DEVICE FOR LEAKAGE DETECTION VIA MASS SPECTROMETRY, HAVING A THREE-STAGE TURBOMOLECULAR PUMP AND A BOOSTER PUMP

The invention relates to a device for leakage detection on a test item, comprising: a mass spectrometer (12); an at least three-stage turbomolecular pump (14), the input stage (18) of which is connected to the mass spectrometer (12) and which has a first intermediate gas inlet arranged between the input pump stage and the central pump stage (26) and a second intermediate gas inlet arranged between the central pump stage (26) and the output pump stage (24); an at least two-stage booster pump, the input pump stage (46) of which can be connected to the test item to be examined and which booster pump has an intermediate gas outlet (54) arranged between the input pump stage (46) and the output pump stage (48); and a forepump (22) which is connected to the outlet (20) of the output pump stage (24) of the turbomolecular pump (14) and is designed to generate a forevacuum pressure of less than 50 mbar at the outlet (20) of the turbomolecular pump (14) and evacuate against atmospheric pressure. The device is characterised in that the intermediate gas outlet (54) of the booster pump is connected in a gas-conducting manner to the first intermediate gas inlet (36) of the turbomolecular pump (14) via a first connecting branch (62), and in that the outlet of the output pump stage (48) of the booster pump is connected in a gas-conducting manner to the second intermediate gas inlet of the turbomolecular pump (14) via a second connecting branch (64).