Generation and acceleration of charged particles using compact devices and systems

Patent metadata

Field	Value
Publication number	US-2016174355-A1
Application number	US-201314436859-A
Country	US
Kind code	A1
Filing date	Oct 17, 2013
Priority date	Oct 17, 2012
Publication date	Jun 16, 2016
Grant date	—

Abstract

A system that generates short charged particle packets or pulses (e.g., electron packets) without requiring a fast-switching-laser source is described. This system may include a charged particle source that produces a stream of continuous charged particles to propagate along a charged particle path. The system also includes a charged particle deflector positioned in the charged particle path to deflect the stream of continuous charged particles to a set of directions different from the charged particle path. The system additionally includes a series of beam blockers located downstream from the charged particle deflector and spaced from one another in a linear configuration as a beam-blocker grating. This beam-blocker grating can interact with the deflected stream of charged particles and divide the stream of the charged particles into a set of short particle packets. In one embodiment, the charged particles are electrons. The beam blockers can be conductors.

First claim

What is claimed is:

1 . A device for generating charged particle packets or pulses, comprising:
a charged particle deflector that receives a stream of continuous charged particles propagating along a first direction and includes deflector elements that deflect the stream of continuous charged particles to a set of directions different from the first direction; and a series of beam blockers located downstream from the charged particle deflector and spaced from one another in a linear configuration as a beam-blocker grating to interact with the deflected stream of charged particles and divide the stream of the charged particles into a set of short particle packets.

2 . The device of claim 1 , further comprising a charged particle source that produces the stream of continuous charged particles to propagate along the first direction.

3 . The device of claim 2 , wherein the charged particle source produces the stream of charged particles as a long-duration charged particle packet.

4 . The device of claim 2 , wherein the charged particle source produces the stream of charged particles as a continuous-wave beam of the charged particles.

5 . The device of claim 1 , wherein the charged particle deflector comprises a pair of parallel plate electrodes.

6 . The device of claim 5 , wherein the charged particle deflector is configured with a ramp voltage applied across the pair of electrodes, wherein the ramp voltage causes the continuous electron beam passing through the charged particle deflector to sweep across the beam-blocker grating.

7 . The device of claim 6 , wherein the ramp voltage is repeated at a predetermined repetition rate for generating a periodic source of charged-particle-packets trains.

8 . The device of claim 1 , wherein the series of beam blockers is arranged along a second direction which is substantially parallel to the first direction.

9 . The device of claim 1 , further comprising a second series of beam blockers located downstream from the charged particle deflector and directly opposing the series of beam blockers, wherein the series of beam blockers and the second series of beam blockers form a drift region for the deflected stream of charged particles to drift toward the beam-blocker grating.

10 . The device of claim 1 , wherein the beam-blocker grating acts as multiple knife-edges to divide the deflected stream of charged particles into the set of short particle packets.

11 . The device of claim 1 , wherein the duration of the short particle packets and the duration between two consecutive short particle packets are functions of the ramp rate of the ramp voltage, kinetic energy of the received continuous charged particles, and geometries of the beam-blocker grating.

12 . The device of claim 1 , wherein the duration of the short particle packets is of sub-picosecond.

13 . The device of claim 1 , wherein the charged particles can be either negatively charged particles or positively charged particles.

14 . The device of claim 1 , wherein the charged particles are electrons.

15 . The device of claim 1 , wherein the series of beam blockers are arranged in a way that each of the beam blockers has its surface substantially parallel to the first direction.

16 . The device of claim 1 , wherein the series of beam blockers are arranged in a way that each of the beam blockers has its surface placed at an angle with respect to the first direction.

17 . The device of claim 1 , wherein the series of beam blockers are a series of conductors.

18 . The device of claim 1 , further comprising a charged particle source that produces the stream of continuous charged particles which propagates along the first direction.

19 . A device for accelerating charged particles, comprising:
a radio frequency (RF) signal generator for generating an RF signal; an RF resonator coupled to the RF signal generator and operable to generate a high-voltage RF drive signal based on the received RF signal; and a linear series of electrode segments to form a path for receiving and accelerating charged particles and coupled to the RF resonator to receive the high-voltage RF drive signal to accelerate received charged particles successively through the linear series of electrode segments, wherein each electrode segment of the linear series of electrode segments is driven by the high-voltage RF drive signal.

20 . The device of claim 19 , wherein the RF resonator is implemented as a coplanar waveguide.

21 . The device of claim 20 , wherein the coplanar waveguide is configured in a meander structure to match the wavelength of the RF resonator.

22 . The device of claim 20 , wherein the coplanar waveguide is formed on one of:
a printed circuit board (PCB); Rogers material; Alumina; Sapphire; or a ceramic substrate.

23 . The device of claim 20 , wherein the coplanar waveguide and the linear series of electrode segments are formed on a common planar platform.

24 . The device of claim 20 , wherein the coplanar waveguide is substantially parallel to the linear series of electrode segments.

25 . The device of claim 20 , wherein the linear series of electrode segments are raised above the coplanar waveguide to minimize the electric field between the ground of the coplanar waveguide and the electric potential of the linear series of electrode segments.

26 . The device of claim 19 , wherein the linear series of electrode segments are coupled to the RF resonator through a set of wire bonds.

27 . The device of claim 19 , wherein the linear series of electrode segments are coupled to the RF resonator through printed conductor wires or planar waveguides.

28 . The device of claim 19 , wherein the linear series of electrode segments are spaced by a set of gaps of a constant size.

29 . The device of claim 19 , wherein the linear series of electrode segments serves the function of traditional drift tubes in a linear particle accelerator (LINAC).

30 . The device of claim 19 , wherein each electrode segment in the linear series of electrode segments comprises a pair of parallel electrode blocks, and wherein the space between the pair of parallel electrode blocks is part of the path for receiving and accelerating the charged particles.

31 . The device of claim 30 , wherein each of the pair of parallel electrode blocks is a multi-layer stack comprising multiple silicon/metal-multilayer structures.

32 . The device of claim 19 , wherein the RF resonator generates the high-voltage RF drive signal by multiplying the amplitude of the received RF signal by a factor less than or substantially equal to the quality (Q) factor of the RF resonator.

33 . The device of claim 19 , wherein the frequency of the RF signal is selected to match the transit time of the charged particles through a single electrode segment stage within the linear series of electrode segments.

34 . The device of claim 19 , wherein the path of the linear series of electrode segments is fabricated by a laser-micromachining process or a Deep Reactive Ion Etching (DRIE) process.

35 . The device of claim 19 , further comprising an RF amplifier coupled between the RF signal generator and the RF resonator for amplifying the RF signal.

Assignees

• Univ Cornell

Inventors

• Lal Amit
• Shi Yue
• Ardanuc Serhan
• Hwang June-Ho
• Rana Farhan

Classifications

• H05H9/045 Primary

  Radio frequency quadrupoles · CPC title

• H05H2007/046

  for beam deflection · CPC title

• H01J37/06

  Electron sources; Electron guns · CPC title

• H01J37/1472

  Deflecting along given lines · CPC title

• H01J2237/063

  Electron sources · CPC title