FP-cavity lock survey during the Linac section changing operation, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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This morning with Daniele, we operated the FP-cavity to be sure there is no issue due to the Linac section changing operation :
- opening/closing the valves due to air pressure break down
- opening/closing the bunker roof |
FP-cavity lock survey during the Linac section changing operation, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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This morning, I locked again the FP-cavity at more than 50kW with 33% of laser amplifier ratio.
the temperature is measured today at 20.5°C despite the fact the air conditionning is still OFF.
the temperature, rising from 18°C, started monday at 11AM roughly. |
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FP-cavity lock survey during the Linac section changing operation, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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from now on, the transmission factor for calculating the FP intra cavity power is 1/1.75ppm ~ 570 000 (changed in the Powermeter software)
this morning the temperature of the water cooling circuit is still very high said Sophie, and the laser amplifier temperature "Temp Amp1"
is at 29°C instead of ~23-25°C |
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FP-cavity lock survey during the Linac section changing operation, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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this morning, I had to restart the chiller. Temp Amp 1 is at 27.5°C after having started the amplifier at 33% ratio.
I removed the 100kohms resistor on the Transmission channel, on the scope (now, it is 1Mohms), to get more sensitivity.
the air temperature is around 21°C and is stable during the last days. |
FP-cavity lock survey during the Linac section changing operation, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics 
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this morning, the computer was restarted and I had to launch all the applications.
no problem except the powermeter for which I had to do a power switch OFF and ON remotely.
the chiller was in error and I had to restart it also. |
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FP-cavity lock survey during the Linac section changing operation, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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this morning, the chiller was in error and I had to restart it.
the air temperature is around 21°C. |
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FP-cavity lock survey during the Linac section changing operation, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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Yesterday, the ThomX water circuit should have been repared,
and yesterday aftenoon, Daniele restarted the chiller and I checked it this morning without any error.
BUT the pump of the ThomX water circuit is again in default... |
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FP-cavity lock survey during the Linac section changing operation, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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the air temperature is between 21°C and 22°C.
I tried to lock the cavity but it was very instable with only short time locks.
I had to increase the parameters of the PID: |
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FP-cavity lock survey during the Linac section changing operation, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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today, I tried to restart the amplifier at 0% (without 3rd stage) but it didn't start... still the same error message.
but the PD_IN power and the PD_PULSE frequency seems correct.... I will try to power the amplifier OFF and ON later to see if one can reset this
error. |
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FP-cavity lock survey during the Linac section changing operation, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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today with Daniele, we disconnected the EOM to increase the injected power of the amplifier, we were at 4.8mW but we still have the "bad sequence"
error => email to Guillaume
we tried also several time again, to stop and restart the amplifier, but it didn't help. |
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New multiplication factor for the Fabry-Perot intra-cavity power, posted by Ronic Chiche at ThomX igloo about lasers and optics
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last week, we measured the transmission of a plan mirror from the same batch than the ThomX mirrors and we got ~ 1.75ppm instead of 3ppm which was the
calculated value by the LMA.
previously, we put 1/3ppm = 333 333 as multiplication factor. |
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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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Laser and FP cavities frequency adjustment, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics
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at the beginning of the procedure, the frequency gap between the new Ring 33MHz frequency (33.3378MHz) and the laser/FP cavities frequency was 12.33kHz
=> the Smaract motor position was at +100µm
=> the FP cavity motor Mot.03 position was at -358 720 steps |
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Laser and FP cavities frequency adjustment, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics
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This afternoon, I did the 2nd half of the travel: dF @ 33MHz = 0Hz
=> the Smaract motor position is now at +1750µm
=> the FP cavity motor Mot.03 position stayed at -200 000 steps |
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lock oscillateur 33MHz - synthé 500MHz, posted by Ronic Chiche at Optical room about detectors and electronics
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pour préparer le lock cavité-anneau, j'ai un setup de lock en salle optique entre le laser OneFive 133MHz et un synthé à
533MHz (133MHz x4).
ce matin, j'ai pu locker les 2 ensembles avec le laselock avec une stabilité RMS, je pense inférieure à la ps. |
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lock oscillateur 33MHz - synthé 500MHz, posted by Ronic Chiche at Optical room about detectors and electronics
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régler le problème 1:
Kevin m'a apporté un déphaseur Minicircuits JSPHS-661 (400-660MHz / 180° de phase) qui permet de déphaser le 500MHz
de ~ 1ns avec une tension DC 0-10V. |
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lock oscillateur 33MHz - synthé 500MHz, posted by Ronic Chiche at Optical room about detectors and electronics
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Today, I installed a DB9-DB9 female-male cable on the PZT connector of the FP-cavity.
the PZT is connected between pins 1 and 2, with a capacitance around 70nF.
