Compact integrated optical sensors and electromagnetic actuators for vibration isolation systems in the gravitational-wave detector KAGRA
Compact integrated optical sensors and electromagnetic actuators for vibration isolation systems in the gravitational-wave detector KAGRA
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DOI：
10.1063/5.0022242
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发表时间：
2020-11-01
影响因子：
1.6
通讯作者：
Kamiizumi, Masahiro
中科院分区：
文献类型：
--
作者：
Akutsu, Tomotada;Arellano, Fabian Erasmo Pena;Kamiizumi, Masahiro
本文报道了一种集成光学位移传感器和电磁执行器的紧凑模块的设计和特点，该模块用于安装在日本3公里基线引力波探测器KAGRA上的隔振系统。在技术概念上，该模块属于其他干涉引力波探测器项目中使用的类似模块的家族树。2016年KAGRA首次试运行后，对传感器部分（一种槽式传感器）进行了修改，将槽的间距从5mm增加到15mm，以避免与传感器标志产生机械干扰的风险。我们确认，尽管进行了修改，但传感器性能与以前的设计相当。我们还证实了传感器噪声与理论噪声预算是一致的。噪声级在1hz时为0.5 nm/Hz(1/2)，在10hz时为0.1 nm/Hz(1/2)，传感器线性范围大于等于0.7 mm。我们测量了执行器的响应为1 N/A，并测量了执行器线圈的电阻和电感，以验证与理论的一致性。还测量了不同自由度之间的耦合系数，结果显示可以忽略不计，设计之间的变化很小。讨论了涡流损耗对热噪声的潜在影响。截至2020年，有42个模块在现场运行。
This paper reports on the design and characteristics of a compact module integrating an optical displacement sensor and an electromagnetic actuator for use with vibration-isolation systems installed in KAGRA, the 3-km baseline gravitational-wave detector in Japan. In the technical concept, the module belongs to a family tree of similar modules used in other interferometric gravitational-wave detector projects. After the initial test run of KAGRA in 2016, the sensor part, which is a type of slot sensor, was modified by increasing the spacing of the slot from 5 mm to 15 mm to avoid the risk of mechanical interference with the sensor flag. We confirm that the sensor performance is comparable to that of the previous design despite the modification. We also confirm that the sensor noise is consistent with the theoretical noise budget. The noise level is 0.5 nm/Hz(1/2) at 1 Hz and 0.1 nm/Hz(1/2) at 10 Hz, and the linear range of the sensor is 0.7 mm or more. We measured the response of the actuator to be 1 N/A and also measured the resistances and inductances of coils of the actuators to confirm consistency with theory. Coupling coefficients among the different degrees of freedom were also measured and shown to be negligible, varying little between designs. A potential concern about thermal noise contribution due to eddy current loss is discussed. As of 2020, 42 of the modules are in operation at the site.