Motivation for the shift
During this shift, several arm scans are made in order to characterize the optical properties of the North and West cavity. The scan will be used in order to:
-> Measure the astigmatism amplitude. From previous measurement (66835), the astigmatism amplitude appeared to be smaller in the North arm when the ring heater is turned off. No measurement has been made for the West arm since the RH were turned off during the change of the WE mirror. The data from this shift will be used to redo the measurement in both arms.
-> Discrepancy between the characterization made at LMA and from scan (VIR-0562A-25). According to previous measurement, there is a discrepancy between the expected g-factor and what is measured from the scan. The estimation will be done again and for both arms.
-> Most of the scans are made with a misalignment of the end mirrors in order to measure the orientation of astigmatism.
Shift report
Date of the shift : 15th December 2025
The table below shows the tasks performed and their time in UTC. The scans are run with the command CARM_SET_scan_FSR(numiteration = 10, f_FSR=110000,timescan = 60.), where one iteration corresponds to one descending ramp + one ascending ramp. One iteration produces two scans, each one is 60 seconds long.
| Time (UTC) | Actions | Comments |
| 10h29 | LOCK_BEATING_BOOST_ON | |
| 10h42 | Run 10 iterations of scan with CARM_SET_scan_FSR(numiteration = 10, f_FSR=110000,timescan = 60.) | Scan ran successfully |
| 11h03 | LOCKED_ARM_IR LOCK_BEATING_BOOST_ON Misalignement of the end mirrors (NE and WE) TX+=0.3urad | |
| 11h13 | Run 10 iterations of scan with CARM_SET_scan_FSR(numiteration = 10, f_FSR=110000,timescan = 60.) | Scan ran successfully |
| 11h34 | LOCKED_ARM_IR LOCK_BEATING_BOOST_ON Misalignement of the end mirrors (NE and WE) TY+=0.3urad | |
| 11h43 | Run 10 iterations of scan with CARM_SET_scan_FSR(numiteration = 10, f_FSR=110000,timescan = 60.) | Scan ran successfully |
| 12h04 | LOCKED_ARM_IR LOCK_BEATING_BOOST_ON Misalignement of the end mirrors (NE and WE) TX+=0.29urad TY+=0.08urad | |
| 12h13 | Run 10 iterations of scan with CARM_SET_scan_FSR(numiteration = 10, f_FSR=110000,timescan = 60.) | Cavity unlocked during scan at 12h21 |
| 12h21 | LOCKED_ARM_IR LOCK_BEATING_BOOST_ON Misalignement of the end mirrors (NE and WE) TX+=0.29urad TY+=0.08urad | Same misalgnment as before |
| 12h35 | Run 10 iterations of scan with CARM_SET_scan_FSR(numiteration = 10, f_FSR=110000,timescan = 60.) | Scan ran successfully |
| 12h57 | LOCKED_ARM_IR LOCK_BEATING_BOOST_ON Misalignement of the end mirrors (NE and WE) TX+=-0.08urad TY+=0.29urad | |
| 13h05 | Run 10 iterations of scan with CARM_SET_scan_FSR(numiteration = 10, f_FSR=110000,timescan = 60.) | Cavity unlocked during scan at 13h19 |
| 13h20 | LOCKED_ARM_IR LOCK_BEATING_BOOST_ON Misalignement of the end mirrors (NE and WE) TX+=-0.08urad TY+=0.29urad | Same misalignement as before in order to finish the scan |
| 13h31 | Run 10 iterations of scan with CARM_SET_scan_FSR(numiteration = 10, f_FSR=110000,timescan = 60.) | Scan ran successfully |
| 13h53 | LOCKED_ARM_IR LOCK_BEATING_BOOST_ON Misalignement of the end mirrors (NE and WE) TX+=0.26urad TY+=0.15urad | |
| 14h00 | Run 10 iterations of scan with CARM_SET_scan_FSR(numiteration = 10, f_FSR=110000,timescan = 60.) | Cavity unlocked during scan at 14h17 |
| 14h18 | LOCKED_ARM_IR LOCK_BEATING_BOOST_ON Misalignement of the end mirrors (NE and WE) TX+=0.26urad TY+=0.15urad | Same misalignement as before in order to finish the scan |
| 14h24 | Run 2 iterations of scan with CARM_SET_scan_FSR(numiteration = 2, f_FSR=110000,timescan = 60.) | Only two iterations missing due to the unlock |
| 14h30 | LOCKED_ARM_IR LOCK_BEATING_BOOST_ON Misalignement of the end mirrors (NE and WE) TX+=-0.15urad TY+=0.26urad | |
| 14h33 | Run 10 iterations of scan with CARM_SET_scan_FSR(numiteration = 10, f_FSR=110000,timescan = 60.) | Scan ran successfully |
| 14h55 | LOCKED_ARM_IR LOCK_BEATING_BOOST_ON Misalignement of the end mirrors (NE and WE) TX+=0.21urad TY+=0.21urad | |
| 14h58 | Run 10 iterations of scan with CARM_SET_scan_FSR(numiteration = 10, f_FSR=110000,timescan = 60.) | Scan ran successfully |
| 15h19 | LOCKED_ARM_IR LOCK_BEATING_BOOST_ON Misalignement of the end mirrors (NE and WE) TX+=-0.21urad TY+=0.21urad | |
| 15h24 | Run 10 iterations of scan with CARM_SET_scan_FSR(numiteration = 10, f_FSR=110000,timescan = 60.) | Scan ran successfully |
| 15h45 | LOCKED_ARM_IR LOCK_BEATING_BOOST_ON Run 5 iterations of scan with CARM_SET_scan_FSR(numiteration = 5, f_FSR=110000,timescan = 120.) | The last scans are a test to see if the uncertainty is smaller with longer scans |