Capacitor assembly for a mass spectrometer
A capacitor assembly ( 1 ) for measuring the level of radio frequency voltage in a mass spectrometer. The assembly ( 1 ) includes an RF sensing capacitor ( 2 ) with first and second capacitor plates ( 3, 4 ), a rectifying circuit ( 5 ) and a vacuum housing feedthrough ( 6 ), all of which are mounted within a vacuum enclosure of the mass spectrometer. The first capacitor plate ( 3 ) is adapted for connection to a voltage source and mounted within the enclosure by first insulating spacers ( 31 ). The second capacitor plate ( 4 ) is nested within the first insulating spacers ( 31 ) and mounted within the enclosure by second insulating spacers ( 41 ). The rectifying circuit ( 5 ) is electrically connected to the second capacitor plate ( 4 ) and to the vacuum housing feedthrough ( 6 ).
1. A capacitor assembly for measuring the level of radio frequency voltage in a mass spectrometer, the assembly comprising
a capacitor having first and second superposed capacitor plates mounted within a vacuum enclosure of a mass spectrometer and
a vacuum housing feedthrough electrically connected to circuitry associated with the second plate,
wherein the first capacitor plate is adapted for connection to a voltage source and circuitry associated with the second capacitor plate includes a rectifier contained within the vacuum enclosure.
2. The capacitor assembly of claim 1 , wherein at least one of the first capacitor place the second capacitor plate are mounted within the vacuum enclosure by an insulating spacer.
3. The capacitor assembly of claim 1 , wherein each of the first and second capacitor plates is mounted within the vacuum enclosure by a first and a second insulating spacer respectively.
4. A rectifier circuit comprising one or more capacitor assemblies according to claim 1 .
5. A rectifier circuit comprising two or more capacitor assemblies according to claim 1 .
6. A mass spectrometer vacuum enclosure comprising a capacitor assembly according to claim 1 .
7. A mass spectrometer comprising a vacuum enclosure according claim 6 .
8. A mass spectrometer comprising a capacitor assembly according to claim 1 .
9. A capacitor assembly for measuring the level of radio frequency voltage in a mass spectrometer, the assembly comprising
a capacitor having a first capacitor plate adapted for connection to a voltage source and mounted within a vacuum enclosure of a mass spectrometer by a first insulating spacer,
a superposed second capacitor plate adapted for connection to a rectifier and mounted within the vacuum enclosure by a second insulating spacer and
a vacuum housing feedthrough electrically connected to circuitry associated with the second plate.
10. The capacitor assembly of claim 9 , wherein the second capacitor plate is nested in the first insulating spacer.
11. The capacitor assembly of claim 9 , wherein at least one insulating spacer is connected to a marginal portion of a respective capacitor plate.
12. The capacitor assembly of claim 11 , wherein at least one of the insulating spacers comprises a plurality of spacer elements.
13. The capacitor assembly of claim 12 , wherein each of the spacer elements is connected to a respective marginal portion of the respective capacitor plate.
14. The capacitor assembly of claim 13 , wherein at least one of the insulating spacers comprises at least one of ceramic, quartz and/or fused silica.
15. A rectifier circuit comprising one or more capacitor assemblies according to claim 9 .
16. A rectifier circuit comprising two or more capacitor assemblies according to claim 9 .
17. A mass spectrometer vacuum enclosure comprising a capacitor assembly according to claim 9 .
18. A mass spectrometer comprising a vacuum enclosure according claim 17 .
19. A mass spectrometer comprising a capacitor assembly according to claim 9 .