Vicky, Camilla
Repeated 66946 PSAMs changes with SQZ-OMC scans with a new method of dithering the PZT around the TEM02 mode and minimizing it. With this we improved the mode mismatch from 4% to 3%. It will interesting to see if these settings are still better in full lock. Plots of OMC scan attached and same plot zoomed on peaks attached.
- Increased SEED power from 0.7 to 75mW. SQZ_OPO_LR to LOCKED_SEED_DITHER. Started with 0.07mW on OPO_IR_PD but we're misaligned on SQZT7. This increased to 1.25mW when we move the ZM4/5 alignment. Will need to fix table alignment to match IFO alignment when we're happy.
- Took IMC to OFFLINE (mis-aligns MC2), aligned SRM, misaligned SR2.
- Note, that we should have (but didn't) misalign the ITMs to make the REFL signal cleaner.
- When we bring ZMs back to IFO alignment, SQZ beam is on AS_AIR (a little high).
- Turned on DC 3/4 centering loops and then OMC ASC. Have power on AS_A/B/C. 70 counts on A/B_DC_SUM.
- Locked OMC with SQZ beam: OMC_LOCK guardian to DOWN. Changed H1:OMC-LSC_LOCK_TRIGGER_THRESHOLD from 1.0 to 0.3. Manually scanned using H1:OMC-PZT2_OFFSET. Watched OMC-DCPD_SUM_OUT_DQ and OMC TRANS camera (exposure increased). Autolocker off. When we found the resonance, turned H1:OMC-LSC_SERVO ON, gain to 1, INT and BOOST on.
- Sending in 1.25mW, expect 70% reflected off SRM would be ~0.9mW, get 0.95mW on AS_C_NSUM, get 0.64mW transmitted though OMC.
Took OMC scans using tempalte /sqz/h1/Templates/dtt/OMC_SCANS/Sept10_2024_PSAMS_OMC_scan_coldOM2.xml Unlock OMC and H1:OMC-PZT2_OFFSET to -50 (nominal is-17) before starting scan.
| ZM4/5 PSAMs | TEM00 | TEM02 |
Mismatch
(% of TEM02)
|
Notes | Ref on Plot |
| 5.5V/-0.8V | 0.6362 | 0.02684 | 4.048% | Starting | 0 (pink) |
| 4.0V/0.34V | 0.6602 | 0.02332 | 3.412% | Maximized TEM00 | 1 (blue) |
| 2.1V/0.2V | 0.6611 |
0.02097 |
3.074% | Minimized TEM02 | 2 (green) This is 0V on the ZM4 PZT. |
| 3.0V/0.85V | 0.6609 | 0.02209 | 3.234% | Minimized TEM02 | 3 (orange) |
| 4.0V/0.34V | N/A | N/A | N/A | Minimized TEM02 | Didn't scan, checked that we got similar results with different method of minimumizing TEM02 rather than maximizing TEM00 |
| 8.1V/-0.4V | 0.6422 | 0.03432 | 5.073% |
Minimized TEM02
|
4 (cyan)
Chose similar ZM4 settings to what we found was good in full lock with cold OM2 in 76986
|
|
2.1V/-0.1V |
0.6591 | 0.02162 | 3.176% | Minimized TEM02 | 5 (red) |
|
2.1V/0.2V |
0.6580 | 0.01954 | 2.884% | Back to best ref2 PSAMS values | 6 (brown) LEAVING HERE |
Over 1V and under -1V on ZM5 is bad at most ZM4 strains (tested at 4.0V ZM4). For each step we adjusted ZM4 and then fine adjusted ZM5.
Note OM2 is cold currently for this measurement (and since the vent it seems).
With the orginal PSAMs (5.5V/-0.8V) we had:
- OMC locked 1-2 min, starting from 1410019031.
- TRANS, DCPD_SUM_OUT = 0.65.
- REFL, OMC-REFL_A_LF_OUT between (0.06,0.18)
- OMC unlocked 30s, starting from 1410019336.
- TRANS DCPD_SUM_OUT = 0.009.
- OMC-REFL_A_LF_OUT between (0.86,0.99)
At the better PSAMS settings (2.1V/0.2V) plot attached:
- OMC locked 1-2 min, starting from 1410027768.
- TRANS DCPD_SUM_OUT = 0.67
- OMC-REFL_A_LF_OUT between (0.036, 0.167)
- OMC unlocked 1 min, starting from 1410028000.
- TRANS DCPD_SUM_OUT = 0.0087
- OMC-REFL_A_LF_OUT between (1.008, 0.87)
- DARK OMC 1 min, starting from 1410028321.
- TRANS DCPD_SUM_OUT = 0.0084
- OMC-REFL_A_LF_OUT between (-0.02, -0.01)
