Positronium cooling at cryogenic temperature for advanced experiments

13th International Workshop on Slow Positron Beam Techniques and Applications

Brusa, R.S.^1 ; Di Noto, L.^1 ; Mariazzi, S.^1 ; Nebbia, G.^2

Dipartimento di Fisica, Università di Trento, TIFPA-INFN, Via Sommarive 14, Trento, I-38123 Povo, Italy^1

INFN Padova, Via Marzolo, 35131 Padova, Italy^2

关键词: Antihydrogen;    Collisional cooling;    Cryogenic temperatures;    In-vacuum;    Nano channels;    Ps formations;    Spectroscopy measurements;    Tunabilities;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/505/1/012038/pdf
DOI  :  10.1088/1742-6596/505/1/012038

来源: IOP

【 摘 要 】

New Ps spectroscopy measurements, formation of antihydrogen for antimatter-matter comparison experiments, production of Ps beams require the efficient production of cooled positronium in vacuum. At present the most efficient positron-positronium converters are silica based ordered or disordered porous materials, in which formed Ps decreases its kinetic energy by collisional cooling. Recently new positron-positronium converters based on oxidized nanochannels in silicon were found to be very promising because of the tunability of the nanochannel size, which allows to overcome the limits imposed to the Ps cooling by the quantum confinement. With these converters, Ps with temperatures as low as 150 K was detected in vacuum by a TOF apparatus. The Ps formation, quantum confinement, collisional cooling and emission into vacuum from nanochanneled silicon will be discussed in light of recent results.