Plasma generator using dielectric resonator

• US 9,706,635 B2
• Filed: 10/06/2016
• Issued: 07/11/2017
• Est. Priority Date: 03/13/2013
• Status: Active Grant

• Current Assignee: Radom Corporation
• Original Assignee: Radom Corporation
• Inventors: Menon, Ashok, Jevtic, Jovan, Pikelja, Velibor
• Primary Examiner(s): Vanore, David A
• Application Number:
  US15/287,236
• Publication Number:
  US 20170027051A1
• Time in Patent Office: 278 Days
• Field of Search: 250288, 250215, 250423 R, 250424, 21912148, 21912152, 21912144, 31511121, 31511181, 315 39, 324318, 324633
• CPC Class Codes: G01N 21/718 Laser microanalysis, i.e. with formation of sample plasma
• CPC Class Codes: G01N 22/00 Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more G01N3/00 - G01N17/00, G01N24/00 take precedence
• CPC Class Codes: G21B 1/057 Tokamaks
• CPC Class Codes: H01J 2237/002 Cooling arrangements of objects being observed or treated H01J2237/2001
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma
• CPC Class Codes: H01J 37/3244 Gas supply means
• CPC Class Codes: H01J 37/32467 Material
• CPC Class Codes: H01J 49/10 Ion sources; Ion guns
• CPC Class Codes: H01J 49/105 using high-frequency excitation, e.g. microwave excitation, Inductively Coupled Plasma [ICP]
• CPC Class Codes: H01S 3/0975 using inductive or capacitive excitation
• CPC Class Codes: H05H 1/30 using applied electromagnetic fields, e.g. high frequency or microwave energy H05H1/28 takes precedence
• CPC Class Codes: H05H 1/46 using applied electromagnetic fields, e.g. high frequency or microwave energy H05H1/26 takes precedence
• CPC Class Codes: H05H 1/4652 using inductive coupling means, e.g. coils
• CPC Class Codes: H05H 2242/24 Radiofrequency or microwave generators
• CPC Class Codes: Y02E 30/10 Nuclear fusion reactors

Abstract

A dielectric resonator is excited at its natural resonant frequency to produce a highly uniform electric field for the generation of plasma. The plasma may be used in a optical or mass spectrometer.

Claims

1. A plasma generator comprising:

a volume receiving a gas;

a magnetic field generator adjacent to the volume and including;

(i) a dielectric element;

(ii) a power source driving current in the dielectric element to generate magnetic field lines along an axis through the volume inducing a plasma in the gas primarily by inductive coupling.

2. The plasma generator of claim 1 wherein the gas is nitrogen.

3. The plasma generator of claim 1 wherein the dielectric is a ring.

4. The plasma generator of claim 3 wherein a cross-section taken from a center of the ring in one direction along a radius through the ring is nonrectangular.

5. The plasma generator of claim 4 further including a gas port introducing gas into the ring to flow along the axis.

6. The plasma generator of claim 5 wherein the axis passes through the dielectric element and plasma is sustained along the axis at locations outside of the dielectric element.

7. The plasma generator of claim 1 wherein the power source provides electrical power at a natural resonant frequency of the dielectric resonator structure.

8. The plasma generator of claim 1 wherein the power source is a magnetron.

9. The plasma generator of claim 1 wherein the power source output power in a range from 20 to 1000 megahertz.

10. The plasma generator of claim 1 wherein the dielectric resonator has a quality factor of greater than 100 and a electrical resistivity greater than 1×

10¹⁰Ω

·

cm.

11. The plasma generator of any claim 1 incorporated into a structure selected from the group consisting of an optical laser, a plasma torch, a rocket engine, an electron-cyclotron plasma or ion source, an inductively coupled plasma source for semiconductor processing, and an ion cyclotron plasma heater.

12. A method of generating plasma using a plasma generator including a volume receiving a gas;

and a magnetic field generator adjacent to the volume and including;

(i) a dielectric element;

(ii) a power source driving current in the dielectric element to generate magnetic field lines along an axis through the volume inducing a plasma in the gas primarily by inductive coupling, the method comprising the steps of;

(a) introducing a gas into the volume; and

(b) driving current in the dielectric element to generate magnetic field lines to produce a plasma in the gas primarily by inductive coupling.