BASIC STUDY ABOUT A VERTICAL LASER INTERFEROMETER

主要针对的是Advanced-LIGO、EGO和LCGT等首次引力波探测项目，以及每年事件率为10万分之一的双中子星合并引力波和一个星系。由于这个原因，他们热衷于提高他们的灵敏度，以增加可观测星系的数量。最近，理论上的超新星和超新星爆炸模拟似乎需要非对称（旋转）爆炸过程，这可能会产生极大振幅的引力波（GW）。考虑到一个星系的超新星事件率为2/年，并且它的大振幅GW可以被100米尺度的GW探测器探测到，因此能够像其他天文观测一样识别我们星系中超新星的GW源的位置似乎也很重要。对于位置识别，至少需要三个干涉仪。在这三个ifo位于地球附近的情况下，三个ifo中的一个是理想的……更多的是在垂直方向上有一个臂（法布里-佩罗腔臂），以没有死角。在此背景下，我们开始了在垂直方向上具有法布里-珀罗腔的激光干涉仪的基础研究。我们构建了垂直镜面悬架和隔震摆来构建垂直法布里-珀罗腔。这个钟摆有三个垂直隔离级。第一级采用0.5 Hz mini-GAS滤波器，第二级和第三级采用弹簧式隔离器（12Hz），采用BOLFUR导线的假弹性特性。作为注入法布里-珀罗腔的光，使用波长532nm的激光（Innolight Inc.）。Prometheus-50 50兆瓦)。采用Pound-Drever-Hall法获得了法布里-珀罗空腔长度的误差信号。因此，法布里-佩罗腔的反射镜悬挂在这些垂直摆系统中，已经成功地控制了共振，使用磁力线圈在反射镜质量和线圈之间的驱动力或使用激光频率控制。另一方面，传统的卧式激光干涉仪在20Hz ~ 30Hz的位移灵敏度达到了2 × 10^-16…3 × 10^-17 [m/rHz]，是世界上最好的位移噪声水平，在100Hz时达到了3 × 10^-18 [m/rHz] (LIGO在200Hz时达到了1 × 10^-19 [m/rHz])，是日本有史以来最好的。少

Many projects for the first gravitational wave (GW) detection, such as Advanced-LIGO, EGO and LCGT, GW from binary neutron star coalescence, whose event rate is 1/100000 per a year and a galaxy, is mainly targeted. For this reason, they are enthusiastic to enhance their sensitivity to increase the observable galaxy numbers. Recently, theoretical super and hyper-novae explosion simulations seem to require anti-symmetrical (rotational) explosion process, which might produce extremely large amplitude gravitational waves (GW). Accounting for the supernovae event rate in a galaxy of 2/year and its large amplitude GW that can be detected by 100m-scale GW detectors, it also seems to be important to be able to identify positions of GW sources from supernovae in our galaxy as other astronomical observations. For the position identification, three interferometers (IFOs) are at least necessary. In the case that these three IFOs are situated nearby on the Earth, one of the three IFOs is desirable … More to have an arm (a Fabry-Perot cavity arm) in the vertical direction to have no dead angles. Accounting for this background, we started basic study about the construction of a laser interferometer that has a Fabry-Perot cavity in the vertical direction. We have constructed vertical mirror suspension and seismic noise isolation pendulums to construct the vertical Fabry-Perot cavity. This pendulum contained three vertical isolation stages. The first stage had 0.5 Hz mini-GAS filter and the second and the third stages had spring-like isolators (12Hz) using pseudoelasticity property of BOLFUR wires. As a light to be injected to the Fabry-perot cavity, 532nm wavelength laser was used (Innolight Inc. Prometheus-50, 50mW). A Pound-Drever-Hall method was used to obtain an error signal of a Fabry-Perot cavity length. Consequently, the Fabry-Perot cavity whose mirrors are suspended by these vertical pendulum systems, has been successfully controlled to resonate, using either a magnet-coil actuation force between the mirror mass and coils or using a laser frequency control. On the other hand, the traditional horizontal laser interferometer's displacement sensitivity has reached 2x10^-16…3^*10^-17 [m/rHz] from 20Hz to 30Hz, which was the world best displacement noise level, and 3x10^-18 [m/rHz] at 100Hz (LIGO has 1x10^-19 [m/rHz] at 200Hz), that is ever best in Japan. Less