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

本项目的目的是改进我们的中子自旋回波谱仪，并利用中子自旋回波谱(NSE)研究介观参数，如由动态结构因子推算的界面膜局部尺度上的弯曲模数，以阐明含两亲分子的复杂流体中的自组装机理。用该装置研制的大截面螺旋修正线圈等修正线圈使InSe得到了极大的提升，观测到的中子效率提高了十多倍。我们在J-PARC的脉冲散裂中子源(JSNS)上研制了用于飞行时间NSE谱仪的新型自旋翻转器，它以稳定的电流工作在白色中子束上。利用这笔赠款改进的新型自旋中子束的性能测试表明，这种自旋中子束在脉冲白色中子束中工作得很好。我们通过非平衡散射和小角散射实验研究了dipalmitoylphosphatidylcholine(DPPC)/water/CaCl_2体系、非离子表面活性剂C_(12&gt；E_5)/水/乙醇体系和离子表面活性剂AOT/油/水体系等两亲体系复杂流体的膜波动、介观结构以及温度和压力诱导的结构相变等动力学行为。

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.