The Simulation And Reduction For Time-of-Flight Small Angle Neutron Scattering Based On Virtual Experiments

Small Angle Neutron Scattering(SANS) is one of most powerful tools to detect the material structure from nanometer to micrometer scales. It plays a key role in a variety of areas: nanotechnology, biotechnology, information technology, soft matter, human life, environmental and energy sciences, etc.In the twenty-first century, the first Spallation Neutron Source(CSNS) of China is under construction. And the first Small Angle Neutron Scattering instrument using the Time-of-Flight(TOF) technology will be established. It brings a new challenge on data reduction for TOF-SANS.Until now, there is no spallation neutron source for domestic users, and the number of SANS instruments is very limited too. We develop the virtual neutron experiments based on the Monte Carlo Method. The complete computer simulations for Time-of-Flight Small Angle Neutron Scattering have been carried out, which consist of the neutron transportation through the optical devices, neutron scattering interactions with samples, and responds of neutron detector. The direct, scattering and transmission measurements for sample can be simulated successfully. Furthermore, the divergence, flux and uniformity of the incident neutron spectrum are analyzed. The scattering function and transmission for sample measurements are estimated in detail. It ensures that the virtual neutron experiment enable to simulate the real neutron measurements in Spallation Neutron Source.On the base of the simulated data by virtual experiments, we performed the study of data reduction utilizing the Mantid library. The new workflow is developed for the Time-of-Flight Small Angle Neutron Scattering, which almost covers all the corrections for SANS of Spallation Neutron Source. The data processing includes detector mask, monitor sensitivity, detector efficiency, solid angle and gravity corrections, the wavelength rebinning, normalization for incident neutron, can/background subtraction, etc. The results show that the reduced scattering function I(Q) agrees with those from theoretical calculation and virtual experiment very well.By the investigation based on the virtual experiment, we solved the key issues on the data reduction for Time-of-Flight Small Angle Neutron Scattering. The work will server for data reduction on the coming Small Angle Neutron Scattering of CSNS.