2 Mirror Setup @ 216.6 MHz, posted by Manar Amer at Optical room about lasers and optics | detectors and electronics 
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The SBox cavity setup was changed to have only 2 mirrors M1 plane and M2 spherical, both from ThomX
Distance between the mirror ~ 72 cm , increased from 70 cm to take into account the thickness of the ThomX mirrors
Two lenses (300 mm @ 50 cm , 200 @ 104 cm) were placed to have the beam radius ~ 0.55 mm. |
2 Mirror Setup @ 216.6 MHz, posted by Manar Amer at Optical room about lasers and optics | detectors and electronics
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The cavity was realigned using irises instead of pinholes, gave a better alignment.
The inside of the box, the spherical and the injection mirror were cleaned and placed back inside the box.
we see beating of fundamental mode, previously at the transmission point we placed a wedge to split the beam which resulted in an elliptical |
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2 Mirror Setup @ 216.6 MHz, posted by Manar Amer at Optical room about lasers and optics | detectors and electronics
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Update for Finesse measurement, The cavity was put under vacuum ~ 1.1*10^-1 mbar
and the alignment and coupling improved.
FSR = 210.1 MHz |
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FSR change & Finesse Measurements , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics
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The FSR of the 2 mirror (plan-spherical) Cavity was adjusted from 210 MHz to reach 216.643 MHz
it was done by having two reference irises, one at the injection point and one at the reflection
then changing the position of injection plan mirror to slightly closer distance and monitoring the reflection on the oscilloscope to be max. |
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FSR change & Finesse Measurements , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics
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Yesterday evening the cavity was Vacuum pumped up to pressure of 5.5*10^-2 and locked
changed FSR to be 216.662 MHz and alignment a little and measured the Finesse
in Vacuum we have average Finesse = 30341.6265 |
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FSR change & Finesse Measurements , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics
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a Finesse of 30k with the present mirrors :
T1=120 ppm ;A1=(2.6+1) ppm;
T2=1.5 ppm ;A2=(4.5+0.27) ppm; |
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Installation of D-shaped mirror / Alignment, posted by Manar Amer at Optical room about lasers and optics | detectors and electronics
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To prepare for the amplifier. I installed the D-shapped mirrors after cleaning (using aceton and ethanol) between the cavity 2 mirrors.
Before closing, I observed the back reflection from M1 (injection mirror). both the injection and reflection lines were off, due to that there
was an internal reflection hitting the walls of the cavity. |
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Installation of D-shaped mirror / Alignment, posted by Manar Amer at Optical room about lasers and optics | detectors and electronics
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The D-shaped mirrors are installed properly and not cutting the path of the beam.
The cavity has been aligned again and 00 modes beating observed, and external reference points has been placed.
Manar |
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2 Mirror Setup @ 216.6 MHz, posted by Manar Amer at Optical room about lasers and optics
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Adding information about the 2 mirror cavity setup (plan - spherical) that is currently installed.
From Aurélien at the start of the manipulation.
@ 0 is where the injection mirror is located |
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Amplifier output Beam Profile, posted by Manar Amer at Optical room about lasers and optics
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In preparation to measure the output beam profile from the amplifier at high power, I have placed two wedge mirrors just before the beam dump to be able
to extract the beam.
One of the wedges was taken from ThomX bunker, also the HR and AR mirrors were taken to plic room in case we might need them |
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Amplifier output Beam Profile, posted by Manar Amer at Optical room about lasers and optics
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Beam divergence after amplifier 4.46 mrad
Manar |
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CVBG stretching / Fiber Injection , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics | software 7x
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Before injecting into the amplifier, the pulse needs to be stretched using a CVBG, type attached.
the CVBG is to be used at a small angle, the beam shape and spectrum after the PBS is attached.
After measuring the beam profile, a mirror was placed to direct all the power for fiber injection |
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CVBG stretching / Fiber Injection , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics | software
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closing series
Manar
Amer wrote:
Before injecting into the amplifier, the pulse needs to be stretched |
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Alignment / Table setup , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics | software
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The current setup of the optical table attached.
