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... |
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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Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics
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FYI : to access special menus on the Alphanov software,
login : "Administrator"
pwd : no password |
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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Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics
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the present situation is :
Guillaume asked me to disconnect the "Laser head" cable from the pump diode module, installed on the optical table.
on the pump diode module, the connector has several small pins and 3 larges pins : A1, A2, A3. |
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Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics
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Guillaume and Julien Bour from Alphanov will come on wednesday 24/07 to have a first look and check the amplifier.
to prepare their intervention, I tested this morning the OneFive oscillator : it's still working at 33MHz.
and we have ~5mW in the LAL software without the EOM. |
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Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics
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picture of the connectors used to carry signals between the amplifier pump module and the rack under the table.
DB13W3 standard has been used to carry high current on the 3 dedicated pins:
https://en.wikipedia.org/wiki/DB13W3 |
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restarting CFP system after the long summer shutdown (RF section conditionning) and Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software
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temperature in the casemate ~ 19.5°C stable
this morning, I measured the power directly at the output of the fiber coupler (through the output fiber), after the strecher : ~5mW
then, I connected the EOM used for the PDH technic : ~2.5mW |
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restarting CFP system after the long summer shutdown (RF section conditionning) and Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software
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I refilled the chiller and the stabilized temperature is @ 25°C
we started the 3rd stage of the Alphanov amplifier at 30% => PD_OUT is fluctuating around 1-1.4W => it's not related to the real output
power ! |
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restarting CFP system after the long summer shutdown (RF section conditionning) and Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software
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we had to move the laser cavity motor to find the resonances and change a lot the CEP.
the CEP motor is at -524.1µm
we got ~75kW in the FP cavity without alignment but with CEP optimization. |
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restarting CFP system after the long summer shutdown (RF section conditionning) and Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software
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after doing some alignment (walking procedure on the Y axis), and CEP optimization, I got 83kW for 33% on the laser amplifier with a coupling of ~60%
=> we have to check the input power after the amplifier.
I adjusted the FP and laser cavity motors to have a small 33MHz detuning with the RF reference (~10 Hz of beating @ 33MHz) |
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restarting CFP system after the long summer shutdown (RF section conditionning) and Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software
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this morning with Daniele, we are measuring the amplifier power just before the FP-cavity.
Casemate temperature @19.5°C
@0% : 205mW |
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restarting CFP system after the long summer shutdown (RF section conditionning) and Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software
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After the summer power shutdown, I restarted all the equipements and got quickly ~80kW for 33% amplifier ratio with CEP optimization and without Alignment
optimization.
CEP motor position : -506µm |
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restarting CFP system after the long summer shutdown (RF section conditionning) and Alphanov amplifier issue, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics | software
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amplifier power measurement before the compressor CVBG.
we used a mirror in between the amplifier output and the compressor + a 2-mirror periscope to match the powermeter height.
amp ratio (%) power (W) |
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fixing CVBG issue, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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the CVBG of the compressor module seems to have an issue.
here is the plan of the work :
1) faire des résonances avec la CFP |
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fixing CVBG issue, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics 12x
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1) this morning, I aligned to CFP to get back 82kW in the cavity for 33% of amplifier ratio.
thus, we can ajust the iris positions on the optical table to fix the CFP optical path before touching the CVBG.
2) we aligned the 5 iris. all of them were misaligned by 1-2mm, principaly vertically (maybe because we had to change the CFP frequency some |
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fixing CVBG issue, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics
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this morning with Daniele, we realigned the amplifier beam axis on the iris position.
it was pretty fast an easy => we got rapidely some resonance and we locked back to 87kW @33% amp ratio after tuning CEP and alignment.
we tried to play on the L-shape but we didn't a clear effect. |