Jennie W, Sheila,

On Wednesday Sheila and I compared the measurement of HAM 6 throughput taken in April 2024 where we stepped the DARM offset and then compared the power at the ASC port which is sensitive to DARM with the power on the DCPDs, with the HAM 6 efficiency for this light predicted by the known losses as obtained from the squeezer noise budget.

We found that combining both of these results in a prediction of unknown losses of 12.2% which sort of matches the 10.4% unknown losses predicted from squeezing measurements (alog # 82097).

HAM6 throughput measured in April 2024 from alog #79146.: 80.2%

HAM6 known losses: google sheet (1-0.00072)*(1-0.015)*(1-0.0096)*(1-0.044)*(1-0.02) = 91.3% expected HAM6 throughput

Unknown HAM6 losses based on this measurement = 1-0.802/0.913 = 12.2%

Yesterday I looked at Camilla and Elenna's DARM step measurement from 21st October 2024, and found the unknown loss is 10.2 % using the HAM6 throughput measured in October which matches the 10.4% unknown losses predicted from squeezing measurements (alog # 82097).

HAM6 throughput measured in October 2024 from alog #82204: 82 %

Unknown HAM6 losses based on this measurement: 1-0.82/0.913 = 10.2%