US3767914A

US3767914A - Continuous injection mass spectrometer

Info

Publication number: US3767914A
Application number: US00144112A
Authority: US
Inventors: R Mueller; J Carrico
Original assignee: Bendix Corp
Current assignee: Bendix Corp
Priority date: 1971-05-17
Filing date: 1971-05-17
Publication date: 1973-10-23
Anticipated expiration: 1990-10-23

Abstract

The inventive mass spectrometer operates with an inhomogeneous oscillatory electric field and operates with the continuous injection of charged particles into the electric field. Particles of all species are acted upon by the field, and some of the species ultimately are detected to produce an output which is random with respect to the phase of the oscillatory field. Appropriate parameters of the electric field are varied so that ions of some species bunch up and produce output pulses which are above the random output caused by the detection of the other species which do not bunch. Detection of these pulses and their relationship to the phase of oscillation of the electric field uniquely identifies the bunched species in accordance with the mass-to-charge ratio. Different species can be identified by properly readjusting the electric field parameters to cause bunching of the different species.

Description

United States Patem1 Mueller et al.

[73 I Assignee: The Bendix Corporation, Southfield, Mich. [22] Filed: May 17, 1971 211 Appl. No.: 144,112

OTHER PUBLICATIONS Mass Spectroscopy'Using RF Quadrupole Fields by P. H. Dawson et al., from Advances in Electronics and Electron Physics, Vol. 27, Academic Press, New York, 1969, pages 120-125 & 132-139. TK 7803. A3 Injection and Extraction of Ions in Monopole Mass Spectrometer" by R. F. Lever from IBM Technical Disclosure Bulletin, Vol. 8, No. 1, June, 1965, pages 179 & 180.

Primary Examiner-William F. Lindquist AttorneyLester 1L. Hallacher and Plantc, Hartz, Smith and Thompson 57 ABSTRACT The inventive mass spectrometer operates with an inhomogeneous oscillatory electric field and operates with the continuous injection of charged particles into the electric field. Particles of all species are acted upon by the field, and some of the species ultimately are detected to produce an output which is random with respect to the phase of the oscillatory field. Appropriate parameters of the electric field are varied so that ions of some species bunch up and produce output pulses which are above the random output caused by the detection of the other species which do not bunch. Detection of these pulses and their relationship to the phase of oscillation of the electric field uniquely identifies the bunched species in accordance with the mass-to-charge ratio. Different species can be identified by properly readjusting the electric field parameters to cause bunching of the different species.

19 Claims, '4 Drawing Figures CONTINUOUS INJECTION MASS SPECTROMETER CROSS REFERENCE TO RELATED APPLICATIONS Application Ser. No. 65,574, filed Aug. 20, 1970, by J. P. Carrico and P. F. McGinnes and assigned to the assignee of the subject application, described mass spectrometer structures with which the inventive concepts of this invention can be employed.

BACKGROUND OF THE INVENTION Various types of mass spectrometers are presently available in the art. Among the types available are conventional and dynamic field time-of-flight, acceleration, quadrupole and monopole spectrometers. Although these various types of spectrometers operate differently, they have some common operational features; one of the more important of which is the opera tional dependence upon the mass-to-charge ratio of the ions. Another very important common feature of conventional and dynamic field time'of-flight spectromemm is the mode of injecting charged particles into the spectrometer. In this type of spectrometer, ions are pulse injected and the ions analyzed during the time interval existing between injections of particles. Consequently, the sensitivity of conventional and dynamic field time-of-flight spectrometers is decreased by the on-off duty cycle required by the pulse-injection.

This can be best understood by'briefly considering the operational characteristics of some commonly known mass spectrometers. In a conventional time-of flight spectrometer charged particles, suchas ions, are generated at the input end of the spectrometer. The ions are acted upon bya pulsed electric field in the source region and are acceleratedinto a drift region. The accelerating force is the same for all singly charged ions; obviously an ion having a larger net charge will undergo 'a greater accelerating force. Hereinafter, for the sake of simplicity, only singly charged ions are consideredJBecause the accelerating force is the same for all ions, each species of ion is accelerated toa different velocity according to the mass'of the individual ions While in the drift region,the ions spatially separate in accordance with the different "velocities. A measurement of the time in thedrift region is indicative of the velocity of each species and thus is uniquely characteristic of each mass-to-charge ratio. The ionic m/e ratio information is translated to molecular information which is then used to identify the unknown material.

An acceleration type of .mass spectrometer utilizes time-of-flight principles in, a different manner. lons are sequentially passed through alternately arranged accelcrating regions and drift regions. Accelerating electric .fields are applied to the accelerating regions in an appropriate phase relationship so that only ions of a particular mass-to-charge ratio are properlyphased with the accelerating fields and reach the detector. The ionic m/e ratio is uniquely indicative of a' particular molecule which is then known to exist in the unknown gas. Other molecules can be detected by changing the phase relationship 'of the accelerating field.

Quadrupole and monopole mass spectrometers separate species of ions according to their mass-to-charge ratios by oscillating the ions in a dynamic electric field. Only the ions of a .particular mass-to-charge ratio assume a stable oscillating motion and pass to a detector.

