Onefive 33MHz modelock loss, posted by Ronic Chiche at ThomX igloo about lasers and optics
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For the modulation/demodulation generator for the PDH signal,
after a power shutdown, on can :
1) restart the generator to get the correct parameters: |
Checking the amplifier power, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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this morning, with Daniele, we checked the amplifier power, right after the CVBG (the power meter has to be placed on a metal plate above the large table
hole), and just at the input of the FP cavity, after the 1/4 and 1/2 waveplates (the power meter has to be placed on flat beam dump+ Thorlabs beam dump
+ V metallic mount to be at the right height). |
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Checking the amplifier power, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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we did a long term run (25 mn) with the powermeter located at the FPC position at 33% amplifier ratio.
the initial power was 18W .
then, it goes to 18.5W in 10 minutes, then 5 minutes later, it goes to 18.3W and stay stable until the end the run. |
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Checking the amplifier power, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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I put back and aligned the 1/2 waveplate only and I get 71kW max after its optimization and optimizing the CEP and alignment (without walking procedure).
this waveplate change a lot the reflected power seen on the CH2 of the scope.
to be continued this afternoon... |
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Checking the amplifier power, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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this afternoon, we put back the 1/4 and 1/2 waveplates and after a long alignment/angle tuning/CEP optimization process, we hardly got 80-81kW in the
cavity for 33% amplifier ratio. the transmission photodiode is then ~ 7.5 divisions (500mV/division) on the scope.
BUT during the 1/2 and 1/4 waveplate angle tuning process, we clearly saw: |
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correlations between vacuum gauges and lock losses @ 20Hz, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | vacuum
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the machine people saw a correlation between BPM jumps and vacuum gauges peaks related to breakdowns in the beam pipe.
these breakdowns could produce some accoustic noise which could be related to our lock losses.
=> we tried to do a corrrelation between our lock losses and the vacuum gauge peaks => WE DON'T SEE any correlation !!! |
New power record in ThomX cavity, posted by Ronic Chiche at ThomX igloo about lasers and optics 
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| today, we were able to store more than 93kW in the FP cavity, always with the same parameter : 33% laser amplifier ratio |
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New power record in ThomX cavity, posted by Ronic Chiche at ThomX igloo about lasers and optics
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today, we were able to store more than 94kW in the FP cavity, always with the same parameter : 33% laser amplifier ratio
Ronic
Chiche wrote:
today, we were able to store more than 93kW in the FP cavity, always |
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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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Good Xrays production trend, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | detectors and electronics | software
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| this afternoon, we succeeded to get a quite long Xray production trend around 15-20 minutes with a flux above 25k on i1. |
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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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Electrons-Photons phase stability measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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we installed a measurement at the IP with the BPM for ion cleaning for electrons and we used a fast photodiode at the output of the FP-cavity and measured
with a fast oscilloscope the phase jitter between the 2 signals.
in red, the BPM signal |
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Electrons-Photons phase stability measurement, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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the phase between the 500Mhz ring RF oscillator and the electrons is measured on a BPM and is very stable after 2-3ms (<< 6ps, typically) !
in the same time, we can use the residual phase beating after our 500MHz mixer to estimate the phase noise coming from the laser part.
the rms noise of this signal is around 60mV for 1.25V peak (2.5 pk-pk) signal => ~ 50mrad rms |
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New power record in ThomX cavity, posted by Ronic Chiche at ThomX igloo about lasers and optics
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today, we were able to store more than 95kW in the FP cavity, always with the same parameter : 33% laser amplifier ratio
Ronic
Chiche wrote:
today, we were able to store more than 94kW in |
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New power record in ThomX cavity, posted by Ronic Chiche at ThomX igloo about lasers and optics
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today, we were able to store more than 97kW in the FP cavity, always with the same parameter : 33% laser amplifier ratio
Ronic
Chiche wrote:
today, we were able to store more than 95kW in the FP cavity, always |
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33MHz phase adjustment, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software
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the 33MHz beating signal (phase) is used to start and stop automatically the lock on the 500MHz beating signal.
this 33MHz beating phase has a fixed range (typically +/-0.5V), so it is important to center this beating phase in the middle of its own range
when the 500MHz signal is locked |
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New power record in ThomX cavity, posted by Ronic Chiche at ThomX igloo about lasers and optics
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yesterday, we were able to store more than 98kW in the FP cavity, always with the same parameter : 33% laser amplifier ratio
Ronic
Chiche wrote:
today, we were able to store more than 97kW in |
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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% |