16 Oct 2008



MARI is a chopper spectrometer with continuous detector bank coverage ranging from 3° to 134° degrees.

​​​​​MARI spectrometer.


Recent proposal rounds have seen significant number of beamtime proposals rejected by the panel for similar reasons. The Excitations group and Facility Access Panel wish to help users to submit good proposals so would point out the following reoccurring issues of missing information in proposals that is detrimental to their scores, together with straightforward remedies:

  • Lack of evidence that a large single crystals exists or that a sufficient number of co-aligned crystals can be aligned for the experiment. This can be resolved by including a picture (with scale bars)
  • Lack or unclear presentation of relevant structural and physical property characterisation of the materials to be studied. This can be resolved by presenting diffraction and physical properties characterisation of your samples in the proposal.
  • Lack of details regarding what will be measured during the experiment which makes it challenging or in some cases impossible for the viability and merit of the proposal to be assessed during review. ​This can be resolved by proposers contacting ISIS staff prior to proposal submission.

MARI has a wide angular coverage and a wide energy range and good resolution making it ideal for the study of phonon densities of states in crystalline and disordered systems, and crystal field excitations in magnetic materials. MARI is the only chopper spectrometer at ISIS not to be equipped with a pixilated detector array using position sensitive detectors. This makes MARI the instrument of choice for studies of polycrystalline and powdered samples, and liquids. MARI also boasts the lowest instrumental background of the ISIS suite of chopper spectrometers, making the machine highly sensitive despite the relatively low incident neutron flux.

The MARI spectrometer was funded by the Japanese Ministry of Education, Science and Culture (Monbusho) as part of the UK-Japan Collaboration on neutron scattering. This collaboration, initiated in 1986, was the creation of the late Professor Yoshikazu Ishikawa. The spectrometer is named after Professor Ishikawa's daughter, Mari. The Japanese Symbol for Mari also happens to be the Japanese for truth.

MARI has contributed seminal work in fields such as quantum-fluids, the dynamics of disordered materials and low-dimensional magnetism. It is also used for studies of biological and polymeric materials, catalysts, thermo-electric materials, geological samples, high-temperature superconductors and liquid dynamics.

Instrument Links

Contact information for MARI instrument

Location and contact information for the MARI​ beamline

​​01235 446486