The cavity is aligned and the lock of the fundamental mode has been attempted, but the mode is drifting too quickly to be able to follow.
I have placed the cavity under vacuum for a better stability. |
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Alignment / Table setup , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics | software
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closing series
Manar
Amer wrote:
The current setup of the optical table attached. |
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CELIA amplifier installation, posted by Manar Amer at Optical room about lasers and optics | detectors and electronics | software
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The amplifier was installed on the optical table next to SBox table.
The CVBG that will be used for stretching before amplification needs cleaning (they are very fragile, 'ask victor for best method')
The software to drive the diodes of the amplifier we have is not the compatible one. |
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CELIA amplifier installation + chiller, posted by Manar Amer at Optical room about lasers and optics | detectors and electronics | software
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Amplifier placed next to the pulsed laser on the table under the airflow
The output is in free space with height from the table of about 10 cm, note the injection height into the cavity is between 14 - 15 cm.
a power cable is placed but not plugged. |
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CELIA amplifier installation + chiller, posted by Manar Amer at Optical room about lasers and optics | detectors and electronics | software
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The software to control the CELIA amplifier is on the laptop that was placed in ThomX bunker.
I have placed it in the PLIC room next to the SBox table.
it is called 'Alphanov Control Software' |
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CELIA amplifier installation + chiller, posted by Manar Amer at Optical room about lasers and optics | detectors and electronics | software
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Closing series
Manar
Amer wrote:
The software to control the CELIA amplifier is on the laptop that was |
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"ThomX" CELIA Amplifier commissionning, posted by Ronic Chiche at Optical room about lasers and optics
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The "ThomX" CELIA amplifier is installed on the optical table.
I added all the rubber pieces available between the 2 racks to isolate as best as possible the top rack, which embeds some fans, from the bottom
rack from which the laser beam is going out to the FP cavity. |
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"ThomX" CELIA Amplifier commissionning, posted by Ronic Chiche at Optical room about lasers and optics
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Beam size at the amplifier output:
to make this measurement, I switched ON only 1st and 2nd stage.
the dichroïc mirror seems to work the best in reflection at normal AOI !!! |
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"ThomX" CELIA Amplifier commissionning, posted by Ronic Chiche at Optical room about lasers and optics
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this afternoon, with Fabian, we did some measurements on the 3rd stage.
finally we used the Dichroïc mirror at AOI=45°C as first mirror and a Thorlabs BB1-E03 as 2nd mirror to send the
beam to the powermeter. |
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OEwaves lock and Finesse measurement, posted by Ronic Chiche at Optical room about lasers and optics
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this morning, I locked the FP cavity with the OEwaves CW laser and the "Fred fiber amplifier" used at 500mA of pump current.
the lock was much more easy than with the Koheras.
I had to change the 10GHz EOM which seems damaged as the modulation depth is very low and does not allow a Finesse measurement by modulation |
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Koheras CW laser lock on FP cavity, posted by Ronic Chiche at Optical room about lasers and optics | detectors and electronics
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I locked the Koheras CW on the FP cavity but the lock was pretty noisy and very difficult to acquire.
I tried to produce some modulation sidebands close to 216MHz to measure the Finesse but the power loss was very small so, the signal to extract
the Finesse would be unreadable ! |
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Pulse duration measurement before and after CVBG (as a strecher), posted by Ronic Chiche at Optical room about lasers and optics
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I recorded the pulse shape of the MENHIR 216MHz in its fiber injection setup.
the fiber is then connected to the Labbuddy photodiode (~ 15GHz BW) and then to the R&S RTO2000 4GHz scope (~ 100ps rise time).
1) I put a mirror just before the CVBG. |
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chiller for CELIA amplifier, posted by Aurélien Martens at Optical room about utilities
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The chiller of CELIA amplifier has been moved from the corridor to the changing room in front of PLIC.
