Yesterday we did calibration activities on the NE PCal.

We first performed the installation of WSV at NE at approximately 8h UTC, switched off the laser and started the installation of WSV on the reflection bench.

ADC channel calibration NE:
- Calibration for the temperature channel 5 ADC 0 (10h10 UTC):
with a multifunction calibrator Time series connected to the input of the follower circuit for the PCAL_NE_WSV_temp channel. Here the list of actions performed:
• Changing the channel gain to 200 and offset to 0. in the SNEB_dbox_rack config
• Signal injection from 0 to -6V with 2V steps with the Time Series
• Computing the calibration coefficient (gain and offset) with a linear regression
• updating the coefficient in the config at approximately 10h30  UTC

- Calibration for the power channel ch6 ADC 0 (10h40 UTC):
with a multifunction calibrator Time series connected to the input of the follower circuit for the PCAL_NE_WSV_DC channel. Here the list of the actions performed:

• Changing the channel gain to 2. and offset to 0. in the SNEB_dbox_rack config

• Signal injection from 0 to -6V with 1V steps with the Time Series

• Computing the calibration coefficient (gain and offset) with a linear regression

• updating the coefficient in the config at approximately 12h00 UTC

You will find attached the linear regression associated to both the temperature and power calibration (see figure 1&2).
Here is the tab summaring the old&new values of the gain and offset:

NE Tx_PD1/2 calibration vs WSV measurement 

• Start of background measurement : 11h30 (UTC) for 1h

• Laser turned on at 1.3W : 13h30 UTC

We will have a first glance at the data around 16h00 UTC to see the quality of this latter. We checked the results at about 16h15 UTC and the values were consistent with what was expected (data were stable all along the measurements), we thus interrupted the measurement and run the analysis scripts from which we extracted the following gains/offsets (see figures 3,4,5)

Here is the command used: python3 photodiode_calibration.py 1449930618 5400 1449919818 3600 NE

NE Rx calibration vs Tx_PD1 photodiode

BACKGROUND START 18 UTC (for 1 hour) (see figure 6)

LASER ON 20.50 

MEASUREMENT START AT 22 UTC (for 8 hours) (see figure 7 for the ratio measurements)

Here is the command used:  python3 Rx_sphere_calibration.py 1449957618 28800 1449943218 3600 NE

(using Tx_PD1 as reference is hard-coded)

Finally, the analysis results are as follows:

• Rx sphere new gain : 0.729448, new offset : -0.002623 (using Tx_PD1)
• Rx sphere old gain :  0.730861 , old offset : -0.002632

On the ADC configuration, we updated only the ADC voltage calibration used for the two WSV channels (temperature and power), but we did not update any gains nor offsets for the Tx_PD1,PD2 or Rx photodiodes: all the values are still as they were during O4, since March 2024.