Neutron reflectivity with the Multi-blade detector
The data refers to the measurements performed on the CRISP neutron reflectometer at ISIS with the Multi-Blade detector. The data for the direct beam and three samples: Iridium, Silicon and Fe/Si supermirror, are reported. The raw data from the read-out electronics is reduced to a matrix structure (X,Y,T,λ) which identifies a single neutron event. X and Y are the spatial coordinates of the strips and wires, respectively, in the detector. T is the time of flight of the neutron that reach the detector, while λ is the associated neutron wavelength determined by the time and geometry of the instrument. The data are collected for each digitizer, six in total, and each one corresponds to a cassette of the detector.
The specular reflectivity measurement on the Iridium sample were performed tilting the sample position in step of 0.1 degree in the 0.2-0.8 degrees range.
The specular reflectivity measurement on the Silicon sample were performed using both a collimated and divergent beam, at three and four angle respectively: 0.2, 0.3 and 0.8 degrees in the former configuration and 0.2, 0.3, 0.8 and 1.2 degrees in the latter configuration.
The off-specular measurement on the Fe/Si supermirror sample were performed tilting the sample position in step of 0.01 degree in the 0.2-0.8 degrees range.
The analyzed data for the Iridium and Silicon sample are reduced in (qz, R), where qz is the wave vector transfer and R is the reflected intensity, using the conventional analysis and the θ-corrected reduction. The latter is applied considering both the spatial resolution of the Multi-Blade detector (~0.6 mm) and the state-of-art detectors spatial resolution (~2 mm). The off-specular
data are reduced to a matrix structure (pi, pf, I, pi-pf, pi+pf) where pi and pf are the projections of the initial and final wave vectors, obtained encoding the neutron wavelengths and the incident and reflected angles and I represents the reflected intensity.
The available scripts allow to reduce the initial matrix data (X,Y,T,λ) into the (qz, R) for the Iridium and Silicon sample and (pi, pf, I, pi-pf, pi+pf) for the Fe/Si sample and to plot the final results.