[Aritomi, Yuhang]

Before the evacuation of END chamber, we checked the END suspension. We excited each coils of end mirror and measured transfer function from the excitation to pitch/yaw oplev spectrum (Fig. 1-4).  All coils seem to be working. We also checked END oplev spectra (Fig. 5, 6). The reference in Fig. 5 is one we use for long time, while the reference in Fig. 6 is one measured on 20220128 before we fixed the END magnets. Fig. 6 shows the END oplev spectra become smaller after we fixed the magnets, but Fig. 5 shows that the END oplev spectra are different from the nominal one and still there is a 6.4Hz peak in pitch spectrum.

Anyway, we brought the movable rotary pump from center area to end and started the evacuation. After the pressure in END reaches below 0.1mbar, we switched to the turbo pump. We will open the gate valves between arm/END tomorrow.