Offspec technical information
13 Aug 2009




Technical information for the Offspec instrument


Technical Summary

OffSpec is a low background, polarised, reflectometer optimised for the measurement of off-specular reflection from a wide range of hard and soft-condensed matter systems.

In addition to tradition neutron reflection Offspec is able to non-destructively investigate in-plane length scales at buried interfaces comparable to those studied by atomic force microscopy and other more invasive surface profiling techniques. This new capability is achieved through the use of neutron spin-echo methods that have been developed in collaboration with TU-Delft.

With a primary flight path of 23.7m from the grooved solid methane moderator, the instrument is equipped with a  linear, position sensitive, detector 3.6m from the sample position and a single, well shielded, 3He gas detector at 3.2m.

Polarisation is achieved using a two stage transmission and reflection supermirror polariser which provides at >95% polarised beam. A multi-channel polarising supermirror analyser situated immediately before the detectors allows polarisation analysis of the off-specularly scattered beam.

Instrument Parameters

ModeratorCoupled Grooved H2/CH4
Detectors1 x 300mm linear scintillator detector 1.2mm pixel size
1 x 3He tube
L23.2m (3He tube) or 3.6m (Linear Scintillator)
Resolution~2-5% ΔQz/Qz
Incident Wavelengths1.5-14.5Å
ChoppersCounter - rotating disc chopper (10Hz)