Patent Application
20230082458
Embodiments of the present invention generally relate to techniques for processing sub-atomic particles, and more specifically to method and apparatus for processing a particle shower using a laser-driven plasma.
Generating high energy sub-atomic particles is a challenge, and typically requires huge installations spanning several hundreds or thousands of meters, and several hundred million dollars in costs. Such facilities are not easily accessible of affordable, and severely restrict availability of such particles for experimentation or applications.
Therefore, there exists a need for an improved method and apparatus for processing particles from a particle shower.
SUMMARY
The present invention relates generally to a method and apparatus for processing a particle shower using a laser-driven plasma is provided. The method comprises interacting a particle shower with a processing laser-driven plasma stage, the particle shower comprising at least one particle species, wherein the laser is a high-energy, ultra-short pulse laser. In some embodiments, the method comprises accelerating, decelerating, trapping, or collimating the at least one particle species in the processing laser-drive plasma stage.
So that the manner in which embodiments of the present invention can be understood in detail, a more particular description of the invention may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
Embodiments of the present invention comprise a method and apparatus for processing a particle shower using a laser-driven plasma. More specifically, the techniques disclosed herein enable trapping at least one or more particle species of a particle shower in a laser-driven plasma. The particle shower may be electromagnetic comprising of particles, such as electrons and positrons, or the shower may be hadronic in nature comprising of particles, such as, muons, pions, among other particles. The laser-driven plasma is typically generated in a gaseous medium comprising a gas. The laser is an ultra-short tens of femto-second laser such as a Chirp-pulse Amplified laser with a Ti:Sapphire or a Nd:Glass or a Carbon dioxide active medium, and can be further configured to drive the plasma to collimate, accelerate, decelerate or suspend the trapped particles. It is theorized that the laser excites the plasma to form certain types of traveling structures in the plasma which sustain electron-ion charge separation with associated electromagnetic fields therein to trap, collimate and accelerate particles from the particle shower. In some embodiments, the laser and plasma can be configured to decelerate particles, or even suspend particles in the plasma. The electromagnetic fields of the traveling charge separation structures in the plasma exert a force on the charged particles of the particle shower, and thus process them inside the plasma. The electromagnetic fields of these structures in the plasma tuned to collimate the particles by exerting a focusing force that keeps them together in opposition to their initial transverse velocities. Further, the laser electromagnetic fields may be tuned to generate one or more plasma waves, which are an outcome of alternating regions of electron density compression and depletion due to the laser radiation pressure driven motion of the electrons against the stationary ions, and the plasma waves can be configured to add energy to the particles, accelerating the particles; reduce the energy by opposing the motion of the particles, decelerating the particles; or neither add nor reduce the energy of the particles. The laser-driven plasma stage is implemented in a space spanning less than 1 meter, and as small as 0.5 millimeter.
The solutions rely on the use of a generated particle shower, for example using several known techniques, such as positron-electron pair production by decay of high-energy photon; nuclear decay; proton-proton collision among others. A few such techniques relevant to electromagnetic showers, among other functionalities, technical details and applications, is discussed in the publication titled Sahai, Aakash A., “Quasimonoenergetic laser plasma positron accelerator using particle-shower plasma-wave interactions,” Phys. Rev. Accel. Beams 21, 081301, 8 Aug. 2018, incorporated herein by reference in its entirety.
The processing stage 100 comprises a laser source and a focusing optics 101 capable of providing an ultra-short laser 102, with 500 mJ to 50 J of energy, 10-60 fs pulse length and a focused spot-size ranging from 10-250 microns, and a chamber 104 for a gas 106, the chamber 104 having controllable inlet 108 and controllable outlet 110 for gas 106, and windows 118 and 119 configured for entry and exit of the laser 102 into and from the chamber 104, respectively. The window 118 is also configured for entry of the particle shower 116 into the chamber 104 and the plasma in the gas 106 therein. The processing stage 100 also includes a mirror 103 to direct the laser 102 to the gas 106, for example, into the chamber 104 through the window 118.
When the particle shower is being processed by a plasma in the gas 106, the inlet 108 and the outlet 110 are configured to be sealed, for example by corresponding valves (not shown). When more gas 106 is needed in the chamber 104, the inlet 108 and/or the outlet 110 may be opened. The open and shut states of the inlet 108 and the outlet 110 are managed according to when gas in needed to be introduced in the chamber 106, for example to maintain the pressure in the chamber 106.
The gas 106 has a tunable atomic weight, and includes, for example, Helium, Methane, Nitrogen, Neon, or other gases having low atomic weight, among others. A pressure ranging between 500 Pascals to 500 kilo Pascals is maintained in the chamber 104.
