Reconnecting after cable management operation

Logan, Michael

I introduced Logan to the squeezer clean room and mostly introduced FP cavity, FSR mode spectrum and PDH locking in the context of the green path.

I realigned the green mode cleaner/Mach Zender assembly to 92% mode matching. But the GRMC PD is not connected to the Cable Management Box. It's a bit hard to find in the giant mess of cables (seems to be unlabelled) so we will try next time.

Labview modification

The labview "Complete Integration for Camera" was modified to save data properly. The issue now was that the VI was too fast with averging of 1st order and there were same points being repeated in the dataset. Some changes were done as follows:

1. Added clear buffer for the averaging filter which is triggered when the number of iterations of averaging loop equals the averging order.

2. Added timer inside the averaging loop to make it a bit slower depending on what averging order you do. So, for different order you have different speed. Because the data saving was fine with averging order of 10, but was saving same data 4 times for averging order 1.

Comment to Manipulation 2D polarization (Click here to view original report: 3537)

1 LCD à 0° : Thu, Apr 18, 2024 11-14-30 AM.txt
1 LCD à 90° : Wed, Apr 24, 2024 3-40-14 PM.txt
1st 45° 2nd 0° : Wed, Apr 24, 2024 6-57-43 PM

Manipulation 2D polarization

After I've finished colimate my beam in the camera, I changed the orientation of my HWP and QWP to get 90° for the azymuthal angle and 0° for my elipticity.

Then, I made measurement with only 1 LCD of the polarization when we put a video on the LCD (video = all the 256 RGB value).
I did the same with 1 LCD oriented at 90°.

After doing this, I put the two different LCD and adapt my setup in order to get two different video, which allows you to combine the 256*256 different combinations.

All the setups seems to work.

Note : The camera is not synchronized with the 2 video make with a python.

HWP measurement at different positions

Mounted HWP on roator mount and measured the transmission using polcam. The measurement was taken at the following mentioned positions of the rotator mount.

The LC voltage was scanned from 0-3.5V with 0.1V step.

0deg:

C:\Users\atama\OneDrive\LC-Experiment\Measurement Data\Retarder\HWP\0 deg

Tue, Apr 23, 2024 4-45-43 PM.txt

38 deg:

C:\Users\atama\OneDrive\LC-Experiment\Measurement Data\Retarder\HWP\38 deg

Tue, Apr 23, 2024 5-10-09 PM.txt

The choice of position of rotator mount is random. The measurement is being taken to check if I can reconstruct rotation using the same method as being used for coating.

Mesurement of QWP at different positions

Mounted QWP on roator mount and measured the transmission using polcam. The measurement was taken at the following mentioned positions of the rotator mount.

The LC voltage was scanned from 0-3.5V with 0.1V step.

0deg:

C:\Users\atama\OneDrive\LC-Experiment\Measurement Data\Retarder\QWP\0 deg

Tue, Apr 23, 2024 11-43-44 AM.txt

62 deg:

C:\Users\atama\OneDrive\LC-Experiment\Measurement Data\Retarder\QWP\62 deg

Tue, Apr 23, 2024 11-57-20 AM.txt

Comment to Vacuum Pumping (Click here to view original report: 3529)

The pressure at 8:00 was 4.7*10^-4 Pa. Looking at previous logs, the final pressure is consistent with past values.

I plan to start cooling on Thursday.

I also checked the valves for water supply to compressor are open. So I might not have to worry about cleaning up the water lines. I heard the water is supplied by ATC, but do I need to turn on the water chiller?

Mesurement of coating at different positions

It seems there could be some issue with previous data, as there is some issue with reconstructing rotation of the coating. I took measurement at several position of coating today. The coating BB1EO3 is mounted on a rotator and hence the rotator is rotated at 0 deg, 14deg and 62deg. The voltage scanned was from 0 to 3.5V with 0.1V resolution and averaging of 10th order is implemented.

Also the rotator mount was changed. previoulsy we were using rotator alone and hence it was quite difficult to have finely tuned alignment between the incident and reflected beam. The rotator is now mounted like this and now we could perfectly align the reflected beam with incident beam after the BS

path = "C:/Users/atama/OneDrive/LC-Experiment/Measurement Data/"

0 deg

14 deg

Comment to Vacuum Pumping (Click here to view original report: 3529)

I turned on the TMP at 12:54. The pressure at that time was 3.58*10¹ Pa.

The pressure at 13:05 was 8.1*10^-2 Pa.

I will continue pumping for a while (until Monday).

Note: The TMP is in "local" mode and can only  be operated using the front control panel.

Comment to Rotating coating and measuring at 2 position (Click here to view original report: 3502)

The voltage of 0-3.5V was chosen in contrast to previous choice of 0-5V or 0-25V. It is because most of changes induced in azimuth and ellipticity due to LC is around this range of voltage.

Rotating coating and measuring at 2 position

An old elog that I forgot to post and was in my drafts.

