LIGO Hanford Beam Tube Display
Laser light in LIGO's long detector arms travels through a brown steel tube known as the beam tube, an extra section of which appears in this panorama. The brown color arose from oxidation that occurred during fabrication. The rods visible in the tube act as a deterrent to youngsters who want to crawl through the display. The hole in the display section marks the location where a sample was removed for corrosion testing in 2011. Rotate the panorama and you'll see two display sections of the concrete beam tube enclosure that forms a protective barrier for the eight kilometers of tube that occupy the LIGO Hanford complex. Note the fine example of European motorcycle technology that's using the display enclosure for protection from the elements.
Adjacent to the enclosure sits a 17m length of bright steel tubing with a large flange on the end. This piece carried the input beam for the H1 detector during the Initial LIGO era. Too narrow for the Advanced LIGO input and output beam paths, two of these pieces were removed from the H1 beam line in 2011 and replaced with larger diameter sections. Flanges on the ends provided the mating surfaces to the adjacent vacuum chambers.