New calibration lines turned on 7/25/2023 resulted in unexpected additional inter-modulation products. These new calibration lines were turned off on 8/9/2023.

When looking at coherence data between the main detector and safe channels, we expect no change in the before-during-after periods of the new calibration lines and additional inter-modulation products. However, in “safe” channel CS MAG EBAY LSCRACK Y, we see coherence jump at the specific frequencies of the calibration lines and inter-modulation products. This indicates that the channel may actually be unsafe.

Plots for H1_PEM-CS_MAG_EBAY_LSCRACK_Y_DQ  before / during / after

Research Presentation: https://dcc.ligo.org/G2402592