I took this issue to the Noise sprint on Wednesday and Adrian Helming-Cornell, Jane Glanzer,Vishal Yalla took up the project.
Dave Barker and Erik also apparently tried to also look into this as well and by Wednesday's lunch time there was some sharing of information

The Noise Sprint group started a google doc where we put all the information that we were gathering:
https://docs.google.com/document/d/127y-9zX6So-zWHxpziH0cU9SAjMjV1lUiJrwKRHdB4A/edit

That may not be a clickable link so here is the content:

alog: https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=71725 

 

PCAL X Noise found by Shivaraj

Shivaraj sent Rick and I a message about some noise found on H1:PCALX_TX_PD and H1:PCALX_RX_PD.
https://ldas-jobs.ligo-wa.caltech.edu/~detchar/summary/day/20230703/cal/pcal_x/

This particular noise took place on the 3rd of July, LHO was empty of people except an operator. Clear examples of this type of noise on these channels can also be found on the 4th, the 5th, and 17th of july.


Checking the same channels on EY:
There is some form of noise on H1:PCALY_TX_PD that shows up on the 11th , 12th, and 13th of this month that looks similar, though not as often and not as intense as the noise found on PCALX and it's not always on both the PCALY_TX and PCALY_RX PD at the same time like seen at EX.

I have reached out to Shivaraj, to try to learn more about this and see if it's a problem for DARM. Which it doesn't seem to be according to what he saw in Bruco .

This noise could point to a problem with our PCAL lasers since its in both TX and RX PD's on at EX. But it also could be the AOM, or the OFS being saturated , or otherwise interacting with changes in temp or humidity.

This could also be a DAQ issue, like a chassis or board because it's showing up on both channels at the same time at EX. Shivaraj mentioned that there might be "cross talk between different channels in a board, and if the glitches are in the light and seen by both PD's they would also show up in other channels, which we could likely use to our advantage."

 

PCAL Background: 

-> PCAL = Photon Calibration 

Used for calibration using test masses at the ends stations of the interferometer using a physical force

 

PCAL chassis layout: https://dcc.ligo.org/cgi-bin/private/DocDB/ShowDocument?.submit=Identifier&docid=S1400489&version=5 

 

Potential Causes: 

• Laser 
• AOM
• AOM Power Supply 

 

Tasks:

• See how often this occurs via summary pages
• Try and compare the noise to other channels (list on the way)/look for excitations
• Trend PCAL lines and systematic error in lines, do they affect transfer functions?
• (High Priority) Is H1:GRD-ISC_LOCK_STATE_N in NLN_CAL_MEAS?  State 700? 
  • Are PCAL noise bursts happening in nominal low noise (state 600), calibration measurements (state 700)
  • Can find on IDVW 
  • Alog when Power supply was replaced see if noise was present before this date.
    • We do see this noise before May 2nd in both PCALX and PCALY. April 10th-14th. Rules out power supply change.
• Some noise in the BSC9 (which is in EX) X/Y/Z channels on July 3rd 2023 from about 14-20utc from 20-40ish Hz.
  • BLRMS these channels, any temporal correlations between these guys and TX/RX noise bursts?
  • What about the endstation ground motion SEI system BLRMS?

 

Channel Names: 

(Might have correlation between calibration channels; however chassis channels are not resolving without calibration channels) 

 

• H1:CAL-PCALX_RX_PD_WATTS_OUT
  H1:CAL-PCALX_TX_PD_WATTS_OUT
• H1:CAL-PCALX_SHUTTERPOWERENABLE
• H1:CAL-PCALX_RECEIVERMODULETEMPERATURE   (Jitter on channel) 
• H1:CAL-PCALX_TRANSMITTERMODULETEMPERATURE ( Jitter on channel) 
• H1:CAL-PCALX_OPTICALFOLLOWERSERVOOSCILLATION
• H1:CAL-PCALX_OFS_AOM_DRIVE_MON_OUTMON 
  • H1:CAL-PCALX_OFS_AOM_DRIVE_OUTMON (Plotting)
• H1:CAL-PCALX_WS_PD_OUTMON
• Effectively any channel that starts with H1:CAL-PCALX_ [ varable ]
  AOM , OFSPD, OFS, TX, RX, OPTICALFOLLOWER

 

Calibration channels:  

Link to GSTAL If you find a time that the kappas have some weird signals then check out the GSTAL data for those times as well.

