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Reports until 17:19, Tuesday 14 June 2022
H1 ISC
filiberto.clara@LIGO.ORG - posted 17:19, Tuesday 14 June 2022 - last comment - 16:21, Wednesday 15 June 2022(63589)
HAM1 Ground Loop Check

HAM1 ground loop checks for the LSC sensors (LSC REFL_A and LSC POP_A) and ASC sensors (ASC REFL_A and ASC REFL_B) are complete.

Have issues with the small suspensions (RM1 and RM2) and one of the beam diverter cables. All three have the back shell tied tied to chamber ground. Will continue troubleshooting at chamber feedthrough tomorrow.

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keita.kawabe@LIGO.ORG - 20:06, Tuesday 14 June 2022 (63594)
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At first newly swapped ASC REFL_A had the ground loop, but it turns out that one of the dog clamps was subtly touching the WFS body, bypassing the insulation. Once it was slid out a bit everything was fine.

For LSC REFL_B sensor, as I understand the DB25-DB9 in-air cable had an issue. Fil and Mark had to fix the cable. Sounds as if this was never properly tested when it was originally installed.

filiberto.clara@LIGO.ORG - 13:48, Wednesday 15 June 2022 (63603)
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Ground loops for HAM1 complete. We are leaving the known short seen on the beam diverters as is. No attempt was made to correct issue.

A summary of issues/corrections:

  1. Short in beam diverters. Backshell in CER tied to chamber ground. Issue not corrected
  2. Short in the ASC_REFL_A cable was fixed by adjusting the dog clamp that were touching the WFS body
  3. Short on the LSC_REFL_B was fixed by reassembling the back shell on the chamber side
  4. Short on RM1 was fixed by adding Kapton between one of the BOSEMs
  5. Short on RM2 was fixed by adding Kapton between three of the BOSEMs

F. Clara, K. Kawabe, M Pirello, and  B. Weaver

filiberto.clara@LIGO.ORG - 13:55, Wednesday 15 June 2022 (63604)
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Summary of cables tested:

HAM1 Flange D1
Beam_Diverter_REFL (Cable ISC_314)
Beam_Diverter_POP (Cable ISC_315)

HAM1 Flange D6
ASC_REFL_A (Cable ISC_223)
ASC_REFL_B (Cable ISC_224)
ASC_REFL_A_RF_PD (Cable RF22, 5-way coaxial)
ASC_REFL_A_RF_PD (Cable RF23, 5-way coaxial)
ASC_REFL_B_RF_PD (Cable RF24, 5-way coaxial)
ASC_REFL_B_RF_PD (Cable RF25, 5-way coaxial)

HAM1 Flange D5
LSC_REFL_A (Cable ISC_221)
LSC_REFL_POP (Cable ISC_222)
LSC_REFL_A_RF_PD (Cable RF21, 5-way coaxial)
LSC_REFL_POP_RF_PD (Cable RF30, 5-way coaxial)

HAM1 Flange D4
Picomotor (Cable ISC_227)
LSC_REFL_B (Cable HAM1_RFPD1)
LSC_REFL_B_RF_PD (Cable HAM1_RFPD1)
RM1 (Cable ISC_228)
RM2 (Cable ISC_229)

Beam_Diverter_REFL (Cable ISC_314)
Beam_Diverter_POP (Cable ISC_315)

betsy.weaver@LIGO.ORG - 16:21, Wednesday 15 June 2022 (63612)
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I only added 1 kapton separator on the UR BOSEM of RM1 and the ground loop went away. Lucky. I added 3 on RM2 for UL, UR, and LL. I absolutely could not loosen the mini BOSEM connector screws which were tucked upside down under the bottom BOSEMs. I just managed to wedge 1 kapton piece into place on the RM2 LL and the ground loop disappeared there too. Called it good enough. I took a peak at both RM Y,P,L TFs after this - all still healthy. 

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