Yesterday, 15 Oct 2019, I added beam tubes to IO GigE1 and IO GigE2, in order to shield their sensors from room lights.  Typically when the PSL is in Commissioning and the lights are on in the enclosure both of these cameras are completely saturaded by the room lights, even when only one light switch is on, and two light switches are off.  The new beam tubes improved the camera performance, enough that both beams were visible with only one light switch on.  The GigE camera mounts are very secure, so I don't anticipate that either camera shifted in position or angle, but because the beam tubes are attached to the front of the cameras, there is a possibility that the weight had a small effect on the alignment.  There is limitted space for a beam tube on GigE3, and the beam remains visible even with all three light switches on, so there was no physical change to this camera, however, in order to get a beam profile for the IMC_IN beam, the Bottom Periscope Transmitted Beam, the steering mirror to GigE3 was adjusted for the beam scan and then adjusted back for the camera, so the location of the beam spot on GigE3 changed.

Images attached show GigE1 and GigE2 with their new beam tubes.

- Cheryl, Ethan, Jason