Mass spectrometer scanning

Claim 2

A scanning system for a double-focussing mass spectrometer, the spectrometer including ion accelerating means having an accelerating voltage applied thereto, and electrostatic analyzer having a deflection voltage applied thereto, a magnetic analyzer having a variable magnetic deflection current applied thereto for producing a magnetic scan at a first scanning rate of an ion beam across a collector and producing ion current at said collector, the improvement in a scanning system comprising: a. selectively operable sweep means for scanning the mass-charge ratio by scanning a ratio between said accelerating voltage and said deflection voltage at a second scanning rate substantially faster than said first scanning rate through a predetermined range of ratios, including a normal operating ratio for the mass spectrometer; and, b. first switch means effective during at least a portion of said scanning variation for providing at least one first output signal representative of an instantaneous value of ion current at said collector.

Claim 3

The system of claim 1 wherein said sweep means varies said accelerating voltage to produce said scanning variation of said ratio.

Claim 4

The system of claim 2, further including second switch means for changing said accelerating voltage from a normal operating value to a second value prior to initiation of said scanning variation, said second value being offset from said normal value in a sense opposite to the sense of said scanning variation.

Claim 5

The system of claim 3, wherein said second switch means returns said accelerating voltage to said normal value upon termination of said scanning variation.

Claim 6

The system of claim 3, wherein said first switch means is effective at least at a beginning and ending of said scanning variation for providing second output signals indicative of instantaneous values of said ratios.

Claim 7

The system of claim 1, further including a flux stabilizEr for producing a magnetic field in said magnetic analyzer for counteracting said magnetic scan during variation of said ratio between said accelerating and deflection voltages.

Claim 8

A scanning system for a double-focussing mass spectrometer, the spectrometer including ion accelerating means having an accelerating voltage applied thereto, an electrostatic analyzer having a deflection voltage applied thereto, a magnetic analyzer having a variable magnetic deflection current applied thereto for providing a magnetic scan of an ion beam across a collector, the improvement in a scanning system comprising: a. selectively operable sweep means for scanning a portion of a mass spectrum by scanning a ratio between said accelerating voltage and said deflection voltage through a predetermined range of ratios, including a normal operating ratio for the mass spectrometer; and, b. first switch means effective during at least a first portion of said scanning variation for providing at least one first output signal representative of an instantaneous value of ion current at said collector and effective during at least a second portion of said scanning variation for providing at least one second output signal indicative of an instantaneous value of said ratio.

Claim 9

A scanning system for a double-focussing mass spectrometer, the spectrometer including ion accelerating means having an accelerating voltage applied thereto, an electrostatic analyzer having a deflection voltage applied thereto, a magnetic analyzer having a variable magnetic deflection current applied thereto for providing a magnetic scan of an ion beam across a collector, the improvement in a scanning system comprising: a. selectively operable sweep means for scanning a portion of a mass spectrum by scanning a ratio between said accelerating voltage and said deflection voltage through a predetermined range of ratios, including a normal operating ratio for the mass spectrometer; and, b. first switch means effective during at least a first portion of said scanning variation for providing at least one first output signal representative of an instantaneous value of ion current at said collector and effective during at least a second portion of said scanning variation for providing at least one second output signal indicative of an instantaneous value of said ratio.

Claim 10

The system of claim 7, wherein said first switch means is effective during at least a portion of said scanning variation for alternately providing said first and second output signals.

Claim 11

The system of claim 8 wherein said sweep means varies said accelerating voltage to produce said scanning variation of said ratio.

Claim 12

The system of claim 9, further including second switch means for changing said accelerating voltage from a normal value to a second value prior to initiation of said scanning variation, said second value being offset from said normal value in a sense opposite to the sense of said scanning variation.

Claim 13

The system of claim 10, wherein said second switch means returns said accelerating voltage to said normal value upon termination of said scanning variation.

Claim 14

The system of claim 8, further including threshold means for enabling said first switch means when said ion current at said collector is greater than variation predetermined level.

Claim 15

The system of claim 12, further including a flux stabilizer for producing a magnetic field in said magnetic analyzer for counteracting said magnetic scan during variation of said ratio between said accelerating and deflection voltages.

Claim 16

The system of claim 7, further including a flux stabilizer for producing a magnetic field in said magnetic analyzer for counteracting said magnetic scan during variation of said ratio between said accelerating and deflection voltages.

Claim 17

The system of claim 7, further including a flux stabilizer for producing a magnetic field in said magnetic analyzer for counteracting said magnetic scan during variation of said ratio between said accelerating and deflection voltages.

