Virgo Logbook

AdV-DAQ (Calibration)

grimaud, masserot, rolland - 18:37 Thursday 07 November 2024 (65487)

Test on NE PCal glitches

Some Glitches have been seen on NE PCal since october.
One hypothesis is that it's coming from the Tx_PD1 photodiode (either from electroniv glitches or beam clipping) and being trickle down by the laser control loop.
To test this we want to switch and use Tx_PD2 for the control loop and see if the glitches ar still present

Test timestamp

Removing PCal NE Lines - 16h38 UTC - 1415032698

Switching TX_PD1 to Tx_PD2 for the control loop - 16h40 UTC - 1415032818

switching to Tx_PD1 - 16h59 UTC - 1415033994

Opening control loop - 17h UTC - 1415034048

CLosing control loop - 17h02 UTC - 1415034184

Switching to Tx_PD2 - 17h05 UTC - 1415034341

Putting back PCal NE lines -> 17h11 UTC 1415034697

Comments to this report:

grimaud, masserot, verkindt - 11:40 Friday 08 November 2024 (65494)

After switching Tx_PD1 to Tx_PD2 for the PCal NE control loop last night, the NE PCal lines were not properly subtracted in hrec.
The problem was coming from the fact that hrec uses channel V1:PCAL_NE_PD1_hpcal to subtract the lines and it is constructed using Tx_PD1.

We changed it to use Tx_PD2 to construct the channel and the line is subtracted well again.
We are going to make this process automatic when switching control loop photodiodes and reload the NE PCal_Fast config during next tuesday maintenance.

grimaud, masserot, verkindt - 10:28 Tuesday 12 November 2024 (65515)

The NE and WE PCal config has been changed to allow more transparent switch of control loop photodiodes. When the switch button is pressed it will automatically change the photodiode use to create the hpcal channel used by hrec to do the line subtraction. The channel are now named V1:PCAL_*_PD_hpcal instead of V1:PCAL_*_PD1_hpcal.

For NE the control loop photodiode has been put back to Tx_PD1, as using Tx_PD2 was not solving the glitch issue.

Hrec and HrecN were restarded at 9h27 UTC.