Abstract: The invention relates to a switchable ion mobility spectrometer (IMS) with ring electrodes divided into half-rings, which surround the drift chamber of the IMS. In a first operating condition, the two half-rings of each ring electrode are at the same potential and the various ring electrodes are at different potential varying monotonously along the drift path. In this way, ions are transported in the conventional manner along the drift path. In a second operating mode, the half-rings of the ring electrodes are at different potentials, by which the ions are each deflected toward one of the half-rings. The currents thus resulting are captured by the corresponding half-rings, amplified and an ion mobility spectrum is produced. A favorable design for the IMS can be used in many different modes of operation.

Abstract: An ion mobility spectrometer (IMS) with electric drift fields directed at a central detector electrode. The IMS is rotationally symmetrical and has a disk shape.