Laser excitation of the n=3 level of positronium for antihydrogen production

We demonstrate the laser excitation of the n = 3 state of positronium (Ps) in vacuum. A combination of a specially designed pulsed slow positron beam and a high-efficiency converter target was used to produce Ps. Its annihilation was recorded by single-shot positronium annihilation lifetime spectroscopy. Pulsed laser excitation of the n = 3 level at a wavelength lambda approximate to 205 nm was monitored via Ps photoionization induced by a second intense laser pulse at lambda = 1064 nm. About 15% of the overall positronium emitted into vacuum was excited to n = 3 and photoionized. Saturation of both the n = 3 excitation and the following photoionization was observed and explained by a simple rate equation model. The positronium's transverse temperature was extracted by measuring the width of the Doppler-broadened absorption line. Moreover, excitation to Rydberg states n = 15 and 16 using n = 3 as the intermediate level was observed, giving an independent confirmation of excitation to the 3 P-3 state

Positron bunching and electrostatic transport system for the production and emission of dense positronium clouds into vacuum

We describe a system designed to re-bunch positron pulses delivered by an accumulator supplied by a positron source and a Surko-trap. Positron pulses from the accumulator are magnetically guided in a 0.085 T field and are injected into a region free of magnetic fields through a μμ-metal field terminator. Here positrons are temporally compressed, electrostatically guided and accelerated towards a porous silicon target for the production and emission of positronium into vacuum. Positrons are focused in a spot of less than 4 mm FWTM in bunches of ∼8 ns FWHM. Emission of positronium into the vacuum is shown by single shot positron annihilation lifetime spectroscopy

Positron manipulation and positronium laser excitation in AEgIS

Production of antihydrogen by using the charge exchange reaction, as proposed by AEgIS (Antimatter Experiment: gravity, Interferometry, Spectroscopy), requires the formation of a dense cloud of positronium atoms excited to Rydberg states. In this work, the recent advances in AEgIS towards this result are described. Namely, the manipulation of positrons to produce bunches containing more than 108 particles and the laser excitation of positronium to Rydberg states, using n=3 as intermediate level, are presented

Positron manipulation and positronium laser excitation in AEgIS

Production of antihydrogen by using the charge exchange reaction, as proposed by AEgIS (Antimatter Experiment: gravity, Interferometry, Spectroscopy), requires the formation of a dense cloud of positronium atoms excited to Rydberg states. In this work, the recent advances in AEgIS towards this result are described. Namely, the manipulation of positrons to produce bunches containing more than 108 particles and the laser excitation of positronium to Rydberg states, using n=3 as intermediate level, are presented

Towards a gravity measurement on cold antimatter atoms

The present status of the AEGIS experiment at CERN (AD-06), on the way of forming anti-hydrogen for a first gravity measurement, is reviewed. Recent results in trapping and cooling positrons and antiprotons in the main electromagnetic traps are presented, including the storage time measurement obtained during the 2014 run with antiprotons, the observation of centrifugal separation of a mixed antiproton/electron plasma and positron accumulation and transfer results obtained during 2015

Laser excitation of the n = 3 level of positronium for antihydrogen production

We demonstrate the laser excitation of the n = 3 state of positronium (Ps) in vacuum. A combination of a specially designed pulsed slow positron beam and a high-efficiency converter target was used to produce Ps. Its annihilation was recorded by single-shot positronium annihilation lifetime spectroscopy. Pulsed laser excitation of the n = 3 level at a wavelength λ ≈ 205 nm was monitored via Ps photoionization induced by a second intense laser pulse at λ = 1064 nm. About 15% of the overall positronium emitted into vacuum was excited to n = 3 and photoionized. Saturation of both the n = 3 excitation and the following photoionization was observed and explained by a simple rate equation model. The positronium’s transverse temperature was extracted by measuring the width of the Doppler-broadened absorption line. Moreover, excitation to Rydberg states n = 15 and 16 using n = 3 as the intermediate level was observed, giving an independent confirmation of excitation to the 3 3 P stat