Improvement of our neutron spin echo (NSE) spectrometer and NSE studies on dynamics in complex fluids

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The purpose of this project is to improve our neutron spin echo spectrometer iNSE and to investigate mesoscopic parameters like the bending modulus on the local scale of the interfacial membrane deduced from the dynamical structure factor using neutron spin echo spectroscopy (NSE) in order to elucidate the self-assembling mechanisms in complex fluids involving amphiphiles. Correction coils such as wide cross section spiral correction coils developed using this grant led to great upgrade of iNSE and the observed neutron efficiency increased more than ten times. We have developed the new-type spin flippers, which operate with steady current for a white neutron beam, for a time-of-flight NSE spectrometer at a pulsed spallation neutron source (JSNS) in J-PARC. The performance test of the new-type spin flippers improved using this grant showed that the flippers worked well for a pulsed white neutron beam. We have studied dynamics such as membrane undulation, mesoscopic structures and the temperature-and the pressure-induced structural phase transition in complex fluids involving amphiphiles such as dipalmitoylphosphatidylcholine(DPPC)/water/CaCl_2 systems, the non-ionic surfactant C_<12>E_5/water/ethanol systems and ionic surfactant AOT/oil/water systems by means of NSE and small angle scattering experiments.