The windows 118 and 119 are made from materials that provide minimal deterioration of the properties of the laser 102 and/or the particles from the particle shower 116 and suffer minimal damage from the laser and the particle shower particles. For example, the windows 118, 119 are made from one or more of silica or other material transparent to laser radiation.
The mirror 103 is a thin replaceable metal in the form of a ribbon or a foil, for example, aluminum or copper. The mirror 103 selectively reflects the laser 102 at a desirable angle, while causing minimal obstruction to or deterioration of the particles of the particle shower 116.
The particles trapped from the particle shower 116 are processed by the plasma driven by the laser 102, in the gas 106, inside the chamber 104, and emerge from of the chamber 104, for example, in one or more beams, for example, beam 120 and 122, and additional radiation or particles 124 which may or may not be in form of a beam 124. For example, in the illustration of
In one embodiment, the processing stage 100 is configured to trap, collimate and accelerate the oppositely charged particles from the particle shower. The laser 102 is configured to an energy of about 5 J, pulse length 50 fs and spot-size with full-width at half-maximum of 40 microns, the gas is configured at pressure of 5 kilo Pascals over its length ranging between 1 to 10 millimeters. The oppositely charged particles of particle shower are trapped and accelerated to approximately similar energy levels, and emerge as beams. For example, the positrons in the particle shower are accelerated in the gas 104 plasma and emerge as the positron beam 120 having an energy peak around 170 MeV, bunch length of 10 microns and spot-size of 10 microns at the exit with an opening angle of around 5 milli-radians with the particle energy spectra peaked at 170 MeV with a full-width at half-maximum width of <10 percent containing at least 50,000 particles.
In one embodiment, the processing stage 100 is configured to trap, collimate and decelerate the oppositely charged particles from the particle shower 116. Laser parameters are the same as above but spot-size of 10 to 50 microns and the gas pressure is between 200 and 500 kilo Pascals.
In one embodiment, the processing stage 100 is configured to trap and collimate the oppositely charged particles from the particle shower 116, without adding or reducing energy of the particles. In this embodiment, the laser has the same set of parameters but a spot-size of 100-250 microns, the—and the gas 106 has a pressure of 100-1000 Pascals.
In one embodiment, the particle shower 116 is a hadronic particle shower comprising muons and pions and the beam 120 is a positive muon beam, while the beam 122 is a negative muon beam. The positive muon beam 120 has a spot size or radius of 1-100 microns, and bunch length between 1-100 microns any other properties. The negative muon beam 122 has a spot size or radius of 1-100 microns, bunch length between 1-100 microns. The positive muons beam 120 and the negative muon beam 122 are separated by a distance of about 10 to 100 microns. The additional radiation and/or particles 124 may include photons, and high energy electrons and positrons.
In one embodiment, the laser 102 exits the chamber 104 from the window 119, and is directed away from the particles and/or the radiation (e.g., 120, 122, 124) emitted out of the chamber 104, for example, using a mirror 105, similar to the mirror 103, to reduce or eliminate interaction of the exiting laser 102 with the particles and/or the radiation emerging from the chamber 104. In one embodiment, the processing stage 100 does not include the mirror 103, and the source 101 is positioned to direct the laser 102 to the gas 106, for example, through the window 118, directly. In one embodiment, the processing stage 100 does not include the mirror 105.
In one embodiment, the processing stage 100 includes a first magnet 112 positioned to submerge the particle shower 116 or portion thereof in a magnetic field M1. The magnetic field M1 is configured to increase the flux portion of the particle shower 116 which enters the plasma in the gas 106. For example, the magnet 112 is a rare-earth metal magnet or an electromagnet with axial magnetic fields, and the magnetic field M1 varies from 1 to 10 Tesla.
In one embodiment, the processing stage 100 includes a second magnet 114 positioned to submerge the emerging particles 120, 122 or portion thereof in a magnetic field M2. The magnetic field M2 is configured to direct the oppositely charged particle beams 120 and 122 apart from each other, for example, to utilize each of the two beams (120, 122) individually. For example, the magnet 114 is a dipole magnet, and the magnetic field M2 varies from 0.5 to 2.5 Tesla.
