End cap voltage control of ion traps
First Claim
1. An ion trap comprising:
- a conductive ring-shaped central electrode having a first aperture extending from a first open end to a second open end;
a signal source generating a trap signal having at least an alternating current (AC) component between a first and second terminal, wherein the first terminal is coupled to the central electrode and the second terminal is coupled to a source reference voltage potential;
a conductive first electrode end cap disposed adjacent to the first open end of the central electrode and coupled to a first reference voltage potential, wherein a first intrinsic capacitance is formed between a surface of the first electrode end cap and a surface of the first open end of the central electrode; and
a conductive second electrode end cap disposed adjacent to the second open end of the central electrode and coupled to a second reference voltage potential with a first electrical circuit means for impressing a fractional part of the trap signal on the conductive second electrode end cap,wherein a second intrinsic capacitance is formed between a surface of the second electrode end cap and a surface of the second open end of the central electrode, andwherein the fractional part of the trap signal is impressed on the second electrode end cap as an excitation voltage in response to a voltage division of the trap signal by the second intrinsic capacitance and an impedance of the first electrical circuit means.
2 Assignments
0 Petitions
Accused Products
Abstract
An ion trap for a mass spectrometer has a conductive central electrode with an aperture extending from a first open end to a second open end. A conductive first electrode end cap is disposed proximate to the first open end thereby forming a first intrinsic capacitance between the first end cap and the central electrode. A conductive second electrode end cap is disposed proximate to the second open end thereby forming a second intrinsic capacitance between the second end cap and the central electrode. A first circuit couples the second end cap to a reference potential. A signal source generating an AC trap signal is coupled to the central electrode. An excitation signal is impressed on the second end cap in response to a voltage division of the trap signal by the first intrinsic capacitance and the first circuit.
418 Citations
25 Claims
-
1. An ion trap comprising:
-
a conductive ring-shaped central electrode having a first aperture extending from a first open end to a second open end; a signal source generating a trap signal having at least an alternating current (AC) component between a first and second terminal, wherein the first terminal is coupled to the central electrode and the second terminal is coupled to a source reference voltage potential; a conductive first electrode end cap disposed adjacent to the first open end of the central electrode and coupled to a first reference voltage potential, wherein a first intrinsic capacitance is formed between a surface of the first electrode end cap and a surface of the first open end of the central electrode; and a conductive second electrode end cap disposed adjacent to the second open end of the central electrode and coupled to a second reference voltage potential with a first electrical circuit means for impressing a fractional part of the trap signal on the conductive second electrode end cap, wherein a second intrinsic capacitance is formed between a surface of the second electrode end cap and a surface of the second open end of the central electrode, and wherein the fractional part of the trap signal is impressed on the second electrode end cap as an excitation voltage in response to a voltage division of the trap signal by the second intrinsic capacitance and an impedance of the first electrical circuit means. - View Dependent Claims (2, 3, 4, 5, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
-
-
6. An ion trap comprising:
-
a central electrode having an aperture; a first end cap electrode having an aperture; a second end cap electrode having an aperture; an electronic signal source that generates a trap signal applied to the central electrode; a passive circuit means for impressing a fractional part of the trap signal on the first end cap electrode; an electrical connection between said first end cap electrode and said passive circuit means; and an electrical connection between said passive circuit means and a voltage potential, wherein said first end cap electrode, connected to said voltage potential via said passive circuit means, bears an excitation voltage due to capacitive coupling between said electronic signal source and said passive circuit means. - View Dependent Claims (7, 18, 19, 20, 21, 22, 23, 24, 25)
-
Specification