2v Other species of ions assume unstable oscillatory motion and are absorbed by the electrodes of the instrument and thus are not detected.

A class of spectrometers, which is perhaps the most sophisticated spectrometer available, is the dynamic field time-of-flight spectrometer. In this type of spectrometer, ions are pulse-injected into a dynamic electric field and the time a species of ion spends in the' field is indicativeof the mass-to-charge ratio. While in the field the ions are caused to assume an oscillatory motion in order to separate the various species within the spectrometer. Different species can therefore be detected by changing the amplitude of the oscillatory molecules of the gas to be analyzed to create'ions from the molecules. When pulse injection is used it is usually necessary to pulse the electron source. This requires somewhat complex circuitry because of the pulse widths (in time) which are involved.

In order to obtain accurate output information in time-of-flight spectrometers, it is'necessary to precisely time the injection of the ions into the field and their exit from the field. This requires accurate control and measuring systems. This problem is further complicated by the lag in theexit times of ions from the source into the analyzer region which results in a degradation of resolution. Resolution in the conventional time-of-fli'ght mass spectrometeris also affected by spread in the initial energy of the ions. In theinventive system the arrival time of the ions at the detector is independent of the initial energy of the ion. This is a very important ad- SUMMARY OF THE INVENTION The inventive mass spectrometer overcomes the principal disadvantages of existing time-of-flight mass spectrometers by operating with a'continuous injection of ions without a direct measurement of time-of-flight. Upon injection into the spectrometer ions are subjected to a dynamic electric field which temporally separates them in accordance with their mass-.to-charge ratios. All species of ions are acted upon by the field and a wide range of;mass-to-charge ratios are detected. By properly adjusting the field parameters, ions of at least one particular species are bunched together. All other species are either not detected or are detected as a random background upon which a peak output representative of the bunched specie is superimposed. It is possible that more than one species can be simultaneously bunched. However, the respective positions of each specie with respect to' the phase of the electric As used herein, a charged particle, or ion, is defined as any particle having a net electrical charge. A dynamic electric field is defined as any oscillating electric field and may optionally include a steady state component. Inhomogeneous electric field is defined as an electric field in which the field parameters along the coordinate axes (in at least two directions) at a given physical point and instant in time are different from those at other physical points at the same instant. Such a field can also be defined as a heterogeneous electric field.

The acceleration of a particle as a function of time in the electrical field configuration of the preferred embodiment is defined by the Mathieu equation. Accordingly, three such equations can be used to define the motion of particles along the three axes. The equations of motion include the mass-to-charge ratio which uniquely identifies the species of ions. Because the positional information relating to a species of ions can be separately defined for each axis, a particular species can be made to bunch up with respect to one axis, or

in one direction, by properly varying the field parameters. Bunching is effected by slowing some ions and speeding others, so that most ions of a particular species approach a median velocity. The bunching results in a pulse output when the ions impact with a detector. Ions of other species are also detected. However, these ions are not bunched, and accordingly their detection occurs at random times, resulting in a random output. The pulse output rises above the random output, and therefore correlation of the position of the pulse output with respect to the phase of the dynamic field component of the electric field yields information relative to the mass-to-charge ratio of the bunched species and thus of the material being analyzed.

The electric field is mathematically described by an expression which includes a constant D.C. component as well as the amplitude and frequency of an A.C. component as parameters. Additionally, the expression includes the mass-to-charge ratio of ion species and the phase of the A.C. component. Accordingly, a particular species can be identified by properly adjusting either the D.C. component or the A.C. amplitude or the AC. frequency or any combination of the three. The required phase information is obtained by the use of external circuitry of a convenient type. For example, the external circuitry can include an oscilloscope, the X input of which is actuated by the signal generator which produces the desired waveform of electric field. The Y axis of the oscilloscope is actuated by the output from the detector of the mass spectrometer so that the output from the detector can be directly correlated to the phase of the field-producing waveform.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a preferred embodiment of the inventive system.

FIG. 2 is a waveform showing the output from the detector. I

FIG. 3 is a waveform showing a display which can be shown on the oscilloscope face.

FIG. 4 is a block diagram of a signal generator which can be used to produce the electric field.

DETAILED DESCRIPTION In the preferred embodiment shown in FIG. 1, the mass spectrometer Structure is enclosed in an Evacuable Casing 11. The spectrometer structure includes a Field Generating Rod 12 and a V-Shaped Trough 13 which provides a retaining medium for the ions traveling along the trough within the electric field. Both Rod 12 and Trough 13 are conductive so that they support the electric field. An appropriate Lead 14 connects a Field Generator 16 to the Field Producing Rod 12.

V-shaped Trough 13 contains an Aperture 17 through which ions to be analyzed enter the electric field. After traveling the length of Trough 13 the ions exit by way of Aperture 18 and impinge upon Detector 19. The voltage output produced by the impingement of ions on Detector 19 is coupled to the Y input of an oscilloscope by way of an appropriate Lead 22.