I need to make a prolongator cable BNC-DB9 female to connect it to the feedback system. |
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lock oscillateur 33MHz - synthé 500MHz, posted by Ronic Chiche at Optical room about detectors and electronics
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Today, I connected the BNC-DB9 female prolongator cable to the FP-cavity PZT cable (DB9-DB9) and to the channel B of the Laselock.
I additionnaly connected the reflected laser beam (normally connected to scope ch2) to the spectrum analyzer @ 1GHz to observe the 30th harmonic
of the laser comb. |
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lock oscillateur 33MHz - synthé 500MHz, posted by Ronic Chiche at Optical room about detectors and electronics
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this afternoon, I installed the frequency detection scheme in the bunker :
- I changed the large reflected photodiode DET100 by a fast small DET10.
- a 50ohms splitter is connected to the photodiode : |
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lock oscillateur 33MHz - synthé 500MHz, posted by Ronic Chiche at Optical room about detectors and electronics
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this afternoon, I tried to lock the FP-cavity on a local 500MHz synthesizer as a frequency reference
(it's faster to change the frequency from the sythesizer than from the FP cavity !!!)
I found some parameters on the PID of the Laselock to phase-lock the reference and the FP-cavity |
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lock oscillateur 33MHz - synthé 500MHz, posted by Ronic Chiche at Optical room about detectors and electronics
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this morning, I added a Thorlabs lowpass filter at 1kHz after the mixer and a resistor at the Laselock output to the FP-cavity PZT.
I set the PID with P=10 and I=D~0
in attachement, a plot of the 500MHz mixer output, before and during the lock. |
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lock oscillateur 33MHz - synthé 500MHz, posted by Ronic Chiche at Optical room about detectors and electronics
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this afternoon, I firstly connected the HV output of the Laselock to the FP-cavity PZT : https://elog.lal.in2p3.fr/FPC/THOMX+commissioning/248
locking the FP-cavity on the local synthesizer works better with the improved HV output range.
the ~20Hz oscillation in the beating signal of the FP-cavity/synthesizer is still there. |
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lock oscillateur 33MHz - synthé 500MHz, posted by Ronic Chiche at Optical room about detectors and electronics
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this afternoon, we were able to lock the laser on the FP-cavity and the FP-cavity on the Ring reference oscillator in a same time from the control room.
the procedure when laser, cavity and reference oscillators are far in frequency, is :
1) start the amplifier to get the laser signal in the reference photodiode used to measure the 33MHz. |
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lock oscillateur 33MHz - synthé 500MHz, posted by Ronic Chiche at Optical room about detectors and electronics
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after a sudden FP-cavity Finesse increase, we had to install the Fast Feedback Loop in order to continue to lock the cavity.
this afternoon, I was able to lock both the FP-cavity and the Laser on the 500.25MHz oscillator reference.
I had to change the CEP to reduce the effective Finesse and help to get a better stabililty => P ~ 25kW inside the FP-cavity for 30% of laser |
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lock oscillateur 33MHz - synthé 500MHz, posted by Ronic Chiche at Optical room about detectors and electronics
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This morning with Daniele, we changed the laser/RF locking scheme :
1) we use the laser 33MHz internal photodiode to do some beating with the 33MHz RF generator (A Rigol generator locked on the 500MHz Ring oscillator).
this beating is only for monitoring purpose, in order to manually adjust the laser frequency at the beginning of a run. |
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Laser cavity temperature/pressure sensitivity, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics
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laser cavity :
when one decreases the laser motor position, the laser repetition rate increases (laser cavity length decreases).
