# US 9,883,576 B2 · Low-power, compact piezoelectric particle emission

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- Number: US 9,883,576 B2
- Document ID: US9883576B2
- Status: Granted
- Kind: B2
- Application number: 14/898,438
- Filed: 2014-06-13
- Published: 2016-04-28
- Granted: 2018-01-30
- Earliest claimed: 2013-06-14
- Assignees: The Curators of the University of Missouri
- Applicants: The Curators of the University of Missouri
- Inventors: Scott D. Kovaleski; Brady B. Gall; Andrew L. Benwell; Peter Norgard; James Vangordon
- Web page: https://patentgrep.com/patent/US9883576B2

## CPC

- H05H 3/06: Generating neutron beams (targets for producing nuclear reactions H05H6/00; neutron sources G21G4/02)
- H01J 35/065: {Field emission, photo emission or secondary emission cathodes}
- H01J 35/14: Arrangements for concentrating, focusing, or directing the cathode ray
- H05G 1/10: Power supply arrangements for feeding the X-ray tube {(supply circuits with converters in general H02M; supply circuits for emitters and amplifiers H04B1/16 - H04B1/1623)}
- H01J 2235/02: Electrical arrangements
- H05G 1/06: X-ray tube and at least part of the power supply apparatus being mounted within the same housing
- H05H 1/2481: {the plasma being activated using piezoelectric actuators}
- H05H: PLASMA TECHNIQUE (apparatus or processes specially adapted for producing X-rays H05G2/00); PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)
- H05G: X-RAY TECHNIQUE (investigating or analysing materials by the use of X-rays G01N23/00; apparatus for X-ray photography G03B42/02; X-ray tubes H01J35/00; TV systems having X-ray input H04N5/321)

## Abstract

A low-power, compact piezoelectric particle emitter for emitting particles such as X-rays and neutrons. A piezoelectric transformer crystal receives an input voltage at an input end and generates a higher output voltage at an output electrode disposed at an output end. The emitter is in a vacuum and the output voltage creates an electric field. A charged particle source is positioned relative a target such that charged particles from the charged particle source are accelerated by the electric field toward the target. Interaction between the accelerated charged particles and the target causes one of X-rays and neutrons to be emitted.

## Claims

### Claim 1

A low-power, compact piezoelectric neutron generator comprising:
a piezoelectric transformer crystal formed from a piezoelectric material having an input end and an output end;
an output electrode electrically connected to the output end;
a voltage source electrically connected to the input end to apply a first voltage to the crystal and create a second voltage that is higher than the first voltage at the output end caused by the piezoelectric effect, the second voltage creating an electric field generally originating at the output electrode; an ion source configured to produce a plurality of ions, the ions being accelerated as an ion beam by the electric field, the ion beam having an ion beam path; and,
an ion target electrically connected to the output electrode, the ion target being positioned in the ion beam path so that the charged particles interact with the ion target to generate neutrons;
a vacuum chamber containing the piezoelectric transformer crystal, the ion source and the ion target.

### Claim 2 (depends on 1)

The neutron generator of claim 1 wherein the ion source comprises a piezoelectric transformer plasma source.

### Claim 3 (depends on 2)

The neutron generator of claim 2 wherein the piezoelectric transformer plasma source comprises a piezoelectric transformer configured to generate a high electric field in an aperture and a gas flow supplied to the aperture, the high electric field of the piezoelectric transformer plasma source being configured to cause ionization of gas supplied to the aperture by the gas flow.

### Claim 4

A low-power, compact emitter of atomic particles comprising:
a piezoelectric transformer crystal formed from a piezoelectric material having an input end and an output end;
an output electrode electrically connected to the output end;
a voltage source electrically connected to the input end to apply a first voltage to the crystal and create a second voltage that is higher than the first voltage at the output end caused by the piezoelectric effect, the second voltage creating an electric field generally at the output electrode;
a charged particle source for emitting charged particles; and,
a target for receiving the charged particles;
a vacuum chamber containing the piezoelectric transformer crystal, the charged particle source and the target;
whereby in operation the electric field accelerates the charged particles toward the target such that the charged particles interact with the target to emit one of neutrons and X-rays.

### Claim 5 (depends on 4)

The emitter of claim 4 wherein the piezoelectric transformer crystal has a length, a width, and a height, and the crystal is configured for electric transformation in a length extensional mode.

### Claim 6 (depends on 5)

The emitter of claim 5 wherein the piezoelectric transformer crystal has a crystallographic polarization being rotated 45° from vertical about a width-wise axis of the crystal.

### Claim 7 (depends on 5)

The emitter of claim 5 wherein the piezoelectric transformer crystal is mounted between brackets at its mid length.

### Claim 8 (depends on 7)

The emitter of claim 7 wherein the voltage source is an alternating current voltage source having a frequency equal to about a resonant frequency of the piezoelectric transformer crystal.

### Claim 9 (depends on 4)

The emitter of claim 4 wherein the piezoelectric transformer crystal is mounted between brackets at its one-quarter length and other brackets at its three-quarters length.

### Claim 10 (depends on 9)

The emitter of claim 9 wherein the voltage source is configured to supply an alternating current voltage having a frequency equal to about two times a resonant frequency of the piezoelectric transformer crystal.

### Claim 11 (depends on 4)

The emitter of claim 4 wherein the voltage source is configured to supply an alternating current voltage to the input end of the piezoelectric crystal in an amplitude modulated mode.

### Claim 12 (depends on 4)

The emitter of claim 4 wherein the voltage source is configured to supply an alternating current voltage source to the input end of the piezoelectric crystal in a frequency modulated mode.

### Claim 13 (depends on 4)

The emitter of claim 4 further comprising an electric field shaper.

### Claim 14 (depends on 13)

The emitter of claim 13 wherein the electric field shaper houses a length of the piezoelectric transformer crystal adjacent the output end, the charged particle source, and the target.

### Claim 15 (depends on 13)

The emitter of claim 13 wherein the electric field shaper includes a voltage control configured to maintain the electric field shaper at a voltage relative to ground.

### Claim 16 (depends on 4)

The emitter of claim 4 wherein the charged particle source is positioned at the output electrode of the piezoelectric transformer crystal and the target is spaced apart therefrom.

### Claim 17 (depends on 4)

The emitter of claim 4 wherein the target is positioned at the output electrode of the piezoelectric transformer crystal and the charged particle source is spaced apart therefrom.

### Claim 18

A low-power, compact piezoelectric X-ray generator comprising:
a piezoelectric transformer crystal formed from a piezoelectric material having an input end and an output end;
an output electrode electrically connected to the output end;
a voltage source electrically connected to the input end to apply a first voltage to the crystal and create a second voltage that is higher than the first voltage at the output end caused by to the piezoelectric effect, the second voltage creating an electric field generally at the output electrode;
an electron emitter configured to emit a beam of electrons accelerated by the electric field;
a bremsstrahlung target positioned in the electron beam so that the electrons interact with the target to generate X-rays;
a vacuum chamber containing the piezoelectric transformer crystal, the electron emitter and the bremsstrahlung target.

### Claim 19 (depends on 18)

The X-ray generator of claim 18 wherein the electron emitter comprises a thermionic emitter spaced apart from the output electrode.

### Claim 20 (depends on 18)

The X-ray generator of claim 18 wherein the electron emitter comprises a high field electron emitter electrically connected to the output electrode.