It was not functionning well (quick drop of flow below 0.9l/min). After several cleanings of the filter, shorting the water circuit a stable
2.1l/min flow was obtained. Then the water circuit was elongated to go close to the amplifier but not into it. Allowing to get about 1.3l/min stable. Now |
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chiller for CELIA amplifier, posted by Aurélien Martens at Optical room about utilities
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today, temperature of the chiller has been set to 23°C.
measured temperature in the chiller reaches 23°C after approximatively 10 minutes
Aurélien |
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Images of ThomX mirrors , posted by Manar Amer at Optical room about lasers and optics
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Under the microscope,
the spherical mirrors show the deposit of metal dots on the reflecting surface and not on the back of the mirrors
The mirror with fewer spots near the center was used in the setup. |
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Images of ThomX mirrors , posted by Manar Amer at Optical room about lasers and optics
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Mirror images in the previous log showing the metal deposit of the coating of the spherical mirrors
(not sent by mail due to large size of images)
Manar |
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SBox Finesse at 216.6625 MHz, posted by Manar Amer at Optical room about lasers and optics | vacuum
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The Sbox currently has the injection from ThomX installed T ~ 120 ppm , M2 planar from Sbox spare and M3 / M4 spherical mirrors from Sbox installed.
The last finesse measurement that was done gave a Finesse of ~ 19300 (After cleaning M2 using ethanol + aceton + pure water)
on Friday the whole optical table was cleaned again and the inside of the box was cleaned (even with a lot of dust inside the box the Finesse |
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SBox Finesse at 216.6625 MHz, posted by Manar Amer at Optical room about lasers and optics | vacuum
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Max Finesse obtained @ 4 mirror setup was ~ 19 300
With M1 from ThomX , M2/M3/M4 from SBox
Manar |
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SBox Finesse at 216.6625 MHz, posted by Manar Amer at Optical room about lasers and optics | vacuum
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Manar
Amer wrote:
Max Finesse obtained @ 4 mirror setup was ~ 19 300 |
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Telescope - Spacial Matching , posted by Manar Amer at Optical room about lasers and optics
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Divergence of the CW beam out of the collimator measured after 1 meter to be
2 x = 0.7425 mrad --> x = 0.37125 mrad
2 |
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Divergence of the CW beam after collimator , posted by Manar Amer at Optical room about lasers and optics
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Closing the series of the telescope for the beam @ 133.33 MHz
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Fundamental Mode TEM00, posted by Manar Amer at Optical room about lasers and optics
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The current setup for the SBox has a beam viewer and 2 photodiodes placed at reflection and transmission.
The CW laser piezoelectric crystal was driven using the lase lock system to observe the 00 mode.
Mode Observed and has no reflection (from what was previously seen) |
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Fundamental Mode TEM00, posted by Manar Amer at Optical room about lasers and optics
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Adding images from the transmission after the spherical mirrors M3 and M4 window for a resonating mode inside the cavity.
There appears to be some misalignment from the center of the mirror ???
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Fundamental Mode TEM00, posted by Manar Amer at Optical room about lasers and optics
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Images of the Transmitted beam at M2 mirror at different days.
The first one was from last week, the second from yesterday.
There is misalignment (drift due to temperature) from the position where the beam was initially. ( reference taken between centers of mode and |
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Fundamental Mode TEM00, posted by Manar Amer at Optical room about lasers and optics
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Closing series of 00 mode for FSR @ 133.33 MHz
Manar |
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Cavity Lock , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics | software
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Start with the cavity lock images attached, taken from last week, at start we have a coupling ~ 5% and started improving on the
alignment .
