arnaud.pele@LIGO.ORG - posted 08:43, Thursday 04 June 2026 - last comment - 10:24, Thursday 04 June 2026(90476)
CRS Report June 3 - 1st CRS suspended
Shoshana, Alexandra, Jim, Arnaud, Fil
Yesterday's activity log:
- Shoshana and Jim suspended the first CRS with flexures and after a first round of balancing obtained a resonant frequency of 37mHz (using the Panasonic optical interferometer -HL-G105- to read the frequency, see picture). We had to add x8 8-32 screws (8) at the bottom of the CRS to compensate for a high COM. As per the SW model the balance mass type 2 in d230099 used in the mass adjuster, and the new coupler (-v4) move the COM up by 43um (compared to the MIT build). We will swap d230099 to type 1, which will help reduce the number of Ti screws we have to use. Table below shows the COM position wrt to the flexure center point with different mass adjuster configurations:
| Nominal | New Fork (D2300094-v4) | New Fork + D230099 type2 (4g vs 2g type 1) | |
| Z | +186um | +189.8um | +229.2um |
| X | -2.4um | -3.75um | -3.75um |
- Alexandra confirmed the signal chain from each HOQI was working with the TIA we received from Caltech. The HOQI board D2300154 has some minor wiring issues on the monitor signals, but we can use the TP internal to the board instead for now.
- Fil has started wiring the interlock system to the H2-PSL enclosure so we can turn on the laser.
Images attached to this report
Comments related to this report
The monitor channels in the CRS pre-amp D2500390 are connected up incorrectly. The following table details the current connections: HoQI/TEST POINT CONNECTION - MON CHANNEL CONNECTION HA PDS - HD PDS HA PDC - HA PDC HA PDMC - HD PDMC HB PDS - HC PDS HB PDC - HB PDC HB PDMC - HC PDMC HC PDS - HB PDS HC PDC - HC PDC HC PDMC - HB PDMC HD PDS - HA PDS HD PDC - HD PDC HD PDMC - HA PDMC