In this section
Emu
Emu is a versatile instrument for μSR studies. With a detector array optimised for high data quality and a variety of sample environments, it allows users to explore larger parameter spaces and run measurements efficiently. It is used to study magnetism, semiconductors, energy materials, chemical kinetics and more. In addition, the flypast geometry and the unique arrangement of detectors allow measurements on very small samples.
Instrument scientists
To find out more about each team member, click the + symbol.
John Wilkinson
Instrument scientist
Koji Yokoyama
Instrument scientist
Stephen Cottrell
Instrument scientist
We support a wide range of science on this instrument and will put you in touch with the Muon Group team member who is best able to support your experiment.
Technical information
Emu is a 96-detector µSR spectrometer that is optimised for zero field and longitudinal field measurements.
Magnetic fields
- Active ZF to <0.01 G
- Longitudinal fields up to 4,500 G (or 5,000 by prior arrangement)
- Transverse fields up to 150 G
Temperatures
- Dilution fridge (50 mK – 300 K)
- He4 cryostat (1.5 K – 400 K)
- Flow cryostat (4 K – 600 K)
- Sorption cryostat (300 mK – 40 K)
- CCR (10 K – 600 K)
- Furnace (300 K- 1000 K)
- Optical furnace (20˚C – 1000˚C)
The count rate is typically 120 MEv/hour with a beam size of 10 x 15 mm (FWHM) and can be controlled by changing the collimating slits upstream. Flypast geometries are available on request to measure samples of area as small as 4×4 mm2. Equipment is available to condense gas samples with the flow cryostat and the CCR.
Related resources
Technical summary
Production target: 5, 7, or 10 mm graphite at 45° to proton beam
Beam: positive muons, at or near surface momentum
Incident momentum: 26.5 MeV/c, 10% momentum bite
Pulse structure: single pulse, 80 ns fwhm
Contamination: e+ /µ+ < 0.15 with separator voltage > 70 kV
Beam size at focus: Vertical: 10 mm fwhm, horizontal: adjustable, 10-27 mm fwhm
Intensity: 4×105 µ+ /s shared by the three south-side muon areas
Data rate: event rates of typically 120 million events per hour (5mm muon production target, ISIS current of 180 µA
Muon polarisation: 100%
Muon energy; range: 3.2 MeV; range approx. 100 mg.cm2 for surface momentum
Background: histograms contain a constant background of approx. 10-5 times the number of counts in the first bins
Instrument geometry: longitudinal (LF) or zero (ZF) applied magnetic fields, low transverse fields (TF)
Detectors: 96 scintillator segments in two circular arrays.
Data acquisition: Instrument controlled by IBEX
Timing resolution: 96 TDCs with time resolution settings of 8, 16, 24, or 32 ns
Measurable frequencies: 0.1-10 MHz (upper limit due to finite muon pulse width)
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)
- Dilution refrigerator (50 mK – 4 K)
Recent publications
Instrument reference
All publications and datasets based on experiments using Emu should cite that the data is collected by DOI: 10.5286/isis.instrument.6948. Experiment DOIs follow the format 10.5286/ISIS.E.RBXXXXXXX, where XXXXXXX is the 7-digit experiment (RB) number and these can be viewed via the Data Gateway.