Influence of polarisation analysis on buffer subtraction in biology

Protein dynamics play a vital role in biology. Quasi elastic neutron scattering is an ideal method to access these, data analysis is performed based on the assumption that the scattering spectrum is incoherent. To observe the full range of dynamical changes the proteins need to be observed in solution. This solution is usually a fully deuterated buffer, while the protein remains deuterated. It is generally assumed that while the buffer leads to a coherent contribution, which can be taken into account during data analysis by subtracting the buffer contribution from the sample spectrum. Polarised QENS experiments on LET allow for the coherent and incoherent contributions to be separated. By comparing the results from the polarised QENS experiment and the standard analysis method from unpolarised QENS it will be possible to experimentally check the current approach to data analysis.