Studies of Nucleons and Nuclei Using the Electromagnetic Probe

在这项拟议的工作中，我们将研究原子核的基本结构以及原子核的组成部分--中子和质子的性质。测量将使用托马斯·杰斐逊国家加速器设施生产的非常精确、强烈和高能的电子束进行。大多数实验将研究原子核不超过两个质子和两个中子的原子。当电子被用来研究这种相对简单的系统时，人们可以将结果与非常准确的理论预测相比较。将在氦原子核上进行实验，以研究这些系统在极端条件下的结构，包括质子和中子非常接近的条件。其他实验将轰击由单个质子组成的氢核，以研究质子结构的特殊特征。一项实验将研究复杂铅原子核的结构。为了支持这些测量，我们将继续开发和建造用于容纳被电子束轰击的材料的目标装置。这项工作包括建造能够在绝对零度以上几度的温度下容纳高压气体的结构。我们还将建造一个冷却的铅靶，使我们能够使用高功率电子束，而不会熔化铅。在所有这些努力中，我们将继续特别重视与学生，特别是本科生和选定的高中学生和教师开展工作。这一努力正在与我们领导的一项面向当地拥有大量少数族裔学生的高中的外展项目相协调。

0072404Margaziotis In the proposed work we will study the fundamentalstructure of the nucleus of the atom and the nature of theconstituent parts of the nucleus, the neutrons and protons. Measurementswill be made using the very precise, intense, and energetic electronbeam produced by the Thomas Jefferson National Accelerator Facility.Most of the experiments will study atoms whose nucleus has no morethan two protons and two neutrons. When electrons are used to probesuch relatively simple systems one can compare the results to veryaccurate theoretical predictions. Experiments will be performed on heliumnuclei to investigate the structure of these systems under extreme conditionsincluding those in which the protons and neutrons are very close to each other.Other experiments will bombard the hydrogen nucleus, which consists of asingle proton, to study particular features of the proton structure. Oneexperiment will study the structure of a the complex lead nucleus. In support of these measurements we will continue our work in developing and building the target devices used to contain the materials that are being bombarded by the electron beam. This work involves building structures that cancontain high pressure gases at temperatures a few degrees above absolute zero.We will also build a cooled lead target that will allow us to use the highpower electron beam without melting the lead. In all these efforts we willcontinue to place particular emphasis on working with students, particularlyundergraduate students and selected high school students and teachers. Thiseffort is being coordinated with an outreach program that we are leading directedtowards high schools in the local area that have large populations of minority students.