Phase space compression of a positive muon beam in two spatial dimensions

TL;DR

This paper demonstrates the first successful two-dimensional phase space compression of a positive muon beam, significantly enhancing its brightness for advanced physics experiments.

Contribution

It introduces a novel method for compressing muon beams in two dimensions using cryogenic helium gas, magnetic, and electric fields, advancing muon beam technology.

Findings

Achieved simultaneous 2D phase space compression of muons.

Demonstrated a method to produce high-brightness muon beams.

Lays groundwork for future muon beam extraction into vacuum.

Abstract

We present the first demonstration of simultaneous phase space compression in two spatial dimensions of a positive muon beam, the first stage of the novel high-brightness muon beam under development by the muCool collaboration at the Paul Scherrer Institute. The keV-energy, sub-mm size beam would enable a factor 10$^5$ improvement in brightness for precision muSR, and atomic and particle physics measurements with positive muons. This compression is achieved within a cryogenic helium gas target with a strong density gradient, placed in a homogeneous magnetic field, under the influence of a complex electric field. In the next phase, the muon beam will be extracted into vacuum.