After installing the second pd behind ACVA, I tried to re-measure RIN behind ACAV and RCAV again. The measured RIN from ACAV and RCAV are about the same as we measured before.

    I was having problem with the measured RIN after we installed the second PD for ACAV. It turned out that the beam was not dumped properly. The measurement was done after I realigned the beam to ACAV/RCAV and centered the beam on the PD. I'll use the coupling we measured in PSL:1008 to add the contribution from RIN in ACAV to beat noise (assuming no common mode rejection).