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.

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

Today, Manu and Eric changed the cavity valves pressure system to open and close them.

during the lock of the OneFive+Amp or of the Koheras, we saw a very noisy PZT signal at 30Hz with increasing/decreasing amplitude very slowly.
this noisy signal was not seen at the begining of the experiment.
as it is independant of the laser source, we guess it should come from the cavity.
at this moment, one only see these valves (which tend to close by themself when there is some leakage) as a source of frequency noise.
we will see if, with this cabling change, the noise on the PZT signal changes also.

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")

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...

19/06/2020

The first part of the edge installation was on done by Yann and Ronic
- close the 2 valves of the cavity
- stop the ionic pump on the edge side
- go to ambient pressure with the special filter
- install the edge on its moving arm
We stopped the installation because of a problem with the flange screws which are touching the moving arm structure => Yann modified the moving arm structure.

01/07/2020

Today, Titouan and Yann finished the installation of the edge in one of the vessels of the FP cavity (the vessel which does not contain the input mirror).
they fully cleaned the arm which holds the edge and goes inside the vessel to cut a part of the cavity beam to block the high order modes.
after closing the vessel, they start the primary pumping:

primary vacuum   : 8e-2 mbar
pumping duration : 1h30.

and then, they start the turbo pumping:

turbo vacuum : 6e-6 mbar
pumping duration: 2h30.

Tomorrow, they plan to wait to have a vacuum level, compatible with ionic pumping (below 1e-7 mbar), to start the vacuum ionic pump (only on the "edge side") and stop primary and turbo pumping.
the question is: what is the tolerable vacuum difference between the two parts of the cavity, to open the valves?
one has to ask the vacuum group for that.

02/07/2020

This morning, after a night with primary pump + turbopump on, the vacuum was between 1e-6 mbar and 2e-6 mbar.
at the end of the day, the pressure was still the same... it is the turbopump limit more or less.
Then, I started the ionic pump WITH protection ON, several times.
each time, the pressure increases a lot (to 1e-5 mbar) as the ionic pump releases particles, and then the protection stops automatically the ionic pump.

the ionic pump was started several times WITH protection ON until the maximum pressure is below 5e-6 mbar, then I remove the protection of the ionic pump to let the pumping process going below 2e-6mbar.
NEVER let the ionic pump without protection if you don't stay beside to stop it in case of.
once the pressure is below 2e-6 mbar, I put back the protection and the ionic pump HV is increasing to 7kV and the pressure is going down.
after 1h of all pumps working:

5 pm: pressure is 1.9e-7 mbar

Then, I closed slowly the valve between the turbopump and the cavity (the primary pump is still ON) and stopped the turbopump.
now, the ionic pump is pumping alone the cavity.

6.30pm : pressure is 1.3e-7 mbar

03/07/2020

This morning, I closed the valve of the primary pump, pumping the edge side, and stopped it.
8 am: pressure is 7e-8 mbar (on the edge side).

the other side of the cavity, closed by 2 valves, was around 1.3e-9 mbar.

3 pm: pressure is 6e-8 mbar (on the edge side).

The problem is to open the valve between the tube (which was not pumped for 2 weeks) and the "edge" vessel which was pumped by the ionic pump (6e-8 mbar).

With Frederic, we just stopped the ionic pump (the vacuum increased a little bit) and directly opened the valve on the edge side.
the vacuum raised above 1e-6 mbar and then we restarted primary and turbo pumps until we reached a level below 1e-6 mbar.
then, we switched on the ionic pump again and stopped turbo and primary pumps.

Now the edge side AND the tube are pumped together with the ionic pump alone.
Frederic advised me to tighten a little bit more the screw of the valve of the turbopump to avoid any leakage.

4 pm: pressure is 5.2e-8 mbar

Frederic changed the configuration of the ionic pump controller from "fixed HV" to "stepped HV" to adapt the HV to the level vacuum (if the vacuum is good enough, the HV is automatically decreased from 7kV to 5kV or 3kV to improving pumping efficiency).

Frederic mentioned also the possibility to use mass spectroscopy installed on the cavity to make some leakage measurements with a Helium bottle.

06/07/2020

Today, after pumping all the week-end with the ionic pump, the vacuum was 1.5e-8 mbar.
I opened the second valve and the vacuum changed to 1.2e-8 mbar.
Now, the cavity is completely open and pumped by the 2 ionic pumps.

07/07/2020

09:00 am: pressure is 7.3e-9 mbar
16:30 pm: pressure is 7e-9 mbar

08/07/2020

09:00 am: pressure is 6e-9 mbar

10/07/2020

11:00 am: pressure is 4.2e-9 mbar

13/07/2020

06:00 pm: pressure is 3.2e-9 mbar

15/07/2020

04:00 pm: pressure is 2.8e-9 mbar

Operations before moving the optical table from the optical room to the Igloo.

— the cavity has been filled with clean nitrogen to reach ambient pressure.
— the two valves have been closed using 5 bar air pressure to properly clamp them.
— the dummy tube between the 2 vessels has been removed and the 2 bellows have been protected with plastic covers.
— all the vacuum equipments have been disconnected from the cavity (only turbo and ionic pumps still remain).
— all the optical elements have been removed from the optical table (only some plates and empty mounts still remain, fixed on the table).
— all the electric cables have been removed when possible. Cables for cavity motors are difficult to disconnect from the vessel side due to the housing. They are still in place. Cables which cannot be removed have been fixed with adhesive tapes and/or clamps.

