Spatz: the time‐of‐flight neutron reflectometer with vertical sample geometry at the OPAL research reactor

The Spatz neutron beam instrument is the second time‐of‐flight neutron reflectometer to be installed at the OPAL research reactor. The instrument was formerly the V18 BioRef reflectometer at the BER‐II reactor in Berlin and was transferred to Australia in 2016. Subsequently the instrument was re‐installed in the neutron guide hall of the OPAL reactor at the end position of the CG2B cold‐neutron guide and recommissioned. The instrument performance has not been compromised by the move, with reflectivity achieved down to 10−7 and good counting statistics within a reasonable time frame using a wavelength range of 2–20 Å. Several different samples at the solid–air interface and the solid–liquid interface have been measured to demonstrate the instrument's capabilities. The performance of the Spatz neutron reflectometer is demonstrated. It has a variable wavelength resolution to suit experimental needs for reflectometry at air–solid and solid–liquid interfaces.