Claim 18

A scanning system for a double-focussing mass spectrometer, the spectrometer including ion accelerating means having an accelerating voltage applied thereto, an electrostatic analyzer having a deflection voltage applied thereto, a magnetic analyzer having a variable magnetic deflection current applied thereto for producing a magnetic scan of an ion beam across a collector, the improvement in a scanning system comprising: a. selectively operable sweep means for scanning the mass-charge ratio by varying a ratio between said accelerating voltage and said deflection voltage at a second scanning rate substantially faster than said first scanning rate through a predetermined range of ratios, including a normal operating ratio for the mass spectrometer; and, b. first switch means effective during at least a portion of said scanning variation for providing at least one first output signal representative of an instantaneous value of ion current at said collector.

Claim 19

A scanning system for a double-focussing mass spectrometer, the spectrometer including ion accelerating means having an accelerating voltage applied thereto, an electrostatic analyzer having a deflection voltage applied thereto, a magnetic analyzer having a variable magnetic deflection current applied thereto for producing a magnetic scan of an ion beam across a collector, the improvement in a scanning system comprising: a. selectively operable sweep means for scanning the mass-charge ratio by varying a ratio between said accelerating voltage and said deflection voltage at a second scanning rate substantially faster than said first scanning rate through a predetermined range of ratios, including a normal operating ratio for the mass spectrometer; and, b. first switch means effective during at least a portion of said scanning variation for providing at least one first output signal representative of an instantaneous value of ion current at said collector.

Claim 20

The system of claim 16, wherein said first switch means is also effective iN response to said ion current substantially reaching said peak for providing a second output signal indicative of an instantaneous value of said ratio at that time.

Claim 21

The system of claim 17, further including a flux stabilizer for producing a magnetic field in said magnetic analyzer for counteracting said magnetic scan during variation of said ratio between said accelerating and deflection voltages.

Claim 22

A scanning system for a double-focussing mass spectrometer, the spectrometer including ion accelerating means having an accelerating voltage applied thereto, an electrostatic analyzer having a deflection voltage applied thereto, a magnetic analyzer having a variable magnetic deflection current applied thereto for producing a magnetic scan of an ion beam across a collector, the scanning system comprising: a. selectively operable sweep means for scanning the mass-charge ratio by varying a ratio between said accelerating voltage and said deflection voltage through a predetermined range of ratios, including a normal operating ratio for the mass spectrometer; b. first switch means effective during at least a portion of said scanning variation for providing at least one first output signal representative of an instantaneous value of ion current at said collector; and, c. first threshold means for operating said sweep means to initiate said scanning variation after said ion current at said collector exceeds a first predetermined level as a result of said magnetic scan.

Claim 23

A scanning system for a double-focussing mass spectrometer, the spectrometer including ion accelerating means having an accelerating voltage applied thereto, an electrostatic analyzer having a deflection voltage applied thereto, a magnetic analyzer having a variable magnetic deflection current applied thereto for producing a magnetic scan of an ion beam across a collector, the scanning system comprising: a. selectively operable sweep means for scanning the mass-charge ratio by varying a ratio between said accelerating voltage and said deflection voltage through a predetermined range of ratios, including a normal operating ratio for the mass spectrometer; b. first switch means effective during at least a portion of said scanning variation for providing at least one first output signal representative of an instantaneous value of ion current at said collector; and, c. first threshold means for operating said sweep means to initiate said scanning variation after said ion current at said collector exceeds a first predetermined level as a result of said magnetic scan.

Claim 24

The system of claim 19 wherein said sweep means varies with accelerating voltage to produce said scanning variation of said ratio.

Claim 25

The system of claim 20, further including second switch means for changing said accelerating voltage from a normal operating value to a second value prior to initiation of said scanning variation, said second value being offset from said normal value in a sense opposite to the sense of said scanning variation.

Claim 26

The system of claim 21, wherein said second switch means returns said accelerating voltage to said normal value upon termination of said scanning variation.

Claim 27

The system of claim 21, further including first time delay means for initiating said scanning variation at a predetermined time after said accelerating voltage is changed to said second value.

Claim 28

The system of claim 23, wherein said second switch means returns said accelerating voltage to said normal value upon termination of said scanning variation.

Claim 29

The system of claim 23, further including second threshold means for enabling said first switch means during said scanning variation when said ion current at said collector is greater than a second predetermined level.

Claim 30

The system of claim 23, further including a flux stabilizer for producing a magnetic flux in said magnetic analyzer for counteracting said magnetic scan during variation of said ratio between said accelerating and deflection voltages.

Claim 31

The system of claim 19, wherein said first switch means is effective during at least a portion of said scanning variation for alternately providing said first and second output signals.

