Device for collecting ions in a mass spectrometer
The invention relates to a device for collecting ions, in particular in an isotope mass spectrometer. At least one secondary electron multiplier (SEM) is provided, this being constructed in the manner of a card, namely box-like and with a thickness which is low in comparison with its length and width. The SEM is held in a frame. In addition, a flat flexible printed circuit board with a plurality of parallel conductors is connected to the SEM. The flexible printed circuit board permits the positioning of the SEM in order to match the ion paths to be sampled.
1. A device for collecting ions, in particular in a mass spectrometer, having at least one secondary electron multiplier (SEM) formed in the manner of a thin box-like card with four sides and a channel characterized in that the SEM channel has an ion inlet opening on one side and is adapted to be held in a thin frame having an opening for receiving ions whereby when the SEM is inserted in the frame, the ion inlet opening coincides with the frame opening for receiving ions.
2. A device according to claim 1 characterized in that a flat flexible printed circuit board having a plurality of parallel conductors is connected to the SEM.
3. A device according to claim 1 in which a channel is connected to the inlet opening and the channel input of the SEM is earthed.
4. A device according to claim 1 or 3 further characterized in that the frame is adapted to be connected to a holder at its narrow underside.
5. A device according to claim 4 characterized in that the frame has holding means to connect the frame to at least one guide means.
6. A device according to claim 1 or 4 characterized in that a plurality of SEMs are provided with frames, the frames being held on at least one common guide means and being capable of being positioned relative to one another at defined intervals on the common guide means.
7. A device according to claim 6 characterized in that, in addition, at least one Faraday cup whose external dimensions correspond to those of the frame is held on the guide means.
8. A device according to claim 6 characterized in that groups of frames are provided
which contain either at least one Faraday cup and otherwise at least one SEM or which contain more than one SEM at least one Faraday cup or SEMs in a group connected to a holder by their narrow underside and the Faraday cups and SEM within the same groups are arranged on one or more common guide means via holding means and capable of being positioned relative to one another.