=> +/- laser motor step => +/- laser cavity roundtrip length => -/+ |
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Laser cavity temperature/pressure sensitivity, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics
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Now, I placed a temperature probe stuck on the laser housing itself.
fig. 1
one can compare the temperature measured at the surface of the laser housing and the beating frequency with the 500MHz reference oscillator |
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Laser cavity temperature/pressure sensitivity, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics
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the last thing we did with Daniele, is to start/stop the airflow on top of the housing (closed) to see a possible pressure effect on the laser frequency
drift.
fig 1 : in green, the temperature measured with the probe stuck on the laser housing. |
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Laser cavity temperature/pressure sensitivity, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics
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today, I swapped the 500MHz RF reference oscillator for a Siglent 500MHz DDS oscillator.
see the attached plot : the beating frequency with the 500MHz laser harmonics produces the same behavior as before.
so, the oscillations should come from the laser temperature regulation. |
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Laser cavity temperature/pressure sensitivity, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics
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long-term correlation, over 5-6 days, between the temperature measured in the bunker, outside of the housing (blue curve) and the temperature measured
with a probe stuck on the laser housing, inside of the FP-cavity housing (green).
it's a perfect correlation with almost the same temperature scale : 1°C outisde the housing => 1°C of laser housing |
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Laser cavity temperature/pressure sensitivity, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics
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this morning, I did a 500MHz beating frequency (Laser vs RF) drift test with the Smaract motors configured with "Sensor Mode" OFF over 50 minutes
(~ 1500 acquisitions)
compared with previous measurements, one observes a much more smooth "exponential-like" drift compared to "Sensor Mode" ON |
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locking, posted by Ronic Chiche at ThomX igloo about detectors and electronics
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during the last days we changed the FP-cavity - RF reference locking system to force the right bucket:
in addition to the 500MHz beating which is the signal input to the PID, we added a 33MHz beating signal which is the trigger signal of the PID.
then, the lock is triggered only when this trigger signal is close to 0. |
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33MHz (FP-cavity vs RF) phase stability, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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this morning, with Vincent Chaumat, we made a beating (phase detection) between the laser 33MHz and the 33MHz coming from the Rigol generator locked
by the 10MHz link onto the 500MHz ring generator.
once the laser and the FP-cavity are locked on the RF reference, the 33MHz phase detection is stabilized and confirm the laser/FP-cavity lock |
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33MHz (FP-cavity vs RF) phase stability, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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today, I locked the laser on the FP-cavity and the FP-cavity on the RF reference with 47kW inside the FP-cavity.
equivalent jitter :
when lock is OFF : sine signal V=V0*sin(phi(t)) with V0=300mV => Vrms = 300/sqrt(2)) = 210mV rms |
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controller M1 & M4 (plan mirrors) with IcePap controllers, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | cabling
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previously, we have connected motor M4 with an IcePap controller.
see this post : https://elog.lal.in2p3.fr/FPC/THOMX+commissioning/278
due to the backlash behavior of the FP-cavity motors, it is impossible to work in both directions on one motor when the FP-cavity is locked. |
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controller M1 & M4 (plan mirrors) with IcePap controllers, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | cabling
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this double motors scheme works good.
if motor P4 is used by increasing value, the FP-cavityPZT signal (pink signal on scope) goes HIGHER
if motor P1 is used by increasing value, the FP-cavityPZT signal (pink signal on scope) goes LOWER |
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controller M1 & M4 (plan mirrors) with IcePap controllers, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | cabling
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at the begining of each session, it will be mandatory to avoid any backlash for the motors :
- for the P4 motor : one can go 2k steps DOWN, then 2k steps UP to go back to -360 000 and use the
steps UP without any backlash |
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First stable X-rays production, posted by Ronic Chiche at ThomX igloo about detectors and electronics
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this morning, we locked the laser on the FP-cavity with about 48-49kW stable in the FP-cavity (for 32% of amplifier ratio).
and then we locked the FP-cavity on the RF reference (500MHz beating lock + 33MHz beating for starting lock search).
the starting lock search voltage has been chosen between -20mV and +20mV. |
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Adding one photodiode in reflection, posted by Ronic Chiche at ThomX igloo about detectors and electronics
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this morning, I added a DET36 photodiode in reflection (I used a thin beam splitter) to better measure the coupling over the full beam size.
this DET36 photodiode is sent to the "laser locking" oscilloscope with the other signals :
CH1 :transmission |
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Restarting equipements after Christmas shutdown, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software
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this morning, I plugged back the 4 power cables which supply all the equipments.
all the equipments have restarted without problem, but the shutter of the laser amplifier needs a ThomX safety system grant to let the beam propagate
to the cavity... |
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Restarting equipements after Christmas shutdown, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software
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the laser coupled into the amplifier is still measured at ~3mW at the input, on the Alphanov software, once the Amp stage are started at 0% of power
ratio.
this afternoon, Kevin restarted the 3rd safety system of ThomX to grant the opening of the beam shutter => now the shutter can be opened. |
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Restarting equipements after Christmas shutdown, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software
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this morning, I set the Ring frequency at 500.25MHz and after switching ON the power supply of the amplifiers for the RF signal coming from the laser,
I saw the beating frequency (between ring RF and laser harmonic frerquencies at 500.25MHz) that I canceled, playing with the Smaract motor.
