论文标题
在低温温度下Kagra低温恒温器的振动分析
Vibration Analysis of KAGRA Cryostat at Cryogenic Temperature
论文作者
论文摘要
卡格拉（Kagra）使用低温药将其蓝宝石测试质量降低至20 k，以减少热噪声。然而，低温冷却器振动和冷冻夫妇的结构共振测试质量，并可能污染检测器灵敏度。我们在低温温度下对冷却系统进行了振动分析，以研究其对检测器敏感性的影响。我们的测量表明，低于1 Hz的屏蔽振动不受冷冻机的操作或结构共振的影响，并遵循地面运动。即使没有冷冻冷却器操作，也观察到1-100 Hz中盾牌的噪声底比地震运动大于地震运动。冷冻机的操作不会改变噪声层，而是在整个频谱（1-100 Hz）中观察到2.0 Hz峰及其谐波。这些结果用于计算冷却系统振动与测试质量的耦合。我们得出的结论是，冷却系统的振动不会限制Kagra设计敏感性。
KAGRA uses cryogenics to cool its sapphire test masses down to 20 K to reduce the thermal noise. However, cryocooler vibration and structural resonances of the cryostat couple to test mass and can contaminate the detector sensitivity. We performed vibration analysis of the cooling system at cryogenic temperature to study its impact on detector sensitivity. Our measurement show shield vibration below 1 Hz is not impacted by cryocooler operation or structural resonances and follows ground motion. The noise floor of the shield in 1-100 Hz was observed to be 2-3 order of magnitude larger than seismic motion even without cryocooler operation. The operation of cryocoolers does not change the noise floor, but 2.0 Hz peaks and their harmonics were observed over the entire spectrum (1-100 Hz). These results were used to calculate the coupling of cooling system vibration to the test mass. We conclude that vibration from the cooling system does not limit KAGRA design sensitivity.
