On Tuesday, August 18, and over the following two days, I installed the DAS fiber on the vacuum chamber and along sections of the LVEA floor with the help and guidance of Robert.

The DAS interrogator system is located at the H1 TCS Chiller and is connected to the LVEA through the mechanical cable tray. From there, the fiber is routed across the piping bridge and down beneath the vacuum chamber to the seismometer (SEI GND STS). At the seismometer location, we created a fiber loop to enable a direct comparison between the DAS and seismometer recordings.

The main objective is to compare the coherence between the DAS and seismometer measurements and to investigate the extent to which the intrinsic noise of the DAS system limits its performance in recording seismic and vibration signals.

From the seismometer, the fiber was routed back and attached to the vacuum chamber, with approximately five to six turns around the chamber. The fiber was then routed back to the seismometer, where an additional loop was created around the instrument. 

I also performed several tapping tests to georeference the DAS channels and identify the different sections of the fiber. Based on these tests, we were able to distinguish the individual fiber sections and associate them with their corresponding physical locations.

Photos of the installation are attached.