RUI: Ultracryogenic Acoustic and Thermal Evaluation of Metals for Gravity Wave Detectors

RUI：重力波探测器金属的超低温声学和热学评估

• 批准号: 9511613
• 负责人: William Duffy
• 金额: $ 10.83万
• 依托单位: Santa Clara University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-07-15 至 2000-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9511613&HistoricalAwards=false
• 关键词: RUI; Ultracryogenic; Acoustic; Thermal; Evaluation

Professor Duffy will continue ultracryogenic studies of the mechanical quality factor (Q) of selected polycrystalline technical materials. The quality factor will be measured on torsional resonators machined in the unique configuration developed by him. The configuration permits audio frequency measurement (typically at 1 kHz) over a wide range of Qs (103 - 108) and a wide range of temperatures (50mK - 300K). Since only a small piece of material is involved (typically 6 cm diameter by 6 cm long), the cost of operation and the turn-around time of the complex dilution refrigerator cryostat needed for the very low temperature measurements are kept low. The work is to be carried out in support of cryogenic (4K) and ultracryogenic (100 mK) resonant mass gravity wave antenna development both in the United States and abroad. Close contact will be maintained with the gravity-wave- detector community. Materials to be studied include those which offer the most promise for use as gravitational wave detectors of high sensitivity. This requires materials of high Q, which also have appropriate inertial, elastic and thermal properties. Specific materials which are the focus of this study include an explosively bonded aluminum alloy 5056 and a series of copper and aluminum alloys. Grain size and hardness will be evaluated. Appropriate heat treatments will be developed, which have been found to be so essential for obtaining high ultracryogenic Qs in the materials studied to date. Ultralow temperature heat capacity and thermal conductivity studies of selected materials will be carried out. In addition to supporting gravity wave antenna development, the results should contribute to the fundamental understanding of acoustic loss mechanisms.

Duffy教授将继续对选定的多晶技术材料的机械质量因子(Q)进行超冷研究。质量因子将在他开发的独特结构的扭振器上进行测量。该配置允许音频测量（通常在1 kHz）在宽范围的Qs（103 - 108）和宽范围的温度（50mK - 300K）。由于只涉及一小块材料（通常为6厘米直径6厘米长6厘米），因此用于极低温测量的复杂稀释冰箱低温恒温器的操作成本和周转时间保持在较低水平。这项工作将支持美国和国外低温（4K）和超低温（100 mK）共振质量重力波天线的发展。将与引力波探测器社区保持密切联系。要研究的材料包括那些最有希望用作高灵敏度引力波探测器的材料。这需要高Q的材料，它也有适当的惯性，弹性和热性能。具体的材料是本研究的重点，包括一个爆炸粘合铝合金5056和一系列的铜和铝合金。将评估晶粒尺寸和硬度。将开发适当的热处理，这是迄今为止所研究的材料中获得高超冷Qs的必要条件。对选定的材料进行超低温热容和导热研究。除了支持重力波天线的发展，研究结果应该有助于对声损失机制的基本理解。