The Muon Science: An introduction to a new research field for materials
On Tuesday, 23rd of January 2018, advanced materials research group again held a guest lecture inviting Dr. Isao Watanabe from Advanced Meson Science Laboratory, RIKEN Nishina Center, Japan. The lecture was on the introduction of the muon science to study materials.
Muon is unstable elementary particle discovered in 1936 by Carl D. Anderson and Seth Neddermeyer as the secondary radiation from cosmic rays. It is simply a “heavy electron” with the mass of about 200 times heavier than that of the electron and also a “light proton” with the mass of about 1/9 of the proton. The muon carries the half spin and the large gyromagnetic ratio (2π × 13.55 kHz/G) which therefore acts as a very sensitive probe to study local magnetic fields. The muon spin polarizes after its production, and this self-spin-polarization can allow us to carry out experiments even in the zero-field condition. Muon’s spin and charge are exquisitely sensitive as a local magnetic probes of matter. A technique based on these unique properties of the muon is named as the μSR technique. μSR is an abbreviation of muon-spin rotation/relaxation/resonance. Low energy muons which are required for μSR are produced at intermediate energy particle accelerator facility. There are currently five facilities around the world producing muon beams: TRIUMF in Canada, ISIS in the UK, PSI in Switzerland and JPARC in Japan. μSR technique provides an excellent method to study materials in complement to the other experimental techniques.