Today with Ronic,
starting with major events that happened (Water circulation + ThomX valves )
- Early in the morning a company worked on the water network, it seemed it was not restarted properly so there was no water circulation in the main ThomX pipes.
- There was an error on the ThomX amplifier chiller , which was noticed at the end of the morning work , where we couldn't find the cavity resonance , could be due to the temperature increase of the amplifer.
- Solved : the issue was solved by restarting the water network and the amplifier chiller was restarted an no error found and temp. Stabilized around 25°
- Around 12h15 ThomX there was a power cut off for less than a second (micro cutt), which cased all the valves to close, the valve air compressor did not restart after the power cut off, we restarted it with Daniele in the evening with the help of Marie and the valves open around 5-6 bar , you will see then all the controllers green and the valves will open.
Results of the day :
- All the power supplies and function generators are under the table, nothing on the table (reduced noise on the signal)
- EOM of Oscillator Off (for now, might turn on if needed)
- Amplifier on 0% , output ~ 300 mW
- Locked on the first resonance of the cavity, lase lock parameters to be optimized better
- Transmitted power increased to ~ 267.2 uW
- Average power inside cavity = 89. 06 W , peak power = 0.2 kW (pulse width = 12.6 ps , frep = 33.36 MHz )
- current effective cavity gain > 300
Oscilloscope :
- error signal, not shown as it was too noisy to have in the image
- blue : reflection (low bypass filter ), yellow : transmission (resistance of 100 k ohm added), green : piezo signal
- 1st image : showing lock and scan regions.
- 2nd image: time zoom on the locked signal
oscillators controller / smartAct:
- Frequency and CEP control , the parameters in the photo attached are the best for the moment to see the smooth change of the resonance peaks when operating the motors, and we can stay FSR range and compensate the variation easily.
- even though we stayed at closed loop (for easier adjustment), we still managed to lock , will try to switch off later to see if reduces a lot of noise.
| Manar Amer wrote: |
|
Today, I installed a power meter at the transmission point of the 1st spherical mirror , transmission 3 ppm (direct from cavity window beam profiler, no filter)
We locked the cavity at 2 different resonances of the fundamental mode, the lock in both cases was stable for a round 1 minute.
at different transmitted power of 33.85 uW ( 11 W average inside cavity) and then locked again at 82.65 uW (27.5 W average inside cavity) transmitted power
Note : the coupling is almost zero for both of the resonances locked !!!!
Oscillator : 33.33 MHz ( 33.356 MHz , frequency read on LAL software)
power injected into amplifier (after injecting into fiber and an EOM) : 3.886 mW (on LAL software)
Amplifier power : 0% (injected power into cavity ~ 300 mW)
Both images of oscilloscope have same voltage scales, only difference timescale and the color code is :
yellow : transmission
blue : reflection
green : piezo voltage
red : error signal
| Manar Amer wrote: |
|
Yesterday, with Ronic we locked ThomX cavity on the second resonance
Laser : 33.36 MHz , Amplifier : 0 % (worked with no errors all day)
adding image for the lock on the second resonance (locked), 00 Mode image, fit, Beam measurements
and image of the first resonance signal (not locked)
Info : when locking on the secondary resonance, we aligned better and adjusted on the oscillator CEP and increased the transmission signal
Controllers connected to computer
through Ethernet :
- Cavity Mirror motors
- Lase lock
- oscillator CEP and Frequency motors (easier to follow the drift with this controller, and we can see it moving)
by USB :
| Manar Amer wrote: |
|
This morning, while trying Guillaume solution of disconnecting the 24 V necessary to the second and third stage and raise the threshold of Temp preamp 1 (to only operate the ampli with first stage only)
Ronic disconnected the 24 volt connection, turned on amplifier LAL software but no MMD3 error or a big temp on Temp preamp 1 , software worked fine with no issue.
we connected the 24 V again and the software worked with no issues.
Still not sure what happened for it to work correctly !!!!!!!!!!
- We used the amplifier at 0% all day with no errors (to test , I turned it for 10 minutes @ 10% with no error too)
- We changed the lase lock box with ThomX one (having Ethernet connection), it was connected to computer and works ok
- Ronic installed a signal amplifier for the PDH error signal. (yet to be fully optimized)
- we see a better coupling than before in the cavity.
- The dominant mode is 00 mode, but we see many higher order modes, need to alight better.
| Manar Amer wrote: |
|
Today with Ronic and Daniele we attempted to lock the cavity, but the alphanov amplifier did not turn on because of an error in MMD3 (related to the third stage)
the new error is having the MMD3 error show on the alarm window of the LAL software, and having the Alarms on the line 3 of the alphanov software red for both EXT/CPU and Laser T Max (never been red before)
this is after a 2-week work stop, but the last time when Daniele changed the fiber connector it worked for 3 hours with no errors.
Ronic, is in contact with Guillaume from Alphanov to fix the issue !!!
Work scheduled all Wednesday, in hopes the issue is fixed by then.
| Manar Amer wrote: |
|
Added Note: the coupling we get is at low power, only preamplifier is on (~ 300 mW)
was done at the end due to excitation of higher order modes.
Wanted to improve the fundamental first, then increase the power.
| Manar Amer wrote: |
- On Monday with Daniele,
- we did full characterization of amplifier beam @ 10% amplification, adjusted the telescope accordingly and injected into the cavity aligned and improved on the fundamental mode.
- On Tuesday with Daniele and Kevin
- I added a low pass filter between 1 - 1.9 MHz on the reflected signal, to reject the oscillator signal (33.33 MHz)
- removed the external resistors on the signal, only the internal resistance of the oscilloscope used ( transmission : 1 M ohm , Reflection : 50 ohm )
- We connected the motors to control the CEP and adjusted on them until we reached ~ 5 -10% coupling
- Images:
- 1st : showing the size of the beam just before injecting into the cavity @ 10%
- 2nd: signal with only improved alignment (not CEP adjustment yet), no low pass filter added yet
- 3rd : zoom on the signals (reflection and error) while adjusting on the CEP
- 4th :attempting to lock the cavity , after getting the max coupling using the CEP motors
Note : the voltage ranges are not the same between the images
| Manar Amer wrote: |
|
Yesterday,
- we installed the second high power reflecting mirrors at the output of the amplifier.
- We aligned and installed a telescope that has adjustable distance between the 2 lenses of -100 mm, and + 200 mm, with approximate diameter at the injection window of ~ 4.5 mm.
- Amplifier was turned on only at the first stage only (output power ~ 300 mW) aligned and injected into the cavity.
- Measured the repetition frequency of the One Five oscillators, Frep = 33.326239 MHz
- Changed the FSR of the cavity to match it.
- Using the Piezo scan on the oscillator, we observed 00 Mode, Fundamental. the shape is the same
- We see transmission on the diode, but there was zero coupling observed (yet to be investigated experimentally )
- a reason could be the CEP of the oscillator ,
- bad matching of the beam waist position,
- noise from the amplifier (as we were operating it at very low power)
- additional alignment needed,
|
|
|
|
|
|
|
|