Reports until 21:39, Thursday 19 October 2023
H1 PEM (DetChar)
oli.patane@LIGO.ORG - posted 21:39, Thursday 19 October 2023 (73607)
Noise pattern in OAF-RANGE_RLP_1

Tony and I noticed a strange pattern of noise that happened twice in close succession in the OAF-RANGE_RLP_1_OUTPUT BLRMs channel(bandpassed between 10-20Hz)(attachment1-red trace). It starts around 10/19 22:58UTC and ends at 23:08 before then repeating between 23:08 and 23:20.

We know that the garbage truck was onsite today and slammed a dumpster down at ~23:14 before leaving the site at 23:16, so we think this could be caused by the truck's movement onsite. The OAF-RANGE_RLP_{2,3,4}_OUTPUT BLRMs channels (20-34, 38-60, and 60-100Hz, respectively) all saw a spike at 23:14:41(attachment2-orange,yellow,green traces), and Lance's previous alog(72404) shows clear noise in GDS-CALIB_STRAIN up to ~50/60Hz.

However, this noise being caused by the truck would mean that the truck was onsite for 20 minutes, which seems way too long. Additionally, I did a quick look back at when the garbage truck was onsite from Lance's alog (08/24 and left at 23:05UTC), and although I did not see anything that looked similar during when the truck was onsite, I did find a similar-ish pattern that happened between 08/24 23:11 and 23:36UTC(attachment3-red trace), ten minutes after the truck would have left, meaning that the noise could not have been caused by the truck. But this could also be my brain trying to fit this random noise into a pattern that resembles the noise from today, so please take with a grain of salt.

Images attached to this report