Now, I need to adjust the FP-cavity length to follow the laser cavity length but the IcePap DS (controlling the FP-cavity motor) freezes too |
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Restarting equipements after Christmas shutdown, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software
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on last friday (12/01/2024), the IcePap DS issue was solved and I was able to control the FP-cavity motors properly.
I was able to quickly lock either the laser on the FP-cavity and the FP-cavity on the RF reference as before.
then, we can close these posts on restarting the equipments after the Christmas shutdown |
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Variable focal lens validation, posted by Ronic Chiche at ThomX igloo about lasers and optics
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we plan to use Electrically Tunable Lenses EL-10-30-C NIR to build the ThomX telescope but they need to be compatible with the powerful laser beam.
for CW regime, on the datasheet (see attached file), the optical damage threshold is 10 kW/cm².
with 70W laser power and 1mm² beam surface (which is much smaller than the real beam size), we are at 7kW/cm². |
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Christmas shutdown, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software
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this morning, I shut off all the equipements (especially the computer) except the ones powered by the UPS : laser controller, laser peltier controller,
laser motors controller.
and I disconnected the cables from the power plugs of the wall (to prevent any possible overvoltage). |
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Christmas shutdown, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software
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this afternoon, I checked visually what happens when the AC power of the UPS is broken down => the laser controller has still its "emission"
button ON... no AC interruption.
so, I guess the UPS switched properly the output AC line from the input AC line to the internal batteries. |
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Temperature control of the FP-cavity length, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | detectors and electronics
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as the CFP motors displacements induce a cavity unlock, we try to change the cavity length by changing the temperature of elment of the cavity.
yesterday, we tried to put a "heating cable" borrowed to the vacuum group to change the temperature of one bellows between the FP-cavity
and the electron ring. |
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Temperature control of the FP-cavity length, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | detectors and electronics
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several days ago, we installed a heating cable around the output flange (close to the X-hutch) of the FP-cavity vessel.
we are able to heat this cable by applying a DC voltage coming from 2 DC voltage supplies in serie (2 devices with 2x 0-30V / 3A => 0-120V /
3A). |
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Temperature control of the FP-cavity length, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | detectors and electronics
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today, I removed one of the DC voltage supply (as with 30V, we are already able to 30°C on the heating cable).
the remaining DC voltage supply is configured in series (2x30V = 60V max) and is at the IP address : 192.168.1.101
Ronic |
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Temperature control of the FP-cavity length, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | detectors and electronics
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this afternoon, I started the heating cable after the warm-up of the FP-cavity :
14h20 : start to fill 50kW in the cavity
15h : start of the heating cable @10V (2x 5V) (iteration 2300) |
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Temperature control of the FP-cavity length, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | detectors and electronics
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last friday, I locked the cavity and then, switched ON the heating cable after waiting the cavity reaches a steady state in frequency drift : see the
figure.
blue : temperature of the probe on the heating cable |
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Temperature control of the FP-cavity length, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | detectors and electronics
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on last tuesday, I did a long-term measurement of the frequency drift when the heating cable is powered ON at 20V (2x 10V) @ t=0mn.
the freqeuncy drift (between the laser, locked in open loop on the FP-cavity, and the RF reference oscillator) acquisition was made by the National
Instrument software. |
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Temperature control of the FP-cavity length, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | detectors and electronics
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today with Fatematuj, we did a long-term frequency drift measurement between the FP-cavity loaded with 50kW and the RF reference frequency... and without
any other thermal source (no heating cable !)
we had a small lock loss at t ~ 120mn. |
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Strecher and fiber injection alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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Today, after laser was modelocked, we checked the power inside the fiber coming from the Alphanov Strecher box.
it was almost zero, at the nW level.
after doing some very rough alignment, we clearly saw some power (with the powermeter) correlated with the position of mirrors, when turning |
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Strecher and fiber injection alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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This morning with Viktor, we started the alignment of the CVBG and fiber.
we did a better alignment of the 2-pass CVBG.
we are able to the see a spot after PBS (after the 2 CVBG pass) which means the alignment is OK even if it can be improved. |
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Strecher and fiber injection alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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In preparation for tomorrow morning, I did a test with a 45° mount to have a power pickup inside the injection box.
