Torsional Oscillator Experiments under DC Rotation with Reduced Vibration
Torsional Oscillator Experiments under DC Rotation with Reduced Vibration
复制标题
减振直流旋转下的扭转振荡器实验
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
M. Kubota
中科院分区：
文献类型：
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作者：
M. Yagi;A. Kitamura;Nobutaka Shimizu;Y. Yasuta;M. Kubota
我们描述了一个高度稳定的，旋转的低温恒温器设计的扭转振荡器实验下直流旋转，涡线渗透已被研究的3D超流体的单层He膜，以及在hcp固体4 He的超固态。特别是hcp固体4 He的扭振实验对10 μm/s量级或更小的线速度非常敏感，因此，如果仪器的振动不小于或等于建筑物或地面本身的振动，就可能破坏测量结果。这里描述的扭转振荡器性能通常在中等速度的稳定旋转下比在静止条件下给出更好的数据。本文简要介绍了东京大学ISSP的两台旋转恒温器的设计思想，并讨论了直流旋转下的扭振实验。这是一个真正的高速旋转低温恒温器，其最大旋转速度至少为每秒6转，用于TO实验。它还在合理的低转速下提供了高得多的稳定性，这是因为双框架结构的良好规划的结构，该结构具有用于旋转的上部驱动框架的大量质量，以及除了驱动模式运动之外几乎机械隔离的旋转低温恒温器，该旋转低温恒温器具有用于低温恒温器安装件的内框架的高得多的稳定性。量子化涡线穿透宏观超流体的现象给出了关于超流体本身的独特信息。简要介绍了利用TO技术探测涡线穿透事件的方法。
We describe a highly stable, rotating cryostat designed for torsional oscillator experiments under DC rotation, where vortex lines penetration has been studied for 3D superfluids made of monolayer He films as well as for the supersolid state in hcp solid 4He. Especially, torsional oscillator experiments on hcp solid 4He are known to be quite sensitive to small vibrations or linear velocities on the order of 10 μm/s or less. Thus, vibrations of the apparatus may destroy the measurements if they are not smaller than or equal to those of the building or the ground itself. The torsional oscillator performance described here often gives better data under steady rotation at moderate speeds than under stationary conditions. The article describes briefly a design idea shared by the two rotating cryostats at ISSP, the University of Tokyo, and discusses the torsional oscillator (TO) experiments under DC rotation. This is truly a high speed rotating cryostat with maximum rotational speed of at least 6 revolutions per second for TO experiments. It gives also much higher stability at reasonably low rotational speed because of the well-planned structure of the double frame construction with a lot of mass for the upper drive frame for rotation and the almost mechanically isolated, except for the drive mode motion, rotating cryostat with much higher stability of the inner frame for the cryostat mount. Phenomena of quantized vortex lines penetration through a macroscopic superfluid give unique information about the superfluidity itself. A method for detection of vortex lines penetration events using TO technology is also briefly reviewed.