| 摘要 |
The monitor device according to the invention comprises an axial excroissance bounded by a gastight peripheral wall permeable to magnetic fields and connected to a chamber, such as a process chamber, where gaseous species to be monitored are present. A light radiation sensor is placed at the end of the axial chamber excroissance and allows the light to be transported via an optical fiber ( 4 a) to an optical spectrometer. A plasma generator generates a monitoring plasma in the internal space of the axial chamber excroissance. One or more magnets are placed outside the peripheral wall of the axial chamber excroissance and generate a magnetic field near the sensor in order to form a magnetic barrier that prevents the ionized particles of the monitoring plasma from propagating toward the sensor. Thus, the sensor and the chamber are prevented from becoming fouled.
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