Device for mass-spectrometric leak detection with three-stage turbomolecular pump and booster pump

A device for leak detection on a test object, comprising a mass spectrometer, an at least three-stage turbomolecular pump, whose input pump stage is connected to the mass spectrometer and which comprises a first intermediate gas inlet arranged between the input pump stage and the intermediate pump stage and a second intermediate gas inlet arranged between the intermediate pump stage and the output pump stage, an at least two-stage booster pump, whose input pump stage is configured to be connected to the test object to be examined and which comprises an intermediate gas outlet arranged between the input pump stage and the output pump stage, and a backing pump connected to the outlet of the output pump stage of the turbomolecular pump, said backing pump being configured to generate a backing pressure of less than 50 mbar at the outlet of the turbomolecular pump and to evacuate against atmospheric pressure, is characterized in that the intermediate gas outlet of the booster pump is connected to the first interme