Détection de fuite, posted by Ronic Chiche at Optical room about vacuum
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Mail de Bruno Mercier du 18/10/2018 :
Un petit CR de la journée:
Nous avons effectué une détection de fuite sur l'ensemble des cavités optiques. Une fuite très importante a été |
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Etuvage cavité THOMX, posted by Ronic Chiche at Optical room about vacuum
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Mail de Bruno Mercier du 19/11/2018 :
Une première cavité a été étuvée, la pression est actuellement de
3.10-10 mbar, l' étuvage
de la deuxième cavité vient de commencer et se
finira en début de la semaine prochaine.
Bonne journée,
Bruno
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End of vacuum test and cavity ready for cleaning, posted by Loïc Amoudry at Optical room about vacuum 
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Vacuum tests finished on 19 december 2018.
Spent last two days to discuss the importance of removing aluminium and baking wires before to insert mirrors for cleanliness issues. Finally
we took pictures to support our demand. |
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Cavity under vacuum , posted by Loïc Amoudry at Optical room about vacuum
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The cavity is right now at 6.5e-8 mbar (turbo pumps on for 1 night and ionic pumps for 3h), primary pumps and turbo pumps are cut, ionic pump are on
and the pressure level is still going down.
Therefore there aren't any big leak in the cavity and we can expect a final vacuum level close to e-9 mbar. |
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Pneumatic valves, posted by Loïc Amoudry at Optical room about vacuum
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The pneumatic valves are now plugged on the university air network.
The air valve is fully openned for the moment.
We still have to check if there is some minor leakage close to the pneumatic valve to improve the setup. |
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Vessels vacuum at ambiant pressure, posted by Ronic Chiche at ThomX igloo about vacuum
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Last Friday and this morning, with Bruno, we close the ring/cavity valves and put some dry air in the two vessels through a filter to avoid turbulences.
Now, the two vessels are at ambient pressure and ready for opening (to remove the mirrors).
One can let the ambient pressure in the vessels as long as we want, the ring/cavity valves have been chosen to be compatible with the high vacuum |
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End of cleaning, plastic fixed on cavity, posted by Loïc Amoudry at Optical room about utilities
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| 08/02/19 - End of the cleaning process. |
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Power shut down on Saturday the 18th, posted by Ronic Chiche at ThomX igloo about utilities
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All the equipments have been switched off on Friday 17th due to a power shut down on Saturday 18th :
CW and Onefive oscillators, computers, laser amplifier, cavity mirror motors, chiller, etc... |
Power shut down on Saturday the 18th, posted by Ronic Chiche at ThomX igloo about utilities
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Today, I restarted all the equipements :
Chiller
: ok, temperature converged quickly to the set temperature : 25°C |
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correct parameters for locking the FP-cavity, posted by Ronic Chiche at ThomX igloo about software
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Today, we restarted the FP-cavity locking, after 3 weeks without using it.
those 3 weeks have been used to set the machine ring at the new (better) frequency : 500.067MHz (corresponding to a change of -183kHz)
or 33.3378MHz in fondamental frequency (corresponding to a change of -12.2kHz) |
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correct parameters for locking the FP-cavity, posted by Ronic Chiche at ThomX igloo about software
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this morning I solved the problem of the 33MHz frequency beating which should be ~12kHz between the generator (at the new frequency 33.3378MHz) and the
laser cavity frequency (still at the old frequency which is 33.35MHz)...
the generator providing the 33MHz frequency has 2 channels, and only one was set at the proper frequency ! |
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correct parameters for locking the FP-cavity, posted by Ronic Chiche at ThomX igloo about software
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this morning, I finished the FP-cavity alignment with the new ring RF frequency.
I get back 50kW @ 33% amplifier ratio.
I'm also able to lock very smoothly on the 500MHz ring RF frequency. |
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New password for login on the ThomX computer, posted by Ronic Chiche at ThomX igloo about software
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the previous password has expired.
the new access from the computer :
login : .\$jehanno |
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strange drift (new effect !?!), posted by Ronic Chiche at ThomX igloo about software
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today, we had a strange effect :
both the laser and the FP cavity were locked on the RF frequency (500.10045 MHz), and we were producing X-rays but with a slowing (several seconds)
fluctuation exactly as the electrons-photons phase was drifting and the fluctuation can goes to 0 Xrays produced even at the "right" phase. |
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Primary vacuum to check dust, posted by Loïc Amoudry at Optical room about mechanics | vacuum
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The cavity has been cleaned then put under primary vacuum (primary pump without vacuum flow control). Dusts presence was checked at air and no significant
changes have been observed.
1ST image before cleaning |
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New direction for cavity motors, posted by Ronic Chiche at ThomX igloo about mechanics | software
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from now on, one reverts the FP cavity motors direction to compensate the long drift from the begining of the project.
the motor MOT.06 will be used for the upward direction (presently -1 082 650 steps)
and the motor MOT.03 will be used for the downward direction (presently +37 170 steps) |
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Power shut down on September 23th, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | vacuum | detectors and electronics | cabling | software | utilities
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to anticipate the power shut down on next tuesday 23/09,
this afternoon, I switched off all the equipments except the oscillator connected on the UPS. |
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Power shut down on September 23th, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | vacuum | detectors and electronics | cabling | software | utilities
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this morning, I restarted all the equipments of the FPC.
everything was fine after being able to get back the correct PDH phase between modulation and demodulation...I got 88kW with 33% amplifier ratio
after basic alignment and CEP tuning. |
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Power shut down on September 23th, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | vacuum | detectors and electronics | cabling | software | utilities
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the 33MHz/500MHz RF frequencies from the Ring seems different from the previous state (maybe working at an energy of 50MeV instead of 70MeV which was
the previous energy ?).
so, I let the FPC at the present position and wait to discuss if it is necessary or not to move the FPC motors for the correct energy... |
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Power shut down on September 23th, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | vacuum | detectors and electronics | cabling | software | utilities
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This morning I did a phase alignment on the PDH signal generator (Rigol DG4102)
this procedure ensure that both phases of the sine wave signals are aligned before finding the correct phase for maximizing the error signal.
so, from now on, in case of power shut down, one just need to : |