MRI: Acquisition of a Dilution Refrigerator with Tunnel Diode System

MRI：购买带有隧道二极管系统的稀释冰箱

• 批准号: 0619801
• 负责人: Kevin Storr
• 金额: $ 32.12万
• 依托单位: Prairie View A & M University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-10-01 至 2009-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0619801&HistoricalAwards=false
• 关键词: MRI; Acquisition; Dilution; Refrigerator; Tunnel

Technical AbstractPrairie View A&M University (PVAMU) seeks to acquire a 10 milliKelvin Dilution Refrigerator System with integrated Tunnel Diode Oscillator (TDO) capabilities. TDO measurements are a contactless means of measuring sample resistivity by observing the changes in skin depth. The Refrigerator and TDO will provide the resolution needed for extensive probing of the electronic and magnetic properties of inorganic and organic materials and heavy fermion systems. It will further permit extensive fermiological studies to be carried out and the investigation of angular magnetoresistance oscillations (AMRO). In addition, the dilution refrigerator will extend the capabilities of standard techniques such as DC electrical transport, magnetization, specific heat and pressure by allowing them to be conducted in an extreme temperature environment. The dilution refrigerator system coupled with the tunnel diode oscillator will allow us to extend the phase boundaries of previously studied materials and firmly establish the phase boundaries of new systems. This system is ideal for heavy fermion systems being currently grown by our collaborators from North Carolina A&T University, Los Alamos National Lab and Greece. It will also help us to continue our Junior Physicist Experience Program which allows high school juniors and seniors to gain valuable laboratory skills at Prairie View A&M University. This program will help increase the number of underrepresented scientists. Non-Technical AbstractA Dilution Refrigerator is a unique instrument which is used to achieve temperatures below -459 oF (the lowest possible temperature, called absolute zero, occurs at -459.67 oF). The lower temperatures act as a magnifying glass of sorts allowing researchers to observe, in more detail, new and interesting properties of the materials being measured. A Tunnel Diode Oscillator station allow measurements to be performed without having to attach wires to the sample. At low temperature samples that are exposed to magnetic fields undergo phase changes which are electronic and magnetic in nature. This is analogous to the phase changes of matter which occur with the addition or removal of heat.. The Tunnel Diode Oscillator is extremely sensitive to these changes and ideal for such measurements. The combination of a Dilution Refrigerator and a Tunnel Diode Oscillator will allow a contactless means of measuring material properties at ultra low temperatures. Understanding these properties is important to producing the next generation of synthetic materials. The acquisition of this equipment will greatly enhance academics, research and outreach at my university. It will afford students the opportunity to learn its operation and maintenance, while improving the quality of thesis and dissertations. Furthermore, we have forged collaborations with several national and international researchers which will increase the exposure of Prairie View A&M University students and faculty to world class scholarship and research. The immediate benefits of the system will be for the existing Physics, Chemistry and Materials Programs and current outreach to local area high schools. The acquisition of this equipment will also provide a 'hands-on' component for current advanced courses and will lead to the introduction of new courses at the university.

Prairie View A M大学（PVAMU）寻求获得具有集成隧道二极管振荡器（TDO）功能的10毫开尔文稀释制冷系统。 TDO测量是通过观察趋肤深度的变化来测量样品电阻率的非接触方式。 冰箱和TDO将提供广泛探测无机和有机材料以及重费米子系统的电子和磁性所需的分辨率。 它将进一步允许进行广泛的费米研究和角磁阻振荡（AMRO）的调查。 此外，稀释制冷机将扩展标准技术的能力，如直流电传输，磁化，比热和压力，允许它们在极端温度环境中进行。 与隧道二极管振荡器相结合的稀释制冷系统将使我们能够扩展以前研究的材料的相边界，并牢固地建立新系统的相边界。 这个系统是理想的重费米子系统目前正在增长的合作者从北卡罗来纳州AT大学，洛斯阿拉莫斯国家实验室和希腊。 它还将帮助我们继续我们的初级物理学家体验计划，让高中三年级和四年级学生获得宝贵的实验室技能在草原视图A M大学。 该计划将有助于增加代表性不足的科学家的数量。稀释制冷机是一种独特的仪器，用于实现低于-459 ° F的温度（可能的最低温度，称为绝对零度，发生在-459.67 ° F）。 较低的温度就像一个放大镜，使研究人员能够更详细地观察被测材料的新的和有趣的特性。 隧道二极管振荡器站允许在无需将电线连接到样本的情况下进行测量。 在低温下，暴露于磁场的样品经历本质上是电子和磁性的相变。 这类似于物质的相变，相变是随着热量的增加或减少而发生的。 隧道二极管振荡器对这些变化非常敏感，是此类测量的理想选择。 稀释制冷机和隧道二极管振荡器的组合将允许在超低温下测量材料特性的非接触方式。 了解这些特性对于生产下一代合成材料非常重要。购置这些设备将大大加强我的大学的学术、研究和外联工作。 它将为学生提供学习其操作和维护的机会，同时提高论文和学位论文的质量。 此外，我们与几个国家和国际研究人员建立了合作，这将增加Prairie View A M University学生和教师对世界一流奖学金和研究的接触。 该系统的直接好处将是现有的物理，化学和材料方案和目前的推广到当地高中。 购置这些设备还将为目前的高级课程提供“实践”部分，并将导致在大学开设新课程。