Extraction of small-diameter beams from single-component plasmas

Danielson, J. R.; Weber, T. R.; Surko, C. M.

doi:10.1063/1.2709522

Cited by 22 publications

(27 citation statements)

References 23 publications

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“…In this case, instead of dumping the entire plasma, the confinement potential V c at one end of the plasma can be lowered slowly while monitoring the number of escaping charges. For a plasma in equilibrium, the escaping particles come from near the radial center of the plasma (Danielson et al, 2007b;Eggleston et al, 1992). Then, when the number of escaping particles is kept small (i.e., δN/N < T /eφ 0 ), the approximate expression for T in a magnetic field B is…”

Section: Particle Energy Distributionsmentioning

confidence: 99%

“…III.D), these techniques typically involve unavoidable losses of particles. A nondestructive technique was developed to produce a beam with narrow transverse width and enhanced brightness, without such losses (Danielson et al, 2007b;Greaves et al, 2002;Weber et al, 2008Weber et al, , 2009.…”

Section: B Centerline Extractionmentioning

confidence: 99%

“…(17), is largest at the radial plasma center, and so particles from this region escape first when an end confining potential is lowered (Danielson et al, 2007b). A schematic diagram of this technique is shown in Fig.…”

Section: B Centerline Extractionmentioning

confidence: 99%

“…Beams with Gaussian radial profiles and diameters as small as D = 50 µm have been extracted from electron plasmas with D ≈ 2 mm before compression (Danielson et al, 2007b;Weber et al, 2008). A simple theory predicts that the beam diameter (full width to 1/e) is D = 4λ D ∝ (T /n) 1/2 , where λ D is the Debye length.…”

Section: B Centerline Extractionmentioning

confidence: 99%

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Plasma and trap-based techniques for science with positrons

Danielson¹,

Dubin²,

Greaves³

et al. 2015

Rev. Mod. Phys.

234

222

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In recent years, there has been a wealth of new science involving low-energy antimatter (i.e., positrons and antiprotons) at energies ranging from 10 2 to less than 10 −3 eV. Much of this progress has been driven by the development of new plasma-based techniques to accumulate, manipulate and deliver antiparticles for specific applications. This article focuses on the advances made in this area using positrons. However many of the resulting techniques are relevant to antiprotons as well. An overview is presented of relevant theory of single-component plasmas in electromagnetic traps. Methods are described to produce intense sources of positrons and to efficiently slow the typically energetic particles thus produced. Techniques are described to trap positrons efficiently and to cool and compress the resulting positron gases and plasmas. Finally, the procedures developed to deliver tailored pulses and beams (e.g., in intense, short bursts, or as quasi-monoenergetic continuous beams) for specific applications are reviewed. The status of development in specific application areas is also reviewed. One example is the formation of antihydrogen atoms for fundamental physics [e.g., tests of invariance under charge conjugation, parity inversion and time reversal (the CPT theorem), and studies of the interaction of gravity with antimatter]. Other applications discussed include atomic and materials physics studies and study of the electron-positron many-body system, including both classical electron-positron plasmas and the complementary quantum system in the form of Bose-condensed gases of positronium atoms. Areas of future promise are also discussed. The review concludes with a brief summary and a list of outstanding challenges.

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Section: Particle Energy Distributionsmentioning

confidence: 99%

Section: B Centerline Extractionmentioning

confidence: 99%

Section: B Centerline Extractionmentioning

confidence: 99%

Section: B Centerline Extractionmentioning

confidence: 99%

See 2 more Smart Citations

Plasma and trap-based techniques for science with positrons

Danielson¹,

Dubin²,

Greaves³

et al. 2015

Rev. Mod. Phys.

234

222

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“…6 shows a flat-top similar to the reported one. 22 The full width at half maximum (FWHM) gave a measure of the diameter of the plasma diameter.…”

Section: B the Electron Plasma Lifetime In A Rectangular Potential Wellmentioning

confidence: 99%

Comparison of non-neutral electron plasma confinement in harmonic and rectangular potentials in a very dense regime

2013

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Comparison of non-neutral electron plasma confinement in harmonic and rectangular potentials in a very dense regime Confinement of high density electron plasmas in a strong uniform magnetic field was experimentally studied in a multi-ring trap (MRT). The trap was housed inside a bore tube and surrounded by a superconducting solenoid. A 5 T magnetic field was used to provide radial confinement while an electrostatic harmonic or rectangular potential well was used for axial confinement. For trapped electrons of N ¼ 1.2 Â 10 10 in a harmonic potential well (HPW) with the trap length of L T ¼ 320 mm, the plasma lifetime was about 10 4 s and it became much longer at lower N ¼ 4.5 Â 10 9. Such long holding times were achieved without application of rotating electric fields. Contrastingly, in a rectangular potential well (RPW), the plasma of N ¼ 1.2 Â 10 10 under the same trap length expanded to cover the whole Faraday Cup within 200 s, where its radial expansion rate was g ¼ 3.2 Â 10 À2 mm/s, which was 20 times faster than HPW. The lifetime for RPW became shorter with increasing L T and scaled as 1/[L T ] 2

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Creation of finely focused particle beams from single-component plasmas

2008

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In a recent communication ͓Danielson et al., Appl. Phys. Lett. 90, 081503 ͑2007͔͒, a nondestructive technique was described to create finely focused beams of electron-mass, charged particles ͑i.e., electrons or positrons͒ from single-component plasmas confined in a Penning-Malmberg trap. This paper amplifies and expands upon those results, providing a more complete study of this method of beam formation. A simple model for beam extraction is presented, and an expression for a Gaussian beam profile is derived when the number of extracted beam particles is small. This expression gives a minimum beam diameter of four Debye lengths ͑full width to 1 / e͒ and is verified using electron plasmas over a broad range of plasma temperatures and densities. Numerical procedures are outlined to predict the profiles of beams with large numbers of extracted particles. Measured profiles of large beams are found in fair agreement with these predictions. The extraction of over 50% of a trapped plasma into a train of nearly identical beams is demonstrated. Applications and extensions of this technique to create state-of-the-art positron beams are discussed.

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Extraction of small-diameter beams from single-component plasmas

Cited by 22 publications

References 23 publications

Plasma and trap-based techniques for science with positrons

Plasma and trap-based techniques for science with positrons

Comparison of non-neutral electron plasma confinement in harmonic and rectangular potentials in a very dense regime

Creation of finely focused particle beams from single-component plasmas

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