This morning, we performed some HWS measurements with the goal to improve the beam alignment without any mask in front of the heater using the closed loop picomotors.

Unfortunately, we encountered some issues related to the control of picomotors that must be fixed before proceeding with the alignment activity. 

This afternoon, we performed a new HWS measurement after optimizing the position of the actuator on the base platform during the activities of yesterday afternoon and this morning. The HWS-DET acquisition started at 13.06 UTC (20230615T1505)  in NI single bounce and B5 drift control disabled.

At around 13.13 UTC, the PA actuator has been switched ON (WF13) at around 11 W (4.331 A, 8 V).

The PA actuator ellipsoidal beam projected on the NI TM appeared clearly in the map (see an example in fig 1).

At 14.03 UTC the PA actuator has been switched off and, at 14.29 UTC, the HWS acquisition has been stopped. 

After that, we tried to perform a new measurement with the ‘smile’ alignment mask (fig. 2) in front of the heater.

A new HWS-DET acquisition started at 14.57 UTC (20230615T1657) and the PA actuator has been switched ON at 13.03 UTC. The mask produces  some ‘structures’  in the HWS maps not clearly recognizable with respect to the expected one (fig.3).

Thus, tomorrow morning, we will continue to roughly align the actuator without the mask in front of the heater by using the picomotors. 

This afternoon, the PA actuator has been switched on to perform an HWS-DET measurement. The ITF configuration was NI in single bounce and B5 drift control disabled.

Before switching on the  PA actuator, we increased the power of the NI CH in order to identify the center of the NI mirror on the HWS map. At 13.07 UTC, HWS-DET acquisition started, at 13.13 UTC, the NI CH power has been increased, and, at 13.22 UTC, the NI CH power has been decreased to the initial value. The OPL induced by the NI CH power increase was well visible in the HWS maps (see an example in fig.1).

At this point, the measurement has been interrupted and the new one started at 13.58 UTC. Between 14.06 UTC and 14.09UTC, the PA actuator has been switched on by applying V=7 V (I~4 A) (WF17 -  WF 22) and it has been switched off at 15.35 UTC (WF180-184).

The actuator heater temperature vs time and the curvature measured on the HWS vs time are shown in fig.2. The curvature has been extracted by removing piston and tilts from the maps.

This morning the cabling of the NI actuator has been completed. The power supply and the thermocouple and picomotors controllers have been definitely positioned in TCS room (see Fig. 1 and 2). 

The picomotor responsible for the movement on the TX axis (with the exit on the lateral part of the actuator) is labelled as PICOMOTORS 1 and the one responsible for the TY (with the exit positioned near the viewport) as PICOMOTORS 2. 

The remote control of the power and the alignment procedures are still ongoing. 

Today afternoon, the PA actuator has been moved from the TCS room to its final position on the NI tower base.

Monday, the electrical cabling will be performed.

Starting from Monday afternoon, different characterization tests have been performed with the actuator of Point Absorbers in TCS room. 

To avoid false contacts in the functioning of the thermocouple, the cables have been insulated with heat shrink tubing (Fig. 1). We calibrated the dedicated DD channel (ENV_TCS_THC_PA2) in order to have temperature values with the use of a multimeter able to read the thermocouple temperature (Fig. 2). By varying the applied voltage to the heater, we checked both the temperature and DD voltage values and estimate the calibration curve (Fig. 3). The fit values have been reported in the configuration file of the channel. 

After the channel calibration, the heater characterization has been performed. By varying the applied voltage and waiting for the thermalization time ( around 25 mins), the heater temperatures have been registered. We supplied the heater with a maximum voltage of 8 V and the respective reached temperature is around 1000 °C.  The characterization results are summarized in Fig. 4. 

Finally, we checked the heating profile with a screen and the thermal camera (see Fig. 5). The shape of the radiation (not squared) is due to the fact that it is not possible to have the screen with the same AOI of the TM. 

This morning the PAs actuator assembly was been completed and it is ready for the preliminary tests in TCS room.

The remote control of the closed-loop picomotors has been tested directly with the definitive cables already installed on the NI tower (see entry 59248). 

Tha switching on test of the heater has been done with different cables wrt the definitive ones to allow to perform the preliminary test in TCS room, without moving the actuator.

A PicoControl server has been added for the Point Absorbers Mitigation (PAM) in the Virgo Online VPM, this is different to the other PicoControllers in operation due to it being able to do Closed-loop operations. To enable the closed loop operations the PicoControl software needed to be updated so a handler could be added to enable/ disable the closed loop operations. This has not been tested yet due to the device still being installed.

In addition, a Hameg server was created to monitor Hameg (Rhode & Schwartz) HMC8041 power supply. Due to differences to the Hameg (Rhode & Schwartz) HMC4040 currently in operation, this required updating the Hameg software to work with the HMC8041 since it has fewer channels (4 vs 1) and a slightly different command set. The new server is up and running and the power supply can be monitored from the web interface.

These changes have been deployed on /virgoDev along with an associated merge request into the relevant software