RickS, Daiki Tanabe, Francisco Llamas

This morning we moved the Xend pcal beams to center them on the input aperture target of the pcal Rx power sensor. This is the initial configuration for a series of pcal beam position movements to test the X/Y comparison ratio. Notes for reference attached as pdf.

09:00 local: Turned off the ALS green laser.

The outer beam was initially off-center, a bit below the target. The inner beam seemed to be centered. See first image (PXL_20240319_162539223) attached. We used the Rx power sensor, H1:CAL-PCALX_RX_PD_WATTS_OUTMON, to maximize the input power from each beam, one at a time. The first beam we maximized was the inner beam, going from 0.211 W to 0.223 W. Next, we maximized the outer beam. We unintentionally moved the outer beam to the lower target, 5 mm below center and found a maximum at 0.209 W. The total power with the target on was 0.432. This "accident" happened because no one was supervising the direction the beam was moving on the Rx input port while the mirror was being moved. The maximum value of the outer beam centered on the target was found at 0.209 W. The total power with the target on was 0.432. Our "accident" leans towards laser power measurement being independent of beam location, within a tenth of a percent. The power, once the target was removed, was 0.491 W. See second attached image (PXL_20240319_170413484) for the beam location after we finished our configuration.

10:20 local: Turned on the ALS green laser.