Removing high order modes, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | detectors and electronics 
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here is the picture of the L-shape arm and the inside of the vessel.
this image corresponds to the "zero" position on each positionner.
Ronic |
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Removing high order modes, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | detectors and electronics
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yesterday with Daniele, we tried again to move the arm horizontally and vertically from the "zero position" to have a better understanding
of the beahvior,
but it is roughly the same : |
Remontage mécanique, posted by Ronic Chiche at Optical room about mechanics
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Mail de Yann du 12/10/2018 :
Je vous fais le bilan des actions effectuées :
1/ La mécanique a été remontée avec changement des billes céramiques, soufflet défectueux, ect... |
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Remontage des vérins, posted by Ronic Chiche at Optical room about mechanics
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Mail de Yann du 8/10/2018 :
Bonjour,
Tous les vérins sont maintenant OK ! Merci Ronic. |
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Recipies for different FPC power, posted by Ronic Chiche at ThomX igloo about lasers and optics
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For ~ 46kW power in the FP-cavity:
Alplhanov amplifier ratio : 20%
Axis 18 position : -0004710 steps |
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Recipies for different FPC power, posted by Ronic Chiche at ThomX igloo about lasers and optics
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For ~ 23kW power in the FP-cavity:
Alplhanov amplifier ratio : 15%
Axis 18 position : -0016014 steps |
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Recipies for different FPC power, posted by Ronic Chiche at ThomX igloo about lasers and optics
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For ~ 66kW power in the FP-cavity:
Alplhanov amplifier ratio : 25% |
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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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Powerup with 2.5ps pulses, posted by Loïc Amoudry at Optical room about lasers and optics
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A power up has been performed on ThomX until 65kW intracavity power. We didn't see any modes but stored power was really unstable since ~60kW (see
image tek00004.png).
Measurement report is shown in the table below. Gain seems to decrease against intracavity power. |
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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 : |
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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... |
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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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Power shut down on August 29th, posted by Ronic Chiche at ThomX igloo about detectors and electronics
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This morning, all the equipments have been switched off due to a power shut down tomorrow morning.
Only the Onefive oscillator is still ON, connected to the Uninterruptable Power Supply (UPS). |
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Power shut down on August 29th, posted by Ronic Chiche at ThomX igloo about detectors and electronics
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after alignment, CEP adjustment and optimizing the PDH phase, I got back ~92kW in the FPC for 33% amplifier ratio.
Ronic
Chiche wrote:
This morning, all the equipments have been switched off due to |
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Possible causes for the noise in the FP-cavity system, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | vacuum | detectors and electronics
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list of possible causes of the high frequency noise which makes the system loosing the lock => to be checked.
(if you have some new idea, I will edit the post)
1- Laser |
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Possible causes for the noise in the FP-cavity system, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | vacuum | detectors and electronics
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4.3 - Vibrations of the mirror mounts due to temperature related to cavity power (the electrons machine is OFF)
1) to test this possible issue, we plan to make a run at low power in the FP-cavity, around 10kW, instead of ~90kW as usual.
for that, I will need to change the diffuser position on axis 18 to get the same error signal for the locking. |
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Polarization, posted by Loïc Amoudry at Optical room about lasers and optics
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Polariztion measured with Input vertically/horizontally polarized (~100% DOLP)
- Transmission (P4) locked on cavity horizontal polarization is ~50% linearly polarized and ~50% unpolarized ?
- Transmission (P4) locked on cavity vertical polarization is ~50% linearly polarized and ~50% unpolarized ? |