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WISH
WISH is a cold neutron diffractometer designed to study magnetic materials and those with large unit cells in powder, single-crystal and thin-film forms. Its high resolution at long d-spacings, combined with a high signal-to-noise ratio, makes WISH ideal for detecting small signals in tiny samples or systems with reduced magnetic moments.
Instrument scientists
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Technical information
WISH is located on TS2 and views the solid methane moderator operated at 45 K. The primary flight path of 40m delivers a useable wavelength band from 0.5 to 10 Å at 10 Hz and from 0.5 to 20 Å at 5 Hz, resulting in the accessible d-spacing range from 0.5 to 50 Å (100 Å) at 10 Hz (5 Hz).
The ballistic elliptical supermirror guides allow an efficient transport of high flux with a variable divergence selected by a set of 5 jaws. In high resolution (HR) mode the beam divergence is 0.2°, which increases to 0.4° in medium resolution configuration.
In the HR mode, the back scattering resolution Δd/d is ~0.35% which gradually degrades down to ~1.2% upon moving towards the forward scattering geometry.
The detectors consist of 1,520 8 mm-diameter, 1m-long ³He tubes positioned along a secondary flight path of 2.2 m. They continuously cover the horizontal scattering plane from 10 to 170° and the out-of-plane coverage of 30°.
A dedicated oscillating radial collimator is used to reduce the sample environment scattering, and an Ar-filled tank, together with a sample environment tank in high vacuum, reduce the air scattering.
Related resources
Sample environment
The WISH instrument can use all the standard ISIS sample environment kits (4He cryostat, CCR, furnaces, etc), plus some dedicated kits.
WISH routinely uses the 8T and 13.2T magnets and the ULT 3He sorb and dilution fridge insert (also in combination with the magnets).
The instrument can use the Paris-Edinburgh press and some dedicated clamp cell for high pressure studies (the pressure-temperature ranges depend on the kits used and on the sample size).
Razorbill cells are available for in-situ uniaxial stress experiment in combination with a 4He cryostat (1.5< T <300K).
Electric fields are also available.
WISH can perform gas loading experiments in MOF- and zeolite-type systems using the gas panel sample environments kits.
Recent publications
Instrument reference
All publications and datasets based on experiments using WISH should cite that the data is collected by DOI: 10.5286/isis.instrument.4938. 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.