Parity and Time Reversal Invariance Test in Very Slow Neutron Reactions

根据顺序研究质子共振吸收反应中奇偶破坏效应的起源大幅度增强，P波共振在Ag、Pd、Sb、Cs、Xe、Th和U型能量区域中的纵向不对称性已被测量。我们构建了一个用于极化中子光束的极化质子过滤器，并将一个自旋触发器反向中子自旋的距离。我们还使用了一个液体闪烁器阵列，作为中子探测器。在任何多级别公式中使用了一个新的计算机代码来计算中子交叉部分已经开发出来，我们找到了47个波共振，其中统计意义大于3δ的更大的复杂性不对称性。“不对称的迹象已经找到了随机的。”一个实验显示，即奇偶校验破坏效应的大增强是p波共振的一个主要特征。The weak spreading widths of n\i（来自D2） have been determined from the experim\values of asymmetries。使用pentacene using a dye laser at the temperature higher than 77 Kelvin的polarized protons。Such a polarized proton target can be used to obtain polarized neutrons。We obtained 50%polarization of La n\i in mono-cr\of LaAlo D23-D2 by means of the dynamic polarization method。一个极化的目标将对中子共振吸收中的时间逆转性暴力的重要性进行衡量。

In order to study the origin of large enhancement of the parity violation effect in neutron resonance absorption reactions, the longitudinal asymmetries in p-wave resonances have been measured for In, Ag, Pd, Sb, Cs, Xe, Th and U targets in the energy region of 1 eV to 350 eV.We constructed a polarized proton filter for polarizing the neutron beam, and a spin flipper to reverse the diection of neutron spin. We used also liquid scintillator arrays as a neutron detector. A new computer code in which multi-level formula is used to calculate the neutron cross section has been developed.We have found 47 p-wave resonances which have large helicity asymmetries with the statistical significance greater than 3δ. The signs of the asymmetries have been found to random. The experiment shows that the large enhancement of parity violating effect is a prevalent feature of p-wave resonances. The weak spreading widths of nuclei (ΓィイD2wィエD2) have been determined from the experimental values of asymmetries . The obtained ΓィイD2wィエD2's agree with estimated value based on the statistical view.Furthermore, we have polarized protons in naphthalene crystals doped with pentacene using a dye laser at the temperature higher than 77 Kelvin. Such a polarized proton target can be used to obtain polarized neutrons.We obtained 50% polarization of La nuclei in mono-crystal of LaAloィイD23ィエD2 by means of the dynamic polarization method. The polarized La target will be of vital importance for the measurement of time reversal violation in the neutron resonance absorption.