The feeder stage 140 comprises a laser 142, for example generated from a laser source (not shown) similar to the source 101, or generated from the laser source 101. The laser 142 is directed into a chamber 144 comprising a gas 146. The laser 142 generates a gas-plasma 146 in the gas 146, which generates high-energy electrons. The high-energy electrons emerge as a beam 156 from the chamber 144. The chamber 144 comprises a controllable gas inlet 148 and a gas outlet 150, which are used to maintain the gas 146 at a desired pressure inside the chamber 144. The laser 142 is directed into the chamber 144 by a mirror 154, and the laser 142 is directed away from the beam 156 by a mirror 158, where the mirrors 154, 158 are similar to the mirror 103. The electron beam 156 is directed to collide with a heavy (high atomic weight (Z)) metal target 158, and the interaction generates an electromagnetic particle shower. Hadronic shower is generated when a >280 MeV proton beam hits a metal target or a gas or a liquid. Such techniques to generate a particle shower are well known, and can be found in, for example, Electromagnetic shower—B. Richter, Design consideration for high energy electron-positron storage rings, SLAC-PUB-240, November (1966); Erikson, R. (ed.), SLAC Linear Collider Design Hand-book, ch. 5, SLAC-R-714 (1984); and Hadronic shower—E. Fermi, Progress of Theoretical Physics 5, Iss. 4, pp. 570-583, (1950); E. Cartlidge, Phys. World 19, iss. 12, p. 13 (2006)
The width of the chamber 104, or the length along the processing laser 102 in the gas plasma 106, approximately denoted by A, is between about 0.5 mm to 2 cm. The distance between the metal target 158 and the chamber 104 (or the window 118), approximately denoted by B is between about 100 microns to about 5 mm. The width of the chamber 144, approximately denoted by C, is between about 5 mm to about 100 mm. The length of the laser 142 in the gas plasma 146 is about 50 femtoseconds (approximately 15 microns). The distance between where the electron beam 156 emerges from the chamber 144 to the metal target 158, denoted approximately by D, is between about 0.5 mm to about 5 mm.
The largest dimension of the apparatus 10 of
It is theorized that the laser driven gas-plasma, for example, the gas-plasma 104 driven by the laser 102 in the apparatus 10, or the gas-plasma 188 driven by the laser 182 in the apparatus 30 generates electromagnetic fields in the respective gas-plasma. The gas-plasma is configured by the lasers to trap particles from particle showers therein. The trapping is an important property of the laser-driven gas-plasma described herein, because such trapping enables a reasonable population of particles for further processing, such as collimating and acceleration or deceleration. The gas-plasma driven by the laser develops plasma structures such as a plasma wave is also believed to have electromagnetic fields configured to collimate the particles. The gas-plasma can be configured to have electromagnetic fields which either accelerate or decelerate the particles trapped in the plasma.
For example, it is theorized that the gas-plasma driven by the ultra-short high-intensity laser as configured above has one or more plasma waves therein. The plasma wave is a spatial oscillation of electromagnetic fields in the plasma with alternating regions of electron density compression and evacuation. Similarly, the polarized electrons in the gas-plasma have electric fields which progressively accelerate positively charged particles trapped in the electric fields of the electrons within the gas-plasma. Particles of the particle shower co-propagating with the plasma wave witness the electromagnetic fields of the wave. In the regions where the electromagnetic fields are focusing for a particle species such as the electron compression regions for positrons in the shower, particles of the shower get trapped. Once trapped if the focusing region also has accelerating fields then the trapped particles get accelerated. The trapped particles are thereby accelerated by electromagnetic fields (of polarized ions and electrons) having a strength of approximately 1011 V/m for a plasma density of 1018 cm−3, and emerge from the gas-plasma gaining a significant amount of energy from the plasma wave.
Forward propagating particles of the shower are trapped if the speed of the plasma wave, its amplitude and its shape is appropriately tuned. A quasi-nonlinear plasma wave with amplitude that is high enough to retain the trapped positive particles as they gain energy but not too high to shrink the positive particle trapping region spatially is demonstrated to be ideal if the positive particle species of the shower has to be trapped. The speed of the plasma wave chosen is demonstrated to depend upon the properties of the particle shower such as its energy spectrum. The shape of the plasma wave is dictated by the laser pulse focal spot which is tuned in consideration of the plasma density and laser intensity. An initially broad plasma wave will trap the shower particles over a larger transverse spatial region.
The phenomenon discussed above is supported by particle-in-cell (PIC) simulations, representations of which are presented in
As shown, each of the electron beam 426 and the positron beam 428 passes through a respective focusing doublet 408, which collimates the respective beams 426, 428 that are divergent with a small opening angle. Thereafter, the beams 426, 428 encounter the magnetic field of the bending magnet 410, which separates the electron beam 426 and the positron beam 428 in opposite directions, and towards the magnetic fields of the magnets 414 and 418, respectively. The electron beam 426 encounters the magnetic field of the magnet 412, which directs the beam 426 to the magnetic field of the magnet 414. Similarly, the positron beam 428 encounters the magnetic field of the magnet 418, which directs the beam 428 to the magnetic field of the magnet 416. The magnet 414 and the magnet 416 directs the electron beam 426 and the positron beam 428, respectively, towards the other beam to collide the beams 426, 428. The beam 426 first encounters the focusing doublet 420, which focuses the beam 426, for example, between 1 nm to 50 nm, and the beam 428 first encounters the focusing doublet 422 focuses the beam 428, for example, between 1 nm to 50 nm. The collision occurs at position 424, generating other relativistic particles, including a yield of negative and positive muons between 50 to 10000 muons per collision which depends upon the number of positrons and electrons colliding and the beam dimensions at collision.