Claim 32

The system of claim 19, further including second threshold means for enabling said first switch means during said scanning variation when said ion current at said collector is greater than a second predetermined level.

Claim 33

The system of claim 19 further including a flux stabilizer for producing a magnetic field in said magnetic analyzer for counteracting said magnetic scan during variation of said ratio between said accelerating and deflection voltages.

Claim 34

The system of claim 19, wherein said first switch means is effective during at least a portion of said scanning variation for alternately providing said first and second output signals.

Claim 35

The system of claim 30, further including recording means for recording said first and second output signals.

Claim 36

The system of claim 31, further including means for digitizing said first and second output siGnals prior to recording.

Claim 37

A scanning system for a double-focussing mass spectrometer, the spectrometer including ion accelerating means having an accelerating voltage applied thereto, an electrostatic analyzer having a deflection voltage applied thereto, a magnetic analyzer having a variable magnetic deflection current applied thereto for producing a magnetic scan of an ion beam across a collector, the scanning system comprising: a. selectively operable sweep means for scanning the mass-charge ratio by scanning a ratio between said accelerating voltage and said deflection voltage through a predetermined range of ratios, including a normal operating ratio for the mass spectrometer; and, b. first switch means effective during at least a first portion of said scanning variation for providing at least one first output signal representative of an instantaneous value of ion current at said collector and effective during at least a second portion of said scanning variation for providing at least one second output signal indicative of an instantaneous value of said ratio.

Claim 38

A scanning system for a double-focussing mass spectrometer, the spectrometer including ion accelerating means having an accelerating voltage applied thereto, an electrostatic analyzer having a deflection voltage applied thereto, a magnetic analyzer having a variable magnetic deflection current applied thereto for producing a magnetic scan of an ion beam across a collector, the scanning system comprising: a. selectively operable sweep means for scanning the mass-charge ratio by scanning a ratio between said accelerating voltage and said deflection voltage through a predetermined range of ratios, including a normal operating ratio for the mass spectrometer; and, b. first switch means effective during at least a first portion of said scanning variation for providing at least one first output signal representative of an instantaneous value of ion current at said collector and effective during at least a second portion of said scanning variation for providing at least one second output signal indicative of an instantaneous value of said ratio.

Claim 39

A scanning system for a double-focussing mass spectrometer, the spectrometer including ion accelerating means, an electrostatic analyzer and a magnetic analyzer positioned to deflect ions projected by said accelerating means at a first scanning rate, and collector means for receiving at least a portion of said projected ions and including monitoring circuit means for developing signals having values representative of the ions received, the improvement in a scanning system comprising: first circuit means coupled to said accelerating means for applying an ion accelerating signal to said accelerating means; second circuit means coupled to said electrostatic analyzer for applying a deflection signal to said electrostatic analyzer; and, control circuit means for scanning the mass-charge ratio by scanning the ratio between the value of said ion accele-rating signal and the value of said electrostatic deflection signal at a predetermined rate substantially different from said first scanning rate.

Claim 40

A scanning system for a double-focussing mass spectrometer, the spectrometer including ion accelerating means, an electrostatic analyzer and a magnetic analyzer positioned to deflect ions projected by said accelerating means at a first scanning rate, and collector means for receiving at least a portion of said projected ions and including monitoring circuit means for developing signals having values representative of the ions received, the improvement in a scanning system comprising: first circuit means coupled to said accelerating means for applying an ion accelerating signal to said accelerating means; second circuit means coupled to said electrostatic analyzer for applying a deflection signal to said electrostatic analyzer; and, control circuit means for scanning the mass-charge ratio by scanning the ratio between the value of said ion accele-rating signal and the value of said electrostatic deflection signal at a predetermined rate substantially different from said first scanning rate.

Claim 41

A scanning system as defined in claim 34 wherein said control circuit means includes sweep circuit means for substantially linearly varying said ratio between the value of said ion accelerating signal and the value of said electrostatic deflection signal.

Claim 42

A scanning system as defined in claim 34 wherein said control circuit means includes sweep circuit means for scanning said ratio between the value of said ion accelerating signal and the value of said electrostatic deflection signal between a predetermined upper level limit and a predetermined lower level limit.

Claim 43

A scanning system as defined in claim 34 wherein said control circuit means includes sweep circuit means for substantially linearly scanning said ratio between the value of said ion accelerating signal and the value of said electrostatic deflection signal between a predetermined upper level limit and a predetermined lower level limit.

Claim 44

A scanning system as defined in claim 34 wherein said control circuit means includes sweep circuit means for scanning said ratio between the value of said ion accelerating signal and the value of said electrostatic deflection signal by scanning the value of said electrostatic deflection signal.