The gas to be analyzed is injected into the Evacuable Casing 11 through a Valve 23 which controls the flow of gas from a Gas Source 24 to the vicinity of a Filament 27 which is coupled to an energizing Source 28. Source 28 is used to heat Filament 27 so that electrons are given off by the filament. It should be understood that any type of electron source can be used within the scope of the invention. Some of the electrons collide with molecules in the vicinity of the filament, stripping an electron from the molecule to form a positively charged ion. The ions are injected into the field through Aperture 17 in Trough 13 where they are subjected to the electric field and move along the Trough 13 until they egress from the trough by way of Aperture 18 and impinge upon Detector 19. The ions impacting with Detector 19 create a voltage output in Lead 22. Detector 19 can be an electron multiplier or some other convenient type of detector.

As will be explained more fully hereinafter, the acceleration experienced by the ions as they travel along Trough 13 is dependent upon the mass-to-charge ratio of the ions. The electric field generated by Field Generator 16 is structured to cause one or more species of ions to bunch into groups according to their mass-tocharge ratios. The ions of other species do not bunch, and therefore produce a random output which establishes a substantially level and continuous output from the mass spectrometer. The grouped ions of the species being investigated cause pulse outputs which rise above the random output. Because Detector 19 is coupled to the Y input of Oscilloscope 21, the output from the detector is visually indicated on the Face 29 ofthe oscilloscope. The output of Field Generator 16 is used to trigger Oscilloscope 21 so that a visual indication of the pulses appearing on Detector 19 is displayed on oscilloscope Face 29. The output from Detector 19 shows a rather constant voltage level which is created by the nonbunched or random ions, and a plurality of pulses created by bunched species of ions. If desired, the output from Field Generator 16 and of Detector 19 can be coupled to the Y input of Oscilloscope 21 and the oscilloscope internally triggered. In this case the waveform of the field-creating electrical signal is displaced on the Oscilloscope 21 face. Superimposed on each cycle of the driving waveform is one or more pulses which represent the bunched ion species. A waveform of this type is shown in FIG. 3.

FIG. 2 is a simplified showing of the output received from Detector 19 and which is applied to the Y input of the Oscilloscope 21. The random output caused by the detection of species of ions which are not being investigated is a substantially constant but slightly varying voltage level indicated in FIG. 2 by reference numeral 31. The pulses created by the impact of grouped ions on Detector 19 are indicated generally by reference numeral 32. Accordingly, each of the pulses 32 in of the A.C. component of Field Generator'16 so that a pulse occurs for each cycle of the A.C. source.

This isbest understoodby reference to FIG. 3 in which the A.C. com'ponentof the signal applied by Field Generator 16 is shown as a sinusoidally varying signal. The sinusoidal A.C.signal does not vary about a zero voltage because Field Generator 16 also supplies a D.C. component. Thefield therefore varies aboutthe D.C. component level rather than the zero level. The D.C. component can, of course, be blocked out by A.C. coupling. A first series of pulses34 is present on each of the positive half cycles of each cycle of the A.C. component. Each of pulses 34 is caused by the impact of a group of ions of the same species of mass-to-charge ratio on Detector 19 of the FIG. 1 embodiment. As willbe explained more fully hereinafter, the positioning of the pulses 34 with. respect to the phase of the Arc. waveform is indicative of the mass-to-charge ratio of the particular species of ions creating the pulses. For this reason, ions of a different mass-to-charge ratio would create a second series of pulses 36 on the A.C. waveform. The phase relationship of the two sets of pulses 3'4 and 36 is different-and is determinative of the m/e ratio of the two speciesalt should be noted that only in some instances will a particular set of field parameters cause two or more sets of output pulses in the manner shownin FIG. 3. Frequently, there will be a single set of pulses, and in orderto investigateanother m/e justing either the A.C. frequency, the A.C. amplitude,-

or the D.C. signal level. :It should be understoodthat the signal shown in FIG. 3'is greatly simplified because the random output from Detector 19 has not been taken account of in the figure. Accordingly, the alternating component is shown as being symmetrical about the DC. voltage level. As an'actual matter, this would not occur because the'random-voltage would add to the positive cycles and subtract from the negative half cycle so that there would be a lack of symmetry about the D.C. level.

As explained hereinabove, a particular species of ion can be detected by properly adjusting the D.C..voltage component of the electric field, the A.C. amplitude, or the A.C. frequency. As shown in FIG. 4, Field Genera tor 16 includes an adjustable D.C. Source 37 andan A.C. Frequency Source 38, the frequency of which is adjustable. An Adjustable Amplifier 39 is used to change the A.C. amplitude independently of the frequency. A Summation Circuit 40 receives the outputs from the D.C. Source 37 and Amplifier 39 so that the required waveform is applied to Rod 12. The exact nature of each of these elements is well known in the art and any of several available techniques can vbe selected by one skilled in the art. Accordingly, the details of Field Generator 16 and its component circuitry are not included herein.

