Fundamentals

In this chapter, we first give a brief historical overview of the discovery of the muon. We introduce its properties and anisotropic decay. We describe how these particles are produced in an accelerator, starting with pion production and decay, and how they can be manipulated to form a polarized beam and be implanted in a sample to perform a muon spin rotation/relaxation experiment, where the positive muon acts as a local magnetic microprobe. The different types of positive muon beams (“surface” and high-energy or decay beams) and their properties are described, and the precession of the muon magnetic moment in a magnetic field is introduced.