Stimulated radiative recombination of and

Rogelstad, Michael; Yousif, F. B.; Morgan, Thomas J.; Mitchell, James B.

doi:10.1088/0953-4075/30/17/018

Cited by 21 publications

(7 citation statements)

References 27 publications

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“…Stimulated radiative recombination has already been proposed as an efficient way to form antihydrogen [52][53][54][55][56]. Following the realization on hydrogen [57,58], a stimulated formation of antihydrogen has been attempted using a CO 2 laser down to n = 11, but without success [59]. The invoked explanation involved the competition with the three body recombination (3BR) that populates several (mostly very excited) levels at a rate [44] Γ 3BR ∼ 160 s −1 n e + 10 8 cm 3 2 10 K T 4.5…”

Section: B Stimulated Radiative Recombinationmentioning

confidence: 99%

Stimulated decay and formation of antihydrogen atoms

et al. 2020

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Antihydrogen atoms are routinely formed at the Antiproton Decelerator at CERN in a wide range of Rydberg states. To perform precision measurements, experiments rely on ground state antimatter atoms which are currently obtained only after spontaneous decay. In order to enhance the number of atoms in ground state, we propose and assess the efficiency of different methods to stimulate their decay. At first, we investigate the use of THz radiation to simultaneously couple all n-manifolds down to a low lying one with sufficiently fast spontaneous emission toward ground state. We further study a deexcitation scheme relying on state-mixing via microwave and/or THz light and a coupled (visible) deexcitation laser. We obtain close to unity ground state fractions within a few tens of µs for a population initiated in the n = 30 manifold. Finally, we study how the production of antihydrogen atoms via stimulated radiative recombination can favourably change the initial distribution of states and improve the overall number of ground-state atoms when combined with the stimulated deexcitation proposed.

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Section: B Stimulated Radiative Recombinationmentioning

confidence: 99%

Stimulated decay and formation of antihydrogen atoms

et al. 2020

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“…The recent review by Hahn [8] on the electron recombination mentions only one, very special version of LAR process, namely one-photon LAR when the laser is tuned in resonance with the energy of free-bound electron transition, and only emission of photons with this particular energy is considered. The study of this special case was initiated quite long ago [9][10][11][12][13] and remains active in connection with the processes in the storage rings [14][15][16][17][18][19][20], formation of positronium [9] and antihydrogen [21][22][23] and even with possible cosmological manifestations [24]. In all these theoretical studies the laser field was presumed to be weak and its influence on an initial and/or final electron states was neglected, except Refs.…”

Section: Introductionmentioning

confidence: 99%

Multiphoton radiative recombination of electron assisted by a laser field

Kuchiev

Ostrovsky

2000

Phys. Rev. A

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In the presence of an intensive laser field the radiative recombination of the continuum electron into an atomic bound state generally is accompanied by absorption or emission of several laser quanta. The spectrum of emitted photons represents an equidistant pattern with the spacing equal to the laser frequency. The distribution of intensities in this spectrum is studied employing the Keldysh-type approximation, i.e. neglecting interaction of the impact electron with the atomic core in the initial continuum state. Within the adiabatic approximation the scale of emitted photon frequencies is subdivided into classically allowed and classically forbidden domains. The highest intensities correspond to emission frequencies close to the edges of classically allowed domain. The total cross section of electron recombination summed over all emitted photon channels exhibits negligible dependence on the laser field intensity.

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“…where I is the laser power (in watts), F is the cross-sectional area of the laser beam, ν is the laser frequency, and ∆ν represents the 'frequency spread of the 13 beam' (that is, ∆ν takes into account that only photons and positrons with energies within the width of the recombination energy level will engage in this process, and since the energy spread of the positrons usually dominates, it can be expressed as ∆ν = (m e + v e + /h)∆v e + , where ∆v e + is the positron velocity spread [76]). …”

Section: 22)mentioning

confidence: 99%

Detection of Trapped Antihydrogen

Hydomako

2013

Springer Theses

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The ALPHA experiment is an international effort to produce, trap, and perform precision spectroscopic measurements on antihydrogen (the bound state of a positron and an antiproton). Based at the Antiproton Decelerator (AD) facility at CERN, the ALPHA experiment has recently magnetically confined antihydrogen atoms for the first time. A crucial element in the observation of trapped antihydrogen is ALPHA's silicon vertexing detector. This detector contains sixty silicon modules arranged in three concentric layers, and is able to determine the three-dimensional location of the annihilation of an antihydrogen atom by reconstructing the trajectories of the produced annihilation products.This dissertation focuses mainly on the methods used to reconstruct the annihilation location. Specifically, the software algorithms used to identify and extrapolate charged particle tracks are presented along with the routines used to estimate the annihilation location from the convergence of the identified tracks. It is shown that these methods can determine the annihilation location with a spatial resolution between about 0.6 to 0.8 cm (depending on the coordinate being measured). Furthermore, a robust analysis to identify and reduce cosmic ray background events is described. The cosmic ray background can obscure the trapped antihydrogen signal, and its suppression leads to a significant increase in the annihilation detection sensitivity. The background suppression analysis involves examining the reconstructed detector event based on several selection criteria, including: the number of charged particle tracks, the radial vertex position, and a fit of a straight line to the event hit positions. By carefully optimizing these criteria, (99.54 ± 0.02)% of cosmic ray events are rejected, while (64.4 ± 0.1)% of antihydrogen annihilation events are retained. Finally, the experimental results demonstrating the first-ever magnetic confinement of antihydrogen atoms are presented. These results rely heavily on the silicon i detector, and as such, the role of the annihilation vertex reconstruction is emphasized.

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Stimulated radiative recombination of and

Cited by 21 publications

References 27 publications

Stimulated decay and formation of antihydrogen atoms

Stimulated decay and formation of antihydrogen atoms

Multiphoton radiative recombination of electron assisted by a laser field

Detection of Trapped Antihydrogen

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