28 Jan 2009



In addition to neutron production, ISIS is the world's most intense source of pulsed muons for condensed matter research.

ISIS EC Muon Beamline separation
​​​​ISIS EC Muon Beamline separation​

The ISIS muon group operates some of the world’s leading muon spectrometers, used to study a diverse range of materials.

Spin-polarised muons are generated at ISIS by collisions between the proton beam and a thin carbon target. For condensed matter studies, positive muons are implanted into materials and the time-evolution of the muon polarisation is observed. Negative muons are also used for elemental analysis.

The muon instruments EMUHiFi, MuSR, ARGUS, CHRONUS and run a very broad science programme, using implanted positive muons both as magnetic probes -  in magnetism, superconductivity and charge transport - and as proton analogues in chemical physics - for investigation of hydrogen behaviour in semiconductors, molecular dynamics, chemical reactions and particle diffusion. 



Main Contact

Instrument Scientists


  • Yue Yuan


  • Innes McClelland
  • Madeleine McRoberts
  • Daniel Snook
  • Leo Collins


The Instruments

The muon instruments are summarised below. For a comparison of instrument capabilities click HERE


EMU is a general-purpose µSR spectrometer which is optimised for zero field and longitudinal field measurements. The experimental work includes, but not limited to, magnetism and ion diffusion in solids.

Fields of up to 5000 G can be applied, and sample temperatures in the range of 50mK to 1500K can be produced using a variety of sample environment equipment. EMU has

  • 96 detector elements
  • high count rate (130 MEv/hr typical)
  • spot 10 x 15mm
  • various sample environment including RF excitation



The high-field muon instrument at ISIS, called HiFi, provides applied longitudinal fields up to 5T

The magnet is a 5T superconducting split-pair, with high field homogeneity over the sample volume and actively compensated stray field.  It has additional z-axis coils up to 400​G for small changes to the main field (for example, for sweeping through level crossing resonances) as well as 100G x- and y-axis transverse coils for calibration measurements, etc. HiFi has the following sample environment equipment:


  • Dilution fridge (30mk - 300K)
  • 4He cryostat (1.5K - 300K)
  • Flow cryostat (4K - 400K)
  • CCR (10K - 600K)
  • Reflector furnace (300K- 1500K)


The MuSR spectrometer is a general purpose instrument. However, the emphasis of the experimental work conducted is investigating magnetism and superconductivity.

MuSR is a 64-detector µSR spectrometer which can be rotated through 90o to enable both longitudinal and transverse measurements to be made. Fields of up to 3000 G can be applied, and sample temperatures in the range of 40mK to 1000K can be produced using a variety of sample environment equipment.

  • 64 detector elements
  • SE kit prepared off-beam
  • 50mK - 1500K​
  • 0 - 3000 G Longitudinal Field
  • 0 - 600 G Transverse Field
  • Spot 10 x 15mm


A muon spectrometer for condensed matter and molecular studies.

The muon instrument Argus (Advanced Riken General-purpose mUsr Spectrometer) is housed in Port 2 of the RIKEN-RAL Muon Facility. It can be used for a wide variety of studies in the areas of magnetism, superconductivity, charge transport, molecular as well as polymeric materials and semiconductors. As well as surface muons decay muons can be used with a momentum up to 120 MeV/C, this makes it particulary useful for studying sealed samples ​such as liquids or pressure cells. It has:​

  • 192 detector elements
  • Data rates ~80 MeV/hr (double pulse)
  • Temperature range 30 mK - 500 ​K
  • Longitudinal field range 0 G - 4000 G LF
  • Transverse field range 0 G - 150 G TF, optimised for low TF measurements. 
  • Dedicated pressure cell avalible with range up to 0.7 GPa​​​



CHRONUS is the newest instrument located in the RIKEN-RAL Muon Facility.

CHRONUS is housed in Port 4 of the RIKEN-RAL Muon Facility. As with ARGUS and the other spectrometers, it can be used for a wide range of studies, from molecular motion to magentism and superconductivity. As with ARGUS, variable momentum muons can also be delivered to CHRONUS, however, as of yet, there is no pressure cell. CHRONUS has:​

  • 606 detector elements
  • Data rates ~80 MeV/hr (double pulse)
  • Temperature range 0.3 mK - 500 ​K
  • Longitudinal field range 0 G - 4000 G LF
  • Transverse field range 0 G - 150 G TF