Granted Patent B2

US 12,739,962 · App. 19/115,802 · Granted Sep 15, 2026

Inventors: Tomonao Hosokai (Osaka, JP); Yanjun Gu (Osaka, JP); Zhan Jin (Osaka, JP)

H05H1/46

Abstract

Claims (31)

1 . An electron beam generation apparatus configured to generate an electron beam by propagating pulsed laser light in a supersonic gas flow, the electron beam generation apparatus comprising:

a supersonic nozzle configured to generate the supersonic gas flow flowing along a first direction under a vacuum atmosphere;

a knife edge configured to be inserted into the supersonic gas flow from one side in a second direction intersecting the first direction and form a shock wave in the supersonic gas flow; and

a radiation unit configured to radiate the pulsed laser light into the supersonic gas flow and propagate the pulsed laser light to pass through the shock wave in the supersonic gas flow,

wherein the supersonic nozzle includes

a convergence portion having a downstream end forming a throat and an upstream end having a flow channel cross-sectional area larger than a cross-sectional area of the throat, and

a flow straightening chamber configured to be smoothly connected to the upstream end of the convergence portion and extend by a predetermined length.

2 . The electron beam generation apparatus according to claim 1 ,

wherein the convergence portion and the flow straightening chamber extend along the first direction, and

wherein the predetermined length is 20 mm or longer.

3 . The electron beam generation apparatus according to claim 1 , wherein the supersonic nozzle includes a flow straightening member configured to be provided inside the flow straightening chamber and have a plurality of fine holes formed along a flowing direction of the flow straightening chamber.

4 . The electron beam generation apparatus according to claim 3 ,

wherein the convergence portion and the flow straightening chamber extend along the first direction, and

wherein the predetermined length is 10 mm or longer.

5 . The electron beam generation apparatus according to claim 3 , wherein the flow straightening member is disposed inside the flow straightening chamber at a distance of 5 mm or longer from an upstream end or a downstream end of the flow straightening chamber.

6 . The electron beam generation apparatus according to claim 1 , wherein at least a tip portion of the knife edge is inclined toward the supersonic nozzle with respect to a direction perpendicular to the first direction.

7 . The electron beam generation apparatus according to claim 1 , wherein the supersonic nozzle is configured to be dividable such that the flow straightening chamber is divided.

8 . The electron beam generation apparatus according to claim 1 , wherein the knife edge is configured to be able to adjust a length by which the knife edge is inserted into the supersonic gas flow.

9 . The electron beam generation apparatus according to claim 1 , wherein the knife edge is configured to be able to adjust an insertion angle being an angle between an extending direction of the knife edge and the second direction in a state where the knife edge is inserted into the supersonic gas flow.

10 . The electron beam generation apparatus according to claim 1 , wherein the knife edge causes a gas density distribution of the supersonic gas flow in the second direction to become a distribution that rises steeply, falls steeply, and then is maintained within a certain range from the one side toward the other side in the second direction.

11 . The electron beam generation apparatus according to claim 10 ,

wherein the pulsed laser light radiated from the radiation unit causes plasma wave crushing to occur, and the electron beam is generated by the plasma wave crushing in a region where the gas density distribution of the supersonic gas flow in the second direction falls steeply, and

wherein the generated electron beam is accelerated in an acceleration region where the gas density distribution of the supersonic gas flow in the second direction is maintained within the certain range.

12 . An electron beam generation method for generating an electron beam by propagating pulsed laser light in a supersonic gas flow, the electron beam generation method comprising:

a first step of generating the supersonic gas flow flowing along a first direction under a vacuum atmosphere by a supersonic nozzle;

a second step of inserting a knife edge into the supersonic gas flow from one side in a second direction intersecting the first direction and forming a shock wave in the supersonic gas flow; and

a third step of radiating the pulsed laser light into the supersonic gas flow by a radiation unit, propagating the pulsed laser light to pass through the shock wave in the supersonic gas flow, and generating the electron beam,

wherein the supersonic nozzle includes

a convergence portion having a downstream end forming a throat and an upstream end having a flow channel cross-sectional area larger than a cross-sectional area of the throat, and

a flow straightening chamber configured to be smoothly connected to the upstream end of the convergence portion and extend by a predetermined length, and

wherein, in the first step, a gas is caused to flow by the predetermined length in the flow straightening chamber, and then the gas converges while being caused to flow in the convergence portion.

Assignments (1)

Priority Claims (2)

Continuity (1)

References Cited (28)