Multi-layer structure of nuclear thermionic avalanche cells

Patent metadata

Field	Value
Publication number	US-11581104-B2
Application number	US-202016880351-A
Country	US
Kind code	B2
Filing date	May 21, 2020
Priority date	May 21, 2019
Publication date	Feb 14, 2023
Grant date	Feb 14, 2023

Abstract

The present disclosure is directed to nuclear thermionic avalanche cell (NTAC) systems and related methods of generating energy from captured high energy photons. Huge numbers of electrons in the intra-band of atom can be liberated through bound-to-free transition when coupled with high energy photons. If a power conversion process effectively utilizes these liberated electrons in an avalanche form through a power conversion circuit, the power output will be drastically increased. The power density of a system can be multiplied by the rate of high energy photon absorption. The present disclosure describes a system and methods built with multilayers of nuclear thermionic avalanche cells for the generation of energy. The multilayer structure of NTAC devices offers effective recoverable means to capture and harness the energy of gamma photons for useful purposes such as power systems for deep space exploration.

First claim

What is claimed is:

1. A nuclear thermionic avalanche cell (NTAC) system comprising:
a radioisotope core configured to emit high energy photons wherein the radioisotope core is substantially cylindrical-shaped and wherein a radioisotope emitter layer surrounds an outer portion of the radioisotope core; and
a plurality of NTAC layers surrounding the radioisotope core wherein the plurality of NTAC layers are substantially cylindrical-shaped and wherein the plurality of NTAC layers further comprise:
a collector;
an insulator; and
an emitter,
wherein the radioisotope emitter layer and the NTAC layer emitter are positioned facing the collector,
wherein the collector is positioned across a thermionic vacuum gap, and
wherein the collector, the insulator, and the emitter are integrated with each other wherein the collector is configured on an interior of the insulator and wherein the insulator is configured on an interior of the emitter;

wherein the plurality of NTAC layers form a coaxially arranged and multilayered NTAC;
wherein the radioisotope emitter and the NTAC emitter layers are configured to capture the photons from the radioisotope core, and by the captured photons free up a number of electrons in an avalanche process from deep and intra-bands of atoms; and
wherein the number of avalanche electrons that are emitted from the emitter passes through the thermionic vacuum gap and arrive at the collector to output a high density avalanche cell current through a photo-ionic or thermionic process of the freed up electrons.

2. The system of claim 1 , wherein the radioisotope core has a diameter and a height that are dependent on the design of the NTAC system according to power requirement.

3. The system of claim 1 , wherein the photons are x-rays, gamma rays, or visible UV light.

4. The system of claim 1 , wherein the radioisotope core is Cobalt-60, Sodium-22, or Cesium-137.

5. The system of claim 1 , wherein a required number of NTAC layers is determined by the complete absorption and exhaustion of high energy photons undergoing the electron avalanche process through the plurality of NTAC layers.

6. The system of claim 1 , wherein the emitter comprises a nanostructured surface of a high Z material.

7. The system of claim 1 , wherein the emitters capture photons from the radioisotope core, and wherein the collectors are configured to capture avalanche electrons from the emitters and lead avalanche electrons to a power circuit.

8. The system of claim 1 , wherein the collector comprises a low or mid Z material.

9. The system of claim 1 , wherein the emitter has a thickness from about 1 mm to about 3 mm.

10. The system of claim 1 , wherein the emitter has a thickness of at least 1 mm.

11. The system of claim 3 , wherein photons, x-rays, gamma rays, or visible UV light are absorbed by the emitters and collectors and converted into thermal energy through inelastic collisions and scattering, and/or wherein the avalanche electrons undergo multiple Coulomb collisions with neighboring electrons generating thermal energy, and wherein a thermoelectric generator is configured to receive the thermal energy and output thermoelectric power.

12. A method of capturing high energy photons to generate power comprising:
receiving high energy photons emitted from a radioisotope core integrated with a nuclear thermionic avalanche cell (NTAC), wherein the NTAC comprises a plurality of NTAC layers configured to receive the photons, wherein the NTAC layer includes an emitter, a thermionic vacuum gap, and a collector, wherein the emitter is positioned between the radioisotope core and the collector;
outputting avalanche electrons using the received photons;
guiding the avalanche electrons to cross over a vacuum gap to a collector;
harnessing a load from the electrons at the collector via a power circuit; and
generating an electrical current.

13. The method of claim 12 , wherein the radioisotope core further comprises an emitter layer, thermionic vacuum gap, and a collector layer.

14. The method of claim 13 , wherein the first emitter layer may have a thickness of at least 1 mm.

15. The method of claim 12 , wherein the photons are x-rays, gamma rays, or visible UV light.

16. The method of claim 12 , wherein the radioisotope core is Cobalt-60, Sodium-22, or Cesium-137.

17. The method of claim 12 , wherein the emitter has a thickness from about 1 mm to about 3 mm.

18. The method of claim 12 , wherein the emitter has a thickness of at least 3 mm.

19. The method of claim 12 , wherein the emitter comprises a nanostructured surface of a high Z material.

20. The method of claim 12 , wherein the collector comprises a low or mid Z material.

21. An energy conversion system comprising:
a radioisotope core configured to emit high energy photons,
wherein the radioisotope core comprises Cobalt-60, Sodium-22, or Cesium-137;

a nuclear thermionic avalanche cell (NTAC) comprising a plurality of NTAC layers integrated with the radioisotope core and configured to receive the photons from the radioisotope core and by the received photons free up a number of electrons in an avalanche process from deep and intra-bands of an atom to output a high density avalanche cell current through a photo-ionic or thermionic process of the freed up electrons, and wherein the avalanche current is fed through power circuit
wherein the plurality of NTAC layers comprise a nanostructured surface of a high Z material,
wherein the plurality of NTAC layers comprise a combination of a collector wherein the collector is at least 1 mm thick, an insulator wherein the insulator is at least 3 mm thick, and an emitter wherein the emitter is at least 3 mm thick; and

a thermoelectric generator configured to receive the thermal energy, wherein the thermal energy is radiatively conducted axially and radially, and output thermoelectric power, and
wherein the thermoelectric generator surrounds the plurality of NTAC layers and
the radioisotope core.

Assignees

• Nasa

Inventors

• Choi Sang Hyouk
• Bushnell Dennis M
• Duzik Adam J

Classifications

• G21H1/106 Primary

  Cells provided with thermionic generators · CPC title

• G21H1/04

  Cells using secondary emission induced by alpha radiation, beta radiation, or gamma radiation · CPC title