Speaker
Description
The muCool project aims to develop an innovative device for generating low-energy, high-intensity, and high-quality muon beams for future high-precision experiments such as muon g-2 measurements, muonium spectroscopy, and muonium gravity studies. These experiments, involving muons and muonium atoms, hold significant potential for testing theoretical predictions of the Standard Model within a purely leptonic system.
The muCool device is designed to reduce the phase space of a standard $\mu^+$ beam by a factor of $10^{10}$ with an efficiency of $10^{-3}$ [1]. The muCool device is a cryogenic helium gas target with a complex electric field geometry inside the active volume, placed in a homogeneous magnetic field of $5\ T$. Muons are transversely compressed by a combination of $E \times B$ drift and drift resulting from collisions with helium gas, as the collision frequency changes vertically due to the gas density gradient. Longitudinal compression is achieved through an electric potential minimum along the length of the muCool device. Combined transverse and longitudinal compression of the muon beam to sub-millimeter size and cooling to $eV$ energies have been demonstrated recently [2]. To make the muCool device compatible with future muon experiments, the muon beam must be extracted from the target volume through an orifice. The extraction step poses a significant technical challenge in maintaining the helium gas density profile inside the muCool target while transitioning from a closed to open volume design. The upgraded design concept and simulation results for muon beam extraction will be presented.
[1] Belosevic, I., Antognini, A., Bao, Y. et al. "muCool: a next step towards efficient muon beam compression". Eur. Phys. J. C 79, 430 (2019). https://doi.org/10.1140/epjc/s10052-019-6932-z
[2] A. Antognini, N. J. Ayres, I. Belosevic et al. "Demonstration of Muon-Beam Transverse Phase-Space Compression". Phys. Rev. Lett. 125, 164802(2020). https://doi.org/10.1103/PhysRevLett.125.164802
