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 3P3 state.

Laser excitation of the n=3 level of positronium for antihydrogen production / S. Aghion, C. Amsler, A. Ariga, T. Ariga, G. Bonomi, P. Bräunig, J. Bremer, R.S. Brusa, L. Cabaret, M. Caccia, R. Caravita, F. Castelli, G. Cerchiari, K. Chlouba, S. Cialdi, D. Comparat, G. Consolati, A. Demetrio, L. Di Noto, M. Doser, A. Dudarev, A. Ereditato, C. Evans, R. Ferragut, J. Fesel, A. Fontana, O.K. Forslund, S. Gerber, M.G. Giammarchi, A. Gligorova, S. Gninenko, F. Guatieri, S. Haider, H. Holmestad, T. Huse, I.L. Jernelv, E. Jordan, A. Kellerbauer, M. Kimura, T. Koettig, D. Krasnicky, V. Lagomarsino, P. Lansonneur, P. Lebrun, S. Lehner, J. Liberadzka, C. Malbrunot, S. Mariazzi, L. Marx, V. Matveev, Z. Mazzotta, G. Nebbia, P. Nedelec, M. Oberthaler, N. Pacifico, D. Pagano, L. Penasa, V. Petracek, C. Pistillo, F. Prelz, M. Prevedelli, L. Ravelli, L. Resch, B. Rienäcker, O.M. Røhne, A. Rotondi, M. Sacerdoti, H. Sandaker, R. Santoro, P. Scampoli, L. Smestad, F. Sorrentino, M. Spacek, J. Storey, I.M. Strojek, G. Testera, I. Tietje, S. Vamosi, E. Widmann, P. Yzombard, J. Zmeskal, N. Zurlo. - In: PHYSICAL REVIEW A. - ISSN 2469-9926. - 94:1(2016), pp. 012507.1-012507.7.

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

M. Caccia;F. Castelli;S. Cialdi;M.G. Giammarchi;Z. Mazzotta;L. Penasa;F. Prelz;M. Sacerdoti;
2016

Abstract

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 3P3 state.
atomic and molecular physics, optics
Settore FIS/01 - Fisica Sperimentale
Settore FIS/03 - Fisica della Materia
2016
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/457488
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