sheila.dwyer@LIGO.ORG - posted 09:59, Tuesday 14 January 2025 - last comment - 16:30, Monday 03 February 2025(82260)
IM4 trans calibration check
Sheila, Mayank
We wanted to double check the calibration of IM4 trans into power on PRM, similar to 63812 and 62213
- 10 Watts, single bounce ITMY 16:24 UTC
- OMC locked 16:35 UTC. Sensor correction was off so this alignment is wobbling more than it otherwise would.
- sensor correction on 16:40 UTC - 16:45 UTC. 1420908058 for 300 seconds
- IM4 trans and AS_C whitening gains were 18dB at the time of this measurement.
- Medians:
- H1:IMC-IM4_TRANS_NSUM_OUT16 9.855005
- H1:IMC-PWR_IN_OUT16 9.997126
- H1:ASC-AS_C_SUM_OUT16 0.007815647
- H1:OMC-DCPD_SUM_OUT16 15.558
- Using Craig's code here to get all the optic transmissions (he cites where the numbers came from at the top of the file), we expect 0.244% of the power incident on PRM to reach HAM6 in single bounce.
- If we continue to trust the calibration of AS_C, and the known transmissions that Craig collected, we would apply a correction of 0.9566 to IM4 trans.
I have updated the IM4 trans calibration with this additional factor of 0.9566. I engaged FM8 in the IM4 trans nsum filter bank, which is now labeled "alog82260".
This indicates that at 60.1 W input power from the PSL, we have 56.6 W of power on the PRM.
Screenshots show the new filter in IM4 trans NSUM, SDF in safe, and SDF in observe.
Sheila will add her code shortly.
code used to check this calibration is attached