Zeeman deceleration of electron-impact-excited metastable helium atoms

TL;DR

This paper demonstrates the first Zeeman deceleration of metastable helium atoms, achieving over 40% kinetic energy reduction and highlighting the importance of phase-space matching for producing a well-defined decelerated atomic packet.

Contribution

It reports the first experimental Zeeman deceleration of metastable helium atoms and details the enhancement of atom generation and phase-space matching techniques.

Findings

Over 40% kinetic energy reduction achieved

Deceleration results agree with 3D numerical simulations

Phase-space matching is crucial for effective deceleration

Abstract

We present experimental results that demonstrate - for the first time - the Zeeman deceleration of helium atoms in the metastable 2^3S_1state. A more than 40% decrease of the kinetic energy of the beam is achieved for deceleration from 490 m/s to a final velocity of 370 m/s. Metastable atom generation is achieved with an electron-impact-excitation source whose performance is enhanced through an additional discharge-type process which we characterize in detail. Comparison of deceleration data at different electron beam pulse durations confirms that a matching between the initial particle distribution and the phase-space acceptance of the decelerator is crucial for the production of a decelerated packet with a well-defined velocity distribution. The experimental findings are in good agreement with three-dimensional numerical particle trajectory simulations.