[Yuzurihara, Yamamura]

We started to investigate the method of detecting the noise from scattered light by the out-of-loop PD.

First, we listed up channels of out-of-loop PD, which were operating during O4a, with Ushiba-san’s help(Fig.1).
We made several plots of Q transformations for each channel. For example, we checked the time of no scattered light noise(6/18 3:00 UTC ~) and the time of contamination by scattered light (6/19 3:00 UTC ~), reported in #klog25704.
We confirmed that the arch-type structures appeared in some of these channels, such as “K1:LSC-REFL_PDA1_RF56_I_ERR_DQ” (Fig.2).

As a next step, we will develop a simple method of detecting such arch-type structures without human inputs. Also, we will identify the parameters of the scattering light, such as the frequency of the scatter object.