The identification of a particular species having a particular mass-to-charge ratio is dependent upon the configuration of the electric field extending .between Rod l2.and Accelerating Trough '13. Accordingly, this field is a complex field which can be mathematically described and which can be used'to define the position of'an ion with respect to the X, Y, and Z coordinates of the spectrometerstructure. As shown in FIG. 1, the Z axis is the propagation axis of ions'through the spectrometer. The physical length and radius of the spectrometer also are instrumental in determining the electric field configuration. Consequently, these can be selected atthe time of fabrication so that a particular frequency range of voltage or a range of m/e ratios is most easily operated with. However, after selecting the physical parameters, they are permanently established.

Before presenting the complex. mathematical equations which definethe field, itis preferable to first define the various parameters which establish the equation. Accordingly:

V electric potential distribution X X axis rectangular coordinate Y'= Y axis rectangular coordinates Z Z axis rectangular coordinate t= time V the alternating component amplitude V static component mt 21rft where f is the frequency of the alternatin component l a geometrical factor for X direction [3 geometrical factor for Y direction.

y I= geometrical factor for Z direction e tut/2, time variable in the Mathieu equation a,, a,,, q,,, and q the canonical parameters in the Matheiu equation m mass of the ions e charge of ions (one electron charge or R distance along the X and Y axes Referring again to FIG. 1 it should be noted that the molecules within the vicinity of Filament 27 will have initial velocities which are different in magnitude and direction. Accordingly, as the molecules are converted into ions by the impact of electrons the ions enter the electric field with initial velocities which vary in both.

magnitude and direction. For this reason spacing exists between ions of a particular'species. Additional spacing exists between ions of a particular species because the ions enter the field region at different times or'phases. Accordingly, some of the ions of a particular species accelerate while others decelerate so that spatial bunching of the ions of a species occurs. In order to accomplish this, it is necessary to define the position of an ion with respect to the coordinate axes X, Y, and Z of the mass spectrometer as the ions are propagated along the length of thespectrometer. It will be appreciated that the length L of the mass spectrometer is defined to be coincident with the Z axis of the coordinate system. The ions are therefore caused to oscillate about the Z axis as they are propagated along that axis. In the embodiment shown in FIG. 1 there is no potential drop along the Z axis, and therefore there is no field along the Z axis. The oscillation amplitude with respect to the X and, Y axes is caused to vary in a stable oscillating manner so that the ions spatially group together and exit from the mass spectrometer in a group and impact with Detector 19. The time spacing between the tential along the Z axis, at a given instant of time is presented as follows:

V(X, Y, 1 v,,. V cos )!)(01X BY (l) where:

a B O The equations of motion which define the paths followed by charged particles in the electric field derived from the potential distribution of Equation (1) with respect to the coordinate axes are as follows:

d xlde (a, Zq cos 2e)X 0 (2a) d"y/de (a,, 2g, cos 2e)Y 0 (2b) d zlde 0 (2c) where:

26 wt 21rft q 2q,, 4e V /m m R The grouping or bunching of ions occurs primarily along the x axis.

For the preferred configuration, the general direction of injection of the ions into the oscillatory field is in the x direction. The detector is arranged so that bunching in this direction is measured. The solution to the equation of motion (Equation 2a) for this direction can be written as X 0 l( .tv qr 5 o) F2011: qr v E0) where x, is the initial position of the ion in the x direction;

and F and F are two suitably chosen linearly independent solutions of Equation (2a); for the preferred embodiment x, 0 and the particles are detected at x 0. Thus, the ions arrive at the detector at times t Ze /w determined from Equation (4) defines implicitly a relation between the arrival time t and the field parameters (V V 1, R), the mass-to-charge ratio (m/e), and the injection phase 2a,. For ions of a given m/e ratio, bunching occurs when the field parameters are adjusted so that the partial derivative of the arrival time with respect to the injection phase is less than unity; i.e., Se /8e, 1. For this situation, ions of the given m/e ratio injected earlier than some median injection time are decelerated in the oscillatory field'and other ions injected later are accelerated so that all the ions injected during one cycle of the A.C. and having the given m/e ratio arrive at the detector in an interval of time less than the period of the A.C. voltage. An inspection of Equation (4) reveals that the arrival time a, is independent of the initial energy of the ion, this is a most important property compared to conventional time-of-flight spectrometers.

Inspection of Equation (2) shows that the position of an ion is dependent upon the mass-to-charge ratio of the ion, the magnitude of the D.C. component V the amplitude V and frequency w of the A.C. field component, and the phase relationship 26 of the ions with respect to the A.C. component at the time of their injection in the field.

It can now be appreciated that an adjustment of one or more of these parameters results in the desired grouping of a particular species of ion as the ions propagate through the mass spectrometer. The phase relationship between the ion pulse and the A.C. waveform will be fixed by the field parameters and thus is indicative of the m/e ratio of the grouped atoms. The grouped ions exit from the electric field and impinge upon Detector 19 resulting in a pulse output.

inspection of Equation (2) also shows that, irrespective of their mass-to-charge ratio, some ions will propagate through the spectrometer and will be detected. Some ions may be caused to assume a nonstable oscillatory motion with respect to the X and Y axes and therefore be lost to the mass spectrometer structure. The ungrouped ions which reach the detector create a random output on Detector 19 as they exit from the electric field. Because the field parameters are known, the mass-to-charge ratio of a particular ion can be directly correlated to the phase of the bunched ion pulse with respect to the A.C. component of the varying field. Accordingly, by measuring the phase relationship in any convenient manner, such as the use of an oscilloscope as described with respect to FIG. 1, the mass-to-charge ratio of the bunched ions can be identified, resulting in the explicit identification of the ion and hence the identification of the unknown gas.

