Intermediate Energy Nuclear Physics with Electromagnetic Probes at Jefferson Lab

杰斐逊实验室的电磁探针中能核物理

• 批准号: 0965606
• 负责人: Paul Stoler
• 金额: $ 51万
• 依托单位: Rensselaer Polytechnic Institute
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2017-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0965606&HistoricalAwards=false
• 关键词: Intermediate; Energy; Nuclear; Physics; Electromagnetic

The present NSF grant primarily funds the RPI group's participation in the the physics program of the Thomas Jefferson National Accelerator Facility, where it is a member of the CLAS Collaboration. The experimental program's goal is to learn about and image the composition of protons and neutrons - generically called nucleons - which comprise nearly all the currently visible matter in the universe. Nucleons are composed of very complicated arrays of quarks immersed in the strong nuclear fields called gluons. The main instrument used is the CLAS spectrometer, inside of which a beam of electrons from the Jefferson Lab accelerator impinges upon a target of protons. Most often the target is in the form of liquid hydrogen atoms. The experiments in which the RPI group are focusing are those in which an electron in the beam strikes and scatters off a proton and part of the energy imparted to the proton produces either a single photon (a quantum of electromagnetic radiation), or a single meson, which is a particle consisting of a quark and antimatter quark pair. By studying this reaction as the imparted energy and direction of the scattered electron is varied, the group seeks to obtain a three dimensional image of the distributions of the quarks in the proton, which has never yet been accomplished. During this grant period the group will continue work on a new CLAS spectrometer, called CLAS12, which is part of the ongoing project at Jefferson Lab to double the energy of the electron beam. The component of the CLAS12 spectrometer on which the RPI is specifically contributing is called a high threshold Cherenkov counter (HTCC), which will be used to identify the scattered electrons. This is in addition to the more general role the Principal Investigator plays in the upgrade as chairman of the CLAS12 steering committee. RPI is a technology based university whose primary goal is to prepare future scientists and engineers for the most advanced technological demands of society. The complexity of the experiments in this research require the development and use of the most advanced scientific equipment and computational techniques. RPI graduate and undergraduate students, as well as post-doctoral associates, participate one way or another in programs such as this, and in the present case directly carry out most of the direct work on the experimental program, enabling them to become the scientific and engineering leaders of a technologically competitive society.

目前的NSF拨款主要用于资助RPI小组参与托马斯·杰斐逊国家加速器设施的物理计划，在那里它是Clas合作的成员。该实验计划的目标是了解质子和中子--通常被称为核子--的组成并对其进行成像，它们几乎构成了宇宙中目前所有可见的物质。核子是由非常复杂的夸克阵列组成的，这些夸克沉浸在被称为胶子的强核场中。使用的主要仪器是Clas光谱仪，在光谱仪内部，来自杰斐逊实验室加速器的电子束撞击质子目标。大多数情况下，目标是液态氢原子的形式。在RPI小组聚焦的实验中，束流中的一个电子撞击并散射出一个质子，赋予质子的部分能量要么产生单个光子(电磁辐射的量子)，要么产生单个介子，这是一个由夸克和反物质夸克对组成的粒子。通过研究这种反应，当给予的能量和散射电子的方向不同时，该小组试图获得质子中夸克分布的三维图像，这一点尚未完成。在这一资助期间，该小组将继续研究一种名为CLAS12的新Clas光谱仪，这是杰斐逊实验室正在进行的将电子束能量增加一倍的项目的一部分。RPI具体贡献在CLAS12光谱仪上的组件称为高阈值切伦科夫计数器(HTCC)，它将用于识别散射电子。此外，首席调查员在升级为CLAS12指导委员会主席的过程中发挥了更广泛的作用。RPI是一所以技术为基础的大学，其主要目标是为社会最先进的技术需求培养未来的科学家和工程师。这项研究中实验的复杂性要求开发和使用最先进的科学设备和计算技术。RPI的研究生和本科生以及博士后助理以这种或那种方式参与了这样的项目，在目前的情况下，他们直接执行实验项目的大部分直接工作，使他们能够成为一个技术竞争激烈的社会的科学和工程领导者。