At 9h30 in the morning, the pressure on the mirror chambers is:

• on the left                    :  1.6*10^-9 mbar
• on the right (sortie X)  :  6.5*10^-9 mbar

it appears to have decreased significantly compared to the previous deccend !!!!!!

Leakage test done in the afternoon.

The method :

• an atomic mass spectrometer is connected to the mirror chamber and a measurement is taken to see all the atoms and molecules in the chamber
• after a Helium gas is spread around the outside of the chamber
• there is a leak if there is a spike at Helium (4 amu)

Attached is a picture of the spectrometer plot.

Conclusion: No leak in the cavity and the pressure is expected to decrease in the coming days

The pressure now is:

• on the left                    :  1.6*10^-9 mbar
• on the right (sortie X)  :  1.4*10^-8 mbar

**Note: there is an increase in the pressure after doing the measurement, which is expected from the spectrometer bumping ions to do the measurement.

A plot showing the descend of the vacuum in the mirror chambers (data to plot it obtained yesterday evening)

The regions where there is a drastic decrease is when the ionic pump was turned on.

Today in the morning the pressure was

• on the left                    :  1.3*10^-9 mbar
• on the right (sortie X)  :  4.9*10^-9 mbar

in the evening the pressure was

• on the left                    :  1.4*10^-9 mbar
• on the right (sortie X)  :  4.7*10^-9 mbar

During the weekend 23-24th of October, the lab and ThomX suffered a power breakdown.
All the pumping systems had to restart.

as a consequence, the pressure on Monday 25th morning was 4.3e-9 and 4.6e-9 mbar in the left and right vessels.

this morning, the Tuesday 26th, the pressure is 1.4e-9 and 3e-9 mbar.
now, these pressures are compatible with the opening of the valves!

Pressure is 1.4e-9 and 2.6e-9 mbar this morning.

In order to find the Alignment of the ThomX cavity, Yann built mounts that could be placed directly on the windows outside the cavity, where we can place an iris at the center.

The center of the iris on the mount corresponds to the center of the mirror.

4 were made, big one for the injection and 3 small ones for the other windows. 

The big one fits, but the small ones don't fit, as the heads of screws exceed the circle boundary.

A change to them will be done so that they will fit where they will be clipped from the side.

The new iris mounts fixed on the small cavity windows.

Need additional 2 irises.

The One Five laser and its controller have been moved from PLIC to ThomX Iglo.

In preparation to Install the Amplifier from Alphanov

Adding the instructions manual for the Alphanov Amplifier SMC Chiller

Installation and Maintenance Manual Water Cooled Thermo Con for Rack Mount HECR Series

The Pneumatic valves are still coming back to "close" position.
Now the air bottle is always "open" to keep the valves "open".

The 30Hz noise is still here. We tried to cut off all the air flows. It only decreased the noise intensity but didn't change its shape.

21/11/2019 :

The pneumatic valves are now connected permanently to the university airflow network.
there is a small air leakage but it is not an issue anymore.

the 30Hz noise has been fixed too as it was coming from the extreme position of M1 and M4 (plan mirrors) and due to mechanical instability in this position (motor "outside")