The optical table is ready to be moved by Bovis on the 26/02 to the Igloo.
 

This morning the Bovis company moved the optical table from the optical room to the Igloo without any problem.

The table is now stored inside the Igloo, just after the large entrance doors, on the right side.
It has been covered with plastic blankets.

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.

On the 19th of May, the optical table has been moved inside the ThomX concrete housing and connected to the Symetrie hexapod and to the electron ring.

Symetrie guys started to test the hexapod and they put some software limits around the predefined zero position.

On the 27th of May, the Airflow has been dismounted from the optical room to be mounted around the optical cavity by the AirC2 company.

here is email from Yann :

Le flux est rentré dans la casemate.
Lundi la société AirC2 revient pour installer les rideaux.
Petits couacs :
- 2 plaques de faux plancher à découper
- le saut de loup à été déplacé (à voir si c'est OK pour tout le monde)
- filet de toit à retendre
- poutres du toit à remettre
- main courante du faux plancher à retirer
- attention au coin du flux au niveau du saut de loup (à baliser et protéger)

The AC plug and the power cord of the airflow were quite hot because they have been dimensioned for 16A current and the total current is above.
AirC2 company should replace them with 32A equipment (6mm2 power cord + 32A Hypra AC plug) in the next days.
 

This morning with Manar, we started to clean the floor around the cavity, the outside part of the panels of the housing, and the optical table.
we will continue this afternoon and, in the end, we will make some dust measurements.
do we know who in ThomX is in charge of the cleanness of the casemate (bringing overshoes, sticky floor, cleaning company for the floor,...)?

the motors controller mini-rack has been installed under the optical table.
but it is still not connected to motors or computer.

we saw a chiller beside the optical table... is it the laser amplifier chiller ?

there is also the hexapod controller which is presently close to the wall.
do you remember where is the final place of this controller?

the two vessels of the FP-cavity are presently at room pressure with nitrogen inside.
it has to be put under vacuum (~ 10**-8) before opening the 2 valves which are separating the vessels from the electron ring.
we can't make any Finesse measurement until the vacuum is made and the valves are open.
we discussed with Bruno about that, and he is aware of the situation. He said he will try to pump the vessels as soon as possible
in order to be able to inject a laser on the next opening, next week.

This afternoon, we continued to clean the housing with Manar and Daniele.
we did a dust measurement after cleaning with the two ceil doors opened and the dust meter in the middle of the table, and it counted ZERO!
it doesn't mean the housing is perfectly clean but it is clean enough to pay attention now to cleanness.

Then from today, we have to wear overshoes at the entrance of the ThomX casemate and wear clean coats below the airflow (we installed the coats inside the FP-cavity airlock).

for cabling motor controllers, we discussed with Aurélien about the Alphanov amplifier position on the optical table.
we don't have the last schemes... so, Aurélien sent an email to Guillaume Machinet and Yann to get them.
normally we could let the computer inside the casemate close to the optical table while the electron beam is not filled inside the ring.
as it is dumped on the opposite side of the casemate, the computer position should be radiation safe for now.

One half-height rack, close to the optical table, has few network devices BUT takes almost all the rack place!
we could easily fit the hexapod controller in this rack with "logical" cabling.

• 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.

This afternoon with Manar, we finished connecting FP-cavity mirrors motors and alignment mirrors motors to their 3 ISP controllers.
We also added an Ethernet hub on top of these controllers to merge the controller's connections to the computer.
We added some cable extensions to the alignment mirrors motors.

We tested the connection and the controlling software made by Didier.
We used the supervisor software as one needs the trick to bypass the Didier safety procedure embedded in its user's software (Chassis12.exe and Chassis3.exe)
We were able to move the motors (tested only upon the 4 motors of the alignment mirrors) but sometimes it seems we have some connection bugs which freeze the access to the ISP controllers.

After some hours of pumping, the vacuum level decreased properly on the left vessel (input mirror) but it seems to decrease slowly on the right vessel (end mirrors).
In consequence, Frederic has been able to start the ionic pumping only on the left vessel (+ Turbo). The right vessel is still pumped by the Turbo pump.
at 5 pm, the pressure was 1.4e-8 mbar for the left vessel and 1.9e-6 mbar for the right vessel.
Depending on the pressure on Monday, Frederic could start the ionic pumping for the right vessel too.

after the WE, the right vessel vacuum level is 1.7e-7 mbar (primary + turbo pumps)

and the left vessel vacuum level is 1.8e-9 mbar (primary + turbo + ionic pumps)

I will ask Frederic to start the right vessel ionic pump.

Now, both vessels are pumped by an ionic pump (both Turbo pumping entrances have been closed).
the primary pump has been removed from the left vessel.
we kept the primary pumping on the right part "in case of".

Now, the pressure on the right vessel is 2.1e-8 mbar.
the pressure on the left vessel is stable around 1.9e-9 mbar.