Cyclic accelerator for accelerating charge carriers and method for manufacturing a cyclic accelerator

• US 10,136,508 B2
• Filed: 01/19/2016
• Issued: 11/20/2018
• Est. Priority Date: 01/19/2015
• Status: Active Grant

• Current Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Original Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Inventors: Haberger, Karl
• Primary Examiner(s): Kao, Chih-Cheng
• Application Number:
  US15/000,777
• Publication Number:
  US 20160212834A1
• Time in Patent Office: 1,036 Days
• CPC Class Codes: B81B 7/02 containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS] B81B7/04 takes precedence
• CPC Class Codes: H05G 2/00 Apparatus or processes specially adapted for producing X-rays, not involving X-ray tubes, e.g. involving generation of a plasma X-ray lasers H01S4/00
• CPC Class Codes: H05H 13/00 Magnetic resonance accelerators; Cyclotrons strophotrons, turbine tubes H01J25/62
• CPC Class Codes: H05H 13/005 Cyclotrons
• CPC Class Codes: H05H 15/00 Methods or devices for acceleration of charged particles not otherwise provided for , e.g. wakefield accelerators
• CPC Class Codes: H05H 7/04 Magnet systems , e.g. undulators, wigglers free-electron laser H01S3/0903; Energisation thereof
• CPC Class Codes: H05H 7/14 Vacuum chambers H05H5/03 takes precedence
• CPC Class Codes: H05H 7/18 Cavities; Resonators travelling-wave tubes H01J23/18; hyperfrequency cavities in general H01P7/04, H01P7/06

Abstract

What is shown is a cyclic accelerator for accelerating charge carriers. The cyclic accelerator includes a charge carrier source configured to generate free charge carriers, a vacuum chamber configured to receive the free charge carriers, wherein the vacuum chamber is produced by means of MEMS technology, and wherein at least a main surface region of the vacuum chamber has a semiconductor material. In addition, the cyclic accelerator has electrodes configured to accelerate the free charge carriers in the vacuum chamber by means of an alternating current field, and a magnetic field generator configured to generate a magnetic field perpendicularly to the direction of movement of the charge carriers.

Claims

1. A cyclic accelerator for accelerating electrons, comprising:

an electron source configured to generate free electrons;

a vacuum chamber configured to receive the free electrons, wherein the vacuum chamber is produced by means of MEMS technology;

electrodes configured to accelerate the free electrons in the vacuum chamber by means of an alternating current field;

a magnetic field generator configured to generate a magnetic field perpendicularly to the direction of movement of the electrons;

wherein an anode which is configured to emit x-rays to the surroundings of the cyclic accelerator by an electron impinging is arranged adjacent to the vacuum chamber,

wherein the cyclic accelerator comprises a first semiconductor subcomponent and a second semiconductor subcomponent which are connected to each other in a vacuum-tight manner to form the vacuum chamber therebetween.

2. The cyclic accelerator in accordance with claim 1, wherein the electrodes are formed from highly doped regions of a semiconductor material.

3. The cyclic accelerator in accordance with claim 1, wherein the vacuum chamber is produced by etching a semiconductor material or by etching a layer of another material applied onto the semiconductor material.

4. The cyclic accelerator in accordance with claim 1, wherein the vacuum chamber comprises a volume of less than 100 mm³ or less than 50 mm³ or less than 10 mm^3.

5. The cyclic accelerator in accordance with claim 1, wherein the air-tight connection is produced by means of a gluing method, anodic bonding or silicon fusion bonding.

6. The cyclic accelerator in accordance with claim 1, wherein the electrodes are arranged to be congruent at a main surface region of the first semiconductor subcomponent and at a main surface region of the second semiconductor subcomponent opposite the main surface region of the first semiconductor subcomponent.

7. The cyclic accelerator in accordance with claim 1, wherein a column which connects the two main surface regions is arranged between a main surface region of the first semiconductor subcomponent and a main surface region of the second semiconductor subcomponent opposite the main surface region of the first semiconductor subcomponent, wherein the column is configured to mechanically support both main surface regions.

