Mass spectrometer having means for observing the radiation emitted when ions collide with a target gas

A spectrometer comprising:

• a vacuum envelope;
• a substantially enclosed collision cell disposed in said vacuum envelope, said collision cell comprising:
• a wall bounding said collision cell;
• an entrance aperture and an exit aperture in said wall, through which an ion beam may be passed to traverse said collision cell;
• an observation region in said collision cell adjacent to said entrance aperture;
• a first window in said wall through which radiation generated in said observation region may pass;
• and
• an exit region in said collision cell adjacent to said exit aperture and in communication with said observation region, said exit region comprising radiation-trapping means for minimizing the transmission to said first window of radiation generated in said exit region;
• said spectrometer further comprising:
• means for passing a beam of ions from an ion source through said entrance and exit apertures;
• and
• a second window in said vacuum envelope through which may pass radiation which has passed through said first window.

A substantially enclosed collision cell comprising:

• a wall bounding said collision cell;
• an entrance aperture and an exit aperture in said wall, through which an ion beam may be passed to traverse said collision cell;
• an observation region in said collision cell adjacent to said entrance aperture;
• a first window in said wall through which radiation generated in said observation region may pass;
• and
• an exit region in said collision cell adjacent to said exit aperture and in communication with said observation region, said exit region comprising radiation-trapping means for minimizing the transmission to said first window of radiation generated in said exit region;
• wherein said radiation-trapping means comprises a blackened coating on the wall of said collision cell in said exit region;
• and
• the wall of said collision dell in said observation region opposite to said first-window comprises a highly polished concave surface.

A spectrometer comprising:

• a vacuum envelope;
• a substantially enclosed collision cell disposed in said vacuum envelope, said collision cell comprising:
• a wall bounding said collision cell;
• an entrance aperture and an exit aperture in said wall, through which an ion beam may be passed to traverse said collision cell;
• an observation region in said collision cell adjacent to said entrance aperture;
• a first window in said wall through which radiation generated in said observation region may pass;
• and
• an exit region in said collision cell adjacent to said exit aperture and in communication with said observation region, said exit region comprising radiation-trapping means for minimizing the transmission to said first window of radiation generated in said exit region;
• wherein said radiation-trapping means comprises a blackened coating on the wall of said collision cell in said exit region;
• and
• the wall of said collision cell in said observation region opposite to said first window comprises a highly polished concave surface;
• said spectrometer further comprising:
• means for passing a beam of ions from an ion source through said entrance and exit apertures;
• a second window in said vacuum envelope through which may pass radiation which has passed through said first window;
• and
• a monochromator and a detector to receive at least some of the radiation passing through said first and second windows to record the optical spectrum of species undergoing spectroscopic transitions in said observation region.

A spectrometer comprising:

• a vacuum envelope;
• a substantially enclosed collision cell disposed in said vacuum envelope, said collision cell comprising:
• a wall bounding said collision cell;
• an entrance aperture and an exit aperture in said wall, through which an ion beam may be passed to traverse said collision cell;
• an observation region in said collision cell adjacent to said entrance aperture;
• a first window in said wall through which radiation generated in said observation region may pass;
• and
• an exit region in said collision cell adjacent to said exit aperture and in communication with said observation region, said exit region comprising radiation-trapping means for minimizing the transmission to said first window of radiation generated in said exit region;
• said spectrometer further comprising:
• means for passing a beam of ions from an ion source through said entrance and exit apertures, said passing means comprising a mass and/or energy analyser for providing a mass and/or energy filtered beam of ions from said ion source;
• a second window in said vacuum envelope through which may pass radiation which has passed through said first window;
• and
• a conventional collision cell disposed in the path of the ion beam before it reaches said collision cell, whereby ions undergo collisions in said conventional collision cell and undergo spectroscopic transitions during their subsequent passage through said collision cell.