Studies on the wave property of neutron and its application to the measurements of space-time symmetries

(1)研究了中子反应中宇称破坏效应大幅度增强的原因。首先，在LANSCE上测量了几个中重核在几百eV到2KeV能量范围内的中子在p波共振中的核吸收的纵向不对称性。我们分析了数据，计算了反应弱矩阵的色散，推导出平均弱扩展宽度（I 'w）为（0.5^^+__-0.3）× 10^<-7>eV。我们还测量了^ La的0.734 eV p波共振中中子的宇称非守恒自旋转动<139>。旋转角为（7.4^^+__-1.1）× 10^<-3>rad/厘米计算结果与s-p混合模型的预测结果吻合较好。(2)首次测量了超冷中子在固体氘中的存活时间。该临界参数提供了对利用固体正氘作为源材料的超热UCN源的有效性的基本限制。(3)本文研究了环形慢化室冷中子源的自调节特性。模拟结果表明，在总热负荷大扰动的情况下，缓冲罐压力和慢化剂室液位是稳定的。(4)我们在不同Ni_ Ti_P样品中观察到了两个中子自旋态间自旋干涉的退相干现象<25><75>。采用机械合金化方法制备了不同球磨时间的试样。我们已经发现，通过增加合金化时间，可见性得到改善。

(1) Origin of large enhancement of the parity violation effect in neutron reactions has been investigated. First, the longitudinal asymmetries is nuclear absorptions of neutrons in p-wave resonances has been measured for several medium and heavy nuclei at LANSCE in the energy of several hundred eV to 2 KeV. We have analyzed the data to calculate the dispersion of weak matrix of the reactions and have deduced the average weak spreading width (I'w) to be (0.5^^+__-0.3) × 10^<-7> eV. We have measured also the parity non-conserving spin rotation of neutrons in the 0.734-eV p-wave resonance of ^<139>La. The rotation angle was determined to be (7.4^^+__-1.1) × 10^<-3>rad./cm. The results agree well with the prediction of the s-p mixing model.(2) The measurements of the survival time of ultra-cold neutrons in solid deuterium have been made for the first time. This critical parameter provides fundamental limitation to the effectiveness of super-thermal UCN sources that utilize solid ortho-deuterium as the source material.(3) Self regulation of the cold neutron source with a cylindrical annulus moderator cell has been investigated. The simulation shows us that the buffer tank pressure and the liquid level in the moderator cell are stable even against large disturbance of the total heat load.(4) We have observed decoherent phenomena in spin interference in between two neutron spin states inserting several different Ni_<25> Ti_<75> power samples. The samples have been made by Mechanical Alloying Method with different milling time. We have found an improvement of the visibility by increasing their alloying time.