8. The cyclic accelerator in accordance with claim 1, wherein the electron source is a heating wire which is insulated thermally from a semiconductor material.

9. The cyclic accelerator in accordance with claim 1, wherein the electron source is covered with an alkaline earth oxide.

10. The cyclic accelerator in accordance with claim 1, wherein the electron source is a carbon nano tube or a Spindt emitter, wherein the Spindt emitter is produced by means of MEMS technology.

11. The cyclic accelerator in accordance with claim 1, wherein the cyclic accelerator comprises another chamber, adjacent to the vacuum chamber and connected to the vacuum chamber via a connection channel, wherein a getter substance configured to react with the gaseous molecules present in the vacuum chamber and thus produce a vacuum in the vacuum chamber is arranged in the further chamber.

12. The cyclic accelerator in accordance with claim 11, wherein the getter substance is configured to locally evaporate by heating using infrared laser radiation penetrating a semiconductor material in order to act as a getter of increased surface.

13. The cyclic accelerator in accordance with claim 11, wherein the getter substance comprises titanium and/or magnesium.

14. The cyclic accelerator in accordance with claim 1, wherein the magnetic field generator comprises a permanent magnet.

15. The cyclic accelerator in accordance with claim 1,

wherein the magnetic field generator comprises at least two pole shoes;

wherein the vacuum chamber is arranged between at least two pole shoes of the magnetic field generator.

16. The cyclic accelerator in accordance with claim 15, wherein a piezo film configured to adjust a distance between the at least two pole shoes such that a desired resonant frequency of the accelerated electrons is achieved is arranged between the at least two pole shoes.

17. The cyclic accelerator in accordance with claim 1, wherein the magnetic field generator comprises a plurality of highly permeable films arranged in layers, configured to form laterally structured pole shoes.

18. The cyclic accelerator in accordance with claim 1, wherein the cyclic accelerator comprises an auxiliary coil through which a current flows, configured to adjust the magnetic field of the magnetic field generator such that a desired resonant frequency of the accelerated electrons is achieved.

19. The cyclic accelerator in accordance with claim 1, wherein the cyclic accelerator comprises a fixed-frequency oscillator or a Gunn diode configured to apply an alternating voltage to the electrodes, wherein the alternating voltage comprises a frequency which is adapted to the geometry of the vacuum chamber.

20. A method for manufacturing a cyclic accelerator, comprising:

providing a substrate which comprises a semiconductor material, for the cyclic accelerator;

applying a mask onto the substrate;

etching a vacuum chamber into a sub-region of the semiconductor material defined by the mask or a layer of another material arranged above the semiconductor material;

producing electrodes at a main surface region of the vacuum chamber;

introducing an electron source into the vacuum chamber;

sealing and evacuating the vacuum chamber in a vacuum-tight manner;

arranging a magnetic field generator such that a magnetic field is generated in the thickness direction of the vacuum chamber;

arranging an anode adjacent to the vacuum chamber, wherein the anode is configured to emit x-rays to the surroundings of the cyclic accelerator by an electron impinging.

21. The method in accordance with claim 20, comprising:

etching a further chamber in a second sub-region of the substrate defined by the mask or the layer of the further material arranged above the semiconductor material;

etching a connection channel in a third sub-region of the substrate defined by the mask or the layer of the further material arranged above the semiconductor material;

introducing a getter substance in the further chamber.

22. The method in accordance with claim 20, comprising:

etching a trench in a fourth sub-region of the substrate uncovered by the mask or the layer of the further material arranged above the semiconductor material;

depositing an anode for generating x-rays in the trench.

23. The method in accordance with claim 20, comprising:

doping the semiconductor material in a main surface region of the vacuum chamber for generating the electrodes;

or

depositing an electrically conductive material on a main surface region of the vacuum chamber for generating the electrodes.