Active stabilization of ion trap radiofrequency potentials

Patent metadata

Field	Value
Publication number	US-9991105-B2
Application number	US-201615389982-A
Country	US
Kind code	B2
Filing date	Dec 23, 2016
Priority date	Dec 23, 2015
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

Disclosed are improved methods and structures for actively stabilizing the oscillation frequency of a trapped ion by noninvasively sampling and rectifying the high voltage RF potential at circuit locations between a step-up transformer and a vacuum feedthrough leading to the ion trap electrodes. We use this sampled/rectified signal in a feedback loop to regulate the RF input amplitude to the circuit. By employing techniques and structures according to the present disclosure we are advantageously able to stabilize a 1 MHz trapped ion oscillation frequency to <10 Hz after 200 s of integration, representing a 34 dB reduction in the level of trap frequency noise and drift, over a locking bandwidth of up to 30 kHz.

First claim

The invention claimed is:

1. A method for actively stabilizing ion trap radiofrequency (RF) potentials comprising:
noninvasively sampling a high voltage potential at a position in a circuit between a step-up transformer and a vacuum feedthrough for electrodes of the ion trap;
rectifying the sampled high voltage potential signal;
applying the rectified signal to a frequency mixer that controls an RF oscillator amplitude;
generating an error signal by comparing the rectified signal to a stable set-point voltage reference;
amplifying the error signal and then applying the error signal to the frequency mixer; and
applying the rectified signal to a feedback loop of the circuit such that an amplitude of an RF input to the circuit is desirably regulated and the ion trap RF potentials are actively stabilized;
wherein the rectification is performed through the effect of a temperature compensating rectifier including two matched diodes configured for passive temperature compensation in conjunction with a low-pass filter configured such that a ripple amplitude of at least 10dB below diode input signal amplitude is produced.

2. The method according to claim 1 further comprising stabilizing a ratio of voltage to frequency (V 0 /Ω) through the effect of a digital counter and divider circuit.

3. The method according to claim 2 wherein the ion trap is a component of a system selected from the group consisting of: quantum information processor, ion trap mass spectrometer, and multipole mass spectrometer.

4. The method according to claim 3 wherein the ion trap exhibits a geometry selected from the group consisting of: quadrupole trap, linear trap, surface ion trap, hexapole trap, and higher-order trap.

5. The method according to claim 4 wherein the sampling and providing are effected under the control of a digital computer.

6. A system for actively stabilizing ion trap radiofrequency (RF) potentials comprising:
means for noninvasively sampling a high voltage potential at a position in a circuit between a step-up transformer and a vacuum feedthrough for electrodes of the ion trap;
means for rectifying the sampled high voltage potential signal;
means for applying the rectified signal to a feedback loop of the circuit such that an amplitude of an RF input to the circuit is desirably regulated. and the ion trap RF potentials are actively stabilized;
means for applying the rectified signal to a frequency mixer that controls an RF oscillator amplitude;
means for generating an error signal by comparing the rectified signal to a stable set-point voltage reference; and
means for amplifying the error signal and then applying the error signal to the frequency mixer;
wherein the rectifying means further includes temperature compensating means including two matched diodes configured for passive temperature compensation in conjunction with a low-pass filter configured such that a ripple amplitude of at least 10dB below diode input signal amplitude is produced.

7. The system according to claim 6 further comprising a voltage to frequency (V 0 /Ω) stabilizing means.

Assignees

• Univ Maryland

Inventors

• Monroe Christopher
• Johnson Kale
• Wong-Campos Jaime David

Classifications

• H01J49/022 Primary

  Circuit arrangements, e.g. for generating deviation currents or voltages (regulating electric or magnetic variables in general, e.g. current, magnetic field G05F); Components associated with high voltage supply (high voltage supply per se H02M) · CPC title

• H01J49/422

  Two-dimensional RF ion traps (ion guides without mass selection H01J49/062) · CPC title

• H01J49/0027 Primary

  Methods for using particle spectrometers · CPC title