Development of neutron phase space transfer optical devices

利用二维中子探测器和飞行时间法研究了振动石英单晶中中子强度和衍射角的变化。实验采用x切割石英单晶，尺寸为3mm×120mm×14mm。石英单晶沿x轴呈极化，因此与该轴垂直切割，即x -切割位移最大。在石英晶体上制备铝电极，施加40 V的偏置电压，使其以22.7 kHz的特征振动频率移动。显微镜下观察到c.a.5 μm的最大位移。在JRR-3M超小角中子散射（ULS）系统上进行了中子衍射实验；采用波长为4.7埃的中子束。采用ZnS:Li闪烁体和位置敏感光倍增器的组合作为中子探测器。用石英单晶在22.7 kHz下振动得到了中子衍射图；中子衍射图样随振动周期的变化。中子强度有两个强分量。4.7埃中子的速度约为840 m/s，在振动周期的一半即44μs内移动1.8 cm。探测器位置变化1.8 cm，中子强度随pi的相移而变化。实验结果与理论估计进行了比较。在多普勒效应引起的位移大于变形引起的位移的情况下，衍射中子强度随时间变化的实验结果与理论结果吻合。

Changes in neutron intensity and diffraction angle form a vibrating quartz single crystal were investigated by a 2D neutron detector and time-of-flight method.A X-cut quartz single crystal in size of 3mm×120mm×14mm was used in an experiment. Quartz single crystal has polarization according to a X-axis, thus, perpendicular cut to this axis, I.e., X-cut has the largest displacement. Bias voltage of 40 V was applied to aluminum electrodes fabricated on the quartz crystal, and it was moved in the characteristic vibration frequency of 22.7 kHz. Maximum displacement of c.a. 5μm was observed using a microscope.A neutron diffraction experiment was carried out on the ULS (Ultra Small angle neutron scattering) system in JRR-3M; neutron beam of wavelength of 4.7 angstrom was used. A combination of a ZnS:Li scintillator and a position sensitive photo multiplier was used as a neutron detector. Neutron diffraction patterns were obtained with a vibrating quartz single crystal in 22.7 kHz; change of neutron diffraction patterns according to vibration period. Neutron intensity had two strong components. Velocity of 4.7 angstrom neutrons are c.a. 840 m/s, thus they move 1.8 cm in 44μs, I.e., a half of the vibration period. By change of 1.8 cm in position of the detector, neutron intensity was changed according to phase shifting in pi.Experimental results were compared with theoretical estimation. In the case of displacement caused by the Doppler effect was larger than that caused by deformation, experimental results of time dependence of diffracted neutrons' intensity were suit for a theoretical result.