• The electron ring has been vacuum inside it, but the valves connecting it to the two mirror chambers are closed. Before commencing to do measurements on the cavity, we must place the mirrors under the proper vacuum and open the valves connecting them to the electron ring.

• The vacuum system is consistent of three levels; Normal (max ~10^-3 mbar), turbo (max ~ 10^-7 mbar) and ionization.
• With the help of  Frédéric LETELLIER and Mercier Bruno from the vacuum department in the morning.
  • Installation of the first level vacuum (normal pump)
  • Installation of the second level vacuum (turbo pump)
    • can reach up to 1350 Hz = 81 000 rotation per min (how fast it reaches max rotation depends on how good the first level pump was done)
  • Installation of the connections to the gauge meter, there are two gauges, one for first level and one for second.
• All turned on !!

• Both are on and can be monitored from ThomX control room
  • The attached photo from the control room shows how we will be able to get a graph of vacuum over time.
    • (we were able to reach approximately for Volume 11 and Volume 12 respectively 4.1*10^-6 and ~8*10^-7)
      • to explain Volume 11 and volume 12 (look at Location of ThomX vacuum valves photo)

• A photo of the control module placed outside the bunker to control the optical cavity vacuum is attached
• This afternoon the third system will be installed and turned on

*** Note after vacuum is set there will be three permeant cables inside the cavity box for monitoring.

the ionic pumps have been also connected this morning but not powered on, yet.
the vacuum group is waiting for a vacuum level below 10**-6 to power them on.

it should be the case this afternoon.

about permanent cables on the optical table for the vacuum system, there are 2 for the gauges and 1 for the ionic pump for each vessel, then 6 in total.

The pressure for the mirror vacuum chambers needs to be ~ few 10^-9 mbar for the valves to be open to the electron ring (the rest of the vacuumed ThomX)

At 10h45 in the morning, the pressure on the mirror chambers is:

• on the left                  :  1.9*10^-9 mbar
• on the right (sortie X)  :  1.6*10^-8 mbar

Reminding: the opening of the valves is the responsibility of the vacuum group only.

At 15h30 in the afternoon, the pressure on the mirror chambers is:

• on the left                    :  2.0*10^-9 mbar
• on the right (sortie X)  :  1.4*10^-8 mbar

the pressure decreased by 0.2 in ~ 5 hours for right , but increased by 0.1 for left

not an accurate reading for the change over time

will need to get the pressure vs time graph from the control room. 

At 10h in the morning, the pressure on the mirror chambers is:

• on the left                    :  1.9*10^-9 mbar
• on the right (sortie X)  :  1.0*10^-8 mbar

Bruno mentions that the pressure on the left is descending too slow,  a leakage check to be done on Tomorrow by the vacuum branch.

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.

as the vacuum level was good enough, I asked Eric Mistretta to open the 2 valves of the FP cavity.

He said the vacuum group made several tests during the last days, opening and closing these valves!
I asked him to not open and close them as it could release some dust on the mirrors.

Eric opened the valves in "local mode", using directly the valves controller (see attached image).
He was unsure of what could happen if he switches to the "remote mode"... the valves could be commanded to close again.
so, for the moment, one stays in "local mode".

after opening the valves, the vacuum level started to decrease inside FP-cavity :
9.7e-10 mbar for the left vessel
1.7e-9 mbar for the right vessel

On Friday the 5th of November, ThomX suffered again from a power breakdown.

all the pumping systems had to be restarted.
this produced a vacuum level increase and the FP-cavity valves shut off for security reasons.

Today the vacuum level is good enough and the 2 FP-cavity valves have been reopened by Eric Mistretta.

We observed 2 issues for the chiller of the new CELIA laser amplifier:

• setting the water temperature to 17°C, the chiller water turns to ice close to the water filling port !!! => temperature too low ?
• even when the water is fluid, one has a flow sensor error ! => pump charge too strong ? => reduce the water pipe length.

We have set the water temperature to 20°C and we shortened the water pipes by 2-3m

         => both problems seem to be fixed.

Now, we can try to reduce the setting temperature.

Today, the chiller worked at 17°C during 3 hours without error, no freezing nor flow sensor error.

Today, Yannick Petrilli removed 5 concrete bars (5-9) from the ThomX housing roof in order to let the optical table be installed on Wednesday with the help of Bovis and Symetrie.

The safety net above the equiments has been removed too (one had to remove the hooks on one side to be able to slide the net).

One steel guiding cable (on the right side of the picture) is still there "in the middle" and has to be removed before Wednesday.

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.

Adding the instructions manual for the Alphanov Amplifier SMC Chiller

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