 

• H1:CAL-CS_TDEP_KAPPA_UIM_OUTPUT 
• H1:CAL-CS_TDEP_KAPPA_PUM_OUTPUT
• H1:CAL-CS_TDEP_KAPPA_TST_OUTPUT
• H1:GRD-ISC_LOCK_STATE_N Look for state 700

 

Chassis documentation: https://dcc.ligo.org/LIGO-D1400153

 

Other instances:

June 9

June 10 - few lines

June 11 - few lines

June 19

June 24

July 3

July 4

July 5

July 11

July 17

July 18

July 19

July 20

July 21 - few lines

July 25 - few lines

 

• DAC update:
  • The channel we use to drive the test mass is sampled at a different rate (16Hz) vs what the pcal photodiodes  (16Khz)
  • Means we may be inserting this noise into the photodiodes because of this difference, if the driving channels are only 16hz. (Later confirmed that this is not the case.) 
  • H1:CAL-PCALX_TX_PD_WATTS_OUT_DQ  and the corresponding RX channels on both X and Y end are all not available on LIGO-DV web. Though they are available on the CDS network and the control room. 
  • Going to get 16kHz DAC readback channels that are faster to try and confirm if this is the issue. Working with Dave and Erik, we have confirmed that the driving channels are 16khz channels but the readback channels are still only 16hz which prevents us from getting analysis results above 8 hz using LIGO DV. 
  • Using ndcscope & Diaggui we have confirmed that there is an issue when the Roaming PCAL X line changes. Which is a PCAL Line that gets changed by a Gaurdian node every 24 hours of NLN Lock state. The issue is that the Roaming X line is changed without a ramp down/up time. This may be the start of the noise that we are seeing but this has not been confirmed yet. The solution to this would be to add a second channel, and ramp down the initial channel and replace the initial frequency of the roaming X line with a ramp up of the next frequency.  

I have 2 gps times that I have narrowed this down to happen between.

Between 1372456038 -1372456158


Calibration channels:  

July 4th, 2023: 16:00:00 - 18:00:00 UTC (1372510818 GPS) 

 

H1:CAL-CS_TDEP_KAPPA_PUM_OUTPUT, raw,start: 2023-07-04 16:00:00 (1372521618) len: 2:00:00.

H1:CAL-CS_TDEP_KAPPA_UIM_OUTPUT, raw,start: 2023-07-04 16:00:00 (1372521618) len: 2:00:00.

H1:CAL-CS_TDEP_KAPPA_TST_OUTPUT, raw,start: 2023-07-04 16:00:00 (1372521618) len: 2:00:00.

 

 

 

 

July 3th, 2023: 14:00:00 - 16:00:00 UTC (1372510818 GPS) 

 

H1:CAL-CS_TDEP_KAPPA_PUM_OUTPUT, raw,start: 2023-07-03 14:00:00 (1372428018) len: 2:00:00.

H1:CAL-CS_TDEP_KAPPA_UIM_OUTPUT, raw,start: 2023-07-03 14:00:00 (1372428018) len: 2:00:00.

H1:CAL-CS_TDEP_KAPPA_TST_OUTPUT, raw,start: 2023-07-03 14:00:00 (1372428018) len: 2:00:00.

 

 

https://ldas-jobs.ligo-wa.caltech.edu/~detchar/summary/day/20230703/cal/pcal_x/ 

 

More searching is needed to ensure that this is resolved.