Claim 45

A scanning system as defined in claim 34 wherein said control circuit means includes a voltage sweep generator means for developing a signal which varies in value at a preselected rate with respect to time; and, third circuit means for applying a said varying signal to said first circuit means to cause the value of a said ion accelerating signal to vary in value at a preselected rate with respect to time to thereby vary said ratio between the value of said ion accelerating signal and the value of said electrostatic deflection signal at a preselected rate with respect to time.

Claim 46

A scanning system as defined in claim 39 including second monitoring circuit means for devEloping signals representative of the values of said ion accelerating signal; and, fourth circuit means coupled to said first and second monitoring circuit means for providing an output indication representative of the value of both said ion accelerating signals and said signals developed by said first monitoring circuit means.

Claim 47

A scanning system as defined in claim 34 wherein said control circuit means includes a voltage sweep generator means for developing a signal which varies in value at a preselected rate with respect to time; and, third circuit means for applying a said varying signal to said second circuit means to cause the value of a said electrostatic deflection signal to vary in value at a preselected rate with respect to time to thereby vary said ratio between the value of said ion accelerating signal and the value of said electrostatic deflection signal at a preselected rate with respect to time.

Claim 48

A scanning system as defined in claim 41 including second monitoring circuit means for developing signals representative of the values of said electrostatic deflection signals; and, fourth circuit means coupled to said first and second monitoring circuit means for providing an output indication representative of the value of both said electrostatic deflection signals and said signals developed by said first monitoring circuit means.

Claim 49

A scanning system as defined in claim 34 including a signal generating means coupled to said magnetic analyzer for applying a magnetic deflection signal to said magnetic analyzer; and, second control circuit means coupled to said signal generating means for scanning the value of said magnetic deflection signal at a first scanning rate.

Claim 50

A scanning system as defined in claim 43 wherein said control circuit means includes variable circuit means for scanning the ratio between the value of said ion accelerating signal and the value of said electrostatic deflection signal at a scanning rate substantially faster than said first scanning rate.

Claim 51

A scanning system as defined in claim 44 including first actuatable switching means coupled to said second control circuit means for terminating said scanning of said magnetic deflection signal when an output signal developed by said monitoring circuit attains a predetermined value; and, second actuatable means coupled to said first control circuit means for, upon termination of said magnetic deflection scanning, actuating said first control circuit means to initiate said ratio scanning.

Claim 52

A scanning system as defined in claim 43 wherein said control circuit means includes sweep circuit means for substantially linearly varying said ratio between the value of said ion accelerating signal and the value of said electrostatic deflection signal.

Claim 53

A scanning system as defined in claim 43 wherein said control circuit means includes sweep circuit means for varying said ratio between the value of said ion accelerating signal and the value of said electrostatic deflection signal between a predetermined upper level limit and a predetermined lower level limit.

Claim 54

A scanning system as defined in claim 43 wherein said control circuit means includes sweep circuit means for substantially linearly scanning said ratio between the value of said ion accelerating signal and the value of said electrostatic deflection signal between a predetermined upper level limit and a predetermined lower level limit.

Claim 55

A scanning system as defined in claim 43 wherein said control circuit means includes sweep circuit means for scanning said ratio between the value of said ion accelerating signal and the value of said electrostatic deflection signal by electronically scanning the value of said ion decelerating signal.

Claim 62

The method as defined in claim 52 including the step of developing an output indication representative of the instantaneous values of both said first and second output signals.

Claim 65

The method as defined in claim 54 including the step of developing an output indication representative of the instantaneous value of both said first and second output signals.

Claim 66

A scanning system fOr a double-focussing mass spectrometer, the spectrometer including ion accelerating means, an electrostatic analyzer and a magnetic analyzer positioned to deflect ions projected by said accelerating means at a first scanning rate, and collector means for receiving at least a portion of said projected ions and including monitoring circuit means for developing signals having values representative of the ions received, the scanning system comprising: first circuit means coupled to said accelerating means for applying an ion accelerating signal to said accelerating means; second circuit means coupled to said electrostatic analyzer for applying a deflection signal to said electrostatic analyzer; control circuit means coupled to said first circuit means and having; a voltage sweep generator means for scanning the mass-charge ratio by generating a control signal having a value which varies as a preselected linear function of time between a predetermined upper and lower limit and at a rate substantially different from said first scanning rate; actuatable switching means for, upon actuation, actuating said sweep generator to initiate generator of a said control signal; variable means for varying the preselected rate at which a said control signal varies; third circuit means for applying a said linearly varying control signal to said first circuit means to cause a said ion accelerating signal to vary as a linear function of time; first monitoring circuit means for developing a plurality of first output signals each having a value representative of the instantaneous value of said ion accelerating signal; second monitoring circuit means for developing a plurality of second output signals each having a value representative of the instantaneous value of said collector monitored signals; indicator circuit means coupled to said first and second monitoring circuit means for developing an output indication representative of the values of both said first and said second output signals.

