MuSR technical information

Technical information for the MuSR instrument

Technical Summary

Production target5, 7, or 10 mm graphite at 45o to proton beam
Beampositive muons, at or near surface momentum
Incident momentum26.5 MeV/c, 10% momentum bite
Pulse structuresingle pulse, 80 ns fwhm
Contaminatione++ < 0.15 with separator voltage > 70kV
Beam size at focusVertical: 10 mm fwhm, horizontal: adjustable, 10-27 mm fwhm
Intensity4x105 µ+ /s shared by the three south-side muon areas
Data rateevent rates of typically 40-45 million events per hour (40Hz)
Muon polarisation100%
Muon energy; range3.2 MeV; range approx. 100 mg.cm-2 for surface momentum
Backgroundhistograms contain a constant background of approx. 10-5 times the number of counts in the first bins
Instrument geometrylongitudinal (LF) or zero (ZF) applied magnetic fields, low transverse fields (TF)
Detectors64 scintillator segments in two circular arrays. Grouped 2x32 for ZF, LF
Sample environment
  • Helmholtz coils (0-400 mT), LF or TF,
  • calibration coils (0-10 mT) TF
  • zero field compensation to <3 µT
  • sorption crysotat (350 mK - 50 K)
  • Oxford instruments cryostat (2 K - 300 K)
  • closed cycle refrigerator (CCR) (12 K - 340 K)
  • furnace (300 K - 1000 K)
Data acquisitionInstrument controlled by SECI
Timing resolution64 TDCs with time resolution settings of 8, 16, 24, or 32 ns
Measurable frequencies0.1-10 MHz (upper limit due to finite muon pulse width)

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