It should be noted that, as is true with all existing mass spectrometers, it is first necessary to calibrate the spectrometer. The calibration is done such that a particular phase relationship between the pulse output and the A.C. component for a given set of field parameters is indicative of a particular mass-to-charge ratio.

The mass spectrometer structure illustrated in FIG. 1 is exemplary only, as other structures can also be used. The primary consideration used in selecting the particular structure is that the structure must be easily defined by three coordinate axes, one of which serves as the propagation axis for the accelerated ions while the other two are capable of defining an oscillatory motion for the ions. Accordingly, other structures such as the quadrupole structure shown in FIGS. 6 and 7 of application Ser. No. 65,574, filed Aug. 20, 1970, bu J. P. Carrico and P. F. McGinnes and assigned to the assignee of the instant application, can also be used. lt should also be appreciated that a change of structure does not affect the mathematical relationships presented with respect to the structure of FIG. 1. However, ion grouping may be realized by using the type of structure shown in FIGS. 6 and 7 of the above-identified application. Physical changes would affect the geometric factor R which depends upon the physical dimensions and also the constants afl, and 7 presented in the general Equation (1). These changes would result in a different set of values for the A.C. frequency and amplitude and D.C. magnitude in order for a particular massto-charge ratio specie of ions to group. However, this is nothing more than a calibration technique within the purview of one skilled in the art.

The primary advantage of the inventive mass spectrometer is now readily apparent. The ions are continuously injected into the electric field of the mass spectrometer and the ions having a particular mass-tocharge ratio are bunched together so that they result in a pulse output on Detector 19. Other species of ions are not bunched together, resulting in a random output on Detector 19. The pulses resulting from the bunched ions rise above the RMS level of the random output and are easily detected so that the phase relationship of the In the inventive system,'the ion specie is identified solely by the phaseof the output pulse with respect to the A.C. field parameters.

We claim: 1. A system for identifying charged particles comprismg:

an evacuable vessel having ular axes; means for creating a dynamic electric field within said vessel, said dynamic field constantly varying along at least one axis of said vessel so that the fields along the individual axes are individually defined and are individually dependent upon the varying parameters of said dynamic field, said dynamic field differently acting upon different species of charged particles in accordance with the mass-to-charge ratio of said charge particles so that at least one species of charged particles having particular mass-to-charge ratios is caused to tempothree mutually perpendicrally group together and other species of charged particles having other mass-to-charge ratios are randomly dispersed through said dynamic field; means for continuouslyinjecting charged particles -into said dynamic field; means for continuously detecting said temporally grouped charged particles at the time said charged particles are so temporally grouped;

and means responsive to the varying parameters of said dynamic field and the means detecting said charged particles for producing an output specifically identifying the temporally grouped charged particles having said at least one. particular massto-charge ratio. 1 7 I 2. The system'of claim 1 wherein said varying parameters are: an A.C. amplitude component, an A.C. frequency, and a DC. magnitude, and said particular specieof charged particles is grouped at a particular phase relationship with respect to said dynamic field so that said particular phase relationship uniquely identifies said at least one mass-to-charge ratio for a particular set of said varying parameters.

3. The system of claim 2 further including means for individually, or collectively inselected combinations, changing said varying parameters to cause said particular specie of charged particles to temporally group within said dynamic field so that the detection ofsaid grouped particles results in a pulse output, and charged particles having said other mass-to-charge ratios results in a random output, said pulse output rising above said random output enabling identification of said grouped charged particles in accordance with the phase relationship between said pulse output and said A.C. amplitude component.

4. The system of claim 3 wherein said axes are defined as X, Y, and Z axes and the axis of propagation of said charged particles is said Z axis; and said dynamic field is generally defined by the equation:

we 1co=fmwx B where:

X and Y are the axes along which said field varies t time f(t) the time variation of said A.C. and DC. components of said electric field afi constants obeying the relationship a B O 5. The system of claim 4 wherein the paths followed by charged particles along the said three axes are defined by:

the X axis path being: d x/de +'[(4e V /m w R) (4e V /m in R cos 26] X 0 the Y axis path being: d y/dc [4e V /m m R 42 V /m (0 R cos 26] Y 0 the Z axis path being: dZ/de 0 where:

2s wt 21rft wherefis the frequency-of oscillation i the axis of propagation of said charged particles is said Z axis; and said dynamic field is generally defined by the equation:

X and Y are the axes along which said field varies t time V said D.C. component V said A.C. amplitude component in 21rft wherein f' is said A.C. frequency 01,3 constants obeying the relationship a+B O.