Claim 67

A scanning system fOr a double-focussing mass spectrometer, the spectrometer including ion accelerating means, an electrostatic analyzer and a magnetic analyzer positioned to deflect ions projected by said accelerating means at a first scanning rate, and collector means for receiving at least a portion of said projected ions and including monitoring circuit means for developing signals having values representative of the ions received, the scanning system comprising: first circuit means coupled to said accelerating means for applying an ion accelerating signal to said accelerating means; second circuit means coupled to said electrostatic analyzer for applying a deflection signal to said electrostatic analyzer; control circuit means coupled to said first circuit means and having; a voltage sweep generator means for scanning the mass-charge ratio by generating a control signal having a value which varies as a preselected linear function of time between a predetermined upper and lower limit and at a rate substantially different from said first scanning rate; actuatable switching means for, upon actuation, actuating said sweep generator to initiate generator of a said control signal; variable means for varying the preselected rate at which a said control signal varies; third circuit means for applying a said linearly varying control signal to said first circuit means to cause a said ion accelerating signal to vary as a linear function of time; first monitoring circuit means for developing a plurality of first output signals each having a value representative of the instantaneous value of said ion accelerating signal; second monitoring circuit means for developing a plurality of second output signals each having a value representative of the instantaneous value of said collector monitored signals; indicator circuit means coupled to said first and second monitoring circuit means for developing an output indication representative of the values of both said first and said second output signals.

Claim 68

A scanning system for a double-focusing mass spectrometer, the spectrometer including ion accelerating means, an electrostatic analyzer and a magnetic analyzer positioned to deflect ions projected by said accelerating means at a first scanning rate, and collector means for receiving at least a portion of said projected ions and including monitoring circuit means for developing signals having values representative of the ions received, the scanning system comprising: first circuit means coupled to said accelerating means for applying an ion accelerating signal to said accelerating means; second circuit means coupled to said electrostatic analyzer for applying a deflection circuit to said electrostatic analyzer; control circuit means coupled to said second circuit means and having; a voltage sweep generator means for scanning the mass-charge ratio by generating a control signal having a value which varies as a preselected linear function of time between a predetermined upper and lower limit and at a rate substantially different from said first scanning rate; actuatable switching means for, upon actuation, actuating said sweep generator to initiate generation of a said control signal; variable means for varying the preselected rate at which a said control signal varies; third circuit means for applying a said linearly varying control signal to said second circuit means to cause a said deflection signal to vary as a linear function of time; first monitoring circuit means for developing a plurality of first output signals having a value representative of the instantaneous value of said deflection signal; second monitoring circuit means for developing a plurality of second output signals each having a value representative of the instantaneous value of said collector monitored signals; indicator circuit means coupled to said first and second monitoring circuit means for developing an output indication representative of the values of both said first and said second output signals.

Claim 69

A scanning system for a double-focusing mass spectrometer, the spectrometer including ion accelerating means, an electrostatic analyzer and a magnetic analyzer positioned to deflect ions projected by said accelerating means at a first scanning rate, and collector means for receiving at least a portion of said projected ions and including monitoring circuit means for developing signals having values representative of the ions received, the scanning system comprising: first circuit means coupled to said accelerating means for applying an ion accelerating signal to said accelerating means; second circuit means coupled to said electrostatic analyzer for applying a deflection circuit to said electrostatic analyzer; control circuit means coupled to said second circuit means and having; a voltage sweep generator means for scanning the mass-charge ratio by generating a control signal having a value which varies as a preselected linear function of time between a predetermined upper and lower limit and at a rate substantially different from said first scanning rate; actuatable switching means for, upon actuation, actuating said sweep generator to initiate generation of a said control signal; variable means for varying the preselected rate at which a said control signal varies; third circuit means for applying a said linearly varying control signal to said second circuit means to cause a said deflection signal to vary as a linear function of time; first monitoring circuit means for developing a plurality of first output signals having a value representative of the instantaneous value of said deflection signal; second monitoring circuit means for developing a plurality of second output signals each having a value representative of the instantaneous value of said collector monitored signals; indicator circuit means coupled to said first and second monitoring circuit means for developing an output indication representative of the values of both said first and said second output signals.