[Ushiba, Takano]
Here is the summary of the REFL table GND investigation.
1. Voltage difference btw asc0 rack and REFL table
The voltage level of asc0 rack in terms of REFL table is ~9mV. This value seems too small to make spark...
Here is the summary of the REFL table GND investigation.
1. Voltage difference btw asc0 rack and REFL table
The voltage level of asc0 rack in terms of REFL table is ~9mV. This value seems too small to make spark...
2. Connection of (Q)PDs and REFL table
- REFL PDA1: Floating
- REFL PDA2; Floating
- REFL QPDA1; Floating
- REFL QPDA2: GND
QPDA2 → RFQPD interface → QPDA1
→ RFPD interface → PDA1, PDA2
3. Flowing current
We measured the current btw the table and PDA1, PDA2, and QPDA1 respectively.
- PDA1 and REFL table: ~8mA
- PDA2 and REFL table: ~8mA
- QPDA1 and REFL table: ~4mA
We also measured the voltage level between PDA1 and the table. Ushiba-san will report about this.
From these measurements we hope that if we disconnect QPDA2 from the rack the PD issues
will be solved. But unfortunately yaw motion of PR3 is too noisy to lock the arm cavity stably and couldn't check this effect...
Before we left we connected again the cables we had pulled in the morning (PDs, QPDs, PZTs, power supply, accelerometer, wave plate rotator).