The image of 00 modes attached corresponds to the coupling seen on the oscilloscope. |
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Cavity Lock , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics | software
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Current setup at SBox for locking the cavity
After spacial matching, the coupling increased to ~ 15 - 20 %
The locking was done for the fundamental mode, tried to improve the coupling with the motors, but the lock is very unstable to be investigated. |
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Cavity Lock , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics | software
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Cavity locked today under vacuum and no airflow, it is stable over a long time
the alignment was improved and an increase of the transmission by 20 % from its original value
unfortunately, data from the oscilloscope was saved, but it was not in the correct format (image) to show. |
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Cavity Lock , posted by Manar Amer at Optical room about lasers and optics | detectors and electronics | software
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Closing the series for the setup
The cavity was only locked @ 133.33 MHz but the Finesse was not measured
The FSR was changed to match the new laser MENHIR 216.6625 MHz |
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Menhir Pulsed Laser, posted by Manar Amer at Optical room about mechanics | lasers and optics | detectors and electronics
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The SBox Length (FSR), was changed to match the repetition rate of the Menhir pulsed laser Frep = 216.6625 MHz
It was changed by removing the 2 D-shaped mirrors placed between M1 and M2, distance between M1-M2 ~= 169 mm
it was still needed to be adjusted with M1 motor to reach the correct FSR. |
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KBox Alignment , posted by Manar Amer at Optical room about lasers and optics 7x
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Starting with the alignment of the KBox using CW Koheras.
The size of the CW output from the collimator at 1 meter from is ~ 2.4 mm, to be adjusted with lenses to match the cavity !!! (attached
image) |
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SBox Alignment , posted by Manar Amer at Optical room about lasers and optics 6x
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SBox alignment, using CW laser Koheras power 1 mW
Finished M1 and M2 alignment using the diffraction patterns seen on the beam profiler,
the beam fit is not very good ?? (image taken)
Positions of Ma1 and Ma2 motors are |
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SBox Alignment , posted by Manar Amer at Optical room about lasers and optics
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After pointers and Advice from Aurélien,
improvement of the beam alignment through M1 and M2 irises was done.
To improve the image on the beam profiler, I cleaned the alignment mirrors and the windows using pure ethanol and optical lens cleaning tissue, |
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SBox Alignment , posted by Manar Amer at Optical room about lasers and optics
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Remember to update the position of the reference Irises tomorrow !!!!
Manar
Amer wrote:
After pointers and Advice from Aurélien, |
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SBox Alignment , posted by Manar Amer at Optical room about lasers and optics 9x
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Adjust the placement of the Irises (done at the start of the day, adjusted at the end
when M1 mirror was placed)
Improvement on the
Ma1 and Ma2 (The Alignment Mirrors)
Improves the alignment a bit. There is an observation where there |
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SBox Alignment , posted by Manar Amer at Optical room about lasers and optics
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Finished the alignment of the SBox with M1 of SBox placed, to be changed to gamma factory mirror later
Observed what seems to be transmission through M2 mirror, to be confirmed. image attached shows it
a PowerPoint attached showing the details of today's work. |
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SBox Alignment , posted by Manar Amer at Optical room about lasers and optics
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Last week In FP cavity we had all SBox mirrors including the damaged M1 mirror.
The beating was observed with just a slight adjustment on M4 alignment.
In addition, it was also observed while driving the piezo of the CW laser. |
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SBox Alignment , posted by Manar Amer at Optical room about lasers and optics
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Today; replaced the M1 SBox mirror with M1 from gamma factory , following the previous alignment.
Removed all mirrors and cleaned them one by one.
Started with no M1, placed M2 did its alignment through M3 pinhole, then placed M3 aligned it through M4 pinhole, then placed M4 aligned it through |
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SBox Alignment , posted by Manar Amer at Optical room about lasers and optics
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Yesterday, to find the source of why the mode is deformed, I tried to rotate the mirrors to see if there is a change.
I started with M2 and rotated it by ~ 90 degrees, there is a change in the shape of the beam.(image attached)
Will see if changing M2 to the spare M2 from SBox can fix the issue. |
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SBox Alignment , posted by Manar Amer at Optical room about lasers and optics
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M2 Sbox changed to spare. Alignment of M2 was redone.
With the help of Ronic , We observe fundamental mode of the cavity with higher order modes. A frequency scan on the piezo was done to find the
beating frequency , the shape is elliptical with no clear deformation. |
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SBox Alignment , posted by Manar Amer at Optical room about lasers and optics 7x
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The external and internal alignment was redone.
External Alignment : the collimator position moved so in order to have a good start I placed 2 metallic mirrors and did a rough retrace of it's
line through the cavity box. |
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SBox Alignment , posted by Manar Amer at Optical room about lasers and optics
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Closing Series for Alignment.
