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GEM

The GEneral Materials (GEM) powder diffractometer is a versatile instrument used to investigate the structure of crystalline and amorphous materials. GEM is also well-suited for magnetic and large unit cell structural investigations.

The detectors of the GEM instrument at the ISIS Neutron and Muon Source.
Crystallography
Neutron diffraction
Total scattering
Instrument dashboard

Instrument scientists

To find out more about each team member, click the + symbol.

Alex Hannon at the ISIS Neutron and Muon Source.

Alex Hannon

Instrument scientist
Gabriel Perez

Gabriel Perez

Instrument scientist
Ivan da Silva at the ISIS Neutron and Muon Source

Ivan da Silva

Instrument scientist

Technical information

Moderator  Liquid methane at 110 K 
Incident wavelength  ~0.1 to ~3.6 Å 
Incident flight path    17.0 m 
Secondary flight path  1.03 to 2.77 m 
Incident beam dimensions (max)  40 mm (h) x 15 mm (w) 
Detector coverage  3.86 steradians (7.27 m2) 
Detector 2θ range  5 – 171° 
Q range  0.1 – 60, at best 
ΔQ/Q (%)  4.7 – 0.34 (detector banks 1 – 6) 

 

Related resources

Sample environment

Equipment routinely used on GEM:

  • Automatic sample changer (20 positions, room temperature)
  • Furnace (RT to 1000°C)
  • Top-loading CCR (5 to 300 K)
  • He4 cryostat (2 to 300 K)

Non-standard sample environment:

  • Gas panel kits for continuous gas flow cell or static gas loading experiments.
  • High pressure cells

Visit the ISIS sample environment page or speak to your instrument contact.

Software

Instrument highlights

Our facility supports a broad research programme that generates impact on a national and global scale. Browse through some of the recent research conducted using the GEM beamline.
A graphic showing the crystal structure of the material at x=0 and x=1, and the pair distribution functions at different x values.
Localised areas with different compositions could lead to better performance of thermoelectric materials
A figure showing the crystal structure with and without LLDs.
Total scattering proves to be a powerful tool for studying high entropy alloys
Crystal structure of CeRhSn showing a quasi-Kagome lattice of the Ce atoms shown in green, Rh atom in blue and Sn atoms in red colour.
Quantum spin liquid found in a strongly correlated metallic magnet
The crystal structure, showing the octahedral sites.
New solid-state battery material for next generation batteries
A triangular pyramid, with each corner showing the magnetic degrees of freedom.
Neutrons reveal quantum liquid of octupoles

Recent publications

View all publications

Instrument reference

All publications and datasets based on experiments using GEM should cite that the data is collected by DOI: 10.5286/isis.instrument.4207. 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.

Reference publication: Results on disordered materials from the GEneral Materials diffractometer, GEM, at ISIS, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 551, 1, 2005, 88-107. DOI: 10.1016/j.nima.2005.07.053.

Team member