This afternoon with Yann:
- we changed the shutter base plate position to center the beam axis with the mirrors center => to be checked with the amplifier beam
- on the L-shaped arm, the axis along the cavity beam has been centered. it should be never moved !!! (it corresponds to the less accessible knob).
Yann confirmed the 2 other translation axis of the L-shaped arm follow the back plate position.
These 2 axis have been positioned to put the L-shape plate completely of the beam path.
- the panel of the housing which was shifted has been fixed. now, it is properly aligned.

this afternoon with Viktor, we redid all the power supplies connexions.

4x cables are now connected to the wall sockets.
- 1x extension cable for the mini-rack multi-sockets cable.
- 3x triple-sockets long cables (3.5kW each).

all other cables have been removed and replaced.

we brought the other half-rack next to the first one.

A new circuit breaker has been installed today before the UPS to fix the shutdown issues we observed some months ago when too many devices are connected to the UPS.
it has to be tested...

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)

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

• 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.

Jean-Noel Cayla installed several days ago a Eaton 9PX 11kVA UPS inside the Igloo, outside of the ThomX bunker
and I asked him to place only 1 UPS plug on the wall close to the FP-cavity to supply only the NKT/OneFive oscillator and the Smaract laser cavity motors.

I checked that if I plug a device on this UPS plug, I'm able to follow the power, used by the device, on the UPS monitoring screen.

thus, this morning, I plan to switch off the laser oscillator and move its power cable from a standard plug to the UPS plug and test if we are able to find back the previous performances of the locking.

the present Smaract motor positions are : CH0 => +140µm / CH2 => -177.8µm
as unpowering the motor will put the read position at 0µm, I first go back to 0µm for both channel.
I will put them back at their original values after I plug the motors back to UPS.

finally I installed the OneFive laser, the Smaract motors of the laser and the Arduino Peltier controller of the laser on the UPS plug.
the power "seen" by the UPS is 0W, perharps because the used power is below 100W.
the UPS says it can last 385mn (> 6h) in case of power shut down.

I had to do 10mm step at 10mm/s speed on CH0 of the Smaract motors to get back the laser modelock.
then, I put back the CH0 position at +140µm and the CH2 position at -177.8µm on the Smaract motor.

the present level measured by the laser amplifier is 3.05mW after the power ON of the laser @ CH0=0µm
the level measured by the laser amplifier is 3.012mW after the power ON of the laser @ CH0=+140µm

the level measured by the laser amplifier is 3.125mW after the power ON of the laser @ CH0=+140µm when we switch ON the preamplifier
then, we are able to check the laser repetition rate @ 33.383MHz measured by the amplifier software.

I was able to lock back the FP-cavity.

at one moment, during the alignment optmization process of the infection mirrors of the FP-cavity, I had a huge misalignment moving Ma-Y motor.
I had to realign a lot this motor to get back to the standard power inside the FP-cavity.

=> maybe one needs to make some "walking" procedure on the alignment mirrors to get the best alignment => to be done

presently, the lock @32% of amp ratio produces 50kW inside the FP-cavity.
CH0 Smaract motor = 107µm
CH2 Smaract motor = -113µm
​

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.

Scheme of cabling of the SmarAct motors controllers for acting on Frep and CEP.

this afternoon, because of the test on the electron beam drive in the ring in the next days,
I removed the scope and the desktop computer (but not the display) installed close to the ThomX optical cavity.

they have been stored in the "Viktor" ThomX optical room.

If one needs to work with 3rd stage on the laser amplifier, one needs to make the safety patrol inspection before closing the bunker.

for that, it is mandatory to switch 2 keys on the "key board" in the control room, just before or just after the safety patrol :
- the THOMX key to 1
- the "EXPLOITATION LASERFP" key to 1

for the safety patrol, one has to push the "blinking white" buttons on the walls of the bunker, in the order from 1 to 6, and finish by the south entrance door button.
message " ronde en cours" is shouted during the process.
at the end of the safety patrol, an alarm is triggered for 30sec approx. and then stop.
now, the special keys located at the south entrance door are green and one has to take them (at least 2) to enter the bunker without breaking the safety patrol.

after finishing the controlled intervention, you just have to exit the bunker with the 2 keys and place them back in their location

then the controlled access (colored yellow) will turn to "access interdit" (red colored)

to terminate the closure of the bunker, you just have to turn the two key indicated in the previous image back to their original position.

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.

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.

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