7. The system of claim 6 wherein the paths followed by charged particles along thesaid three axes are defined by: i

the X axis path being:

2e] X 0 the Y axis path being: dy/de [(4e V /m in R 4e V /m w R cos 2e] Y 0 the Z axis path being:

dz/de 0 where:

2: not 21rft e/m mass-to-charge ratio R radius along X and Y axes 8. The system of claim 5 wherein said output pulses occur at a rate of one per cycle of said A.C. frequency; and further including means for determining the phase relationship of said output pulses with respect to said A.C. component to determine the mass-to-charge ratio of a particular specie of charged particle and accordingly explicitly identify said particular specie of charged particle. 9. A mass spectrometer comprising: evacuable container means retaining electric field structure means capable of supporting an electric field; means for introducing an unknown fluid to be analyzed into said container;

means for generating a varying electric field along said electric field structure, said electric field being inhomogeneous so that the electric field existing at one point along an axis of said field at a particular e/m mass-to-charge ratio R radius along X and Y axes 14. A method of analyzing an unknown gas by determining the mass-to-charge ratios of molecules compospoint in time is different from the field existing at ing the gas including the steps of:

all other points along said axis at said particular point in time;

means for producing ions from molecules of said unmeans for continuously injecting said ions into said electric field, said electric field differently operating on said ions in accordance with the mass-tocharge ratio of said ions and in accordance with the varying parameters of said electric field so that ions of one mass-to-charge ratio are temporally bunched within said field and ions of other mass-tocharge ratios are randomly spatially dispersed within said electric field;

means for detecting ions of all mass-to-charge ratios egressing from said electric field, said spatially dispersed ions causing a random output and said temporally bunched ions causing a pulse output which rises above said random output.

10. The spectrometer of claim 9 wherein the mass-tocharge ratio of said bunched ions is indicated by the phase relationship between said pulse output and said electric field;

and further including means for measuring said phase relationship.

11. The spectrometer of claim 10 wherein said electric field has an A.C. component and a DC. component, and different mass-to-charge ratios can be bunched by varying the amplitude of said A.C. component, the frequency of said A.C. component, the magnitude of said D.C. component, or any combination thereof so that all species of ions formed from said unknown fluid can be detected by the selectively varying said electric field and measuring the phase relationship of the output pulses with respect to the phase of said A.C. component.

12. The system of claim 11 wherein the electric potential distribution of said electric field with respect to orthogonal X, Y, and Z axes is defined by the relationship:

V(X, Y, =(V V cos wt) (01X 3Y where:

t time V said D.C. magnitude V said A.C. amplitude component (at 21rft (f= said A.C. component frequency) a and B constants obeying the relationship a B and wherein said Z axis is the propagation axis of said ions.

13. The system of claim 12 wherein the paths followed by charged particles along the said three axes are defined by:

the X axis path being:

the Y axis path being:

a' y/de [4e V /m m R 4e V /m m R cos 26] the Z axis path being:

dz/drs 0 where:

26 =wt 21rft forming ions from all species of molecules composing said gas; continuously injecting said ions into a dynamic electric field having variable parameters including a variable A.C. amplitude, a variable A.C. frequency, and a variable D.C. component; the variation of said parameters affecting the phase relationship of ions with respect to said A.C. amplitude;

selectively adjusting said variable parameters to cause one specie of ion to temporally group within said field and other species of ions to remain randomly dispersed within said field;

detecting said dispersed ions as a random output and said grouped ions as a pulse output rising above said random output;

and measuring the phase relationship between said pulse output and said A.C. amplitude.

15. The method of claim 14 further including the steps of:

readjusting at least one of said parameters to cause a different specie'of ion to temporally group and said one grouped specie to disperse;

and measuring the phase relationship between pulses caused by said different specie and said A.C. amplitude to identify said different specie.

16. The method of claim 15 wherein the steps of claim 15 are repeated for all species of ions formed from said unknown gas so that all gases composing said unknown gas are uniquely identified.

17. A mass spectrometer for analyzing an unknown gas by use of the mass-to-charge ratio of the molecules composing said unknown gas independently of a direct measurement of time-of-fiight comprising:

an evacuable chamber for receiving a sample of said unknown gas;

means for producing different species of ions from different species of said molecules;

means for producing an electric field, said electric field accelerating and decelerating ions in a manner dependent upon the mass-to-charge ratio of said ions and the value of variable parameters of said field; said parameters being the amplitude of an A.C. component of said field, the frequency of said A.C. component, and the magnitude of a DC. component of said field;

means for selectively independently adjusting at least one of said variable parameters to cause ions of a particular mass-to-charge specie to temporally group within said electric field and other species of ions to remain dispersed within said electric field so that said grouped ions cause a detectable output the phase of which with respect to said A.C. amplitude component is indicative of said particular mass-to-charge ratio to uniquely identify one specie of unknown molecules.

