US3812355A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and methods for measuring ion mass as a function of mobility
Assignee: PCP Inc A CORP OF FLORIDA
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Filing: 1971-12-09
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Granted: 1974-05-21
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Expires: 1991-12-09
Abstract
Abstract Ion mass is determined directly as a function of the drift time in a chamber containing gas at atmospheric pressure. The drift time is a function of approximately the cube root of the ion mass for ion mass greater than the mass of the drift gas and a function of approximately the square root of the ion mass for ion mass less than the mass of the drift gas. A measure of the ion mass may be obtained by recording the ion-current output of the drift tube with the time base adjusted to an exponential function of the drift time. Corrections may be made automatically for variations in temperature, pressure and drift field.
Inventors
- 👤 R Wernlund
- 👤 M Cohen
- 👤 D Carroll
- 👤 W Kilpatrick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:22
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/62; G01N27/622; G01N27/623
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
87 words
In a method wherein ions are caused to drift through a drift space containing a drift gas of known mass and at a pressure sufficient to ensure that the length of the mean free path of said ions in said space is substantially less than the dimensions of said space, the improvement for producing a measure of ion mass which comprises producing an output which varies approximately as a cube function of the drift time for ion masses greater than the atomic mass of the drift gas.
Claim 2
Dependent Claim
87 words
In a method wherein ions are caused to drift through a drift space containing a drift gas of known mass and at a pressure sufficient to ensure that the length of the mean free path of said ions in said space is substantially less than the dimensions of said space, the improvement for producing a measure of ion mass which comprises producing an output which varies approximately as a cube function of the drift time for ion masses greater than the atomic mass of the drift gas.
Claim 3
Dependent Claim
32 words
A method in accordance with claim 1, wherein said output is produced approximately as a square function of the drift time for ion masses less than the mass of the drift gas.
Claim 4
Dependent Claim
45 words
A method in accordance with claim 1, wherein the ions are produced by ion-molecule reactions in a reaction space maintained at a pressure such that the length of the mean free path of the ions is substantially less than the dimensions of the reaction space.
Claim 5
Dependent Claim
25 words
A method in accordance with claim 1, wherein the pressure is such that the ions reach substantially constant statistical drift velocity in the drift space.
Claim 6
Dependent Claim
26 words
A method in accordance with claim 1, wherein the ions are caused to drift in said space by the application of an electric drift field thereto.
Claim 7
Dependent Claim
30 words
A method in accordance with claim 5, wherein the producing of said output comprises producing an ion current at a time delayed with respect to the commencement of ion drift.
Claim 8
Dependent Claim
35 words
A method in accordance with claim 6, wherein the producing of said output comprises making a recording of said ion current along a time base which varies as an exponential function of the drift time.
Claim 9
Dependent Claim
32 words
A method in accordance with claim 7, wherein the time base varies as a function of the temperature and pressure of the gas in said space and the potential across said space.
Claim 10
Dependent Claim
33 words
A method in accordance with claim 6, wherein said ions are segregated in accordance with their mobility in the drift space and the ion current is produced in response to the segregated ions.
Claim 11
Dependent Claim
35 words
A method in accordance with claim 8, wherein the segregating of the ions comprises gating a group of ions into the drift space and later gating a portion of the group to an ion collector.
Claim 12
Dependent Claim
110 words
In apparatus including a drift chamber, means including a pair of spaced electrodes for producing a drift field in said chamber, means providing a drift in said chamber at a pressure such that the length of the mean free path of ions in said chamber is substantially less than the dimensions of the drift space between said electrodes, means for providing ions adjacent to one of said electrodes, means for producing an ion current in response to ions adjacent to the other electrode, the improvement which comprises means for producing an output measure of ion mass in response to said ion current as an exponential function of the drift time.
Claim 13
Dependent Claim
110 words
In apparatus including a drift chamber, means including a pair of spaced electrodes for producing a drift field in said chamber, means providing a drift in said chamber at a pressure such that the length of the mean free path of ions in said chamber is substantially less than the dimensions of the drift space between said electrodes, means for providing ions adjacent to one of said electrodes, means for producing an ion current in response to ions adjacent to the other electrode, the improvement which comprises means for producing an output measure of ion mass in response to said ion current as an exponential function of the drift time.
Claim 14
Dependent Claim
29 words
Apparatus in accordance with claim 11, said function being initially approximately a square function of the drift time and then being approximately a cube function of the drift time.
Claim 15
Dependent Claim
17 words
Apparatus in accordance with claim 11, said function being approximately a cube function of the drift time.
Claim 16
Dependent Claim
24 words
Apparatus in accordance with claim 11, said output producing means comprising a recorder having a time base which varies in accordance with said function.
Claim 17
Dependent Claim
26 words
Apparatus in accordance with claim 11, wherein said function includes factors corresponding to the temperature and pressure of said gas and the strength of said field.
Claim 18
Dependent Claim
16 words
Apparatus in accordance with claim 11, said output producing means comprising means for generating a potential.
Claim 19
Dependent Claim
28 words
Apparatus in accordance with claim 16, wherein said potential generating means comprises means for producing a ramp voltage and an exponential function generator controlled by said ramp voltage.
Claim 20
Dependent Claim
15 words
Apparatus in accordance with claim 17, wherein said function generator is a diode-type function generator.
Claim 21
Dependent Claim
25 words
Apparatus in accordance with claim 17, wherein said drift chamber has means for initiating a drift period synchronously with the commencement of said ramp voltage.
Claim 22
Dependent Claim
62 words
Apparatus in accordance with claim 17, further comprising means for producing a voltage proportional to the drift field, means for producing a voltage proportional to the absolute temperature of said gas, means for producing a voltage inversely proportional to the absolute pressure of said gas, and means for obtaining the product of said voltages and controlling the function generator in response thereto.
Claim 23
Dependent Claim
54 words
Apparatus in accordance with claim 17, said output producing means comprising a recorder having orthogonal coordinate axes, one of which is a time base axis, means for controlling the time base in accordance with the output of said function generator, and means responsive to the ion current for controlling recording along the remaining axis.
Claim 24
Dependent Claim
29 words
Apparatus in accordance with claim 11, wherein said ion providing means comprises means including an ion source adjacent to said one electrode for providing product ions by ion-molecule reactions.
Claim 25
Dependent Claim
69 words
Apparatus in accordance with claim 11, wherein said chamber has a pair Of ion gates spaced apart between said electrodes and means for opening and gates sequentially, whereby ions produced adjacent to said one electrode are admitted to the space between said gates and become segregated in accordance with their mobility and whereby a portion of the segregated ions is passed by the second gate to the other electrode.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-20 | 1977-11-19 | 1978-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-20 | 1981-11-19 | 1982-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-20 | 1985-11-19 | 1986-05-21 | $7700.00 | Window Closed / Lapsed |