peter.king@LIGO.ORG - posted 11:06, Thursday 01 September 2016 - last comment - 12:30, Thursday 01 September 2016(29436)
laser tripped
I was about to take a screen shot of the beams from the various PSL cavities when all of a
sudden the screen went black. The laser tripped. I haven't performed any forensics but it
looks like the same problem as last night.
Comments related to this report
jason.oberling@LIGO.ORG - 12:30, Thursday 01 September 2016 (29438)
Preliminary forensics show that indeed this laser trip happened for the same reason as last night's (and Saturday's): something glitched with the FE flow (either a glitch in the flow meter or an actual glitch in the flow), which took the crystal chiller offline, which then shut down the entire laser. The power watchdogs never tripped, only the flow interlocks for the FE and the crystal chiller. In the first attachment the FE flow dropped just before the HPO began to lose power. The second attachment shows the FE flow interlock tripping also just before the HPO begins to lose power, while the 3rd shows the FE losing power before the HPO does. This points to a problem in the FE flow as the cause for this PSL trip. The 4th attachment simply shows that the power watchdogs did not trip in this instance.
Preliminary forensics show that indeed this laser trip happened for the same reason as last night's (and Saturday's): something glitched with the FE flow (either a glitch in the flow meter or an actual glitch in the flow), which took the crystal chiller offline, which then shut down the entire laser. The power watchdogs never tripped, only the flow interlocks for the FE and the crystal chiller. In the first attachment the FE flow dropped just before the HPO began to lose power. The second attachment shows the FE flow interlock tripping also just before the HPO begins to lose power, while the 3rd shows the FE losing power before the HPO does. This points to a problem in the FE flow as the cause for this PSL trip. The 4th attachment simply shows that the power watchdogs did not trip in this instance.
Filed FRS #6133.