Beating observed, beam is in the locking stages
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Spincoater - Mirrror cleaning , posted by Manar Amer at Optical room about utilities
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In preparation for cleaning the mirrors.
The spincoater has been moved with its bump into the sas of the SBox.
The pure water used will be provided by Alice, as the previous source in the workshop is not available. |
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Spincoater - Mirrror cleaning , posted by Manar Amer at Optical room about lasers and optics | utilities
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Used the spincoater and pure water to clean dielectric mirrors which will be installed inside the SBox for directing the reflection line.
The method : place pure alchole on mirror - wipe it using white sterile tissue (in one direction) - clean with pure water in spincoater suing
cotton swap . |
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Spincoater - Mirrror cleaning , posted by Manar Amer at Optical room about lasers and optics | utilities
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Images of the SBox mirrors cleaned at the same time when the cavity was aligned.
Directly from the spincoater to the SBox directly.
PowerPoint attached shows details |
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Spincoater - Mirrror cleaning , posted by Manar Amer at Optical room about lasers and optics | utilities
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PowerPoint shows the detailed images of all the mirrors before and after cleaning.
Images of SBox mirrors and M1 from Gamma factory attached only for the front after cleaning
the lines showing are on the back of the mirrors, they come from the spinning mount the mirrors are fixed on in the spin-coater. |
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Spincoater - Mirrror cleaning , posted by Manar Amer at Optical room about lasers and optics | utilities
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Following the observation that when rotating M2 plan mirror of SBox the deformation position of the mode changes.
M2 was replaced with M2 spare of SBox
images of the mirror front side attached before and after cleaning, no spots at the center, but there seems to be 2 spots far from the center |
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Spincoater - Mirrror cleaning , posted by Manar Amer at Optical room about lasers and optics | utilities
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While repeating the alignment, the mirrors were cleaned using the spin-coater and placed again.
The current mirrors placed in the SBox are
M1 plane injection from Gamma factory |
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Clean Airflow Dust measurements, posted by Manar Amer at Optical room about detectors and electronics | utilities
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The dust meter cap was cleaned using Alcohol, and using the filter white cap the dust count was (0 Av. 10 min)
After the dust counter was hand held in direct airflow, it counted (1581 p/m3 Av. 2 min).
I tested the count also in the SAS, and it counted twice the amount ~ 4500 p/m3 |
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Clean Airflow Dust measurements, posted by Manar Amer at Optical room about detectors and electronics | utilities
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Dust measurement done today on top of the SBox average 10min
Manar
Amer wrote:
The dust meter cap was cleaned using Alcohol, and using the filter white |
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Dust Cleaning of SBox, posted by Manar Amer at Optical room about utilities
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An Initial cleaning of the KBoX outside was done, All the optics and mechanics placed that were on the table were removed.
Only the old Mitylaser amplifier remains on the table.
Since we will be using the ThomX Celia amplifier, we will remove it and place it in a secure location (to be decided). |
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Dust Cleaning of SBox, posted by Manar Amer at Optical room about utilities
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The cleaning was done twice with half an hour interval between the two times
reading on the dust meter was taken after each time, and it was zero averaged over a 10-min
Manar |
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Dust Cleaning of SBox, posted by Manar Amer at Optical room about mechanics | lasers and optics | utilities 6x
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The inside of the cavity was cleaned today. It was very dirty and had big dust particles and fibers inside.
Cleaning was done for everything; wall, floor, fixed mounts, wires (still have some dust difficult to remove), edges.
The dust meter average was measured outside the cavity (2471 p/m3 av 6 min) and inside after cleaning (1424 p/m3 av 10 min). |
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Dust Cleaning of SBox, posted by Manar Amer at Optical room about mechanics | lasers and optics | utilities
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After an overnight where the cavity box was left open, a measurement of the Dust meter was taken:
Outside on the optical table on direct air flux (1701 p/m3 Av 10 min) and
Inside the cavity box (998 p/m3 Av 10 min) |