Ushiba, Tamaki, Tanaka
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We adjusted the roll alignment of ITMX with MN moving mass. The heights of the magnet's centers on +/- Y side is almost same.
### What we did
- We placed a laser leveler and adjusted the laser height to align with the magnet center on the -Y side (fig. 1). In this position, the height of the magnet's center on the +Y side was higher than the laser level (fig. 2), indicating a positive movement in the ITMX roll.
- During the R6 Noto earthquake, we observed an increase of +2000 cnts in the value of the MN photosensor in the roll direction (MN_DAMP_R_INMON) (Fig. 3). This direction was consistent with our visual inspection. Consequently, we initiated roll alignment adjustments in the negative direction using the MN moving mass.
- While monitoring the height of the magnet's center on the +Y side and the dynamic range of the moving mass, we adjusted the roll alignment. Figure 4 displays the time series of the MN photosensor's values during the adjustment process (the significant jump at -45 min resulted from the release of TM, as noted by Ushiba-san, which touched the EQ stopper). The MN photosensor's value changed by approximately 1000 cnts. Since the gain of the photosensor at room temperature is half that at cryogenic temperature, the adjustment made during this time appears consistent with the change caused by the earthquake. Figure 5 illustrates the magnitude of the MN moving mass steps.
- Figures 6 and 7 depict the heights of the magnet's centers on the +/-Y sides, respectively. These heights have become nearly identical.
