Deva technical information
17 Aug 2009



Technical information


​Technical Summary

Production target7, 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 20 million events per hour 
Muon polarisation100%
Muon energy; range3.2 MeV; range approx. 100 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)
DetectorsRF spectrometer has 32 scintillator segments in two circular arrays. Grouped 2x16 for ZF, LF
Sample environment
  • Helmholtz coils (0-200 mT), LF
  • calibration coils (0-2 mT) TF
  • zero field compensation to <3 µT
  • Oxford instruments flow cryostat (4 K - 400 K)
Data acquisitionInstrument controlled by an Alpha 200 4/166
Timing resolution32 TDCs with time resolution settings of 0.5 to 16 ns
Measurable frequencies0.1-10 MHz (upper limit due to finite muon pulse width) for standard mSR.  RF-mSR can give significantly higher precession frequencies.