18. The system of claim 17 wherein the electric potential distribution of said electric field is defined with respect to orthogonal X, Y, and Z axes, and wherein 5 said Z axis is the propagation axis of said ions;

2e 1 Y O the Z axis path being: d z/de 0 where:

26 wt =21rft e/m mass-to-charge ratio R radius along X and Y axes V static component of the dynamic electric field V alternating component amplitude of the dynamic electric field x distance along X axis y distance along Y axis

Claims

1. A system for identifying charged particles comprising: an evacuable vessel having three mutually perpendicular axes; means for creating a dynamic electric field within said vessel, said dynamic field constantly varying along at least one axis of said vessel so that the fields along the individual axes are individually defined and are individually dependent upon the varying parameters of said dynamic field, said dynamic field differently acting upon different species of charged particles in accordance with the mass-to-charge ratio of said charge particles so that at least one species of charged particles having particular mass-to-charge ratios is caused to temporally group together and other species of charged particles having other mass-to-charge ratios are randomly dispersed through said dynamic field; means for continuously injecting charged particles into said dynamic field; means for continuously detecting said temporally grouped charged particles at the time said charged particles are so temporally grouped; and means responsive to the varyinG parameters of said dynamic field and the means detecting said charged particles for producing an output specifically identifying the temporally grouped charged particles having said at least one particular mass-to-charge ratio.

2. The system of claim 1 wherein said varying parameters are: an A.C. amplitude component, an A.C. frequency, and a D.C. magnitude, and said particular specie of charged particles is grouped at a particular phase relationship with respect to said dynamic field so that said particular phase relationship uniquely identifies said at least one mass-to-charge ratio for a particular set of said varying parameters.

3. The system of claim 2 further including means for individually, or collectively in selected combinations, changing said varying parameters to cause said particular specie of charged particles to temporally group within said dynamic field so that the detection of said grouped particles results in a pulse output, and charged particles having said other mass-to-charge ratios results in a random output, said pulse output rising above said random output enabling identification of said grouped charged particles in accordance with the phase relationship between said pulse output and said A.C. amplitude component.

4. The system of claim 3 wherein said axes are defined as X, Y, and Z axes and the axis of propagation of said charged particles is said Z axis; and said dynamic field is generally defined by the equation: V(X, Y, t) f(t)( Alpha X2 + Beta Y2) where: X and Y are the axes along which said field varies t time f(t) the time variation of said A.C. and D.C. components of said electric field Alpha , Beta constants obeying the relationship Alpha + Beta 0

5. The system of claim 4 wherein the paths followed by charged particles along the said three axes are defined by: the X axis path being: d2x/d2 + ((4e Vdc/m omega 2 R2) + (4e Vac/m omega 2 R2) cos 2 epsilon ) X 0 the Y axis path being: d2y/d epsilon 2 + ( 4e Vdc/m omega 2 R2 + 4e Vac/m omega 2R2 cos 2 epsilon ) Y 0 the Z axis path being: d2Z/d epsilon 2 0 where: 2 epsilon omega t 2 pi ft where f is the frequency of oscillation and t is the time e/m mass-to-charge ratio of charged particle R radius along X and Y axes Vdc static component of the dynamic electric field Vac alternating component amplitude of the dynamic electric field x distance along X axis y distance along Y axis

6. The system of claim 1 wherein said at least one axis is three orthogonal axes defined as X, Y, and Z axes and the axis of propagation of said charged particles is said Z axis; and said dynamic field is generally defined by the equation: V(X,Y,t) (Vdc + Vac cos omega t) ( Alpha X2 + Beta Y2) where: X and Y are the axes along which said field varies t time Vdc said D.C. component Vac said A.C. amplitude component omega 2 pi ft wherein ''''f'''' is said A.C. frequency Alpha , Beta constants obeying the relationship Alpha + Beta 0.

7. The system of claim 6 wherein the paths followed by charged particles along the said three axes are defined by: the X axis path being: d2x/d epsilon 2 + ((4e Vdc/m omega 2 R2) + (4e Vac/m omega 2 R2) cos 2 epsilon ) X 0 the Y axis path being: d2y/d epsilon 2 + ((4e Vdc/m omega 2 R2) + 4e Vac/m omega 2 R2 cos 2 epsilon ) Y 0 the Z axis path being: d2z/d epsilon 2 0 where: 2 epsilon omega t 2 pi ft e/m mass-to-charge ratio R radius along X and Y axes

8. The system of claim 5 wherein said output pulses occur at a rate of one per cycle of said A.C. frequency; and further including means for determining the phase relationship of said output pulses with respect to said A.C. component to determine the mass-to-charge ratio of a particular specie of charged particle and accordingly explicitly identify said particular specie of charged particle.

9. A mass spectrometer comprising: evacuable container means retaining electric field structure means capable of supporting an electric field; means for introducing an unknown fluid to be analyzed into said container; means for generating a varying electric field along said electric field structure, said electric field being inhomogeneous so that the electric field existing at one point along an axis of said field at a particular point in time is different from the field existing at all other points along said axis at said particular point in time; means for producing ions from molecules of said unknown fluid; means for continuously injecting said ions into said electric field, said electric field differently operating on said ions in accordance with the mass-to-charge ratio of said ions and in accordance with the varying parameters of said electric field so that ions of one mass-to-charge ratio are temporally bunched within said field and ions of other mass-to-charge ratios are randomly spatially dispersed within said electric field; means for detecting ions of all mass-to-charge ratios egressing from said electric field, said spatially dispersed ions causing a random output and said temporally bunched ions causing a pulse output which rises above said random output.

