Minimizing plasma temperature for antimatter mixing experiments
Abstract
The ASACUSA collaboration produces a beam of antihydrogen atoms by mixing pure positron and antiproton plasmas in a strong magnetic field with a double cusp geometry. The positrons cool via cyclotron radiation inside the cryogenic trap. Low positron temperature is essential for increasing the fraction of antihydrogen atoms which reach the ground state prior to exiting the trap. Many experimental groups observe that such plasmas reach equilibrium at a temperature well above the temperature of the surrounding electrodes. This problem is typically attributed to electronic noise and plasma expansion, which heat the plasma. The present work reports anomalous heating far beyond what can be attributed to those two sources. The heating seems to be a result of the axially open trap geometry, which couples the plasma to the external (300 K) environment via microwave radiation.
Cite
@article{arxiv.2201.01256,
title = {Minimizing plasma temperature for antimatter mixing experiments},
author = {E. D. Hunter and C. Amsler and H. Breuker and S. Chesnevskaya and G. Costantini and R. Ferragut and M. Giammarchi and A. Gligorova and G. Gosta and H. Higaki and Y. Kanai and C. Killian and V. Kletzl and V. Kraxberger and N. Kuroda and A. Lanz and M. Leali and V. Mäckel and G. Maero and C. Malbrunot and V. Mascagna and Y. Matsuda and S. Migliorati and D. J. Murtagh and Y. Nagata and A. Nanda and L. Nowak and E. Pasino and M. Romé and M. C. Simon and M. Tajima and V. Toso and S. Ulmer and U. Uggerhøj and L. Venturelli and A. Weiser and E. Widmann and T. Wolz and Y. Yamazaki and J. Zmeskal},
journal= {arXiv preprint arXiv:2201.01256},
year = {2022}
}
Comments
Proceedings of the Exotic Atoms (EXA) Conference, Vienna, 2021