RUI: Acoustic Loss Evaluation of Metals for Ultralow Temperature Gravity Wave Detectors (Physics)

低损耗金属材料的机械品质因数（Q） 合金和元素将在50 mK 至4K，频率约为1 kHz。 材料选择 将基于预期适用于超低 温度韦伯重力波探测器。 当前 用于计划的探测器的优选材料是铝50-56合金， 但是替代材料表现出优良的上级粘合性、热稳定性 电导率和密度。 几乎没有超低 这些材料的温度Q数据，迫切需要 需要评估它们是否适合建造大规模的 探测器 Qs将从测量的时间中获得 小机械振动衰减常数 谐振器安装在稀释制冷机低温恒温器中。 待研究的材料包括铜合金、铝 合金和过渡元素金属。 实验研究 将强调仔细的冶金特性， 系统地消除外在因素对测量结果的影响 质量因素。 除了支持重力波 探测器的发展，预计结果将 有助于对机械损耗的基本理解 金属在超低温下的反应机理

The mechanical quality factor (Q) of low-loss metallic alloys and elements will be studied at temperatures from 50 mK to 4 K and at a frequency of about 1 kHz. Material selection will be based on anticipated suitability for use for ultralow temperature Weber-bar gravity wave detectors. The currently favored material for planned detectors is aluminum 50-56 alloy, but alternate materials exhibit superior bondability, thermal conductivity and density. There are practically no ultralow temperature Q-data on these materials, and it is urgently needed to assess their suitability for constructing large-scale detectors. Qs will be obtained from the measured time constants of decay of free vibrations of small mechanical resonators mounted in a dilution refrigerator cryostat. Materials to be investigated include copper alloys, aluminum alloys, and transition element metals. Experimental studies will emphasize careful metallurgical characterization and systematic elimination of extrinsic contributions to measured quality factors. In addition to supporting gravity wave detector development, it is expected that the results will contribute to the fundamental understanding of mechanical loss mechanisms in metals at ultralow temperatures.