Since all the particles of the beams 426, 428 do not collide, and several particles of the focused beams simply pass through each other without collision or significant deflection, the beams 426, 428 get collimated in the opposite doublets and continue through the apparatus 400 as follows. For clarity, the beams after collision, the electron beam 426 is shown in broken lines as electron beam 430, and positron beam 428 is shown in broken lines as positron beam 432, in
The beams 430, 432 travel straight in between the magnets 414, 416, and after collision, encounters the focusing doublet 422, which recollimates the beam 430, and encounters the magnetic field of the magnet 416, which directs the beam 430 to the magnetic field of the magnet 418, which directs the beam 430 back to the magnetic field of the magnet 412, thereby forming a loop. Similarly, the beam 432, after collision, encounters the focusing doublet 420, which recollimates the beam 432, and encounters the magnetic field of the magnet 414, which directs the beam 432 to the magnetic field of the magnet 412, which directs the beam 432 back to the magnetic field of the magnet 418, thereby forming a loop. The beams 430, 432 enrich the new beams 426, 428 received from the sources 404, 406, respectively, and the cycle is continued as long as a yield of muons is desired.
In one embodiment, for example, as shown in
The ultrashort channeling radiation source, for example, the source 502 or the source 552, which uses a relativistic particle beam, for example, the positron beam 510, or the electron and positron beams 558, 560 incident from the processing stage on a crystal lattice, for example the undulator 512 or the undulator 562, works using the periodic ionic fields of the lattice where the ions in each lattice plane are in the form of a sheet of positive charge. The periodicity of the lattice ionic field increases for a relativistically propagating electron or positron beam due to Lorentz contraction by a factor of γ. When the relativistic ultra-short positron or electron beam propagates parallel to a lattice plane, its particles oscillate under the influence of the ionic field about the lattice plane in quantum states normal to the plane. The transition between different quantum states results in the emission of channeling radiation, for example, as discussed in M. A. Kumakhov, Phys. Lett. A 57, 17 (1976), hereby incorporated by reference in its entirety. The emission of channeling radiation ranges from soft x-rays (few keV photons) to hard x-rays (many tens of keV photons). The radiated photon energy scales roughly as γ2, and therefore, it is beneficial to accelerate the particle beam to a high energy. The photons are emitted in a relatively narrow spectral peak, and the number of photons is at least 10 times higher than the bremsstrahlung photon number.
According to an embodiment, in
Various embodiments described hereinabove may be placed in high vacuum (103 Torr−107 Torr). Further, various embodiments and components described herein may be combined in different permutations to arrive at apparatus or methods within the scope of the appended claims. For example, processing stage of one embodiment, may be combined with a feeder stage of another embodiment and vice versa. Furthermore, the processing stages described herein may be combined with any number of feeder stages capable of generating particle shower.
The methods described herein may be implemented in software, hardware, or a combination thereof, in different embodiments. In addition, the order of methods may be changed, and various elements may be added, reordered, combined, omitted or otherwise modified.
All examples described herein are presented in a non-limiting manner. Various modifications and changes may be made as would be obvious to a person skilled in the art having benefit of this disclosure. Realizations in accordance with embodiments have been described in the context of particular embodiments. These embodiments are meant to be illustrative and not limiting. Many variations, modifications, additions, and improvements are possible. Accordingly, plural instances may be provided for components described herein as a single instance. Other allocations of functionality are envisioned and may fall within the scope of claims that follow. Finally, structures and functionality presented as discrete components in the example configurations may be implemented as a combined structure or component. These and other variations, modifications, additions, and improvements may fall within the scope of embodiments as defined in the claims that follow.
While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
This Application is a continuation of U.S. Ser. No. 16/770,943, filed on Jun. 8, 2020 and issued as U.S. Pat. No. 11,328,830, which is a National Phase of the International Application No. PCT/US2018/064806, filed on Dec. 10, 2018, which claims priority to U.S. Provisional Application Ser. No. 62/596,265, filed on 8 Dec. 2017; U.S. Provisional Application Ser. No. 62/619,747, filed on 20 Jan. 2018; U.S. Provisional Application Ser. No. 62/756,581, filed on 6 Nov. 2018; and U.S. Provisional Application Ser. No. 62/757,041, filed on 7 Nov. 2018, each of which is hereby incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62596265 | Dec 2017 | US | |
| 62619747 | Jan 2018 | US | |
| 62756581 | Nov 2018 | US | |
| 62757041 | Nov 2018 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16770943 | Jun 2020 | US |
| Child | 17740932 | US |