10. The spectrometer of claim 9 wherein the mass-to-charge ratio of said bunched ions is indicated by the phase relationship between said pulse output and said electric field; and further including means for measuring said phase relationship.

11. The spectrometer of claim 10 wherein said electric field has an A.C. component and a D.C. component, and different mass-to-charge ratios can be bunched by varying the amplitude of said A.C. component, the frequency of said A.C. component, the magnitude of said D.C. component, or any combination thereof so that all species of ions formed from said unknown fluid can be detected by selectively varying said electric field and measuring the phase relationship of the output pulses with respect to the phase of said A.C. component.

12. The system of claim 11 wherein the electric potential distribution of said electric field with respect to orthogonal X, Y, and Z axes is defined by the relationship: V(X, Y, t) (Vdc + Vac cos omega t) ( Alpha X2 + Beta Y2) where: t time Vdc said D.C. magnitude Vac said A.C. amplitude component omega t 2 pi ft (f said A.C. component frequency) Alpha and Beta constants obeying the relationship Alpha + Beta 0 and wherein said Z axis is the propagation axis of said ions.

13. The system of claim 12 wherein the paths followed by charged particles along the said three axes are defined by: the X axis path being: d2x/d2 + ( (4e Vdc/m omega 2 R2) + (4e Vac/m omega 2 R2) cos 2 epsilon ) X 0 the Y axis path being: d2y/d epsilon 2 + (4e Vdc/m omega 2 R2 + 4e Vac/m omega 2 R2 cos 2 epsilon ) Y 0 the Z axis path being: d2z/d epsilon 2 0 where: 2 epsilon omega t 2 pi ft e/m mass-to-charge ratio R radius along X and Y axes

14. A method of analyzing an unknown gas by determining the mass-to-charge ratios of molecules composing the gas including the steps of: forming ions from all species of molecules composing said gas; continuously injecting said ions into a dynamic electric field having variable parameters including a variable A.C. amplitude, a variable A.C. frequency, and a variable D.C. component; the variation of said parameters affecting the phase relationship of ions with respect to said A.C. amplitude; selectively adjusting said variable parameters to cause one specie of ion to temporally group within said field and other species of ions to remain randomly dispersed within said field; detecting said dispersed ions as a random output and said grouped ions as a pulse output rising above said random output; and measuring the phase relationship between said pulse output and said A.C. amplitude.

15. The method of claim 14 further including the steps of: readjusting at least one of said parameters to cause a different specie of ion to temporally group and said one grouped specie to disperse; and measuring the phase relationship between pulses caused by said different specie and said A.C. amplitude to identify said different specie.

17. A mass spectrometer for analyzing an unknown gas by use of the mass-to-charge ratio of the molecules composing said unknown gas independently of a direct measurement of time-of-flight comprising: an evacuable chamber for receiving a sample of said unknown gas; means for producing different species of ions from different species of said molecules; means for producing an electric field, said electric field accelerating and decelerating ions in a manner dependent upon the mass-to-charge ratio of said ions and the value of variable parameters of said field; said parameters being the amplitude of an A.C. component of said field, the frequency of said A.C. component, and the magnitude of a D.C. component of said field; means for selectively independently adjusting at least one of said variable parameters to cause ions of a particular mass-to-charge specie to temporally group within said electric field and other species of ions to remain dispersed within said electric field so that said grouped ions cause a detectable output the phase of which with respect to said A.C. amplitude component is indicative of said particular mass-to-charge ratio to uniquely identify one specie of unknown molecules.

18. The system of claim 17 wherein the electric potential distribution of said electric field is defined with respect to orthogonal X, Y, and Z axes, and wherein said Z axis is the propagation axis of said ions; said electric field being defined by the relationship: V(X, Y, t) (Vdc + Vac cos omega t) ( Alpha X2 + Beta Y2) where: t time Vdc said D.C. magnitude Vac said A.C. amplitude component omega t 2 pi ft (f said A.C. Component frequency) Alpha and Beta constants obeying the relationship Alpha + Beta 0

19. The spectrometer of claim 18 wherein the paths followed by charged particles along the said three axes are defined as: the X axis path being: d2x/d epsilon 2 + ( (4e Vdc/m omega 2 R2) + (4e Vac/m omega 2 R2) cos 2 epsilon ) X 0 the Y axis path being d2Y/d epsilon 2 + ( (4e Vdc/m omega 2 R2) + (4e Vac/m omega 2 R2) cos 2 epsilon ) Y 0 the Z axis path being: d2z/d epsilon 2 0 where: 2 epsilon omega t 2 pi ft e/m mass-to-charge ratio R radius along X and Y axes Vdc static component of the dynamic electric field Vac alternating component amplitude of the dynamic electric field x distance along X axis y distance along Y axis