One of the critical point of the injection subsystem if operated from remote is a possible break down of the chiller cooling the pumping diodes of the neovan.
When it happens the neovan goes in security mode and switches off but it is still seeded by the 20 W of the slave laser. Those 20 W are focused into the neovan head and could possibly drift because of thermal effects that are differents that the ones in normal conditions.
To avoid that, this morning, we installled a flip mirror between the slave laser and the neovan that send the 20 W on a beam dump (see attached picture)
This flip mirror can be driven from remote. From the VPM go in the TCS section, subsection ttl_inj, button INJ_AMP_FLIP_UP to block the beam.
We are also implemented an automatic command in the metatron to flip it automatically when the DC power at the output of the amplifier is too low. More info to come.
We also took advantage to set the current of the pumping diodes of the neovan to 0, reverse the flow of the cooling system by swapping the main chiller of the injection (like we did in entry https://logbook.virgo-gw.eu/virgo/?r=48683 ). This, again, had a positive effect on the peltier corrections that were slowly increasing during the last days (see the attached plot).