The production of a timed tunable beam of positronium atoms

Laricchia, G.; Davies, S A; Charlton, M.; Griffith, T C

doi:10.1088/0022-3735/21/9/013

Cited by 28 publications

(10 citation statements)

References 11 publications

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“…Typical ionization energies are of the order of 10's of eV, and Ps produced in this way using β + particles thus have energies much higher than E B . If a slow positron beam is used instead this methodology can generate quasi-monoenergetic Ps beams [231] at lower energies [232] suitable for performing scattering experiments. The Ps energy spread will be determined primarily by that of the positrons; this could range from meV to eV scales, depending on the positron moderator used.…”

Section: Ps Productionmentioning

confidence: 99%

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Experimental progress in positronium laser physics

2018

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Abstract. The field of experimental positronium physics has advanced significantly in the last few decades, with new areas of research driven by the development of techniques for trapping and manipulating positrons using Surko-type buffer gas traps. Large numbers of positrons (typically ≥10 6 ) accumulated in such a device may be ejected all at once, so as to generate an intense pulse. Standard bunching techniques can produce pulses with ns (mm) temporal (spatial) beam profiles. These pulses can be converted into a dilute Ps gas in vacuum with densities on the order of 10 7 cm −3 which can be probed by standard ns pulsed laser systems. This allows for the efficient production of excited Ps states, including long-lived Rydberg states, which in turn facilitates numerous experimental programs, such as precision optical and microwave spectroscopy of Ps, the application of Stark deceleration methods to guide, decelerate and focus Rydberg Ps beams, and studies of the interactions of such beams with other atomic and molecular species. These methods are also applicable to antihydrogen production and spectroscopic studies of energy levels and resonances in positronium ions and molecules. A summary of recent progress in this area will be given, with the objective of providing an overview of the field as it currently exists, and a brief discussion of some future directions.

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Section: Ps Productionmentioning

confidence: 99%

“…36) [120,559]. Energy tunable Ps beams can be made by passing a positron beam through a gas cell [85,231,560,561], or by glancing angle positron scattering [562]. These methods can generate beams in the energy ranges of approximately 5-500 eV and 10-100 eV, respectively.…”

Section: Ps − Spectroscopymentioning

confidence: 99%

Experimental progress in positronium laser physics

2018

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“…Ps converter particularly from $ð10-100Þ eV [9]. The Ps beam kinetic energy (E Ps ) is tunable via that of the positron (E þ ) according to E Ps ¼ E þ À E th , as verified by time-of-flight measurements which also allow the dominant n state of Ps to be determined [26][27][28]. Positronium-beam production from H 2 is known to produce atoms predominantly in the ground state [28].…”

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confidence: 94%

Resonant Scattering of Positronium in Collision withCO2

et al. 2010

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The total cross sections of positronium (Ps) scattering from a carbon-dioxide molecule have been measured over the range (7-400) eV incident-Ps energy. For the first time in Ps collisions, a resonantlike structure is observed. For the present target, it occurs around 9.5 eV followed by a broader peak at ∼60 eV. Following Brawley et al. [Science 330, 789 (2010)] who have observed similarities between the total cross sections of positronium and of electrons incident upon a given target at the same velocity, a corresponding comparison is made for CO2. The comparison suggests that the former peak corresponds to the well-known 2Π(u) shape resonance which occurs for electrons at an incident velocity of 0.5 a.u. Further features are discussed and theoretical input is sought.

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“…The retarding arrangement between the gas cells is used to prevent any positrons transmitted through the first gas cell from entering the second cell -the Ps scattering cell -containing the gas under investigation. Time-offlight (TOF) spectra [21] were obtained via coincidences between the signals of a ''tagger'' (CEMA1), incorporating a remoderator [22] and the end of beam detector (CEMA2). In front of CEMA2 are three retarding grids.…”

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confidence: 99%

Fragmentation of Positronium in Collision with He Atoms

et al. 2002

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The absolute cross section for the fragmentation of positronium in collision with He atoms has been measured. The results are compared with available theories. The longitudinal energy distributions of positrons resulting from fragmentation have also been determined and are found to display a peak situated just below half the residual energy. This is suggestive of the occurrence of "electron loss to the continuum" in which the two residual charged particles lie in a low relative-velocity Coulomb-continuum state.

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The production of a timed tunable beam of positronium atoms

Cited by 28 publications

References 11 publications

Experimental progress in positronium laser physics

Experimental progress in positronium laser physics

Resonant Scattering of Positronium in Collision withCO2

Fragmentation of Positronium in Collision with He Atoms

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