Voltage-tunable 1D electro-magnet potential and probe system with parallel dipole line trap

Patent metadata

Field	Value
Publication number	US-10082408-B2
Application number	US-201615131443-A
Country	US
Kind code	B2
Filing date	Apr 18, 2016
Priority date	Apr 18, 2016
Publication date	Sep 25, 2018
Grant date	Sep 25, 2018

Abstract

Techniques for manipulating objects and for determining the position of the objects in parallel dipole line (PDL) trap systems are provided. In one aspect, a PDL trap is provided. The PDL trap includes: a pair of dipole line magnets connected to a potential, wherein the pair of dipole line magnets includes magnets having magnetizations perpendicular to long axes of the magnets; a diamagnetic rod levitating above the pair of dipole line magnets; and at least one electrode above the pair of dipole line magnets, adjacent to the diamagnetic rod. The system produces a hybrid one-dimensional electromagnetic potential which is tunable by voltage. Techniques for operating the PDL trap to manipulate the diamagnetic rod and to detect a position of the diamagnetic rod in the PDL trap are also provided.

First claim

What is claimed is:

1. A parallel dipole line (PDL) trap comprising:
a pair of dipole line magnets connected to a potential, wherein the pair of dipole line magnets comprises magnets having magnetizations perpendicular to long axes of the magnets;
a diamagnetic rod levitating above the pair of dipole line magnets; and
at least one electrode above the pair of dipole line magnets, adjacent to the diamagnetic rod.

2. The PDL trap of claim 1 , wherein the electrode is present above the diamagnetic rod, and wherein the diamagnetic rod can pass between the electrode and the pair of dipole line magnets.

3. The PDL trap of claim 1 , wherein the electrode is present both above and below the diamagnetic rod.

4. The PDL trap of claim 1 , wherein the electrode is a cylinder.

5. The PDL trap of claim 1 , wherein the diamagnetic rod comprises a graphite rod.

6. The PDL trap of claim 1 , wherein the electrode is positioned off-center, to one side of the PDL trap.

7. The PDL trap of claim 1 , further comprising:
a voltage source connected to the electrode and to the pair of dipole line magnets.

8. The PDL trap of claim 1 , further comprising:
a capacitance meter connected to the electrode and to the pair of dipole line magnets.

9. The PDL trap of claim 1 , comprising multiple electrodes positioned above the pair of dipole line magnets.

10. The PDL trap of claim 9 , further comprising:
a first electrode and a second electrode positioned above the pair of dipole line magnets, wherein the first electrode and the second electrode are positioned over opposite ends of the PDL trap.

11. The PDL trap of claim 10 , further comprising:
a first voltage source connected to the first electrode and to the pair of dipole line magnets; and
a second voltage source connected to the second electrode and to the pair of dipole line magnets.

12. The PDL trap of claim 10 , further comprising:
resistors that form a double resistor-capacitor bridge with the first electrode and the second electrode.

13. The PDL trap of claim 9 , wherein the electrode comprises at least one cylindrical case electrode having two semi-circular halves which are in a non-contact position relative to one another, and which partially surround the diamagnetic rod.

14. The PDL trap of claim 9 , comprising more than two electrodes positioned above the pair of dipole line magnets.

15. The PDL trap of claim 14 , further comprising:
a multiplexer unit connected to the electrodes, wherein the multiplexer unit has two output channels connected to a double resistor-capacitor bridge.

16. A method of operating a PDL trap, comprising:
providing the PDL trap having a pair of dipole line magnets comprising magnets having magnetizations perpendicular to long axes of the magnets, a diamagnetic rod levitating above the pair of dipole line magnets, and at least one electrode above the pair of dipole line magnets, adjacent to the diamagnetic rod; and
applying a bias voltage to the pair of dipole line magnets and the electrode to change an electric potential of the PDL trap and control a position of the diamagnetic rod in the PDL trap.

17. The method of claim 16 , further comprising:
varying the bias voltage applied to the electrode to tune a one-dimensional potential along the PDL trap, wherein the one-dimensional potential comprises a magnetic camelback potential term and an electric potential term, and wherein the electric potential term is tunable by the bias voltage applied to the electrode and thus by way of the varying the bias voltage applied to the electrode the position of the diamagnetic rod in the PDL trap can be varied.

18. The method of claim 16 , wherein the PDL trap has a first electrode and a second electrode positioned above the pair of dipole line magnets, wherein the first electrode and the second electrode are positioned over opposite ends of the PDL trap, the method further comprising:
applying a first bias voltage to the pair of dipole line magnets and the first electrode to draw the diamagnetic rod towards the first electrode; and
applying a second voltage to the pair of dipole line magnets and the second electrode to draw the diamagnetic rod towards the second electrode.

19. A method of operating a PDL trap, comprising:
providing the PDL trap having a pair of dipole line magnets comprising magnets having magnetizations perpendicular to long axes of the magnets, and at least one electrode above the pair of dipole line magnets;
connecting a capacitance meter to the electrode and to the pair of dipole line magnets;
measuring capacitance of the PDL trap using the capacitance meter to determine a base capacitance C 0 ;
inserting a diamagnetic rod into the PDL trap, such that the diamagnetic rod levitates above the pair of dipole line magnets;
measuring the capacitance of the PDL trap using the capacitance meter with the diamagnetic rod fully underneath the electrode: ΔC;
measuring the capacitance of the PDL trap using the capacitance meter for any position z of the diamagnetic rod in the PDL trap: C(z); and
determining the position z of the diamagnetic rod in the PDL trap using C 0 , ΔC and C(z).

20. The method of claim 19 , wherein the PDL trap comprises multiple electrodes positioned above the pair of dipole line magnets, the method further comprising the step of:
connecting a resistor-capacitor (RC) bridge to the electrodes; and
measuring an output voltage from the RC bridge to determine the position z of the diamagnetic rod in the PDL trap, wherein the output voltage from the RC bridge is related to a differential change in capacitance of the electrodes under which the diamagnetic rod is located and thus the output voltage from the RC bridge depends on the position z of the diamagnetic rod in the PDL trap.

Assignees

• IBM

Inventors

• Gunawan Oki

Classifications

• G01D5/24 Primary

  by varying capacitance · CPC title

• G01D5/2403 Primary

  by moving plates, not forming part of the capacitor itself, e.g. shields · CPC title

• H01F7/0236

  Magnetic suspension or levitation (for vehicles B60L13/04; magnetic bearings F16C39/063) · CPC title

• G01R33/24

  for measuring direction or magnitude of magnetic fields or magnetic flux · CPC title

• H02N15/00

  Holding or levitation devices using magnetic attraction or repulsion, not otherwise provided for (electric or magnetic devices for holding work on machine tools B23Q3/15 {; monorail vehicle propulsion or suspension B60L13/00}; sliding or levitation devices for railway systems B61B13/08; material handling devices associated with conveyors incorporating devices with electrostatic or magnetic grippers B65G47/92; separating thin or filamentary articles from piles using magnetic force B65H3/16; delivering thin or filamentary articles from magnetic holders by air blast or suction B65H29/24; bearings using magnetic or electric supporting means F16C32/04; relieving bearing loads using magnetic means F16C39/06; magnets H01F7/00; dynamo-electric clutches or brakes H02K49/00 {; electric furnaces with simultaneous levitation and heating H05B6/32}) · CPC title