Reports until 14:09, Thursday 15 May 2025
H1 CDS (CDS, SUS)
rahul.kumar@LIGO.ORG - posted 14:09, Thursday 15 May 2025 - last comment - 16:54, Thursday 15 May 2025(84412)
HAM1 ground loop checks done

Fil, Rahul

This morning we finished ground loop checks on HAM1 chamber, since Jim was done with final cabling work. The only grounding issues we found were in RM1 and PM1, hence we removed pin1 from the in-air cable (connecting Satamps).

Comments related to this report
filiberto.clara@LIGO.ORG - 16:54, Thursday 15 May 2025 (84422)
Link

D0902810 aLIGO SUS HAM 1-2 System Wiring
T1200131 Grounding and Shielding at LIGO
D1900511 ISC/SQZ Wiring Diagram

The following were checked for ground loops:

  1. REFL_A LSC DC, cable ISC_221
  2. REFL_B LSC DC, cable ISC_226
  3. POP_A LSC DC, cable ISC_222
  4. REFL_A WFS DC, cable ISC_223
  5. REFL_B WFS DC, cable ISC_224
  6. POP_X WFS DC, cable ISC_225
  7. Picomotors, cable ISC_227
  8. REFL Beam Diverter, cable ISC_314
  9. POP Beam Diverter, cable ISC_315
  10. RM1 Tip Tilt, cable ISC_HAM1_228
  11. RM2 Tip Tilt, cable ISC_HAM1_229
  12. PM1 Tip Tilt, cable ISC_HAM1_311

To get a good chamber ground connection, testing was done at the feedthroughs. Normally done at the ISC racks. Shorts found on RM1, PM1, and both beam diverters.

  1. Beam diverters issue known, see alog 63589. No effort made to repair.
  2. Rahul had tried adding Kapton on the RM1 OSEM. This method repaired the short last vent, alog 63589. Short still present. Pin 13 removed from connector at the SUS field rack
  3. No attempt to remove short inside chamber for PM1. Rahul mentioned in-vacuum cables are dressed/tied down. Pin 13 removed from connector at the SUS field rack.

With suspensions in safe mode, the termination shielding was repaired on the following PM1 cables:

  1. ISC_HAM1_315
  2. ISC_HAM1_319

F. Clara, R. Kumar