics fibres and being mounted in frames (20) which are supported against the housing frame (11) in an electrically insulated manner, with electrically insulating spacing elements (21) defining the spacing between the counting anode (9) and the high-voltage cathode (7).