A new neutron reflectometer at Australia's HIFAR research reactor

A new neutron reflectometer has been built at Australia's 10 MW HIFAR research reactor. The X172 reflectometer operates in a monochromatic, angular dispersive mode collecting reflectivity data as a function of angle. The incident neutron beam is monochromated by a pair of pyrolytic graphite crystals (λ=2.43Å) before being collimated using a pair of motorised sintered B4C slits. Detection of the reflected neutron beam is via a 10-atmosphere, helium-3, linear position sensitive detector. Examples of data collected using the X172 reflectometer at air-solid and solid-liquid interfaces are given. Neutron reflectivity values as low as 10−5 have been measured on this instrument.