I used the 133MHz laser.
output power measured with the powermeter : 45mW |
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Strecher and fiber injection alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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This morning with Manar, we measured the power at different points:
- direct measurement at the output of the 33MHz laser : 35 mW
inside the injection box : |
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Strecher and fiber injection alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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I used the 33MHz spectrum measurement : https://elog.lal.in2p3.fr/FPC/THOMX+commissioning/153
fitted by P=P0*sech²((f-f0)/df)
f0 = c/1030m |
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Strecher and fiber injection alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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Manar + Victor, today in the morning we aligned the CVBG of the stretcher.
The double path using the mirror mounts, reached up to 5.4 mW just before the injection into the fibers
then we rotated the quarter wave plate and the power increased by a factor of ~ 2 to 10.3 mW |
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Strecher and fiber injection alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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This morning with Manar, we continued the strecher CVBG alignment and fiber injection procedure :
- we checked the power at the output of the laser and confirmed the measurement after the Isolator : ~ 36 mW
- we tried to improve the power after the strecher CVBG by rotating the quarter-wave plate but it seems we were already at the maximum : ~ 10.5 |
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Strecher and fiber injection alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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this morning : still 6.2 mW at the output of the fiber.
the powermeter has been removed and the fiber connected to amplifier input fiber (no EOM connected in between).
Ronic |
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Strecher and fiber injection alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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Monday 7/11 morning, the power in the fiber was still 6.2 mW
Ronic
Chiche wrote:
this morning : still 6.2 mW at the output of the fiber. |
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Strecher and fiber injection alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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Today, the power measured at the input of the amplifier (PD_IN on the LAL amplifier software) is 2.5mW instead of >3mW generally measured
The power coming from the NKT/Onefive Origami oscillator is still >37mW (measured directly with the powermeter at the laser output without
OD2). |
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Strecher and fiber injection alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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today, the Alphanov amplifier stopped because of the too low injected power : ~2.5mW (measured by the Alphanov software)
it was still working at ~2.7mW.
normally, the injected power is ~3.1mW (equivalent to 6.2mW measured directly at the fiber output). |
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Strecher and fiber injection alignment, posted by Ronic Chiche at ThomX igloo about lasers and optics
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This morning with Ronic, using a pickup mirror, we measured the power in different locations along the path of the stretcher box
Output power from oscillator : ~35mW
After the isolator : ~ 35 mW |
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New mirrors batch informations, posted by Ronic Chiche at ThomX igloo about lasers and optics
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| the 2 files describe the specfications for the16 mirrors ordered (4 for ThomX + spare, 4 for SBOX + spare) and the measurements made by the LMA. |
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FP-cavity inside power sensitivity, posted by Ronic Chiche at ThomX igloo about lasers and optics
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this morning I monitored the frequency shift between the FP-cavity frequency (the laser is locked on it) and the RF reference frequency @ 500MHz,
during the warm-up time, for 50kW stored in the cavity (the recording started ~ 9h20).
one observes on fig.1 a simple exponential behavior with 500Hz frequency shift @500MHz (equivalent to ~ 10µm) for 50kW stored. |
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Long term lock of Laser-FP cavity-RF reference, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | detectors and electronics
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today for the first time, we were able to make a long term lock of all the elements (Laser on FP cavity and FP-cavity on RF reference) during 20
minutes @50kW without any single loss of lock.
the success of this long term lock was coming from the possibility to drive the Smaract motor in piezo-scan mode and to apply a heating on one |
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Long term lock of Laser-FP cavity-RF reference, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | detectors and electronics
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today, I did a 20 minutes "double lock" run w/o any single lock loss.
the attached file shows the recorded RMS beating voltage between 500MHz signals (laser harmonic and RF reference).
the end of the plot after iteration ~1.8k shows the lock loss to the RF reference. |
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Long term lock of Laser-FP cavity-RF reference, posted by Ronic Chiche at ThomX igloo about mechanics | lasers and optics | detectors and electronics
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this afternoon, we did a new long-term "double lock" run w/o any single lock loss during 1/2h.
we did 2 acquisitions :
fig 1 : phase measurement between the 33MHz signal coming from the laser and the 500MHz RF. |
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Smaract motors parameters and controller, posted by Ronic Chiche at ThomX igloo about mechanics | detectors and electronics
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current Smaract motors parameters :
- Closed loop Max frequency : 5000
- Signal Amplitude threshold : 2047 |