Resonant Antenna for Monitoring Gravitational Wave Bursts in our Galaxy

在这个项目的第一年，几乎所有硬件都完成了；由1.8音铝合金谐振振荡器组成的真空室、支撑天线的隔振堆、真空监测系统、激光换能器主框架等组成。对这些零件的规格进行了实验确认和校核。在这些实验过程中，我们证实了通过节点支撑来保持天线的高力学Q的正确性，并找到了一个简单的公式来设计堆栈隔离系统。我们还发现了对超高真空有害的聚合物材料脱气的知识。由于激光换能器铰链机构的膜内扩散共振产生了巨大的热噪声，我们不得不将铰链改为钟摆，这将给该机构的研制带来更多的困难。在最后一年，我们将激光换能器安装在天线上，并测试了它在空气和真空中的灵敏度。在这些测试过程中，我们遇到了一些麻烦，导致了这个项目的延迟：一个是激光二极管泵浦的YAG激光源故障，导致实验停止了三个月。二是用远低于观测频率（4khz）的反馈波段使摆稳定不容易。数据采集采用VME总线和工作站计算机，并开发了多个软件实现天线的连续工作。总之，我们开发了平面探测器，并获得了一种达到初始目的的技术，但在灵敏度方面我们还没有完全完成。明年开始持续运行，力争达到预期的灵敏度。

In the first year of this project, almost all hardware are completed ; a vacuum chamber containing an resonant oscillator made of aluminum alloy weighing 1.8 tone, vibration-isolation stacks for supporting the antenna, vacuum monitoring system, main frame of a laser transducer and so on. Specifications of these parts were experimentally confirmed and checked. During the course of these experiments we confirmed the correctness of supporting through a nodal point to keep high mechanical Q of the antenna and we found a simple formula to design the stack isolation system. We also found a knowledge about outgassing of polymer material that is harmful to ultra high vacuum. Finding an enormous thermal noise originating in diffused resonance in membranes of a hinge mechanism for the laser transducer, we could not help changing the hinge to a pendulum which would bring more difficulties in this development. In the final year, we mounted the laser transducer on the antenna and tested its sensitivity both in the air and in the vacuum. During these test we had troubles which made a delay in this project : one is a failure of a laser source of YAG laser pumped by laser diode, which stopped the experiment for three months. The second is that it was not easy to set the pendulum stable by feedback with a frequency band far below the observational frequency, which reacked 4 kHz. For data acquisition we adopted a VME bus with a work station computer and developed several software for continuous operation of the antenna.In conclusion we developed the planed detector and obtained a technique to attain the initial end, we have not fully finished in the point of sensitivity, though. In the next year, we start its continuous operation and try to reach the expected sensitivity.