| 摘要 |
<p>Apparatus for leak detection comprises a test line 114 configured to receive a sample 110 containing a trace gas; a mass spectrometer 122 configured to detect the trace gas and having an inlet for receiving the trace gas; a first vacuum pump 120 characterized by a relatively high reverse flow rate for light gases and a relatively low reverse flow rate for heavy gases, said first vacuum pump 120 having a pump inlet and a foreline 140, the pump inlet being coupled to the inlet 162 of said mass spectrometer 122; a second vacuum pump configured to back the first vacuum pump; and a trace gas permeable member 130 coupled between the test line 114 and at least one of the pump inlet and the foreline 140.</p> |
