Tracking hydrogen movement using subatomic particles
A muon is an unstable subatomic particle similar to an electron but with much greater mass. The lifetime of a muon is only a couple of microseconds, but this is long compared with the lifetimes of many unstable subatomic particles. Because of their comparatively long lifetime, positive muons are often used to detect internal magnetic fields in solid materials. However, negative muons have seldom been used for this purpose because a large data set is required to obtain reliable results and experimental data collection times are normally limited. Recently, researchers developed a system that can count muon events at a much faster rate, allowing an experiment to be completed in a suitable time frame. Using this system, a Japanese collaboration has realized the long-standing goal of using negative muons to observe the local nuclear magnetic fields in a solid for the first time.