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 !!!!!!

This afternoon, an electrical operation will be done in ThomX, impacting possibly the casemate power supplies.

Then we shut down all the equipment.

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.
 

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.

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

In preparation to Install the Amplifier from Alphanov

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")

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.

• When connecting the Ethernet cable from the hub to the computer, it must be connected to the correct one (shown in green arrow in photo), it is not the usual internet
• the Motor controllers are under the Cavity table.
• The last image shows the positions of each mirror (To be checked if they are actual readings)

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.

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.

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

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.

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.