Solid State Studies Utilizing an Intense Low Energy PositronBeam

布鲁克海文国家实验室已经建造了一束强度单能、可变的低能正电子束。这比现有的任何来自放射源的束流都要大100多倍。他们建议将低能正电子束流进一步提高两个数量级，并用它进行两种类型的实验。第一种是产生一束正电子原子束，以确定正电子素在固体表面的反射系数与其能量的函数关系，以确定正电子衍射是否将成为分析固体表面结构的有用工具。第二类实验是测量正电子在固体表面湮没产生的湮没辐射的角关联，从而得到表面电子动量密度分布。

An intense monoenergetic, variable low energy beam of positrons has been constructed at the Brookhaven National Laboratory. This is more than 100 times greater than any existing beams from radioactive sources. They propose to increase further the low energy positron beam flux by two orders of magnitude, and to carry out two types of experiments with it. The first is to produce a beam of positronium atoms to determine the reflection coefficient of positronium as a function of its energy from solid surfaces to determine whether positronium diffraction would be a useful tool for analyzing the structure of solid surfaces. The second type of experiment consists of measuring the angular correlation of annihilation radiation resulting from positrons annihilating on the surface of solids, and thereby obtain the surface electrons momentum density distribution.