MUON BEAMS & µSR FACILITIES

Principal CW Muon Facilities

• The µSR Facility at PSI (the Paul Scherrer Institut, near Zürich, Switzerland) and
• our Facility at TRIUMF (the TRI-University Meson Facility in Vancouver, Canada)

Pulsed Muon Facilities

• The µSR Facility of ISIS at the Rutherford Appleton Lab in the U.K. and the associated RIKEN/RAL Muon Facility offer the highest intensity so far.
• The BOOM (BOOster Muon) facility of the KEK laboratory in Japan and the associated Meson Science Lab have now been superceded by the J-PARC accelerator centre in Tokai.

Other Accelerator Labs with Muon Capabilities

• The high-intensity µSR facility at the Clinton P. Anderson Meson Physics Facility (LAMPF) was just beginning to find its optimal use when the facility was shut down. There was hope for utilizing this world's brightest muon source for µSR experiments if the proposed Pulsed Lepton Facility had been built for the Proton Storage Ring, in which case LAMPF would have become a pulsed muon facility.
• There are also µSR facilities at the JINR lab in Dubna (Russia) but their future is uncertain.
• In principle, any high-intensity hadron accelerator of greater than about 400 MeV incident kinetic energy should be capable of producing useful muon beams. A list of the world's accelerators, organized into various categories, is maintained at LANL.

  The time structure of the beam should be either CW or very sharply pulsed (pulse widths as short as possible, but no greater than about 100 ns, with at least 20 µs between pulses) to produce the best results, but time-integral methods can make use of any muon beams.

Editorial comment by Jess Brewer :

The main impediment to expanded use of µSR has always been political: the high energy physics community that used to have sole responsible for the construction of large accelerators is not always enthusiastic about sharing their resources with the materials scientists who make up the bulk of the µSR user community; meanwhile, as the materials science community begins to regard large accelerators as valuable resources, it is predominantly for the sake of their production of spallation neutrons for investigations in k-space. Both communities suffer when they ignore the opportunity for cooperative alliance offered by µSR and continue to see each other (and µSR) as adversaries. There are a few hopeful signs of enlightened self-interest in this decades-old struggle, but the tradition of animosity between narrow interest groups is still the worst enemy of cooperative scientific inquiry.