The LC were scanned from 0-3..5V with 0.1V resolution

Measurements were taken at coating position of 0 and 28deg

All the measurement were saved with the the labview where we can even save std on each parameter.

Input_foldername=os.path.join(path, 'Polarization states/20240401')
input_filename= 'Mon, Apr 1, 2024 9-59-08 AM.txt'

for 0 deg
Output_foldername = os.path.join(path, 'Coating measurement/BB1-E03/20240401/0 deg')
output_filename ='Mon, Apr 1, 2024 3-52-42 PM.txt'

for 28 deg
Output_foldername = os.path.join(path, 'Coating measurement/BB1-E03/20240401/28 deg')
 output_filename ='Mon, Apr 1, 2024 9-25-18 AM.txt'

Measurement

I've made 4 different measurements with the single LCD (monitor screen). I measure the elepticity and the azimuthal of the polarization beam after passing throw the LC of the monitor. On the monitor I put a video which gradually changes from black to white.
4 different video for : fast or low video and different power of the initial beam.

Vacuum Pumping

I turned on the scroll pump today for chamber evacuation. I did not notice any issue with the scroll pump operation.

• Turned on Scroll Pump at 8:03
• Opened right angle valve between TMP and scroll pump at 8:08
• Opened gate valve between chamber and TMP at 8:15 (fully open at 8:18)
• Turned on Vacuum guage at 8:23 (The pressure was 3.75*10³ Pa)

Manipulation 2D polarization

After raising the beam with the help of the mirrors at angle, I have characterized the beam obtained with the Beam profiler and a lens f=30mm.
I find z0 = 31cm et w0 = 9.1μm, (z=0 : Corresponds to the characterization lens --> 79,7cm on the meter of the table).
So I found the characteristics of the initial beam : z0 = -9.915m et w0 = 272μm (z=0 still the same).

After that I rebuilt a telescope with two lenses : F= 500mm Bi-Convexe et F=-25,4 Plano-Concave, second one place at 500 mm because the focal seems to be at 525mm...
I put the single pixel Camera at the end, just after the second lens.

Finally, I put the first LCD in front of the large beam just after the mirrors, and I have a control of the monitor, and it seems to work but several remarks :
-There is an important diffraction of the light due to the array of the LCD ---> important power losses
-I remark that we still have color on the LCD, so we don't only have the LC on the screen...
-We need a second computer to put the image on the screen because we have no idea what we put on the screen except when you use two polarizers and a flashlight to see what is on the screen.

Closing Chamber

With help from Takahashi-san, I closed the vacuum chamber.

I didn't start pumping since I would like to monitor the operation of the pumps over a few hours from a safety point of view (since they haven't been operated in quite a while). Also, I haven't set up any DAQ system to log the pressure. I will start pumping this Thursday or next Monday.

Vacuum Fittings

Overview: I modified the vacuum connections around the TMP. 

Before: The TMP is located at the bottom of the cryostat with a gate valve and 6-way cross fitting in between. The cross fitting has CF (-250?) flanges on either side with four "KF ports" on the cylindrical body. The "KF ports" are located after the gate valve. The outlet port of TMP is KF16 and connected to a "KF16-KF25 adaptor". This adaptor is connected to a "Right angle valve", which is connected to a "KF25 TEE" fitting. One end of the "TEE" fitting should be connected to the scroll pump with a flexible vacuum hose. The other end of the "TEE" was attached to one of the "KF ports" with another "Right angle valve". The remaining "KF ports" had a vacuum gauge, a Swagelock poppet check valve and an inlet valve.

Changes: I replaced the swagelock poppet check valve with a blank flange. Furthermore, the "Right angle valve" on one of the "KF ports" connected to the "TEE" with a flexible vacuum hose was removed and replaced with a blank flange. The "Right angle valve" was connected to the "TEE" with a "KF25-Swagelock adaptor" connected to the other end. This adaptor will be used to inject Helium during warm-up.

Items: For this work, I brought the following items from TAMA: 2*KF25 Blank flanges, 3*KF25 hinge clamps, 5*KF25 O-Rings and 1*KF25 full nipple fittings. Additionally, the "KF25-Swagelock adaptor" was brought from KEK.

NOTE: I noticed the KF16 outlet port was not tightened. I tried to tighten it, but it was still loose. Not sure if this is normal.

Temperature Sensor

I installed a temperature sensor (brought from KEK) on the breadboard inside the cryostat (photo). It is connected to wire bundle C2. I think there is a temperature sensor mounted on the cold-head but I can't find which pin feedthrough it is connected to (this wire perhapas).

Comment to T120#1 (Click here to view original report: 3520)

z = 74.5,mm, Pt = 4.81W : Sat, Apr 6, 2024 10-14-17 AM.txt

Comment to T120#1 (Click here to view original report: 3520)

z = 44.5, Pt = 4.87W : Fri, Apr 5, 2024 9-52-57 PM.txt

Comment to T120#1 (Click here to view original report: 3520)

z = 54.5mm, Pt = 4.87W ; Fri, Apr 5, 2024 5-12-55 PM.txt