Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland.
Institute for Particle Physics, ETH Zurich, 8093 Zurich, Switzerland.
Phys Rev Lett. 2014 Jun 6;112(22):224801. doi: 10.1103/PhysRevLett.112.224801. Epub 2014 Jun 4.
A 10 MeV/c positive muon beam was stopped in helium gas of a few mbar in a magnetic field of 5 T. The muon "swarm" has been efficiently compressed from a length of 16 cm down to a few mm along the magnetic field axis (longitudinal compression) using electrostatic fields. The simulation reproduces the low energy interactions of slow muons in helium gas. Phase space compression occurs on the order of microseconds, compatible with the muon lifetime of 2 μs. This paves the way for the preparation of a high-quality low-energy muon beam, with an increase in phase space density relative to a standard surface muon beam of 10^{7}. The achievable phase space compression by using only the longitudinal stage presented here is of the order of 10^{4}.
一个 10MeV/c 的正 μ 子束在磁场强度为 5T 的几毫巴氦气中停止。使用静电场，μ 子“群”沿着磁场轴（纵向压缩）从 16cm 的长度有效地压缩到几毫米。该模拟再现了慢 μ 子在氦气中的低能相互作用。相空间压缩发生在微秒量级，与 μ 子寿命 2μs 兼容。这为制备高质量低能 μ 子束铺平了道路，与标准表面 μ 子束相比，相空间密度增加了 10^{7}。仅使用这里呈现的纵向阶段可实现的相空间压缩量级约为 10^{4}。
